Abolin Co Cool Roofs EU Kuwait Kisr

THEORY AND CASE STUDIES

Cool roofs impact into building’s thermal

conditions:

Workshop: “National Energy Security – Future prospect” 13 December 2012 KSIR Kuwait

Prokopis Perdikis U.G.I CYPRUS/ABOLIN CO GREECE

Communication Committee: European Cool Roofs Council

http://www.eugcc-cleanergy.net/Membership.aspx

Kuwait: Energy Consumption #1

Residential buildings consume about 60% of national power.

(DC Consortium Report 2009)

Kuwait District Cooling Summit - 2011

Prof. A. Ben-Nakhi



Building sectors are the major consumers of electrical energy with a

share of over 75%; 0ver 65% goes for air- conditioning.

27840 GWh

9744 GWh

7424 GWh

Residential

Sector 60%

Commercial

sectors 16%

Other

sectors 21%

Industrial

sector 3%

Annual electrical consumption in GWh per sector*

1392 GWh

*MEW (2007)

Total: 46400 GWh

Saad Al Jandal, PhD. KISR / EUD- BET

October, 2010 GBC Forum, Doha



Demand of peak power increases @ 5.6% and annual electricity

increases @ 5.3%

6160

6450

6750

7250

7480

7750

8400

8900

31.6 32.3

34.3

36.4

38.6

41.3

43.7

46.4

30

35

40

45

50

5500

6500

7500

8500

9500

1999 2000 2001 2002 2003 2004 2005 2006

Pe

ak P

ow

er

De

man

d (

MW

) Peak power

Yearly Electricity Consumption

Ye

arly Ele

ctricity Co

nsu

mp

tion

(MW

h/y)*

10

Saad Al Jandal, PhD.

KISR / EUD- BET

October, 2010 GBC

Forum, Doha



Ali Ebraheem Hajiah

Building Energy

Technologies Dept. October 2010 Manama


Kuwait: Energy Code 2010 2nd Edition*

*MINISTRY OF ELECTRICITY AND WATER

Energy Conservation Program

CODE OF PRACTICE

MEW/R-6/2010

Second Edition 2010

7.2 Building envelope construction

7.2.1 Walls and roofs

Minimum requirements for wall and roof insulation: Table 7 provides a list of the

maximum allowable overall heat transfer coefficients (U) for variety of wall and

roof constructions and their external color.

Table 7. Maximum Allowable U-values for Different Types of Walls and Roofs.

Description Wall Roof

Heavy construction, medium-light external color 0.568 (0.100) 0.397 (0.070)

Heavy construction, dark external color 0.426 (0.075) 0.256 (0.045)

Medium construction, medium-light external color 0.483 (0.085) 0.341 (0.060)

Medium construction, dark external color 0.426 (0.075) 0.199 (0.035)

Light construction, medium-light external color 0.426 (0.075) 0.284 (0.050)

Light construction, dark external color 0.369 (0.065) 0.170 (0.030)

What About

Cool Roofs ? Workshop: “National Energy Security – Future prospect” 13 December 2012 KSIR Kuwait

What about Cool Roofs ?

The creation of surfaces of high reflectivity and emissivity in the urban

environment constitutes an easily applicable and economic passive

cooling method that contributes in the reduction of urban temperatures.

The creation of such surfaces can be achieved with the use of “cool

materials” which are characterized from :

High solar reflectance

High infrared emittance


How Cool Roofs Work?

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/heatisla

nd.lbl.gov/

incident

sunlight

reflected

sunlight

net emitted

thermal

radiation

opaque surface at temperature T

convection

conduction

• High solar reflectance (Rsol) lowers solar heat gain (0.3 - 2.5 µm)

• High thermal emittance (E) enhances thermal radiative cooling (4 - 80 µm)

high solar reflectance + high thermal emittance = low surface temperature


Five case studies were implemented, within the framework of the Intelligent

Energy Europe (IEE) program SAVE 2007 "Promotion of Cool Roofs in EU" to

demonstrate cool roof capabilities in real buildings, in terms of improving the

thermal conditions in non-air conditioned buildings and reducing the energy

consumption in air-conditioned buildings.

The buildings were selected to achieve maximum geographical and building

typology coverage aiming to promote the benefits coming from this technique with

reference to cooling energy demand and peak savings all around the EU.

The corresponding activities were performed at two levels:

• experimental monitoring in real buildings treated with Cool Roof

techniques (hardware task)

• numerical analysis of the same buildings with a number of variants

(software analysis)

The findings of the case studies show 10-40% energy savings depending on the

climatic conditions. More info about the case studies : www.coolroofs-eu.eu.

Here we present 3 of them implemented in France, Greece and UK.

Carrefour Italy

Cool Roofs – European Case Studies


Cool Roofs –Case Study FRANCE #1

Le Parvis: Collective Dwellings, Poitiers -Non A/C Building

Fig 2. Duplex flat chosen for the case study Fig1 Collective dwellings in Poitiers

The roof slope (11.5%) faces east and is not shaded by adjacent dwellings. The roof was

constructed with steel cladding, insulated with a 100mm mineral wool and sealed with

asphalt. This Cool Roof case study focuses on the dwellings under the roof which are all

duplex apartments of approximately 100m2 each (Fig.2). The walls are insulated with

100mm polystyrene and the windows are made of PVC with double glazing. The attic above

each duplex apartment is also insulated with 200mm mineral wool. The studied building

has no cooling system for summertime. So the impact of the Cool Roof’s technology

application is evaluated in terms of indoor temperature difference for the studied duplex flat

compared to the adjacent duplex flats.

Cool Roofs Project


Cool Roofs –Case Study FRANCE #2

Le Parvis: Collective Dwellings, Poitiers -Non A/C Building

Cool Roof technology

The roof was coated with a white cool paint at the end of July 2009. The cool paint’s

solar reflectance was 0.88 and the infrared emittance 0.90.

The temperatures evolved with the same daily variation, with high maximum temperatures

differences. During the night, the minimum temperatures were very similar. The predicted

mean surface temperature for the cool painted surface is 21.6°C compared to 34.1°C for

the default roof surface for the summer period. The difference in the indoor operative

temperature is less visible due to the good insulation of the attic: the mean operative

temperature in the room decreased from 24.9°C to 24.2°C. In this case, with a very well

insulated roof, there is a predicted gain of approximately 1°C on the maximum operative

temperature, from 30.2°C to 29.3°C.

Cool Roofs Project


Cool Roofs –Case Study GREECE #1

School building in Kaisariani, Athens, Greece Non Insulated No A/C

Figure . School building in Kaisariani, Athens, Greece

Figure . The spectral reflectance of the roof surface before (grey concrete, SR=0.2)

and after the Cool Roof application (ABOLIN Cool Roof barrier, SR=0.89)

This case study involves a 410m2 flat roof school building located at the Municipality of

Kaisariani, a densely built urban area near the centre of Athens (Fig.5). It is a rectangular,

two floor building with a school courtyard and was constructed in 1980. The load bearing

structure of the building is made of reinforced concrete and an overall concrete masonry

construction which is not insulated. The school building is occupied by 120 children and 15

adults (the school staff) and is non-cooled and naturally ventilated. There is an installed

heating system using natural gas. Walls: U value = 2.846 W/m2K , Roof: U value = 1.971

W/m2K , Windows : U value = 2.95 W/m2K .

Cool Roofs Project





The initial roof surface was covered by cement and gravel having a solar reflectance of 0.2.

The cool material used is a white elastomeric coating (Cool Roof Barrier by ABOLIN) with a

solar reflectance of 0.89, infrared emittance 0.89 and SRI 113.

Impact on air temperature

Additionally, a variant of the model has been studied considering the building with

increased insulation. External insulation of 5cm has been added to the walls resulting in a

U-value of 0.417 W/m2K and 7cm on the roof resulting in a U-value of 0.302 W/m2K.

The maximum, minimum and average air temperatures in both cases (non insulated and

insulated) and for the cooling and the heating period are presented.

Impact on energy loads

In order to estimate the impact of the cool roof on energy loads it has been assumed

that the building is cooled during the summer and heated during the winter. Set point for

cooling is set to 26C and for heating is set to 20C. The building is considered to be in use

all year round. Figure 5 displays the absolute and percentage variation of the annual

heating and cooling loads for all the simulation scenarios that have been carried out.

Cool Roofs Project




Air Temperature, Cooling and Heating Loads before and after the cool roof application for the

zone adjacent to the roof

Min [oC] Max [oC] Average [oC]

Cooling period (May – September)

Uninsulated building 0.8 2.8 1.8

Insulated building 0.3 0.7 0.5

Heating period (October – April)

Uninsulated building 0.9 1.2 0.9

Insulated building 0.2 2 0.4

Annual Cooling Loads (kWh/m2) Annual Heating Loads (kWh/m2)

Uninsulated building -40% +10%

Insulated building -35% + 4%

Cool Roofs Project


Cool Roofs –Case Study UK #1

Office at Brunel University, Uxbridge, West London, UK, Colored Cool Roof

Cool Roof Light Red Brown CB 012

The office is located (moderate climate of South East England) on the top floor (flat roof) of a

four storey building of which the top floor was constructed in 1995. The total floor area is

137m2 of which the open office area accounts for 97.6m2. The floor to ceiling height is

approximately 2.65m. The open office area has 6 window openings while each room has one

opening. Each of these openings is approximately 0.9m x 1.5m. The roof is made of 0.15 m

thick concrete slab with a 0.04 m insulation layer on top of the slab and is covered with a layer

of water proofing material (asphalt). Roof: U Value 0.6 (W/m2 K). The external wall structure

is made of 0.125 m thick concrete block work and is protected with 0.18 m insulation layer

and ZnAl cladding.. Wall: U Value 0.184. (W/m2 K) Glazing Argon filled double glazing: U value

1.4 (W/m2 K). The office has a central heating system with perimeter radiators and is naturally

ventilated through open-able windows.

Cool Roofs Project





“Cool Barrier 012 (CB012)” was applied on the roof with an SR of 0.6 The reflectivity of the

original roof was 0.1. The building was monitored from April 2009 until October 2009

Evaluation results:

There is reduction on maximum and average internal air and operative temperatures

during the summer months. For the month of July, maximum internal air temperature is

reduced by 1.3 ◦C and average air temperature by 2.1 ◦C. In terms of thermal comfort,

max operative temperature is reduced by 2.2 ◦C and average operative temperature by

2.5 ◦C improving significantly thermal comfort.

Increasing insulation levels would decrease the potential energy benefits in heating

and cooling demand.

Thermal comfort can be improved by as much as 2.5 ◦C (operative temperature

difference for a change of 0.5 in albedo) but heating demand could be increased by

10%.

Cooling load is decreased, although there is a heating penalty, the overall contribution

is positive.

Cool Roofs Project




Simulated heating and cooling energy demand for the case-study building before and after

the application of the cool roof.

Albedo Heating demand Cooling demand Total energy demand (kWh/year)

Winter, set-point 21◦C Summer, set point 25 ◦C

2 ACH * 2 ACH * 2 ACH *

BEFORE 0.1 1769 2443 4211

COOL ROOF 0,6 2015 2017 4031

*2 air exchanges per hour

Optimum surface albedo is estimated between 0.6 and 0.7 with air exchange rate of 2 air

exchanges per hour. This combination creates an overall heating and cooling load reduction

of 3-6% depending on the set-point temperature for winter and summer.

Cool Roofs Project


Cool Roofs –Carrefour Italy

Hypermarket Carrefour Assago Milan Italy

Date: 14/07/2011

Place: Assago Milan Italy

Total Roof Surface: 17.000 Sqm

Concrete Flat Roof Top Covered with Gray PVC

Application: Cool Barrier Roof Waterbased

Space 1: Non Treated Area – Surface Temperature 50.4 °C

Space 2: Treated Area - Surface Temperature 32.2 °C

“We are about 25% reduction in electricity

consumption for air conditioning “

“Around 65.000€ savings per year”

“Payback period: 2.5 Years”

Energy Manager: Mr. Giovanni Piano

ENERGY CONSUMPTION DATA AND SAVINGS

Consumption (weekly) measured on multimeters

(Week average for the period July-August)

Without Cool Barrier Roof System

2007: 44.573 kWh, 2008: 46.783 kWh, 2009: 46.627

kWh 2010: 45.259 kWh Average: 45.810 kWh

With Cool Barrier Roof System 2011: 33.500 kWh


Energy savings from installing a Cool Roofing Product depends on the local

climate, existing insulation levels, the type of roof replaced, the type of roof

installed, and maintenance. In the best applications, cool roofs have no

incremental cost and deliver a nearly instant payback.

Winter Penalty:

Also known as heating penalty. Just as cool roofs reflect solar radiation

throughout the summer, they also reflect wintertime sunlight. Thus, the winter

penalty is the potential for increased heating demand in winter due to reflected

solar radiation by light colored roofs. Over an entire year, decreases in summer

energy use typically exceed any wintertime increases. (US Environmental Protection Agency –EPA)

The Absolute Benefits of Cool Roofs in a climate hot and sunny, at least in summer

can summarised as follows:

Cool Roofs and Energy Savings


Cooling load reduction - Less heat penetrates into building

Energy Savings - Minimize the need for cooling

Money savings

Improved thermal comfort conditions

Improved public health conditions

Enhanced building’s durability - Less thermal stress

Improved microclimatic conditions - Urban Heat Island Mitigation

Cool Roofs Consequences in Buildings


Urban Heat Island mitigation – Temperature and Smog reduction

Lower surface temperature increase thermal comfort conditions of the

land users.

Lower air temperatures penetrate into the surrounding buildings –

thermal comfort in buildings –energy savings

Downtown Dallas Surface

Temperatures

Cool Roofs Consequences in City Level


Cool Roofs - Peak Demand Reduction

High peak electricity loads oblige utilities to build additional plants in order to

satisfy the demand, but as these plants are used for short periods, the average

cost of electricity increases considerably. Southern European countries face a

very steep increase of their peak electricity load mainly because of the very rapid

penetration of air conditioning. “Kuwait’s peak power demand is set to almost

double by 2020”, according to Suhaila Marafi, director of the Electricity

Ministry’s department of studies, MEED’s Arabian Power & Water Summit in Abu

Dhabi on 6 March 2012

“Cool Roofing products can help reduce the amount of air conditioning needed

in buildings, and can reduce peak cooling demand by 10-15 percent”.

(www.epa.gov)


Cool Roofs – CO2 Emissions

“Cool roofs are one of the quickest and lowest cost ways we can reduce our

global carbon emissions and begin the hard work of slowing climate change,”

U.S. Secretary of Energy Steven Chu “By demonstrating the benefits of cool roofs

on our facilities, the federal government can lead the nation toward more

sustainable building practices, while reducing the federal carbon footprint and

saving money for taxpayers.”

http://iopscience.iop.org/1748-9326/5/1/014005/fulltext/

“We estimate that increasing the albedo of urban roofs and paved surfaces by 0,1 will induce a negative radiative forcing on the earth surface equivalent to removing 44Gt CO2 from atmosphere. “ Hashem Akbari and Surabi Menon Lawrence Berkeley National Laboratory, USA [email protected] Arthur Rosenfeld California Energy Commission, USA [email protected] 2006


Cool Roofs – Policies and Initiatives


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Cool and Photocatalytic Construction Materials

Manufacturer, Athens Greece

www.abolinco.com

Urbanus Green Innovations Cyprus Ltd (U.G.I

Cyprus) operates as a sustainable management

consultant and as a raw materials supplier. U.G.I

focuses on the promotion of specifications and

standards into national and local construction codes

and on the supply of high performance raw materials

for the industrial and construction sector.

Prokopis Perdikis U.G.I CYPRUS/ABOLIN CO GREECE

Email: [email protected], [email protected]

Thank you for your attention !

Technology

Abolin Co Cool Roofs EU Kuwait Kisr