Stage 1 - Energy Efficient &Climate Responsive Design Assistance …. Bharat Mody Hospital... · 2012. 7. 10. · Stage 1 - Energy Efficient &Climate Responsive Design Assistance

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BBaarrooddaa,, GGuujjaarraatt IINNDDIIAA ARCH-MEDES (I) CONSULTANTS PVT. LTD.

Green Park Delhi

Prepared By

(Low Carbon Consultant)

Global Evolutionary Energy Design,

First Floor, D-15 AF Enclave

Jamia Nagar New Delhi – 110025, INDIA

M +91 9873588571,

O +91 011 24537371

E – Mail: [email protected],

Web site: www.geedindia.org

Disclaimer: The entire report is based on certain assumptions which are listed in the different sections of the report; standard

procedures have been employed for calculation of different information entities. These methodologies can be referred from internationally approved documents. Large data handling and complex mathematical calculation leave space for probable errors of which the consultant takes no warranty, though efforts have been made to minimize errors and anomalies.

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Global Evolutionary Energy Design (GEED), E-mail. [email protected] M +91 9873588571, O +91 011 26957717

Table of Contents

Preface .................................................................................................................................. 4

1 Questions Addressed in the Report ............................................................................. 5

2 Summery of Recommendations.................................................................................... 6

3 Introduction..................................................................................................................... 8

4 Weather Data and Design Conditions........................................................................... 9

5 Concept Stage Modeling & Assessments .................................................................. 10

6 Day Lighting Analysis .................................................................................................. 11

6.1 Results ................................................................................................................................................11

6.2 Recommendations ..............................................................................................................................12

7 Optimum Orientation.................................................................................................... 13

7.1 Results ................................................................................................................................................14

7.2 Recommendation ................................................................................................................................14

8 Prevailing Winds........................................................................................................... 15


9 Shadow Ranges............................................................................................................ 18

9.1 Results & Recommendation ...............................................................................................................18


10 Psychrometric Analysis, Passive Techniques Identification................................. 19

10.1 Passive Techniques ............................................................................................................................19

10.2 Design Strategies and Recommendations..........................................................................................20

11 Solar Insolation Level................................................................................................ 23

11.1 Results ................................................................................................................................................23

11.1.1 Autumn............................................................................................................................................23

11.1.2 Spring..............................................................................................................................................24

11.1.3 Summer ..........................................................................................................................................25

11.1.4 Winter..............................................................................................................................................26

12 Weather Profile Assessment .................................................................................... 27

12.1 Results ................................................................................................................................................27

13 Hourly Sun Shading Simulations ............................................................................. 28

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13.1 Results ................................................................................................................................................28

14 Thermal Comfort Analysis ........................................................................................ 29

14.1 Mean Radiant Temperature (MRT).....................................................................................................29

14.2 Predicted Mean Vote (PMV) ...............................................................................................................30

14.3 Results & Recommendations..............................................................................................................30

15 Conclusion ................................................................................................................. 31

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Preface

This report is prepared by Global Evolutionary Energy Design “GEED India” to assist in the best case

energy design of Hospital facility. The report also describes the basic concepts and the need of such

implementation to certain extent.

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1 Questions Addressed in the Report

Following question would be addressed in the current report.

1. What is the amount of day light, i.e. day light factor , Lux level with in the occupancy space due to presence of windows natural light?

2. What is the level of solar insolation attacking on each façade and roofs, where to select which kind of material?

3. What is the amount of solar insolation available in the open Atrium areas?

4. What is the wind profile for the location? Can this be harvested in any form for ventilation of open spaces?

5. What type of climate exists at site and what are the possibilities of doing energy efficiency measure during operation stage?

6. What is the rating of spatial comfort on the landscaped and internal areas which include thematic of Mean radiant Temperature, Percentage discomfort and predicted mean vote?

7. What are the various passive solar techniques that need to be considered early in design for the hospital building?

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2 Summery of Recommendations

• Renewable energy Harvesting: The roof of the hospital will receive 1745KWh/m2/yr.

The area of the roof of both east ad west building is 1717m2 and 1394m2 respectively. If

even 50% of the roof area is used for hot water generation then 1841 MWh of electrically

generated equivalent hot water can be produced.

• Orientation: The proposed structure is minimizing east and west exposures and is more

energy efficient because of the huge solar heat gains associated with east- and west-

facing elevations during cooling months. Although the building is optimally oriented as

per the plot and other FSI constraint, still it is important to understand the necessity of

shading for the walls which is facing this direction. This is recommended to reduce the

heat storage in the wall which eventually increases the mean radiant temperature in the

adjacent zones.

• Day lighting: some further work is needed in improving the situation of day lighting in

the areas. The simulation model shows that the natural light is penetrating only to a

depth of 10 to 15 meters. Some thing like light shelf and reflective ceiling can be

incorporated to increase the depth of natural light penetration.

• The most desirable natural light comes from the north; it has the least solar heat gain

associated with it and is composed of diffused light, which does not cause glare. So it is

recommended to harvest it to the full extent by placing large height glass in atrium and

northern facades.

• The maximum recorded wind is 50Km/hour in autumn, other wise the wind remains in

this within 30 Km/hr range through out the year. Further study of wind frequency chart

can reveal some other fact that might be useful in landscape planning air flow in the

open areas

• The maximum radiation recorded in autumn is of the range of 356kWh/ma. The value is

less compared to other months due to the presence of haze and lower sun inclination in

this period. Also another noticeable thing is that the southern façade is the highest

recipient of the sun radiation due to the lower sun azimuth angle. This is a time when

passive heating might be a good option to maintain comfort temperature in the hospital.

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• Psychrometric analysis shows that the winter would be comfortable for 297 hour,

autumn would be comfortable for 202 hour, summer would be comfortable for zero

hour (so you need most of the air conditioning in this time and passive strategies for this

time) and spring would be comfortable for 126 hours.

• The shadow range for the four season shows that the atrium space is quite shaded in

winters and exposed in summer. A proper design would not recommend such a criteria.

So some sort of pergolas with a specified angle is recommended.

• Approximate values of PMV on a section plane just above the atrium level shows need

of evening shading on the atrium of the west building. A pergola or a building extended

shade would work well if incorporated early in the design.

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3 Introduction

This report presents the results of feasibility study various energy efficiency and passive

architecture measure for main hospital complex. It is a 97,000 m2 hospital consisting of 8 floors.

Situated in Baroda Gujarat.

We have described four stages in which we generally work in our integrated design process;

stage 1 is about the energy assessment of the proposed massing scheme conceptualized by the

architects. This stage includes a pre-feasibility study of various architectural aspects of design

like solar energy falling on various parts of envelop and accordingly the type and quality of the

envelop component can be decided. Similarly it also descried the way the sun is interacting with

the proposed massing scheme and the surrounding landscape. The wind direction and pattern

and various passive architectural measures and comfort strategies can be employed for making

the conventional energy usage to a minimum extent. This report helps the owner and architects

work towards effective and quick decision making.

Figure 3a: the North West view of the proposed massing scheme model

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4 Weather Data and Design Conditions

Location : Baroda

Latitude (oN) : 23°

Longitude (oE) : 72°

Altitude (m) : 55

WMO Station : 426470

Chart 1. Sun Path Diagram for Baroda

The sun path diagram shows that the sun is almost at 90 degree on June first and about 47 degree in the extreme winters.

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Table 1 ISHRAE Design Temperatures for Baroda, Gujarat

Design Temperatures I

Dry Bulb Mean Coincident Wet Bulb

0.4% 42.1 23.4

1% 41 23.3

2% 39.8 23.4

5 Concept Stage Modeling & Assessments

The concept stage of the project is very critical because as the project life cycle advances the

options to make a positive change also becomes less. For example preliminary study for the

Assessment of orientation and aspect ratio of the block can lead to an understanding of the best

orientation of the building but if not incorporated at the design stage this option can be lost and

nothing can be done to rectify this in future.

Generally in a preliminary concept stage of the proposed block assessment of the possibility of

incorporating passive architecture techniques and renewable energy systems is determined. The

study covers the assessment of the amount of solar insolation available in the open landscaped

area and façade, which will then be useful in determination of façade orientation and other

envelop material. It also covers rating of spatial comfort in the form of mean radiant

temperature and also help to determine the predicted mean vote . The calculation of Shadow

ranges and Sun Shading for the proposed blocks is done for giving an understanding to the

architects about the shading elements in the design process.

The site weather profile study plays a vital role in understanding the climate responsiveness of

the building so a weather profile study gives an idea as to how to make the building as climate

responsive as possible. An example is of a high thermal inertia building that could lead to

higher startup loads but will be a good option in a place where the difference of minimum and

maximum temperature of a day exceeds 20 o C. the incorporation of this concept early in design

can be done by selecting high heat capacity materials and using various kinds of reflective and

absorptive paints etc.

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6 Day Lighting Analysis

Natural lighting refers to the ingress of light from the sky into internal spaces of the building

and is a key factor in the design of energy efficient buildings. If the natural light is properly

used, it can result in substantial energy savings by reducing the need for artificial lighting. The

primary aim of natural lighting is to provide sufficient light under all circumstances for the

tasks performed within a space. If such a lighting level cannot be achieved by natural light

alone, then localised artificial task lighting can be used to supplement. The aim of this analysis

is to reduce the usage of artificial lighting as much as possible.

The Lighting simulation is nothing but calculation of daylight factors and day light levels either

within the occupant space or out side occupant space. The basis of simulation is the designed

sky lux levels which in our case taken to be 11500 Lux. Considering a 10% to 15% reflectivity of

the walls and 0.9 as dirtiness factor for the windows. Where “one” refers to absolute clean

window.

6 . 1 R e s u l t s

The results are depicted in figure 6a and 6b in the form of a contour plot. The day light plots

were calculated for two typical floor i.e. the ground floor and the floor above the atrium.

Figure 6a: Day light penetration at the floor plate above the atrium floor

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Figure 6b: Day light penetration in the floor plate

6 . 2 R e c o m m e n d a t i o n s

1. The depth of the floor plate can be further reduced to increase the ingress of natural light if

architecturally possible.

2. If the opening is of 2.5 m as a thumb rule the natural light penetration will be good till the depth

of 15 m. So by replacement of atrium by making it a semi courtyard one can get the desired

natural lighting effects.

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7 Optimum Orientation

This diagram displays the best Orientation of a wall, which maximizes the sun gain in hot and

cold periods. The orientation calculation involves rotating a 1m² vertical surfaces through a full

360° and recording the average daily incident radiation over each of these periods as well as for

the entire year. The graph shows averaged daily values for each orientation in kWh/m². Red

and blue arrows are then drawn through the maximum values for each.

Basically, the analysis aim is to maximize incident solar radiation during the under-heated

period whilst minimizing it at times of over-heating. The ratio between the blue and red lines is

shown in the colored ring around the circumference of the graph. The brighter yellow values

represent the best orientations.

Simply orienting the building to get the most favorable ratio in winter ignores what is

happening in summer. A concurrent aim is to ensure the minimum incident solar radiation

during the overheated period. This will occur if the angle of maximum summer radiation

occurs at 90° to the orientation of the surface.

In many climates, where the two thin red and blue arrows are not at 90° to each other, there

must be some compromise between the two aims. The degree of compromise is based on the

relative amounts of heat and cold stress. This is calculated as the number of degree hours spent

above the comfort zone in the over-heated period compared to the degree hours spent below it

in the under-heated period.

Thus, the two thicker yellow and red arrows show the adjusted maximums which should be at

exactly 90° to each other. The thick yellow arrow represents the best orientation for the selected

climate – with the representative surface being automatically set to this angle at the completion

of the calculation.

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7 . 1 R e s u l t s

The result of the analysis depicts that the average daily radiation on a wall facing south

(precisely 177 o measured from north line in clockwise manner) receive maximum radiation.

Whose value reaches to 1.68kWh/m2/yr.

7 . 2 R e c o m m e n d a t i o n

Although the building is optimally oriented as per the plot and other FSI constraint, still it is

important to understand the necessity of shading for the walls which is facing this direction.

This is recommended to reduce the heat storage in the wall which eventually increases the

mean radiant temperature in the adjacent zones.

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8 Prevailing Winds

The prevailing wind, its direction, frequency of occurrence, temperature and humidity are quit

repetitive if observed in an annual cycle. Keeping this fact in mind the passive structure can be

design or the landscape area can be evolved with certain feature which are actively or passively

using these natural elements to impart better and low energy intensive comfort to the space.

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The maximum recorded wind is 50Km/hour in autumn, other wise the wind remains in this

within 30 Km/hr range through out the year. Further study of wind frequency chart can reveal

some other fact that might be useful in landscape planning.

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9 Shadow Ranges

This analysis shows the sun shadow ranges in the four seasons that is winter summer spring

and autumn

9 . 1 R e s u l t s & R e c o m m e n d a t i o n

a)-Spring

b)-Summer

c) - winter b)- autumn

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The shadow ranges for the four season shows that the atrium space is quite shaded in winters

and exposed in summers. This is not the criteria on which a proper design works. So some sort

of pergolas with a specified angle is recommended.

10 Psychrometric Analysis, Passive Techniques Identification

The Psychrometric analysis is an important tool in determination of energy efficient design. By

overlaying the hourly data on the Psychrometric chart and by virtue of the knowledge that

specific area in the chart belongs to a specific passive strategy the architects and HVAC

consultant can understand the significance of incorporating site and need specific design at the

early stage of the project planning.

This entire process leads to significant saving in heating ventilation and air conditioning. It also

enhances the building occupants comfort.

1 0 . 1 P a s s i v e T e c h n i q u e s

• Use of Thermal Mass

This technique involves the use of high thermal mass materials within the building

fabric, both in the external envelope and internally. This has a capacitative effect which

tends to even out internal both diurnal and seasonal internal temperature fluctuations.

• Night-Purge Ventilation

This technique requires high levels of exposed thermal mass within the building.

Overnight in summer, when external air temperatures are relatively cool, the building is

opened up and high-volume air flow is encouraged. This cools the internal mass down

to night-time temperatures. The building is then closed up completely during the day.

This has the effect of reducing both internal air and mean radiant temperatures, this

significantly increasing comfort levels within the spaces. For it to work properly,

however, the thermal mass must be exposed, not covered over with carpet or ceiling

tiles.

• Direct Evaporative cooling

Air is basically drawn through a fabric or gauze that is saturated with moisture. As the

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hot air evaporates some of the moisture, energy is lost in the form of latent heat of

vaporisation. A direct evaporative system ducts cooled air directly into the space. In

most instances this is fine, however in areas sensitive to high humidities it can be a

problem.

• Indirect Evaporative cooling

In this system evaporative cooling occurs external to the space. The cooled air then

interacts with the supply air via a heat exchanger. This way there is no addition of

moisture vapour to the air entering the space even if the cooled air approaches

saturation. This means increased efficiency even if there are losses in the heat exchange

as more vapourisation can be allowed.

1 0 . 2 D e s i g n S t r a t e g i e s a n d R e c o m m e n d a t i o n s

For winter internal heat gain will be a best and most effective tool to enhance the comfort. For

around 774 hour in winters i.e. from December to February the internal heat gain from sun is

recommended to be utilized. Other strategies are listed in the figure 10.2a. The criteria in

summers are to have conventional air conditioning for most of the time because there is no

other way left to maintain comfort temperature. Although in spring and autumn there are some

places we can use direct and indirect evaporative cooling

Information which will give an idea about the necessity of these measures is that the winter

would be comfortable for 297 hour, autumn would be comfortable for 202 hour, summer would

be comfortable for zero hour (so you need most of the air conditioning in this time) and spring

would be comfortable for 126 hours. Other detailed design strategies are depicted in the

following section of the report.

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Figure 10.2a: Psychrometric analysis for December to February (Winter)

Figure 10.2b: Psychrometric analysis for March to May (Spring)

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Figure 10.2c: Psychrometric analysis for June to August (summer)

Figure 10.2d: Psychrometric analysis for September to November (autumn)

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11 Solar Insolation Level

This is an important aspect of design. Solar insolation analysis would give an idea of the availability of

different fraction of solar radiations. This intern let us understand the ability of the system to harness the

sun’s energy in the form of solar water heaters, solar dryers and solar photovoltaic systems and also it

works out good in the selection of façade glass thermal properties.

1 1 . 1 R e s u l t s

Solar insolation have been calculated for four distinct seasons i.e. winter, spring, summer and autumn all

the insolation levels have been demonstrated on each components of the façade in section 11.1.1 to

11.1.4.

1 1 . 1 . 1 A u t u m n

Figure 11.1a: Solar insulation level in autumn

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Figure 11.1a. Shows the insolation level on the façade component in all the four direction. It is observed

that the total availability of energy in autumn is of the range of 294 kWh/m2. The insolation plots also

shows that the roof and the south façade of the envelop are the highest recipient of the sun heat. Measures

needs to be formulated to reduce sun heat in the southern side of the building. And proper shading

element can be incorporated to overcome this passive measure.

1 1 . 1 . 2 S p r i n g

Figure 11.1b shows the availability of solar insolation on façade components in spring. Generally in the

hotter climate that too is not a welcome entity. The highest level is received again on the roof of the

building, which is around 447 KWh/m2 .

Figure 11.1a: Solar insulation level in Spring

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1 1 . 1 . 3 S u m m e r

Figure 11.1c shows the availability of sun’s energy in summer, which is considered to be a period starting

from June till august. This period impinges maximum amount of sun energy on the roof of envelop,

which is around 448KWh/m2. This figure also shows the potential for harnessing it in one way or the

other. For hospital it would be good options to use this energy to generate low temperature hot water for

in-house use.

Figure 11.1a: Solar insulation level in summer

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1 1 . 1 . 4 W i n t e r

Figure 11.1d shows the level of solar insolation available in all the envelop components. The maximum

radiation recorded in autumn is of the range of 356kWh/ma. The value is less compared to other months

due to the presence of the haze and lower sun inclination in this period. Also another noticeable thing is

that the southern façade is the highest recipient of the sun radiation due to the lower sun azimuth angle.

This is a time when passive heating might be a good option to maintain comfort temperature in the

hospital.

Figure 11.1d: Solar insulation level in winter

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12 Weather Profile Assessment

- Typical/Extreme Period Determination

Extreme Hot Week Period selected: May 6:May 12, Maximum Temp= 44.20°C, Deviation=| 8.687|°C

Typical Week Period selected: Jun 3:Jun 9, Average Temp= 32.79°C, Deviation=| 0.052|°C

Extreme Cold Week Period selected: Dec 24:Dec 30, Minimum Temp= 11.20°C, Deviation=| 7.902|°C

Typical Week Period selected: Nov 19:Nov 25, Average Temp= 24.81°C, Deviation=| 0.371|°C

Typical Week Period selected: Aug 26:Sep 1, Average Temp= 29.14°C, Deviation=| 0.002|°C

Typical Week Period selected: Feb 26:Mar 4, Average Temp= 23.77°C, Deviation=| 0.681|°C

1 2 . 1 R e s u l t s

Figure 12.1a and b are depicting the monthly variation in dry bulb temperature, corresponding humidity

level and monthly average temperature ranges respectively.

Figure 12.1a: Dry bulb temperature and corresponding humidity on a monthly average basis

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Figure 12.1b: Dry bulb temperature ranges on monthly maximum and minim recorded basis.

13 Hourly Sun Shading Simulations

Hourly Sun shading analysis is a precise way to understand the approach of sun’s rays into any

part of the building. It also clarifies possible shading impacts of other building or self shading of

the building. Once these shading simulations are understood it gives ideas to the architects to

utilize few of the self shading schemes of the building for creating a better climate

1 3 . 1 R e s u l t s

The results are presented as animation file which can be viewed in any animation viewer

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14 Thermal Comfort Analysis

Spatial Comfort analysis help develop an understanding of percentage satisfaction and dissatisfaction at

any given time. In the current analysis the radiant temperature is plotted which represent the monthly

average data for the site.

1 4 . 1 M e a n R a d i a n t T e m p e r a t u r e ( M R T )

Mean Radiant Temperature is the uniform temperature of the surface of an imaginary enclosure where the

radiant exchange of heat between this enclosure and a man would be equal to the radiant exchanges in the

actual environment.

a) - Morning

b) - Evening

c) - Noon

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1 4 . 2 P r e d i c t e d M e a n V o t e ( P M V )

The Predicted Mean Vote (PMV) refers to a thermal scale that runs from Cold (-3) to Hot (+3), originally

developed by Fanger and later adopted as an ISO standard. The original data was collected by subjecting

a large number of people to different conditions within a climate chamber and having them select a

position on the scale the best described their comfort sensation.

Figure 14.2a: Predicted mean vote for the facilities landscape

1 4 . 3 R e s u l t s & R e c o m m e n d a t i o n s

The predicted mean vote rating for the spatial domain has been calculated. Figure 14.2a is depicting the

approximate values of PMV on a section plane just above the atrium level. The thematic plot shows a

c)- Noon

a) - Morning

b)- Evening

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need of evening shading on the atrium of the west building. A pergola or a building extended shade would

work well if incorporated early in the design.

15 Conclusion

This pre feasibility analysis on the massing scheme provides a detailed account for the optimization and

opportunities that can be considered at the stage two of the design process. The study covered various

aspects of sun insolation, shading, and optimum orientation of the walls. The report also highlights the

harshness of sun on various component of building envelop. This indicates the right strategy that needs to

be incorporated for dealing with the various facade options in the most energy efficient way.

The stage two involves energy efficiency and engineering report that will give an exact idea of the capital

and the return on investment on various proposed energy efficiency measures.

Documents

Stage 1 - Energy Efficient &Climate Responsive Design Assistance …. Bharat Mody Hospital... · 2012. 7. 10. · Stage 1 - Energy Efficient &Climate Responsive Design Assistance