Heat Exchanging Asphalt Layers

Heat Exchanging Asphalt Layers

Supervisors: ing. W. Van den bergh

ing. K. Cousheir

Final report by Pau Blaya and Stefan Müller

European Project Semester at Artesis Hogeschool

Antwerpen:

Final Report: HEAL-Project Pau Blaya / Stefan Müller EPS 2011

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Abstract

This final report describes the work of a research team during an so called

“European Project Semester” (EPS)1 at the Artesis Hogeschool, Antwerp. The aim of

the project was to describe a state of the art Heat Exchanging Asphalt Layer system

with an underground thermal heat storage system. Together they are used to collect

the heat and cold of an asphalt pavement during summer, respectively winter, and

store it in the underground. The energy is than used in the following season to either

cool the building and the road in summer, or to heat both in winter. The focus lays on

the necessary heat exchangers and the storage systems.

Furthermore a basic approach to calculate the energy output of such a system

is included, with a focus on a laboratory prototype of such an asphalt collector. The

main objective is to give a basic understanding of the functions of a HEAL-system.

1 http://www.europeanprojectsemester.eu/info/Introduction, cited on 7th of June, 2011

http://www.europeanprojectsemester.eu/info/Introduction


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Content

Abstract ....................................................................................................................... 2

1.1. Description of the HEAL-System .......................................................................... 6

2.1. Benefits of HEAL system ...................................................................................... 9

2.2. Weather conditions in Belgium ........................................................................... 12

2.3.Heat exchanger ................................................................................................... 15

2.3.1. Introduction .................................................................................................. 15

2.3.2. Types ........................................................................................................... 16

a. Shell and tube heat exchangers ..................................................................... 16

b. Double pipe heat exchangers ........................................................................ 17

c. Compact heat exchangers ............................................................................. 18

d. Plate and frame heat exchanger .................................................................... 19

e. Spiral heat exchangers .................................................................................. 20

f. Regenerative heat exchanger ......................................................................... 21

g. Scraped surface heat exchangers ................................................................. 22

h. Transverse high finned heat exchangers ....................................................... 23

2.3.3. Comparative ................................................................................................ 24

2.3.4. Conclusion ................................................................................................... 26

2.3.5. Exchanged of HEAL system (Plate and frame heat exchanger) .................. 27

Beginning of functioning ..................................................................................... 27

Principal characteristics ..................................................................................... 28

Advantages and disadvantages ......................................................................... 29

Study of heat transfer: ........................................................................................ 31

2.4 Heat storage systems ......................................................................................... 32

2.4.1 Introduction ................................................................................................... 32

2.4.2 Technologies for geo-energy exchange ........................................................ 32

Groundwater cooling .......................................................................................... 32

Ground Source Heat Pump – GSHP .................................................................. 33

Underground Thermal Energy Storage – UTES ................................................. 33

2.4.3 Possible problems ........................................................................................ 36

2.4.4 Solution ......................................................................................................... 37

2.4.5. Dimensions .................................................................................................. 38

2.5. Water pump ........................................................................................................ 39

2.5.1. Introduction .................................................................................................. 39

2.5.2. Types. .......................................................................................................... 41

According to the principle of operation ............................................................... 41

Depending on the type of actuator ..................................................................... 43

2.5.3. Pump characteristics ................................................................................... 43

Flow ................................................................................................................... 43

Efficiency: ........................................................................................................... 43

Performance Characteristics of Pump ............................................................... 43

Volumetric efficiency .......................................................................................... 44

Mechanical efficiency ......................................................................................... 45

Types of loss ...................................................................................................... 46

Working Pressure .............................................................................................. 46

Life ..................................................................................................................... 47

2.5.4. How to select a hydraulic pump: .................................................................. 47


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2.5.5. Conclusion ................................................................................................... 48

2.6. Heat pump .......................................................................................................... 49

Overview ............................................................................................................ 49

Beginning function ............................................................................................. 49

2.7. Asphalt collector , , , ............................................................................................ 51

3. Simulation of the system ....................................................................................... 53

3.1. Sources for weather data, ............................................................................... 53

3.2 Assumptions .................................................................................................... 54

3.3 Note to the volumetric flow rate ....................................................................... 56

3.4 Calculation and results .................................................................................... 59

a. Θex and Σq as a function of the thermal conductivity ...................................... 59

b. Θex and Σq as a function of the entering mediums temperature ..................... 60

c. Θex and Σq as a function of the pipes depth ................................................... 61

d. Θex and Σq as a function of the flow rate ........................................................ 62

e. Conclusion of the calculations ........................................................................ 63

4 Measurements and results ..................................................................................... 65

4.1. Position of the sensors (Appendix 2: 05302011-position-of-sensors.xls) ........ 65

4.2. Temperature of the asphalt without cooling (Appendix 3: 06012011-temperature-without-cooling) ................................................................................. 66

4.3. Conclusion of the measurements ................................................................... 68

5.1. Conclusion ......................................................................................................... 70

5.2. Personal reflection, Pau Blaya ........................................................................... 70

5.3. Personal reflection, Stefan Müller ...................................................................... 72

Websites: .................................................................................................................. 74

Books ........................................................................................................................ 75

Websites: .................................................................................................................. 77

1.1. Description of the HEAL-System .................................................................... 77

2.2. Benefits of HEAL system ................................................................................ 77

2.3. Heat exchanger .............................................................................................. 77

2.4. Heat storage system ................................................................................... 77

2.5. Water pump ................................................................................................ 78

2.6. Heat pump .................................................................................................. 78

2.7. Asphalt collector .......................................................................................... 78

4.1. Position of the sensors ................................................................................ 78


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I. Introduction


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1.1. Description of the HEAL-System

Overview 2, 3, 4

A HEAL-System consists of four main parts: The asphalt collector, a heat

exchanger and a heat storage. The surrounding buildings, as a heat source in

summer, or heat sink in winter, are the fourth part.

During summer water is pumped within a closed circuit through the asphalt

layer and the heat exchanger. In there, its heat is transferred to groundwater, that is

pumped from the cold well at a temperature around 8 °C2 to the hot well, both in the

aquifer. Depending on the model, a third circuit is used to transfer waste heat from

buildings, e.g. from the air conditioning, to the groundwater. It is also possible to use

the same circuit for the street and the building. The output temperature of the water

when exiting the asphalt collector can reach up to 24 °C and more2. However, as

2 Arian de Bondt, 2009: “Asphalt Roads as a Source of Energy”, Santander {Presentation}

3 de Bondt, Jansen, 2009: „Generation and Saving of Energy via Asphalt Pavement Surfaces“, Ooms

Nederland Holding bv 4 C. Sullivan, A.H. de Bondt, R. Jansen, H. Verweijmeren: „Innovation in the produchtion and useof

energy extracted from asphalt pavements“, prepared for 6th Annual International Conference on Sustainable Aggregates, Asphalt Technology and Pavement Engineering, Liverpool John Moores University, United Kingdom, 21st and 22nd February 2007

Illustration 11.1. HEAL-system in summer.


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there are legal limits for the maximum temperature one can heat up the groundwater

(25 °C4), there are limits for the output temperature as well.

During winter all the circuits are ran in reversed mode. Warm water from the

aquifer is pumped through the heat exchanger to the cold well. The heat is used to

keep the street free of snow and to prevent cracking. If the heat is used to warm up

facilities, the buildings must either be specially designed for that, or a heat pump is

necessary, as the temperature of the hot well is often not high enough for heating a

building.

Illustration 11.2. HEAL-system in winter.


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II Review of Literature


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2.1. Benefits of HEAL system

HEAL system has a wide range of applications. In particular the systems are

suitable for large scale and mixed-use developments. They can also be used in

commercial buildings, office buildings, and large residential estates, campus sites in

educational or health sectors and for industrial cooling. HEAL systems can be

applied in new developments or added during refurbishment of old buildings.

• Best where both heating and cooling exist

• Suits residential, commercial and mixed use or community systems

• Advantageous for an Energy Service Company ( ESCO) application

• Can work in conjunction with CHP5

• Opportunity to use new buildings with net cooling requirements to meet heat

demands of existing buildings with net heating requirements, in a low carbon

Urban Heat Sharing network.

• Can reduce peak electrical loads, improve load security and cut costs for

buildings with primarily cooling requirement.

• Suits medium to large scale heating and cooling developments (>500 KW).

The main beneficiary of the HEAL

system are buildings, houses or residencies

that these will win an energy supplement.

Thereafter, we will explain how the system

works for a building, in this explanation we will

use approximate data of temperature, but in

any case are exactly, each study has different

5 CHP = cogeneration.

Illustration 21.1. Example of the cycle of

HEAL system.


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temperature ranges.

The technology uses the principle that at a certain underground level, the

ground has the ability to store thermal energy for a substantial period of time. During

the warm season, water from the cold store at around 7-10°C is passed through a

heat exchanger providing direct cooling water to the building. The heat pump is

available automatically as support in periods of peak demand. The store circuit water

will pick up energy from the building and thus be raised in temperature to around 18-

20°C (or higher for fresh air load). This water, the temperature of which is higher than

the natural groundwater temperature, will be run to an underground „warm energy‟

store.

The heat stored in the warm energy store is used for heating during the winter.

Water from the store at around 20°C is passed through a heat exchanger and

connected into a heat pump, which in tur n provides water around 40-50°C for use in

building heating. While the groundwater passes through the heat pump it cools to

around 7°C. The cooled water is run to the underground „cold energy‟ store. The cold

stored in the „cold energy‟ store is used for

cooling, completing the annual cycle Any excess

heat or cold in the system over a year is balanced

using an external heat exchanger.

In parallel, the road is the second major

benefit, because with the movement of water

through it for different seasons, it can avoid

excessive temperatures.

Illustration 21.2. Example of snow and

ice in the road


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For example, in winter, the formation of ice or snow on the road is a great

danger and inconvenience to drivers. Circulating hot water under the road will do that

not be possible to form ice sheets or large quantities of snow, keeping the road free

from danger and thus avoiding the possible harm that the asphalt may suffer.

In summer it is also very useful. Since the high temperatures that help our

system to capture heat, also these temperatures make damage to the road, causing

deformations in the pavement. The circulation of water with small temperature will be

avoided such high temperatures, thus avoiding the deformation of the asphalt.

Finally, using a green energy, renewable

energy is a very significant for nature. Because no

contamination issues and does not consume

natural resources, only uses the sun's heat to

work.

Illustration 21.3. Symbol of green energy.


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2.2. Weather conditions in Belgium6

To study the weather in Antwerp, we made an investigation of the meteorology

of Belgium last year. As a result, we have prepared a table with the corresponding

graph where we can see the evolution of temperature versus time (months).

Jan Feb Mar Apr May Jun

Hours of sunshine 52 76,7 106,5 151 193,1 180

Number of rainy days 13,4 10,1 13,1 11,3 11,9 10,5

Jul Aug Sep Oct Nov Dec

Hours of sunshine 191,9 169,1 139,1 113,1 65,2 41,7

Number of rainy days 10 10 9,5 10,2 13 12,7

6 http://www.locationflanders.be/production-guide/facts-and-figures/climate-and-weather/

0

50

100

150

200

250

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Ho

urs

Months

Hours of sunshine

Graph 22.1. Graph about the evolution of hours of sunshine in Belgium per month last year.


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We have taken last year because it is the more similar meteorology to theorize

the weather next year, which we will work in our study. Our two graphs show the

evolution with a continuous line respect time, measured in months during a year. We

analyzed the hours of sunlight and days of rain a year, this study makes us see how

many hours it will have on heat collection.

The following table shows the temperature ranges in which we will work. This

calculation is divided into three parts:

The average working temperature, where temperatures will be common work.

Maximum working temperature, which is the maximum temperature that may

leave.

Minimum working temperature, lower temperature calculated to work.

Jan Feb Mar Apr May Jun

Average temperature [ºC]

3,1 3,5 6,3 8,9 13,2 15,6

Average maximum temperature [ºC]

5,6 6,4 9,9 13,2 17,7 20

0

2

4

6

8

10

12

14

16


Ra

iny d

ays

Months

Number of rainy days

Graph 22.2. Graph about the evolution of number of rainy days in Belgium per month last year.


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Average minimum temperature [ºC]

0,7 0,6 2,9 4,8 8,9 11,5

Jul Aug Sep Oct Nov Dec


17,7 17,7 14,5 10,6 6,2 4,1


22,3 22,5 18,7 14,4 9,1 6,5


13,6 13,3 10,8 7,6 3,7 2

0

5

10

15

20

25


Te

mp

era

ture

[ºC

]

Months




Graph 22.3. Graph about the evolution of average temperature in Belgium per month last year.


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2.3.Heat exchanger7

2.3.1. Introduction

A heat exchanger is a device that is used for transfer of thermal energy

(enthalpy) between two or more fluids from one medium to another, at differing

temperatures and in thermal contact, usually without external heat and work

interactions.8

Heat exchangers are normally used only for the transfer and useful elimination

or recovery of heat without an accompanying phase change. The fluids on either side

of the barrier are usually liquids, but they may also be gases such as steam, air, or

hydrocarbon vapours; or they may be liquid metals such as sodium or mercury.

Fused salts are also used as heat-exchanger fluids in some applications.

The exchangers are used to recover heat between two streams in a process;

these fluids may be single compounds or mixtures. Typical applications involve

heating or cooling of a fluid, and heat recovery or heat rejection from a system. It has

other applications, as for example to sterilize, pasteurize, fractionate, distil,

concentrate, etc. But for our objective, the principal function will be change heat with

the best efficiently, for obtain the energy transfer with minimum losses.

7 http://www.cie.unam.mx/~ojs/pub/HeatExchanger/Intercambiadores.pdf

8 http://www.britannica.com/heatexchanger

Illustration 23.1. Example the heat exchanger. You can see the difference between inlet and outlet

temperaturas.

http://www.cie.unam.mx/~ojs/pub/HeatExchanger/Intercambiadores.pdf

http://www.britannica.com/heatexchanger


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In most heat exchangers, the fluids are separated by a heat transfer surface,

and ideally they do not mix. Such exchangers are referred to as the direct transfer

type, or simply recuperator. In contrast, exchangers in which there is an intermittent

heat exchange between the hot and cold fluids via thermal energy storage and

rejection through the exchanger surface or matrix are referred to as the indirect

transfer type or storage type, or simply regenerators. Such exchangers usually have

leakage and fluid carryover from one stream to the other.

Heat exchangers may be classified according to transfer process,

construction, flow arrangement, surface compactness, number of fluids and heat

transfer mechanisms or according to process functions. The different types of heat

exchanger are described in the following paragraphs.

2.3.2. Types

a. Shell and tube heat exchangers

Overview

Shell-and-tube heat exchangers are fabricated with round tubes mounted in

cylindrical shells with their axes coaxial

with the shell axis. The differences

between the many variations of this basic

type of heat exchanger are found in their

construction features and the provisions

made for handling differential thermal

expansion between tubes and shell.

Illustration 23.2. Example the Shell and tube

heat exchanger. You can see its difference parts.


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Applications

They are extensively used as process heat exchangers in the petroleum-

refining and chemical industries; as steam generators, condensers, boiler feed water

heaters and oil coolers in power plants; as condensers and evaporators in some air-

conditioning and refrigeration application; in waste heat recovery applications with

heat recovery from liquids and condensing fluids; and in environmental control.

b. Double pipe heat exchangers

Overview

Essentially, it consists of one pipe placed concentrically inside another one of

larger diameter, with appropriate end fittings on each pipe to guide the fluids from

one section to the next. The inner pipe may have external longitudinal fins welded to

it either internally or externally to increase the heat transfer area for the fluid with the

lower heat transfer coefficient. The double-pipe sections can be connected in various

series or parallel arrangements for either fluid to meet pressure-drop limitations and

LMTD9 requirements.

9 The logarithmic mean temperature difference (LMTD) is used to determine the temperature of the

driving force for heat transfer in flow systems. It uses a logarithmic calculation because of this temperature is not linear and can be better represented by a logarithmic calculation. LMTD is the logarithmic mean temperature difference between hot and cold streams at each end of the exchanger.

Illustration 23.3. Example the Double pipe heat exchanger. You can see its difference parts.


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Applications

The major use of double-pipe exchangers is sensible for heating or cooling of

the process fluid for small heat transfer areas (typically up to 50 m.) are obligatory.

They may also be used for small amounts of boiling or condensation on the process

fluid side. The advantages of the double-pipe exchanger are largely in the flexibility of

application and piping arrangement, also the fact that they can be erected quickly

from standard components by maintenance crews.

c. Compact heat exchangers

Overview

One variation of the fundamental compact exchanger element, the core, is shown

after this. The core consists of a pair of parallel plates with connected metal

components that are bonded to the plates. Compact heat exchangers may be

classified by the types of elements that they employ. The compact elements usually

fall into five classes:

• Circular and flattened circular tubes.

• Tubular surfaces.

• Surfaces with flow normal to banks of

smooth tubes.

• Plate fin surfaces.

• Finned tube surfaces.

Illustration 23.4. Example the Compact heat exchanger. You can see the water circuits.

)


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Applications

Compact or plate-fin heat exchangers have a wide range of applications that

include:

• Natural gas liquefaction.

• Cryogenic air separation.

• Ammonia production.

• Offshore processing.

• Nuclear engineering

d. Plate and frame heat exchanger

Overview

These exchangers are usually built of thin plates (all principal surfaces). The

plates are either smooth or have some form of corrugations, and they are either flat

or wound in an exchanger. Generally, these exchangers cannot accommodate very

high pressures, temperatures, and pressure and temperature differentials. These

exchangers may be classified as plate, spiral plate, sheets , and plate exchangers of

coil.

Applications

These exchangers are relatively compact surfaces and lightweight heat

transfer, making them attractive for use in confined or weight-sensitive locations such

as on board ships and oil production platforms. Pressures and temperatures are

limited to comparatively low values because of the gasket materials and the

construction.


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They are often used for exchanging heat between two liquid streams in

turbulent flow and occasionally as condensers for fairly dense vapours (for example:

ammonia) or as vaporizers for a reboiler.

e. Spiral heat exchangers

Overview

There are several different versions of the spiral plate exchanger available.

This exchanger is formed by two metal long plates, parallel plates into a spiral using

a mandrel and then suitably welding the alternate edges of adjacent plates to form

the channels. The plates are held apart by raised bosses on one of the plates.

Connections are made at the centre of the coil of each channel for to act as

inlet in one case and outlet in the other. Similar connections are made at the outer

end of each channel. The spiral exchanger can be enclosed in a pressure vessel, or

the outer panel can be incorporated to form the outside of the unit. The heat

exchanger is closed at the upper and lower covers screwed to the outer shell of the

exchanger

Illustration 23.5. Example the Spiral heat exchanger. You can see 2 pictures, one is

hot/cold water circuits and another is real exchanger example.


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Applications

In accordance the top and bottom, the heat exchanger is very clean and

therefore it is ideal for applications involving a high degree of contamination. In fact, it

is extensively used for heating and cooling of the mixtures.

f. Regenerative heat exchanger

Overview

The regenerator represents a class of heat exchanger in which heat is stored

and it is alternately removed from a surface. This heat transfer surface is usually

referred to as the matrix of the regenerator. For continuous operation, the matrix

must be moved into and out of the fixed hot and cold fluid streams. In this case, the

regenerator is called a rotary regenerator. If, on the other hand, If, however, hot and

cold fluid flows are switched in and out of the matrix the regenerator is known as a

fixed matrix regenerator. In both cases the regenerator suffers from leakage and fluid

entrainment problems, which must be considered during the design process.

Illustration 23.6. Example the Regenerative heat exchanger. You can see 3 pictures: (a) rotary, (b) fixed-

matrix and (c) rotating hoods.


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Applications

Rotary regenerators are used extensively in electrical power generating

stations for air preheating. They are also used in gas turbine power plants, in

cryogenic refrigeration units, and in the food dehydration industry.

Fixed bed or fixed matrix regenerators are used extensively in the

metallurgical, glassmaking, and chemical processing industries

g. Scraped surface heat exchangers

Overview

In cases where a process fluid it is likely to crystallize on cooling or the degree

of contamination it is very high or including the liquid it is very high viscosity it is often

used in heat exchangers Scraped surface in which a rotating element has adapted a

leaf spring to clean the inside surface of a tube that it can usually be 0.15 m in

diameter. Double pipe construction is used often with a jacket, say 0.20 m in

diameter, and a common arrangement it is connect several sections in series or to

install several pipes within a common

depository. The units of scraping the

surface of this type are used in plants for

evaporating viscous materials or sensitive

materials in high heat vacuum.

Illustration 23.7. Example the Scraper blade

of scraped-surface exchanger.

)


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Applications

The range of applications covers a number of industries, including food,

chemical, petrochemical and pharmaceutical. The DSSHEs are appropriate when the

products are prone to fouling, very viscous, particulate, heat sensitive or crystallizing.

h. Transverse high finned heat exchangers

Overview

Pipes and tubular sections with external fins have been used extensively for

heating, cooling, and dehumidifying air and other gases. The cooler fin is a device

which distributes hot process fluids, usually liquids, the flow inside the tubes

extended surface and atmospheric air outside the tubes or induced on the surface

extended.

High fin tubes also can be removed directly from the metal tube wall, as in the

case of the pipe integral low fin. However, it is increasingly difficult to remove a flap

from high ferrous alloys as hard as those required for high temperature services,

which are often susceptible to strain hardening, while the flap is being formed.

Applications

The large majority of applications are for the transfer of heat to atmospheric

air. Tubes with fins can be used in: of the product water cooling and air cooling

products, heat exchangers and oil heaters, industrial and residential air, steam, hot

water or heating elements of resistance inside the laminate finned tube, refrigeration

and food industry and the automotive industry.


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2.3.3. Comparative10

Shell and Tube Double Pipe Compact Plate and Frame TYPES

Tªmax (ºC) Normal 600 600 150 175

Special designs - - - 200

Tªmin (ºC) Normal -100 -100 -200 -25

Special designs - -

-40

ΔTª (ºC) Maximum - - 50 -

Minimum -268 -268 down to 0,1 -272

Fluids Few since can be Few since can be Limited by Mainly limited

built of many metals built of many metals material by gasket

Size small big small medium-big

Heat exchange area medium large and ample small large and ample

Maintenance difficult very difficult medium easy

Life large medium medium large

Maximum design Shell side 300 300 250 25

pressure (bar) Tube side 1400 1400 - 40

Effectiveness ( ε ) 0.9 0.9 0.89 0,98

COMPARE ITEMS

10 http://www.sedical.com/web/productos.aspx?CAT_ID=29

http://www.sedical.com/web/productos.aspx?CAT_ID=29


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To better analyze the comparison table we have made a graph with the two

main points: performance and life. To obtain the life we had to make an investigation

of each of the exchangers, the percentage is based on a study of how Interchange is

still functioning properly over a period of 5 years. This graph represents the

information given to us by different companies.

* the life calculation is approximate, but provides an idea of expected performance.

By examining the graph we can see that the Plate and Frame Heat Exchanger

is the best, and provides an optimal result and better working conditions.

Shell and Tube Heat

Exchangers

Double Pipe Heat

Exchangers

Compact Heat Exchangers

Plate and Frame Heat Exchanger

Life 93,33 88,89 84,44 91,11

Effectiveness ( ε ) 90 90 89 98

75,00

80,00

85,00

90,00

95,00

100,00

Durability

Graph 23.1. Graph about the life and effectiveness of the different heat exchanger.


Page 26 of 83

2.3.4. Conclusion

As explained in the report, the different types of heat exchangers have many,

varied applications. The specific application of a heat exchanger determines which

type to select. The overall design process can be summarized in the calculation of

the area required for the transfer of heat from one fluid to another. Only the designer

can determine the current mechanical design parameters and meet the physical and

chemical conduct of fluids to be used.

The report examines the most common types of heat exchangers used for

industry. Although the applications of each type of exchanger are different, some

types not specifically designed to meet the needs of our project could still be used

with less efficiency.

In the previous comparative table we analyzed the technical parameters of the

exchanger types most suitable for our project and determined that the plate and

frame heat exchanger was the most appropriate for the HEAL-system. I would like to

emphasize efficiency, because with better efficiency we will have less heat loss and

better transmission. We also need to emphasize the importance of the heat transfer

area, because a greater area will reduce the size of the exchanger and gain usable

space. Our view has been re-enforced by different examples such as Terra Energy

Company. In our visit to their installations, we learned that they also utilize this type

of heat exchanger. This opinion is also supported by Marcel Hendriks, an IFTEC11

worker, who is an expert on this subject.

11

www.iftec.es

http://www.iftec.es/


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2.3.5. Exchanged of HEAL system (Plate and frame heat exchanger)1213

Beginning of functioning

The plate heat exchangers are composed of a series of metal plates of

standard sizes for each manufacturer, each one is coupled with another in greater or

lesser number as the thermal requirements in a frame that supports them together.

To ensure that the plates are correctly facing each other, each plate is

equipped at the top and bottom with two openings, through which, the plates can

slide along the guides of the frame. The top opening also allows the plate to be

suspended from the guide.

Each plate has 4 openings where the fluids circulate in parallel while a fluid is

driven by plate pairs and the other for the plate

odd. Getting the necessary exchange of heat

between them.

The plates are separated by rubber

gaskets, facilitating the maintenance of them. We

can also have heat exchangers of brazed plate

without joints, being more efficient, but

maintenance is no longer possible.

The materials of which these exchangers

are constructed remain fundamentally dependent

upon the characteristics of the heat exchange fluids. Principal conditions for the

selection of the material for the plates will follow:

12

http://www.comeval.es/pdf/cat_tec/intercambiadores/intercambiadores_A4_esp.pdf 13

http://www.acpro.com.ar/m3.pdf

Illustration 23.8. Example of the

functioning the heat exchanger.

)

http://www.comeval.es/pdf/cat_tec/intercambiadores/intercambiadores_A4_esp.pdf

http://www.acpro.com.ar/m3.pdf


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• Easy to form by compression.

• Small thermal resistance.

In view of these conditions, the materials normally used in the construction of

the plates are stainless steel and nickel alloys, chromium, and titanium, while

silicone, natural and synthetic rubber is used for the gaskets.

Principal characteristics

• Compact construction, with a large exchange surface and plates together

provide greater thermal efficiency requiring less installation space.

• High thermal efficiency; have a good precision of exchange and greater of

heat exchange surface. The circuits operate against current and this offers a

great heat transfer.

• Safety; Absence of contamination between circuits due to the fact that both

are sealed independently by gaskets. The middle area vented to the

atmosphere in case of breakage or wear of gaskets, thus avoiding the

unwanted indoor air pollution.

• Light, design provides easier handling, shipping and safety to use in the

installation.

• Contamination minimum; due to the self-cleaning design of the plates.

• Minimum corrosion and wear of materials.

• Minimal operating costs.

• Expansibility and durability; Possibility of extension the number of plates for an

increased thermal efficiency in the future and renewal of effectiveness with the

change of plates.


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Advantages and disadvantages

Advantages:

High turbulence stream. That allows lower flow rates in fluids and decreases

the risk of contamination.

Minimum heat losses. Because only the edges of the plates are exposed to

the outside environment, and they are also very thin and can be easily isolated.

Easy to Remove and Clean. Plate Heat Exchangers are easy to clean by

removing the tie bolts and sliding back the movable frame part. Then the plate pack

can be inspected, pressure cleaned, or removed for refurbishment if required. In the

case of damaged gaskets, the fluid leaks outwards. The repair is immediately

possible, and the mixing or contamination of the fluids can be avoided.

Expandable. A very significant feature of the plate heat exchanger is that it is

expandable. Increasing the heat transfer requirements means simply adding plates

instead of buying a new heat exchanger, saving time and money.

High Efficiency. Because of the pressed patterns in the plates and the

relatively narrow gaps, very high turbulence is achieved at relatively low fluid velocity.

This combined with counter directional flow results in very high heat transfer

coefficients.

Compact Size. As a result of the high efficiency, a smaller heat transfer area is

required, resulting in a much smaller heat exchanger than would be needed for the

same duty using other types of heat exchangers. Typically a plate heat exchanger

requires between 20-40% of the space required by a tube and shell heat exchanger.


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Illustration 23.9. Example of Plates

)

Close Approach Temperature. The same features that give the plate heat

exchanger its high efficiency also make it possible to reach close approach

temperatures, which is particularly

important in heat recovery and

regeneration applications. Approach

temperatures of 0.5ºC are possible.

Multiple Duties in a Single Unit. The

plate heat exchanger can be built in

sections, separated with simple divider plates or more complicated divider frames

with additional connections. This makes it possible to heat, regenerate, and cool a

fluid in one heat exchanger or heat or cool multiple fluids with the same cooling or

heating source.

Less Fouling. Very high turbulence is achieved as a result of the pattern of the

plates, the many contact points, and the narrow gap between the plates. This

combined with the smooth plate surface reduces fouling considerably compared to

other types of heat exchangers.

Disadvantages:

The limitations that the gaskets impose are,

that they can't work with temperatures exceeding

250 º C or pressures above 20 atm.

Pressure loss. The pressure loss in a frame

and plate heat exchanger is greater than in other exchangers.

Illustration 23.10. Example of the

functioning the Gaskets.

)


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Expensive. Compared to a “multi pipe” heat exchanger, a frame and plate heat

exchanger is more expensive.

Study of heat transfer:

Fundamental equations:

The selection of plate heat exchanger depends on the following factors:

• Quality of water / fluid on both sides

• Flow, power and thermal jumps on both sides of the Heat Exchanger

• ΔT between the primary circuit and secondary circuit

For all types of heat exchanger, considering only the conditions of entry and

exit of fluids, you can set the global heat balance of the device by setting the amount

of heat Q lost by the hot fluid equal to the amount of heat Q gain of the cold fluid,

while heat losses are ignored.

Q = M ( H1 - H2 ) = m ( h2 - h1 )

Capital letters are reserved for the hot fluid and lower case letters for the cold

fluid, while the indices 1 and 2 correspond respectively to the conditions of entry and

exit. M and m represent the mass flow of the fluid, while H and h are the enthalpies of

fluids depending on their temperatures, T and t.

You can apply the Fourier equation of the entire device:

Q = U A·tm

• A = Total area of exchange of the device.

• U = Global transfer coefficient.

• tm = average temperature difference between the two fluids


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2.4 Heat storage systems14

2.4.1 Introduction

Ground Source Heat Pump (GSHP) and Underground Thermal Energy

Storage (UTES) use the basement for the exchange of thermal energy (heat and

cold) for heating and cooling in an effective way of buildings, roads and industrial

processes. The applications of refrigeration wells and GSHP's systems are based on

natural temperature underground, using the ground as a heat source or as a heat

dump. UTES's applications are based on seasonal storage of heat and cold for later

use. The heat energy stored can be used directly for heating or cooling or in

combination with a heat pump.

2.4.2 Technologies for geo-energy exchange

There are different technologies that can be used to exchange heat with the

ground. Some use the underground as a heat source or as a heat dump. Others are

based on storage (seasonal) heat and cold. Another point of distinction is whether

the system is open or closed. With an open system we can extract and inject water

from and into the underground. With a closed system we cannot extract water of

underground, but exchange the heat indirectly.

Groundwater cooling

A cooling system wells require the presence of an aquifer from which we can

extract groundwater with a well catchment. The extracted groundwater is used by

means of a heat exchanger to cool the building. The building heat increases the

temperature of the water where this is recharged in another aquifer (injection well).

The temperature of the water recharge is often high, up to 15 K higher than the

14

www.iftec.es



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extraction temperature. Sometimes the water does not recharge but then transferred

to a sewer or a river for safety.

Ground Source Heat Pump – GSHP

A geothermal heat pump (GSHP) is a heat pump that uses the subsoil as a

heat source, operating at heating mode, or as a contributor of heat for cooling mode.

For the exchange of heat, the heat pump is connected the soil with a loop. The

implementation of a system GSHP is based on natural temperature of the subsoil.

The most common connection is a closed loop, existing pipes in form as "U" high

density polyethylene inserted in holes 50 to 200 meters deep. Another design is the

direct use of water from an aquifer (often called open-loop system), simulate a

cooling system wells. For this system the kind of water use will be water current with

a series of previously treated for maximum efficiency.

Underground Thermal Energy Storage – UTES

While a GSHP remove or dissipate heat, UTES is based on heat and cold

storage in the subsoil to later use. In majority of cases applies UTES as seasonal

storage. The stored energy can be used directly for heating or cooling or in

combination with a heat pump. In general we can distinguish two types of systems:

• Aquifer Thermal Energy Storage- ATES

• Borehole Thermal Energy Storage – BTES

ATES System

ATES system is an open system for the seasonal storage oh thermal energy.

In summer, it extracts water from the well "cool" for using it to cooling buildings. The

building waste heat heats the water that is injected into the well "hot". In winter, the

process is reversed. The water is pumped from the hot well hot and it is used as a


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heat source, such as for heat pumps. The cooled down water is injected to the warm

well. ATES system doesn‟t consume groundwater and doesn't discard the water in

the aquifer. All water extracted from a well is injected into another well. This means

that there isn't extraction of underground water, which minimizes the negative

impacts on the environment. ATES system requires that it be possible to obtain

relatively high flow of water. Due of this, the application depends directly on the hydro

geological conditions of the underground.

BTES System

The BTES system consists of several boreholes. Instead of penetrating the

aquifer as in the open ATES system, BTES system is, however, a closed loop

system. A loop tube of polyethylene is introduced to the boreholes to avoid a mixing

of the heat transfer medium and the surround soil or aquifer. To obtain a good

thermal contact with the surrounding subsoil, one has to fill the remaining space with

a material with high thermal conductivity. The loops function as a ground heat

Illustration 24.1. ATES: Aquifer Thermal Energy Storage


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exchanger. In winter the heat exchanger is used to extract heat from the subsoil, for

example, for a geothermal heat pump.

In summer, the heat flow in the system BTES is the reversed. The "cold

energy" stored in the subsoil is extracted and passes through a heat exchanger,

providing cooling to the building, either in direct mode (passive cooling) or with the

support of the heat pump in reverse mode (active cooling).

Due to transport and building heat extraction, the fluid temperature increases

circuit. This fluid with a temperature above the natural temperature of the subsoil

returns to the boreholes, where the "hot energy" is stored in the surrounding land for

the next season when heating is needed.

The BTES system with closed loop circuit depends less on the hydro

geological conditions of the site as the ATES system. For this reason, it is more

suitable for zones where the aquifer cannot be used for heat storage.

Illustration 24.2. BTES: Borehole Thermal Energy Storage. (HP = Heat Pump; HE = Heat Exchanger)


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2.4.3 Possible problems

If groundwater is used only for cooling, the dissipated heat will cause a

gradual increase in temperature in the aquifer. This can cause problems such as:

• Perturbation of the cooling system for increasing extraction temperatures.

• Limited possibilities of new systems in the near existing systems.

• Possible changes in chemical properties, physical and biological

characteristics of aquifer.

• Legislation to restrict the introduction and implementation of such systems.

An increase of temperature causes a decrease in thermal gap (difference in

temperature between the groundwater before and after heat exchange with the

building), resulting in a lower power of the cooling system. It is possible that the

functioning of existing systems is affected for new systems in the near or in the case

of a poor design for a thermal short circuit between the injection well and extraction

well.

A change in temperature of groundwater can change the chemical balance

and cause an acceleration in the growth of micro-organisms. There is research to

show that the velocity of chemical and biological processes significantly increases

with increasing temperature. These effects can be observed with changes in

temperatures above 20 K. However, below 40 º C the effect is not significant. Field

tests to observe the effect of change in temperature on chemical and microbiological

processes show that the impact is less than the natural variation in groundwater

quality.


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Warming the aquifer could be considered a thermal pollution. This may be one

reason for the competent authorities when granting or denying permits. To avoid this,

often great efforts in education of the authorities and the public have to be done.

2.4.4 Solution

In many countries groundwater used for cooling. In some countries, such as

the Netherlands. It is not permitted to dissipate heat to an aquifer without heat

balance. The law often demands a period of one to five years an equality in the

quantity of heat dissipated into the aquifer and the quantity of heat extracted from the

aquifer. If the system uses both to cooling and heating or cold is recharged during the

winter, the condition is fulfilled.

Figure 24.3 shows the beginning of an improved system for cooling and

heating with a flow of extraction well into the injection well. For cooling it would be

better to lower the temperature with applying a seasonal storage with an ATES

system (Figure 24.4.)

Illustration 24.3. Improved ATES-system.


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The open geothermal systems (Figure 2.3) always require the use of a chillier

or heat pump to provide the necessary cooling power and temperature requirements.

In general, the heat pump provides full cooling capacity, using only ground water to

cool the condenser. With ATES most of the cooling power is provided by ground

water from direct cooling. From the energy point of view, direct cooling is more

efficient than the application of a chillier. Therefore, energy conservation for summer

cooling is much greater with ATES system with an open geothermal system.

2.4.5. Dimensions

The system requires a flow groundwater system, it depends on the maximum

potency covering and the jump thermal. The simplified equation is:

• P = power in kW.

• Q = flow in m3 / h.

For example, if the required power is 300 kW and the design ΔT is 6K, the

groundwater flow system will be about 43 m3 / h.

Illustration 24.4. ATES system with variable flow for seasonal storage of thermal energy.


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The number of wells (doubles) needed to obtain this flow depends on the

aquifer properties (thickness and conductivity). In the case of Antwerp will probably

possible to do with a “doublet” (a pair of wells). A very important factor for the design

of the well is the velocity in the borehole wall. It cannot be too high. If it is too high,

the water can drag thin particles that it cans causing obstructions wells. The well

design is the work of specialists. There are some formulas, but we must apply

correctly.

2.5. Water pump

2.5.1. Introduction

A pump is a hydraulic generator machine that converts energy, usually

mechanical, in hydraulic energy of the moving fluid. The fluid may be liquid, a mixture

of liquids or solids, such as concrete before it sets or paper pulp. Increasing the

energy of the fluid increases its pressure, its speed or its height, all as demonstrated

by the Bernoulli principle

The principle of Bernoulli15, also known as Bernoulli's equation or Bernoulli

trinomial, describes the behaviour of a fluid moving along a streamline. The energy of

a fluid at any time consists of three components:

• Kinetics: the energy due to the speed that holds the fluid.

• Gravitational potential: the energy due to the altitude of the fluid.

• Energy flow: the energy that a fluid contains due to its pressure.

15

http://en.wikipedia.org/wiki/Bernoulli%27s_principle:/

http://en.wikipedia.org/wiki/Bernoulli%27s_principle


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The next equation, known as Bernoulli's equation, consists of these same

terms:

Where:

• V = flow velocity in the studied section.

• g = gravitational acceleration

• z = height in the direction of gravity from a reference.

• P = pressure along the streamline.

• ρ = density of flow.

In general, a pump is used to increase the pressure of a liquid adding energy

to the hydraulic system, to move flow from an area of lower pressure or altitude to

another of higher pressure or altitude.

Illustration 25.1. This picture shows the theorem Bernoulli


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2.5.2. Types.16

According to the principle of operation

The main classification of the pumps are determined according to the

principles of operation upon which they are based:

Positive displacement or volumetric pumps:

Where its operating principle is based on the hydrostatic, so that increased

pressure is performed by the pressure of the chamber walls which vary its volume. In

this type of pump in each cycle the principal propellant generates in a positive way a

specified volume, so too are called volumetric pumps. If we can change the

maximum volume of the cylinder is talk of variable volume pumps. If this volume

cannot be changed, then we say that the pump is fixed volume. In the same time

these pumps can be divided into:

· Reciprocating piston pumps, in which there are one or more compartments

fixed, but variable volume, by the action of a piston or a membrane. In

these machines, the fluid motion is discontinuous and the processes of

loading and unloading are performed by valves that open and close

alternately. Examples of such pumps are piston reciprocating pump, rotary

piston pump or piston pump with actuator axial.

· Rotary positive displacement pumps or 'rotorystatic' , in which a fluid mass

is inside in one or more compartments that it travel from the entrance area

( of low pressure) to the starting area ( of Rotary positive displacement

pumps or 'rotorystatic' , in which a fluid mass is inside in one or more

16

http://avdiaz.files.wordpress.com/2008/10/tipos-de-bombas.pdf



Page 42 of 83

compartments that it travel from the entrance area ( of low pressure) to the

starting area ( of high pressure ) of the machine.

· Some examples of this type of machines are the vane pump, gear pump,

screw pump or peristaltic pump high pressure of the machine. Some

examples of this type of machines are the vane pump, gear pump, screw

pump or peristaltic pump17.

Rotodynamic pumps:

In which the operating principle is based on the exchange of quantity of

movement between the machine and the fluid, using hydrodynamics. In this type of

pump, there are one or more impellers with blades that turn to generate a range of

pressures in the fluid. In this type of machines fluid flow is continuous. These

hydraulic generating turbo machines can be subdivided into:

• Radial or centrifuges, when the fluid motion follows a trajectory

perpendicular to the axis of the rotor drive.

• Axial, when the fluid passes through the channels of the blades following a

trajectory contained in one cylinder.

17

A screw pump is a positive displacement pump that use one or several screws to move fluids or solids along the screw(s) axis. A peristaltic pump, or roller pump, is a type of positive displacement pump used for pumping a variety of fluids. A gear pump uses the meshing of gears to pump fluid by displacement. A lobe pump offers superb sanitary qualities, high efficiency, reliability, corrosion resistance and good clean-in-place and steam-in-place (CIP/SIP) characteristics. A rotary vane pump is a positive-displacement pump that consists of vanes mounted to a rotor that rotates inside of a cavity. http://en.wikipedia.org/rotodynamicpumps

http://en.wikipedia.org/


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• Diagonal, when the trajectory of the fluid is performed in a different

direction from the above, this means, in a cone coaxial trajectory with the

rotor shaft.

Depending on the type of actuator

• Electric pumps. Generally, are those actuated by an electric motor, to

distinguish them from pumps, usually powered by internal combustion.

• Pneumatic pumps are positive displacement pumps in which the input energy

is pneumatic, usually from compressed air.

• Hydraulic pumps, like the air pump or waterwheel.

• Manual pumps. A type of hand pump is the pump beam.

2.5.3. Pump characteristics18

Flow

The pump flow is determined by the following relationship:

The flow rate obtained from this operation is called "flow theory", which is just

higher to the real flow depending on the volumetric efficiency of the pump, we can

see that exist internal leaks pump and these lead to decreases in performance.

Efficiency:

Performance Characteristics of Pump

The increase of actual charge won by the fluid through a pump can be

determined using the following equation: Where 1 and 2 are the sections of inlet and

outlet of the pump.

18

http://www.todomonografias.com/bombas/



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.

The power won by the fluid is given by:

And this quantity, expressed in terms of horsepower is traditionally called force

or power hydraulic. In addition to the charge or power added to fluid, the total

efficiency is given by:

Where the denominator represents the total power applied to the pump axis

and it is often called brake power. The overall efficiency of the pump is affected by

water loss in the pump and also by mechanical losses in bearings and seals. Also it

can exist some loss of power due to leakage of fluid between the back surface of the

impeller hub plate and the box, or through other components of the pump.

Volumetric efficiency

The volumetric efficiency of the pump is the quotient obtained by dividing the

flow of fluid that compresses the pump and theoretically should be compressed,

according to its geometry and its dimensions. Volumetric efficiency is defined as the

ratio between the actual flow and flow theory:


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In other words express the volumetric efficiency of fluid leakage is in the pump

during the compression process. Volumetric efficiency is a factor of the pump very

important because from it we can analyze the design capacity and the wear condition

of pump, so if the volumetric efficiency decreases with a high rate of change, wear of

its elements is too much. Volumetric efficiency is also affected by the pressure of

hydraulic fluid that is transported and also by the temperature.

The volumetric efficiency ranges between 80% and 99% depending on the

type of bomb, its construction and internal tolerances, and according to the specific

conditions of speed, pressure, viscosity, temperature, etc.

Mechanical efficiency

The mechanical efficiency measured mechanical energy losses produced in

the pump due to friction and internal friction mechanisms. It is essential to prevent

friction and friction within the pump, in such a way that the energy transmitted to the

pump axis can be reversed, to the greatest extent possible to increase the fluid

pressure and not to overcome friction and excessive friction between mechanical

parts of the pump. In general terms we can say that a pump mechanic with low

efficiently is a pump with accelerated wear, mainly due to friction gets moving parts.

Total or overall efficiency

The total or overall efficiency is the product of volumetric and mechanical

efficiency. Is called total because it measures the overall efficiency of the pump in its

function of pumping liquid pressurized, with minimal energy input to the pump axis.


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The overall efficiently of a new pump can range between 50% and 90%,

values decrease with use and wear of the internal elements sealing of the pump

itself.

Types of loss

Energy losses within the pump are three types:

Hydraulic loss, due to continuous friction the fluid passing through the pump,

for to avoid it we have to use the formulas that you can read before.

Volumetric losses: Due to leakage which eventually can produce the fluid

when passing through the pump, the losses can be seen in differences in pressure.

Other major leaks are due to the creation of gases or vapours as they occupy a

volume concentrated in the interior of the pump causing the decrease in flow.

Mechanical losses, due to mechanical friction in the fixed and the pump parts,

for example the die and bearings, between pistons and cylinders, etc..

Working Pressure

All manufacturers give to their pumps a value called maximum working

pressure, some include burst pressures or maximum intermittent pressure, and other

attached graphics pressure / life of their pumps. These values are determined by the

manufacturer in relation to a reasonable duration of the pump working in specific

conditions.

The value of the maximum working pressure is usually calculated for a life of

10000 hours, in some cases also specifies the maximum intermittent or struts

pressure.


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Life

The life of a pump is determined by the working time from the moment it is

installed until the time that the volumetric efficiency has decreased to an

unacceptable value, however this point varies greatly depending on the application.

For example there are installations where efficiency cannot be less than 90%, while

others use the pump even when performance is below 50%. The life of a pump also

varies greatly depending on the level of contamination of the fluid that is working.

2.5.4. How to select a hydraulic pump:19

The pumps should selected according to concept of the work to do, based on:

Maximum working pressure.

Pump's efficiently

Precision and safety of operation

Easy maintenance

Maximum flow

• Control needed in the start up phase.

19

http://sisbib.unmsm.edu.pe/bibvirtualdata/tesis/ingenie/monge_t_m/anexo-8.pdf

Illustration 25.2. This graph shows the pump life depending on the

pressure.

http://sisbib.unmsm.edu.pe/bibvirtualdata/tesis/ingenie/monge_t_m/anexo-8.pdf


Page 48 of 83

The mechanical properties of the pumps are defined by the conditions of

operation, such as pressure, temperature, suction condition and materials being

pumped. The hydraulic characteristics are inherent in each type of pump and are

influenced by the density, viscosity, type of operation and type of control.

2.5.5. Conclusion

The HEAL system will be used submersible pumps with variable flow. Usually

there is one per well, although some projects have 2 pumps per well. However

redundancy is more about security than flow.

The selection depends mainly on the flow pump

(maximum) and the pressure height required

(depends on the level dynamics in the well and

the head loss in the underground system).

A submersible pump is a pump with a

sealed impeller in the housing. The assembly is

immersed in the liquid to be pumped. The

advantage of this type of pump is that it can

provide a significant lifting force as it does not

depend on external air pressure. And with the

variable flow we can regulate the flow of water by controlling the pressure and speed.

Illustration 25.3. Example the submersible

pump.


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2.6. Heat pump

For an example of common application to the HEAL system such as the

building, we will briefly mention heat pumps. The heat pump is very important in the

building as energy support, because It will solver as peak of energy demand that

HEAL system cannot cover.

Overview

A heat pump is a machine or device that diverts heat from one location (the

'source') at a lower temperature to another location (the 'sink' or 'heat sink') at a

higher temperature using mechanical work or a high-temperature heat source. A heat

pump can be used to provide heating or cooling. Even though the heat pump can

heat, it still uses the same basic refrigeration cycle to do this.

Beginning function

A heat pump uses an intermediate

fluid called a refrigerant which absorbs

heat as it vaporizes and releases the heat

when it condenses. It uses an evaporator

to absorb heat from inside an occupied

space and rejects this heat to the outside

through the condenser. The refrigerant

flows outside of the space to be conditioned, where the condenser and compressor

are located, while the evaporator is inside. The key component that makes a heat

pump different from an A/C is the reversing valve. The reversing valve allows for the

Illustration 26.1. A simple stylized diagram of a heat

pump's vapour-compression refrigeration cycle:

1) condenser, 2) expansion valve, 3) evaporator,

4) compressor.

http://en.wikipedia.org/wiki/Vapor-compression_refrigeration


Page 50 of 83

flow direction of the refrigerant to be changed. This allows the heat to be pumped in

either direction.

To meet requirements in a changing climate the heat pump will serve as a

help energetic for heating or cooling a building. To demonstrate the demand curve of

heat for a building, this graph illustrates what part of the energy demand is the heat

pump and what part is the HEAL-system.

Illustration 26.2 shows the demand curve of heat for a building. As we can see

in the graph, the building requires the maximum load for only a few hours a year.

During this time the heat pump will help to cover the entire energy demand to HEAL-

system. The shape of the curve depends on the type of building. For example, in the

case of a hospital (which requires 24 hours of operation) the curve tends to be flatter

than in the case of an office building (which operates intermittently).

Peak charge: Heat pump

Basic charge: HEAL-system

% annual demand (MWh)

Hours (h)

Illustration 26.2 Example of the demand curve of heat from a building.


Page 51 of 83

2.7. Asphalt collector 20, 21, 22, 23

The task of the asphalt collector is to gather the heat in summer. In winter it

works as a big “floor heating” for the ground, or, with another point of view, as a

collector for the cold. Generally, there are three types of asphalt collectors. A detailed

description in Dutch can be found in J. Michielsens masterthesis21.

The “Winnerway-concept”22 was developed by Winnerway in the Netherlands.

With this system, heat and cold is collected either by piping the water through

concrete or asphalt layers or by letting the water flow through a porous asphalt layer,

which is located underneath the dense top layer.

The second system is called Road Energy System23 by Ooms Avenhorn,

Netherlands. Here a system with tubes is used, too, similar to the first Winnerway-

concept. But in contrast to that, the tubes are supported by a plastic grid. This grit

reinforces the tubes especially during the construction and compacting phase.

The third system was developed by KWS and is called Zonneweg24. It works

likewise the second variant of the Winnerway-concept: Between two layers of dense

asphalt is a layer of porous asphalt, where the water can flow.

20

Johann Michielsen, 2009: “Masterproef: Heat Exchanging Asphalt Layers: Portfolio”, Artesis Hogeschool Antwerpen 21

http://winnerway.nl/sites/het_concept.html cited on 7th of June, 2011 22

http://www.roadenergysystems.nl/pdf/RES%20%28NL%29.pdf cited on 7th of June, 2011 23

http://www.zonneweg.nl/ cited on 7th of June, 2011

http://winnerway.nl/sites/het_concept.html

http://www.roadenergysystems.nl/pdf/RES%20%28NL%29.pdf

http://www.zonneweg.nl/


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III Simulation


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3. Simulation of the system

The target of the simulation is to calculate the average energy output of a

HEAL-system for a certain amount of radiance, shadow, rain, snow, wind, etc. Due to

the limited time we decided to focus on the basic calculation without taking wind, rain,

snow or shadows into account. Unfortunately, we couldn‟t proof our calculations to be

wrong or write, due to a lack of time. Nevertheless, there are some interesting results

both from the calculation and the measurements.

3.1. Sources for weather data,

Although we started our calculation with a known surface temperature it might

be interesting for future projects to take the influences of sun, wind, etc. into account

and therefore need a reliable source for weather data. For the quantity of energy

from the sun one can use several references. The “Photovoltaic Geographical

Information System“24 by the European Commission Joint Research Centre is a tool

to gather information about relevant data for the installation of solar panels, among

other facts the daily and monthly irradiation of the sun for a certain area in Europe.

Another one is the “EnergyPlus Energy Simulation Software”25 by the U.S.

Department of Energy. This database gives not directly the amount of irradiation, but

several numbers on the weather for a certain location. Data about the ground

temperature is collected by most weather stations. But it is usually not open to public

and must be bought from the weather services.

24

http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php# cited on 8th of June 2011 25

http://apps1.eere.energy.gov/buildings/energyplus/ cited on 8th of June 2011

http://re.jrc.ec.europa.eu/pvgis/cmaps/eu_hor/pvgis_solar_horiz_BE.png

http://apps1.eere.energy.gov/buildings/energyplus/


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3.2 Assumptions

To calculate the heat flow from the asphalt to the pipes, a two dimensional,

steady-state conduction case as described in “Fundamentals of Heat and Mass

Transfer”26 p 207, with an outer radius equal to the depth of the pipes, is assumed:

Following assumptions are made:

• the thermal conductivity k of all layers in the road is the same

• the heat outside of the relevant area has no influence on the temperature of

the pipe

• Θ1 and Θ2 are each the same in every 10-cm section

• the tubes have the same temperature as the water and no influence on the

heat transport

All dimensions refer to the prototype of the department of „Industriële

Wetenschappen” as described in: „Masterproef: Heat Exchanging Asphalt Layers:

Portfolio”27, p. 22. The street collector is separated into parts of 10 cm length in z-

direction. When the heat flow from the asphalt to the tubes is known, the heat flow to

26

Incropra, DeWitt, Bergman, Lavine, 2007: “Fundamentals of Heat and Mass Transfer” 27

Johann Michielsen, 2009: “Masterproef: Heat Exchanging Asphalt Layers: Portfolio”, Artesis Hogeschool Antwerpen

Illustration 32.1. Description of the assumptions

D

d

Θ2

Θ1

q

Asphalt surface

Tube

Relevant area for heat transfer

z

y

x


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the water can be calculated and the energy output is known. The heat flow from the

asphalt to the pipe can than be calculated with:

q = k * 2π *L / ( cosh-1 ( D2 + d2 / (2Dd))) * ΔΘ1-2

with:

• q: heat transfer rate to the outside layer of the tube [ W ]

• k: thermal conductivity [ W / ( m * K ) ]

• L: length of one part of the asphalt [ m ]

• D: diameter of the relevant area [ m ]

• d: diameter of the tubes [ m ]

• Θ1: temperature on the top outside layer of the tube [ K ]

• Θ2: temperature on the edge of the relevant area [ K ]

The thermal conductivity of Asphalt is assumed to be 0,75 W / (m*K)28.

The radius D of the relevant area is the distance from the axis of a tube to the

surface, 68 mm. The external diameter d of the tubes is 20 mm, the internal is 17mm.

We assumed different temperatures for the calculation, but there are possibilities to

calculate or measure them: The temperature Θ2 can be measured with the prototype.

The average between the surface temperature Θsurface and the temperature of the

ground in 136 mm depth can be considered as Θ1. The surface temperature can be

calculated with:

Θsurface = Θi + ( ( he – U ) / he ) * ( α * qsun / he + Θe – Θi )

with:

• Θi: temperature of the soil [ K ]

• he: heat transfer coefficient [ W / ( m² * K ) ]

28

http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html cited on 6th of June 2011

http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html


Page 56 of 83

• U: overall heat transfer coefficient. [ W / ( m² * K ) ]

• α: absorption factor of the asphalt [ - ]

• qsun: irradiance of the sun [ W / m² ]

• Θe: dry bulb temperature of the air [ K ]

As we didn‟t focus on the surface temperature anymore, we will leave this for

future projects.

The calculation works as follows:

With q = k * 2π *L / ( cosh-1 ( D2 + d2 / (2Dd))) * ΔΘ1-2 the heat transfer to

the first 10 cm of water is calculated. The exit temperature of the line section is than

calculated according to

Θex = mmedium / cmedium * q * t + Θin29

with:

• Θex: exit temperature [ K ]

• mmedium: mass of the medium within the 10 cm section [ kg ]

• cmedium: Specific heat capacity of the medium [ J/(kg*K) ]

• q: heat transfer rate [ W ]

• Θin: temperature at the beginning of the section [ K ]

This exit temperature is than used as the temperature of the top outside layer

of the next sections tube and the exit temperature of the final section is the final

temperature of the water.

3.3 Note to the volumetric flow rate

In order to get a good heat transfer between the medium flowing in the tubes

and the tube itself, a turbulent flow is preferred rather than a laminar one. The type of

29

Kuchling: „Taschenbuch der Physik, Auflage 17“, Fachbuchverlag Leipzig, 2007, p. 259


Page 57 of 83

flow is determined by the ratio between viscous and inertial forces30. The number,

that describes that ratio is the „Reynolds-number“. At a low Reynolds-number, the

viscous forces dominate and the flowing fluid or gas tends to be laminar. At a

Reynolds number under 2300, the streaming in a pipe or tube is always laminar.

Above 4000, the streaming can be turbulent, when the flowing medium gets any

interferences31. The Reynolds number for a pipe is32:

R = vm * D / ν

With:

• R: Reynolds number [-]

• vm: mean velocity of the fluid [m/s]

• din: diameter of the pipe [m]

• ν: kinematic viscosity of the fluid [m²/s]

To calculate the minimum speed needed for a turbulent flow the equation is

rearranged to solve it for vm:

vm = R * ν / din

With:

• R = 4000

• ν = 0,805 * 10-6 m²/s (water at 30 °C)33

• din = 0,02 m

vm,min = 4000 * 0,805 * 10-6 m²/s / 0,02 m

vm,min = 0,161 m/s

The volumetric flow rate Vflow [m³/s] in a pipe is34:

Vflow = A * vm

30

Elemér: „Fluid mechanics for petroleum engineers“, Elsevier, 1938, p. 161 31

Elemér: „Fluid mechanics for petroleum engineers“, Elsevier, 1938, p. 235 32

Heinz / Schade / Ewald / Kunz: „Ströhmungslehre“, de Gruyter, 2007, p. 99 33

http://hydro.ifh.uni-karlsruhe.de/download/Kap01ps.pdf, cited on 05.05.2011 34

Kuchling: „Taschenbuch der Physik, Auflage 17“, Fachbuchverlag Leipzig, 2007, p. 162

http://hydro.ifh.uni-karlsruhe.de/download/Kap01ps.pdf


Page 58 of 83

With:

• A = area cross section [m²]

The volumetric flow rate equals to:

Vflow = (din / 2)² * π * vm,min = (0,02 m / 2)² * π * 0,161 m/s

Vflow = 0,505 m³/s = 0,505 m³/s * 1000 l/m³ / 60 s/h = 8,42 l/h

Hence, the minimum flow rate one would want is ~ 8 l/h. There are enough

possibilities in the tubes to disturb the laminar flow (sensors, bends, fittings). The

average flow rate in an asphalt collector is around 200 l/h, according to Arien de

Bondt, Ooms Avenhorn.


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3.4 Calculation and results

Several calculations have been done. The most interesting results will be

summarized in this chapter. Note, that the values count for ~ 0,14 m2 of asphalt

collector (the prototype is 2 m long, the area of influence as an diameter of ~ 7 cm).

For the detail calculation please have a look at appendix 1: Calculations.xls

a. Θex and Σq as a function of the thermal conductivity

The k values vary in the range we found on the internet. The calculation shows

the linear dependence of the k-factor.

100,000

150,000

200,000

250,000

300,000

350,000

400,000

450,000

288,500

289,000

289,500

290,000

0,800 1,000 1,200 1,400 1,600 1,800 2,000 2,200 2,400 2,600

Σq

[W

]

T_

ex

[K

]

k_asphalt [W/(m*K)]

T_ex and Σq as a function of k_asphalt

T_ex Σq


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b. Θex and Σq as a function of the entering mediums temperature

The most interesting in this chart is the developing of the heat transfer rate.

The amount of heat gain is around 8% higher for each 5K temperature difference

between entering medium and asphalt (area of influence).

100,000

150,000

200,000

250,000

300,000

350,000

284,000

289,000

294,000

299,000

304,000

309,000

314,000

319,000

324,000

329,000

334,000

283,000288,000293,000298,000303,000308,000313,000318,000323,000328,000

Σq

[W

]

T_

ex

[K

]

T_in [K]

T_ex and Σq as a function T_in

T_ex = Σq


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c. Θex and Σq as a function of the pipes depth

This has probably nothing to do with the real reason why the energy output

decreases with an increase of the depth. In our simulation it comes due to the fact,

that we increase the "thickness of the insulation", the asphalt around the "water-wire",

which leads to a better insulation of the "water wire".

0,000

50,000

100,000

150,000

200,000

250,000

300,000

288,200288,300288,400288,500288,600288,700288,800288,900289,000289,100289,200

0,025 0,030 0,035 0,040 0,045 0,050 0,055 0,060 0,065 0,070

Σq

[W

]

T_

ex

[K

]

D_center

T_ex and Σq as a function of the pipes depth

T_ex Σq


Page 62 of 83

d. Θex and Σq as a function of the flow rate

This result is the most interesting one, as it shows, that by setting the flow rate,

one can already regulate to have a bigger amount of heat on a lower temperature

level, or a lower amount of heat on a higher temperature level. The difference is not

that big in numbers, what might be due to the simulation model. But it's significant

and the explanation is, that a higher flow rate means a bigger volume, that is heated,

but also means a higher flow speed, which results in a lower heat transfer per volume

and thus in a lower temperature.

The fact, that a low flow rate results into a worse heat transfer due to laminar

streaming is not respected. But as this only occurs with flow rates <8 l/h, it is not an

important issue.

25,000

35,000

45,000

55,000

65,000

75,000

85,000

95,000

105,000

115,000

125,000

275,000

280,000

285,000

290,000

295,000

300,000

305,000

310,000

315,000

1,000 50,000 100,000 150,000 200,000 250,000 300,000 350,000 400,000 450,000

Σq

[W

]

T_

ex

[K

]

V_flow [l/h]

T_ex as a function of the flow rate

T_ex Σq


Page 63 of 83

e. Conclusion of the calculations

As written in the next chapter, we couldn‟t prove the calculations. But at least

the phenomenon from (d) was reconfirmed by Arian de Bondt in a personal meeting.


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IV Test with prototype


Page 65 of 83

4 Measurements and results

Unfortunatly we couldn‟t prove the calculation to be wrong or right, as we were

running out of time and didn‟t got a flow meter to measure the flow rate. However, we

made some measurements on which future projects can built up.

4.1. Position of the sensors (Appendix 2: 05302011-position-of-sensors.xls)

Since the description of the position of the sensors in the prototype is in dutch

and we got a strange result during our first measurements, we decided to make a

test to make sure, where the sensors are.

• Aim: Varify the position of the sensors

• Tair: 17,8 °C (08:30h 27.05.2011)

• 1 lamp switched on 07:35h 30.05.2011 – 08:35h 30.05.2011

• Distance lamp surface <–> asphalt: 26 cm

• No water in tubes

• Position of lamps and sensor 2.7:

15

20

25

30

35

40

45

50

55

60

7:36 7:56 8:16 8:36 8:56 9:16 9:36 9:56

Sensors 1.4-1.8 (Tube Layer)

1.4

1.5

1.6

1.7

1.8

2.7

Out

In


Page 66 of 83

The position of the sensors according to Michielsens master thesis and the

meassurments are as follows:

Unfortunately the depth of sensors 1.1 –1.3 is not recorded.

4.2. Temperature of the asphalt without cooling (Appendix 3: 06012011-

temperature-without-cooling)

There were two aims for this measurement. First, to see, how long it will take,

until a steady and stable situation is reached within the asphalt collector. Note, that

an cooled collector will probably take way less time. Second, to see, how hot the

prototype gets without cooling. If one compares these temperatures to a cooled

prototype, maybe an statement to the increment of the durability due to a cooler

asphalt can be made.

• Aim: Temperature without cooling; time till steady situation is reached;

Illustration 41.1. Position of the Sensors


Page 67 of 83

• Tair: 17,2 °C (07:35h 30.05.2011) 4 lamps switched on 07:30h 31.05.2011 –

07:45h 1.06.2011

• Distance lamp surface <–> asphalt: 26 cm

• No water in tubes

• Position of lamps and sensor 2.7:

The test showed, that it takes around 20h until the uncooled prototype is

stable and that it reaches a temperature around 45 °C in the bottom layer and 55 °C

in the tube‟s layer when the surface has a temperature of ~ 58 – 63 °C. It also

showed, that opening the door of the lab has an influence on the temperature of the

sensor 2.7 (but not necessarily on the surface temperature, due to the bigger heat

capacity of the asphalt compared to the sensor).

18

23

28

33

38

43

48

53

58

63

Temperature without cooling(31/05/2011 07:31 - 01/06/2011 07:26)

Sensor 1.1

Sensor 1.5

Sensor 2.7

Out

Out

In


Page 68 of 83

4.3. Conclusion of the measurements

Unfortunately we did way to less work and tests with the prototype. However,

the results are interesting for following projects done with the asphalt collector.


Page 69 of 83

V Conclusion and Personal Opinion


Page 70 of 83

5.1. Conclusion

We didn‟t succeed totally improving the prototype and doing many

measurement with it. But looking back we can say we are proud of the work done

during this period of time. We would have liked to work on an example and put all our

study in practice, but we would have needed more time. Future projects can built on

the description of the several parts.

We would like to stress the importance of teamwork, and above all maintaining

contact with people and companies with special expertise in the subject. Through

contact with professionals, we have been able to focus our work and define our

questions in an incisive, because usually we don't have the possibility to contact

them. For that reason we are very grateful to all those companies and persons who

have helped us on a personal basis or by mail

5.2. Personal reflection, Pau Blaya

With my skills, my expert input is based on the electrical aspects, both in the

storage system, preservation and application of this. I would also like to mention my

contribution on renewable energies, as this project works with one of them. Apart

from my specialized notions, I‟m helping in the search ability, analyzing and

structuring of information.

I have focused my work in search of information, first beneficiaries of the

HEAL-system, the calculation of Meteorology in Belgium, because we can assume

that will be the same to Antwerp, and finally about the different components of the

HEAL-system. The beneficiaries of the HEAL-system, I wanted to teach the goals

and priorities about this system. For the weather I made a short analysis of weather


Page 71 of 83

last year, as this is the one that most will appear in the future, so that we will be

working with these temperatures. Finally, to explain the HEAL system, I wanted to

make a study of the different parts and analyze and compare important to know

which is the best and explain it.

At first, we tried to do more than we could, and this was our problem. Sincerely

we were a bit lost; we were working with many technologic fields and we had many

questions about them. Later, we could focus and do the work more specific,

separating the tasks between us. To be two in the group, each focused on one

aspect of the project, for we can finish so successfully. On my part, I have worked in

research of information and literature, and by my colleague in the calculation and

analysis of prototype.

Personally, I think that I have contributed with my knowledge, my ability to

search, analysis, imagination, technical support for my colleagues on the project. I

enjoyed this experience and I am satisfied with our work and learning. On a personal

level, I think I've improved a lot with language, have to talk constantly have helped

me.

Looking the final work, I can say that has helped me to know much more about

this type this type of renewable energy production, and I like that, because I want

work with these energies in the future. I also contributed to the study and research of

elements, here I could develop more detailed texts.

Honestly, I'm glad I lived this experience of the EPS and have met wonderful people.


Page 72 of 83

5.3. Personal reflection, Stefan Müller

My focus on the project work was on the calculation part. In the beginning both

of us did research on general information on the topic, but soon after we split the

work. I also did most of the communication with the different persons from the

companies, as long as they were not from Spain. I also helped with the gathering of

information on the topic, especially when it came to more difficult English

expressions.

Describing the work process is not too easy. The beginning was complicated,

as we did not have clear view on the topic and especially on the expectations. We

had too many different problems in mind and needed some time to focus on view

points. During the research for the calculations I had a lot of problems with

understanding the physical and thermo dynamical formulas. I had some of the topic

in former lessons and courses but it was never a main focus of my studies. I also did

not think, that I would have so many difficulties with understanding scientific papers

in English. But after all, I am pleased with the work process, as I could improve my

English and my knowledge in the field of heat transport.

The progress since the midterm report / presentation was quiet good in my

opinion. The meeting with Ooms and the start of the measurements with the

prototype were quiet interesting. Looking back, I wish, we would have start earlier

with working on and with the prototype, as the time got pretty short in the end.

As the team did not grow since the midterm report, I just can repeat: There is

no big „group dynamic“ in a „team“ of two. We worked together as good as the

language barrier let us. But I wish, we would have been a bigger team, at least three

or maybe four persons. It is easier to keep the motivation up, when the team is a little

bit bigger.

Although there were a couple of disappointments during the EPS, I do not

regret that I took part. I learned a lot about heat transfer, road design, scientific work

and not at least about a (for me) new culture and country.


Page 73 of 83

VI Literature references


Page 74 of 83

Websites:

• [1] http://www.europeanprojectsemester.eu/info/Introduction

• [6] http://www.locationflanders.be/production-guide/facts-and-figures/climate-

and-weather/

• [7] http://www.cie.unam.mx/~ojs/pub/HeatExchanger/Intercambiadores.pdf

• [8] http://www.britannica.com/heatexchanger

• [10] http://www.sedical.com/web/productos.aspx?CAT_ID=29

• [11] http://www.iftec.es

• [12] http:// www.comeval.es/pdf/cat-tec/intercambiadores/intercambiadores-

A4-esp.pdf

• [13] http://www.acpro.com.ar/m3.pdf

• [14] http://www.iftec.es

• [15] http://es.wikipedia.org/wiki/Principio_de_Bernoulli

• [16] http://avdiaz.files.wordpress.com/2008/10/tipos-de-bombas.pdf

• [17] http://en.wikipedia.org/rotodynamicpumps

• [18] http://www.todomonografias.com/bombas/

• [19] http://sisbib.unmsm.edu.pe/bibvirtualdata/tesis/ingenie/monge-t-m/anexo-

8.pdf

• [21] http://winnerway.nl/sites/het_concept.html

• [22] http://www.roadenergysystems.nl/pdf/RES%20%28NL%29.pdf

• [23] http://www.zonneweg.nl

• [24] http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php

• [25] http://apps1.eere.energy.gov/buildings/energyplus/

• [28] http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html

• [33] http://hydro.ifh.uni-karlsruhe.de/download/Kap01ps.pdf

http://www.europeanprojectsemester.eu/info/Introduction

http://www.cie.unam.mx/~ojs/pub/HeatExchanger/Intercambiadores.pdf

http://www.britannica.com/heatexchanger


http://en.wikipedia.org/


http://sisbib.unmsm.edu.pe/bibvirtualdata/tesis/ingenie/monge-t-m/anexo-8.pdf

http://sisbib.unmsm.edu.pe/bibvirtualdata/tesis/ingenie/monge-t-m/anexo-8.pdf

http://winnerway.nl/sites/het_concept.html

http://www.roadenergysystems.nl/pdf/RES%20%28NL%29.pdf

http://www.zonneweg.nl/

http://apps1.eere.energy.gov/buildings/energyplus/

http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html

http://hydro.ifh.uni-karlsruhe.de/download/Kap01ps.pdf


Page 75 of 83

Books

• [20] Johann Michielsen, 2009: “Masterproef: Heat Exchanging Asphalt Layers:

Portfolio”, Artesis Hogeschool Antwerpen

• [26] Incropra, DeWitt, Bergman, Lavine, 2007: “Fundamentals of Heat and

Mass Transfer.

• [27] Johann Michielsen, 2009: “Masterproef: Heat Exchanging Asphalt Layers:

Portfolio”, Artesis Hogeschool Antwerpen

• [29] Kuchling: „Taschenbuch der Physik, Auflage 17“, Fachbuchverlag Leipzig,

2007, p. 259.

• [30] Elemér: „Fluid mechanics for petroleum engineers“, Elsevier, 1938, p.

161.

• [31] Elemér: „Fluid mechanics for petroleum engineers“, Elsevier, 1938, p.

235.

• [32] Elemér: „Fluid mechanics for petroleum engineers“, Elsevier, 1938, p. 99.

• [34] Kuchling: „Taschenbuch der Physik, Auflage 17“, Fachbuchverlag Leipzig,

2007, p.162..


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VII The illustration


Page 77 of 83

Websites:

1.1. Description of the HEAL-System

• Illustration 11.1. http://www.artesis.eu/upload/docs/08-EPS-Presentation-Heat-

Exchanging-Asphalt-Layers.pdf

• Illustration 11.2. http://www.artesis.eu/upload/docs/08-EPS-Presentation-Heat-

Exchanging-Asphalt-Layers.pdf

2.2. Benefits of HEAL system

• Illustration 21.1. http://www.iftec.es

• Illustration 21.2. http://en.wikipedia.org/ Ice_road_saimaa.JPG

• Illustration 21.3. http://ingcastaneda23.blogspot.com/

2.3. Heat exchanger

• Illustration 23.1. http://www.google.com/images/heatexchanger

• Illustration 23.2. http://www.shell-tube.com

• Illustration 23.3. http://www.ghtthx.com/Design.aspx

• Illustration 23.4. http://www.google.com/images/Compactheatexchanger

• Illustration 23.5. http://www.ewp.rpi.edu

• Illustration 23.6. http://www.google.com/images/regenerativeheatexchanger

• Illustration 23.7. http://www.google.com/images/Scraped_exchanger

• Illustration 23.8. http://www.deltathx.com/

• Illustration 23.9. – 23.10 http://www.iq.uva.es

2.4. Heat storage system

• Illustration 24.1.- 24.4. http://www.iftec.es

http://www.artesis.eu/upload/docs/08-EPS-Presentation-Heat-Exchanging-Asphalt-Layers.pdf





http://en.wikipedia.org/wiki/File:Ice_road_saimaa.JPG

http://ingcastaneda23.blogspot.com/

http://www.google.com/images

http://www.ghtthx.com/Design.aspx


http://www.ewp.rpi.edu/


http://www.google.com/images/Scraped

http://www.deltathx.com/ContentPg.aspx?itemid=651

http://www.deltathx.com/ContentPg.aspx?itemid=651



Page 78 of 83

2.5. Water pump

• Illustration 25.1. http://en.wikipedia.org/wiki/Bernoulli%27s_principle:/

• Illustration 25.2. http://www.todomonografias.com/bombas/

• Illustration 25.3. http://www.fortunecity.es/.html

2.6. Heat pump

• Illustration 26.1. http:/ wikipedia.org/Heat_pump

• Illustration 26.2. photography given by iftec company

2.7. Asphalt collector

• Illustration 26.1. http:/ wikipedia.org/Heat_pump

• Illustration 26.2. photography given by iftec company

4.1. Position of the sensors

• Illustration 41.1. Stefan made this illustration.

http://en.wikipedia.org/wiki/Bernoulli%27s_principle








Page 79 of 83

VIII Appendix


Page 80 of 83

Appendix 1.: calculation_for_prototype.xls

Appendix 2.: 05302011_position_of_sensors.xls

Appendix 3.: 06012011_temperature_without_cooling.xls


Page 81 of 83

IX Acknowledgements


Page 82 of 83

We would like to thank for all the support that we have had when we were making the

project. So we decided to record the names of persons and companies who have

helped us in our project in a special section.

• Wim Van den bergh, supervisor EPS-HEAL (tutor)

• Karolien Cousheir, supervisor EPS-HEAL (tutor)

• Dieter Seghers, assistant-supervisor (lab support)

• Luk Allonsius, supporter heat transfer (Artesis teacher)

• Hans Hoes, worker in terra-energy (Belgium company)

• Arian de Bondt (Ph.D. – M.Sc), worker in Ooms Aven (Nederland company)

• Marcel Roozendaal, worker in Ooms Aven (Nederland company)

• Marcel Hendriks, worker in Iftec company (Spanish company)

• Artesis Hogeschool (Antwerpen)


Page 83 of 83

Documents

Heat Exchanging Asphalt Layers