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ARC 6780 Building Environment Simulation Analysis ECO HOUSE AASIYA TASNEEM ASLAM MSc SUSTAINABLE ARCHITECTURAL STUDIES 110118909

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Page 1: Building Simulation

ARC 6780 Building Environment Simulation Analysis

ECO HOUSE

AASIYA TASNEEM ASLAM

MSc SUSTAINABLE ARCHITECTURAL STUDIES 110118909

Page 2: Building Simulation

1 ARC6780 Building Environment Simulation Analysis

TABLE OF CONTENTS

Introduction…………………………………………………………………………………………….2

Analyses tools adopted…………………………………………………………………………………2

Eco House, Cyprus……………………………………………………………………………………..3

Codes Compliance……………………………………………………………………………………...4

Eco house in New Delhi, India

Site and climate…………………………………………………………………………………………..5

Design Considerations……………………………………………………………………………………7

Performance Checks

Thermal………………………………………………………………………………………......11

Lighting…………………………………………………………………………………………..14

Resource consumption…………………………………………………………………………...18

Renewable Energy source………………………………………………………………………..20

Eco house in Montreal, Canada

Site and climate………………………………………………………………………………………….21

Design Considerations…………………………………………………………………………………..22

Performance Checks

Thermal……………………………………………………………………………………..……26

Lighting……………………………………………………………………………………….….29

Resource consumption……………………………………………………………………….…..33

Renewable Energy source…………………………………………………………….………….35

Comparisons……………………………………………………………………………………………36

Conclusions……………………………………………………………………………………………..38

References………………………………………………………………………………………………39

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2 ARC6780 Building Environment Simulation Analysis

ECO HOUSE- Design Interventions and Analysis

Introduction:

Architectural designs, in today’s scenario, demand accuracy of energy consumption and

generation. It is seldom that designs do not take into account the impact they producing on the

environment or how efficient their construction and systems are. To confirm their environmental

performance, various design analysis tools are developed to constantly guide the designer through

various stages of design. These analysis tools are proven most effective, when utilised from the concept

stage of design, to create guidelines of design and energy checks of the building. The analysis tools

also tell the designer the performance of the building in the context it is located within and which

aspect of the building is causing discomfort to its occupants, which system is consuming most energy

or how the building is performing to the ideas stated by the designer.

Of the several developed softwares like Autodesk Revit, E-Quest, IES, etc., Autodesk Ecotect

and Design Builder will be used to carry out simulations of the Eco house project. The Eco House

project is analysed in two disparate climatic conditions namely that of India and Canada. With the

demand that climate will make on the design of the Eco house, suitable solutions will be proposed to

improve the performance of the building and the comforts of its occupants. Having proposed solutions,

these will be analysed to achieve best building performance in terms of heating/cooling loads,

illuminance level and near zero carbon standards.

Analysis tools adopted:

Autodesk Ecotect is utilised to carry out Thermal and lighting analysis. In order to get

familiarised with other analyses softwares, Design Builder is also used, to calculate the thermal

performance of the Eco house for an alternate location. Of the two, Autodesk Ecotect has a relatively

easier user interface and appears to be more resilient while constructing the 3d model. Despite its

advantages in constructing the model, Ecotect is often suspected of not producing accurate results. Since

Design Builder is associated with energy plus, it generates better results.

The calculations and analyses carried out for this project are- Thermal analysis, Day lighting

analysis and Resource consumption for each of the two locations that the Eco house is based in. Day

lighting calculations will be done solely in Radiance, because of the limitation of the older versions of

Design builder software.

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3 ARC6780 Building Environment Simulation Analysis

ECO HOUSE DESIGN, CYPRUS

Image.1- Eco house design (Views) - Ecotect

Image.2- Floor plans- Eco house, Cyprus

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4 ARC6780 Building Environment Simulation Analysis

CODES COMPLIANCE

The Indian Green Building Council has stipulated certain criteria for all new constructions in India to

achieve sustainability and make the buildings more energy efficient. The rules that apply to this design

are regarding the building construction elements and their U values. The U values target is as follows:

Element U values W/m2.K

Walls 0.3-0.6

Glazing 1.7 – 3.0

Roof 0.7-2.0

Floors 0.7-2.0

[IGBC, India (online)]

The Canadian Energy Code for the best practice in construction requires the following target values:

Element U values W/m2.K

Walls 0.35

Glazing 4.5

Pitched Roof 0.2

Floors 0.45

The requirements for mechanical ventilation as per ASHRAE are:

Equipment Type Size

Category Minimum

Efficiency

Air Cooled, with condenser electrically Operated < 150 ton 2.80 COP

2.80 IPL

≥150 ton

Air cooled without condenser, electrically Operated All capacities 3.10 COP

3.10 IPL

Water cooled, electrically operated, positive

displacement (reciprocating)

All capacities 4.20 COP

4.65 IPL

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5 ARC6780 Building Environment Simulation Analysis

ECO HOUSE- New Delhi, India

Site Analysis and Location:

LOCATION DATA

Location New Delhi

Latitude 28.6⁰

Longitude 77.2⁰

Altitude 216.0m

Time Zone +5.5 hours

Climate Composite- hot humid summers

and cool dry winters

(US Department of Energy)

Image.5- Wind directions-Ecotect

New Delhi is the capital city of India and also one

of the four metropolitan cities of India, located in

the northern part of India (see.image.1). New Delhi

is located in the Indo-Gangetic Plains and is

surrounded by hills. New Delhi is a landlocked

city. New Delhi falls under the seismic zone-IV,

meaning it is susceptible to earthquakes. New

Delhi experiences a composite climate with high

variations between its summer and winters. The

hottest part of the year is late May to early June

and the August is when the monsoons set in

(Wikipedia, climatic data of Chennai, see image 4).

The coldest periods are from November to January.

Image.3- Location of New Delhi on

the world map (Google maps)

Image.4- Monthly Weather data

(Wikipedia)

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6 ARC6780 Building Environment Simulation Analysis

Image.6- Degree hours-Heating, Cooling and Solar-Ecotect

Design Considerations:

Factors Analysis Solutions Image.

Building

orientation

Optimum building orientation

reduces direct solar gains and

overheated periods of the

building.

Building will be oriented in the

East-West axis so that only the

shorter side of the building receives

the harshest western sun(190⁰ from

North). The ancillary space such as

the garage and store will be facing

the western side and main living

space on the East.

8, 9

Construction wall

elements

Right choice of materials can

prevent the ingress of heat into

interior spaces.

Brick cavity wall with insulation

within the air cavity will be

provided.

10

Prevailing Breeze From the North west direction,

cooler evening breezes

Adding a portico (veranda) in the

front of the house with large

openings in the front.

13, 14

From image2, it is evident that

the hottest temperatures are attained

in May (around 39.6⁰C), although

45⁰C has also been recorded as the

highest and 7.3⁰C as the lowest. (The

Hindu, 2003, Retrieved 25 April

2007). Winters are cool and dry.

Humidity levels are high, around

49.2% annual average (Delhi

climate, Wikipedia). New Delhi also

experiences heavy rainfall during

August (258.7mm). Image 5 shows

the monthly diurnal average and the

comfort band to be achieved at 19-

26⁰C. The prevailing breeze

direction is North West in the

evenings (see image 5).

Image.7- Monthly Diurnal Temperatures, comfort levels-Ecotect

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7 ARC6780 Building Environment Simulation Analysis

Fenestration

design

Design of windows and

openings should prevent

excess solar ingress into the

building.

Large windows with deep recess

shall be provided.

Double glazed windows with air

gap in between, having timber

frames.

-

Sun shading

devices

Due to high solar exposure,

windows need sun shading

devices, especially the ones in

the west.

Horizontal sun shading devices will

be provided on all windows.

Reduced size of openings on the

west side.

15

Ventilation In order to improve the scope

of naturally ventilated spaces

and reduce the dependence of

artificial ventilation and

reduce the humidity levels

indoors.

Cross ventilation will be provided

in the interior spaces by providing

large windows.

16

Lighting Maximise day lighting and

reduce glare conditions.

Windows opening in the north side

to get glare free north light will also

be provided.

14

Orientation:

Construction elements:

Constrtion Elements:

Optimum orientation for New Delhi is the East-west

Orientation as Southern faces have the potential for more

solar ingress during winters and lesser during summers

(see image 8). The living spaces are oriented to face the

east, so that it can enjoy the cool eastern sunshine in the

morning. The ancillary space like store and garage on

the west side will act as a buffer to the penetration of hot

midday sun into the living spaces (see image 9).

Providing a lawn in front of the southern façade which

will be accessed from the living space of the ground

floor will potentially minimise the reflected solar heat

onto the south façade.

Image.8- Best orientation-Ecotect

Image.9- Eco House orientation

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8 ARC6780 Building Environment Simulation Analysis

• External Walls- Brick cavity wall with polyurethane insulation provided in the air gap. The

thickness of external walls is 0.28 m. with the break up 0.110 m masonry +0.050m air cavity+0.050m

polyurethane foam as insulation + 0.110m brick masonry+ internal plaster. The u-value attained is

0.53 W/m2K. Admittance is 4.96 W/m

2.K. Attaining a low U value will keep the summer heat outside

in the mornings and release coolth into the interiors.

• Internal walls- 115 mm brick wall with plaster. The U-values attained is 2.62 W/m2.K.

Admittance is 4.39 W/m2.K.

• Ground floor slab- starting from outermost consists of 10mm ceramic tiles+ concrete screed of

50 mm+ polystyrene insulation 50 mm+ plain cement concrete 100mm + compacted soil

1500mm. The U value attained is 0.36 W/m2.K. Admittance is 4.07 W/m

2.K.

Image.10- External Wall layers and Properties- Ecotect

Materials

Image.11- Internal Wall layers and Properties- Ecotect

Materials

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9 ARC6780 Building Environment Simulation Analysis

• Roof slab (ground floor) – Suspended concrete ceiling consisting of a concrete slab of 150

mm+ air gap of 600mm+ gypsum of 12mm. U value of this assembly is 1.77 W/m2.K. Admittance is

2.09 W/m2.K.

• Floor slab (first floor) - From the outermost layers 10mm ceramic tiles+ concrete screed of 50

mm+ polystyrene insulation 50 mm+ concrete slab 150mm. U value of this assembly is 0.93

W/m2.K. Admittance is 4.07 W/m2.K.

• Roof slab- Starting from the outermost layers 20mm plaster board+ air gap of 500 mm+

concrete slab 150mm+ Concrete Screed 75 mm + Polystyrene as insulation 100mm+ Bitumen felt

20mm + light coloured ceramic tiles 10mm. U value of this assembly is 0.51 W/m2.K. Admittance is

3.56 W/m2.K.

• Glazing- Double glazed with aluminium frame consisting of 8 mm of glass on either side

sandwiching 20 mm of cellulosic insulation in the air gap. The U value of this assembly is 1.18

W/m2.K. Admittance is 1.17 W/m2.K.

Prevailing Breeze:

Since the prevailing breeze direction is

from the north-west in the evenings, the

entrance is projected out into a semi open

portico (veranda) which will draw in fresh

air into the living spaces through large

shaded windows in the front of the house.

This also shades the house in peak

summers.

Image.12- Floor Slab layers and Properties- Ecotect

Materials

Image.13- Prevailing breeze direction in plan- Ecotect

Materials

Page 11: Building Simulation

10 ARC6780 Building Environment Simulation Analysis

Thermal Analysis:

Fenestration and Sun shading devices:

The windows are recessed in the walls to

avoid the glare of the sun into the interiors. Double

glazed windows with aluminium frames are

selected as its performance proved to have the

highest impact on the entire thermal performance of

the building. Horizontal shading devices are

provided over the window to reduce the impact of

the sun in the hottest days of the year. These

shading devices project out by 0.60m from the

windows (see image 15). Internal venetian blinds

also prevent excess glare.

Ventilation:

In order to reduce the humidity levels in the

interiors all living spaces and bedrooms are

provided with cross ventilation (see image 16). For

the purpose of calculations a mixed modal system

with 95% efficiency is selected. The image below

shows the new location of the bedroom to enable

provision of windows on opposite walls promoting

cross ventilation.

Lighting:

The living spaces have increased window

sizes to capture glare free north lighting into the

interiors. The windows of the living room in the

south side are shaded by a semi open terrace. As

sky lights bring in excess heat also into the

building, it is advisable to rely on natural day

lighting through windows only. The Average

Daylight Factor achieved is 9.53% for the rooms in

the first floor.

Image.15 - Design Interventions- Ecotect Visualise Tab

Image.14- Design Interventions- Ecotect Visualise Tab

Image.16 - Design Interventions- Ecotect Visualise Tab

Image.17 - Design Interventions- Ecotect Visualise Tab

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11 ARC6780 Building Environment Simulation Analysis

The thermal calculation was run and displayed the following result for the Average hottest day in

and average coldest day in New Delhi:

Image.19(a), (b)- Thermal Analysis for Hottest day Average,30th

June, in New Delhi

Total Conductance (AU): 1613 W/°K

Total Admittance (AY) : 11061 W/°K

It can be seen from the graph that upper band of Comfort zone is achieved between major parts of the

day (4:00-20:00) around 26⁰C. At night time in New Delhi, the temperature inside rises to maintain

warmth inside the house. The First floor experiences more heat at night because of the open terrace and

more exposed opaque surfaces. Hence light surface tiles are proposed for the external surfaces of the

first floor terrace to reflect off heat rays. However, both zones are comfortably lower than the outside

air temperature. A significant change in internal comfort is seen when the infiltration rate is changed to

cross ventilation with 200ach. This implies that providing cross ventilation in the living spaces can

reduce the cooling loads (see image 19b). Internal temperatures can further be regulated by operating

Thermal Analysis:

For calculation of the thermal performance of the eco house,

certain considerations were followed:

• The model was simplified in terms of zones namely the

Ground floor (zone1), first floor and roof top structure

(zone 2) and garage and store services as (zone 3).

• The thermal zones were given the following values-

Mixed Modal system (95% efficiency) was selected

which means the provision of both natural and artificial

system of ventilation, activity as sedentary-70W,

clothing as 0.6 clo, Air speed as 0.5 m/s, lighting level

as 300 lux with infiltration as 1 ach.

Image.18 – Alternate Materials

Settings- Ecotect

Page 13: Building Simulation

12 ARC6780 Building Environment Simulation Analysis

the venetian blinds. However, Ecotect does not account for such strategies. The average temperature of

the building in summer is 24.4 ⁰C.

Image.20- Thermal Analysis for Average Coldest day, 1st January, in New Delhi

The graph for the Average coldest day in New Delhi reveals that both zones have achieved comforts

around 18⁰C for most parts of the day. The temperature is low in the early part of the day and rises to

achieve comfort around mid-day finally reaching 18⁰C. The first floor achieves better conditions, again

because of its exposed roof slab. Average temperature of the building in winter is 13⁰C.The graph also

shows the peak solar radiation around mid-day.

During the average hottest day in New Delhi, the heat gains that occur by the fabric are 11 0404Wh

which is maximum at 16 hrs (because of the evening sun in the west), which is less as the fabric keeps

the heat from penetrating the building. However, the gains by the HVAC system are around 50

32507Wh. The maximum gain occurs by the penetration through opaque surfaces of wall and roof

around day (around 5:00 am to 5:00 pm). The maximum direct gains by the windows and openings

occur in April around 32 425 Wh from the west and east faces of the building at 11 am. The comfort of

occupants can be regulated by providing internal blinds.

Total Conductance (AU): 1613 W/°K

Total Admittance (AY) : 11061 W/°K

Image.21 – Hourly temperature gains- Hottest day Image.22 – Indirect Solar Gains- Hottest day

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13 ARC6780 Building Environment Simulation Analysis

The graph for the average coldest day shows that the losses by the opaque surfaces of fabric are 8 7800 Wh,

where most fabric losses occur early morning at 6 am. Although the inter-zonal heat is nearly constant,

most conduction and HVAC loss occurs during the night time and early parts of the day. There is a small

internal temperature gain in the early morning. The most direct gain is 3 0235 Wh at 11 am during

February.

Max Heating: 2 8524 W at 05:00 on 23rd December

Max Cooling: 8 3179 W at 09:00 on 24th June

The distribution of temperature annually is between 16- 28⁰C. The most attained temperature level is

26⁰C. The building achieves comfort for 6570 Hrs (100.0%) in total for the entire year.

Image.23, 24 – Temperature Distribution and Sun Path on Hottest Day

Image.25 – Hourly temperature gains- Hottest day Image.26 – Direct Solar Gains gains

Image.27 – Temperature Comparison- Ecotect Image.28 – Sun path Diagram- Coldest day

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14 ARC6780 Building Environment Simulation Analysis

While comfort has been achieved in most cases, a few limitations of the software prevent

accurate results displaying the performance of the building with the effect of natural cross ventilation.

While the capability of cavity walls to retain heat in the morning and dissipate it during the night is not

included as a source of improved thermal performance of the Eco house. In this case, Ecotect has just

assumed the effect of the orientation and building fabric, for calculating the thermal performance of the

building.

Lighting Analysis:

In order to understand the effect of natural lighting in this model, it was necessary to calculate

the Average Daylight factor and the Illuminance for each room and check if they have achieved the

standard prescribed by CIBSE.

A comparative tabulation of the lighting analysis was made:

The Daylight Factor measured in percentage and

is the ratio between the actual Illuminance at a

point inside a room and the illuminance possible

from an unobstructed hemisphere of the same sky

(McMullan, R., 2007). Design Sky values are

derived from a statistical analysis of dynamic

outdoor sky illuminance levels. They represent the

horizontal illuminance value that is exceeded 85%

of the time between the hours of 9am and 5pm

throughout the working year. Thus they also

represent a worst-case scenario that you can

design to and be sure your building will meet the

desired light levels at least 85% of the time

(Natural Frequency, 2012). Ecotect has the ability

to perform the calculations by itself to detect the

design sky component. This can be specified

either by the Tregenza Formula or by the Latitude

of the site. However, Tregenza calculator was

utilised for this instance which detect the sky

component to be 8875 Lux.

Image.29 – Design Sky Values( Natural frequency)

Image.30 – Design Sky Values by Latitude

Image.31 – Stereographic diagram-Vertical sky component

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15 ARC6780 Building Environment Simulation Analysis

Space Required (CIBSE) Achieved Accepted Refer

image. Daylight

Factor (%)

Illuminence

(Lux)

Daylight

Factor (%)

Illuminence

(Lux)

Living rooms and

Dining rooms

1.5 5-200 32.19 1200 Yes 34

Bedrooms 1 100 GFa- 3.7

FFa – 4.6

FFb- 2.8

FFc- 2.3

GFa- 500

FFa-750

FFb-350

FFc-350

Yes 35

Kitchen 2 300 13.68 450 Yes 36

Bathroom - 100 GFa-1.06

FFa- 1.1

FFb-1.2

GFa-200

FFa-250

FFb-275

Yes 37

Office 2-4 300 3.77 400 Yes 38

The following images show the light analyses for the ground and first floor respectively. Most of the

spaces are adequately lit. The day lighting analysis for individual spaces will be discussed in detail.

Image.32 – Daylight Analysis- ground floor Image.33 – Daylight Analysis- first floor

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16 ARC6780 Building Environment Simulation Analysis

The following analyses were made by exporting the data to radiance the settings selected were-

Intermediate sky (mid season) settings, Using Ecotect’s sun angles and design sky which generates the

following images according to the camera settings.

Living room- Lighting Analysis shows abundant lighting levels achieved. The ‘False colour’ settings

enable to give a more uniform result of the space. More than 475 Lux is achieved uniformly. The ADF is

32.19 %.

Bedroom 1- Lighting Analysis of the ground floor bedroom shows that more than 500 Lux is achieved

uniformly. The ADF is 3.7 %.

Image.34 – Daylight Analysis- Living room

Image.35 – Daylight Analysis-Bedroom (ground floor)

Image.36 – Daylight Analysis-Kitchen

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17 ARC6780 Building Environment Simulation Analysis

Kitchen- After analysing the lighting in the kitchen, it was found that it was below the required 300 lux

and 2% ADF. Hence another linear window was added on the wall facing the main entrance. Since it is

facing the main entrance it had to be at a higher level for the sake of privacy of the interiors. The ADF

now is 13.68%

Study- Lighting Analysis of the study shows that more than 500 Lux is achieved uniformly. The ADF is

3.77 %.

Lounge (F.F.)- Lighting Analysis of the ground floor bedroom shows that more than 600 Lux is

achieved uniformly. The ADF is 3.5 %.

Image.37 – Interventions to the Kitchen with analysis

Image.38 – Daylight Analysis-Study

Image.39 – Daylight Analysis-Lounge First Floor

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18 ARC6780 Building Environment Simulation Analysis

Image 40-Bathroom- 200 lux and ADF is

1.06%

Having generated the analyses for the worst case scenario, it is evident that better natural lighting is

possible for sunny skies. The radiance tool is more accurate in displaying results related to lighting. The

other spaces were also tested to achieve satisfactory results.

Resource Consumption:

The resource consumption calculation is essential in understanding how much energy is consumed by

the building in order to maintain comfort and achieve everyday activity. Resources include electricity,

water, gas, petrol, diesel and oils. At the moment, only solar collection and water are considered as

production resources (Ecotect Help).

To supplement the load of the HVAC system and the electric loads, photovoltaic panels are added. The

system chosen is a mixed mode system with 95% efficiency. The maximum cooling is required in June

and maximum heating in January. The monthly heating and cooling loads indicate that 3 55 7304 Wh

is needed for heating, 17 14 0620Wh is required for cooling and 15 01 8696 Wh for electricity

(appliances, light fixtures). To reduce the impact on the environment, Compact fluorescent lamps are

suggested, which are energy efficient as compared to ordinary lamps. A 38 Watt lamp (specified for

lamps in the project) generates same illuminence as a 150 Watts ordinary lamp. Hence, more energy can

be conserved.

The images below illustrate the monthly heating and cooling loads consumed by the building. The first

graph( image 41) shows that during summers cooling of 41 52 8328 Wh is required and during winters 7

68 3341Wh of heating is required. However, when the infiltration values of air change rate are changed

to 50ach (cross ventilation), the second graph is generated (image 42). Now the cooling loads is reduced

to 22 36 3184 Wh which indicates that cross ventilation of the living and bed spaces can substantially

reduce the cooling loads. However it also increases the heating loads during winters as too much wind is

undesirable during winters. This can be manually controlled by shutting the windows during winters.

Image.41 – Resource Consumption Image.42 – Resource Consumption (@ 50 ach)

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19 ARC6780 Building Environment Simulation Analysis

To relieve the building of excess load consumption for cooling during summers, PV cells are introduced

on the roof. The panels occupy a total of 70.7 m2. Ideally, the optimum orientation for solar panels

mounting is derived by the formula Optimum angle (in degrees) = (your latitude x 0.9) + 29. Hence for New Delhi,

the ideal orientation is a 54⁰ tilt towards the southern direction. The efficiency of the solar collectors was

set 95% for efficiency and 90% for space heating efficacy. During the summers, when there is maximum

sunshine, the solar panels can collect 19 84 1492 Wh of energy which is roughly a quarter of the energy

consumption of the building. When part of the resources is derived from renewable sources, the Eco

house is closer to attaining a low energy standard. The graphs below describe the solar energy

generation (19 84 1492Wh) and the hourly electricity usage (15 01 8696 Wh).

A chart describing the peak sun hours suitable for solar collection is shown below

Image.43 – Monthly Loads Image.44 – Monthly loads (@ 50 ach)

Image.45 – Hourly Electric Usage Image.46 – Total Solar Energy collected

Image.48 – Solar panels on roof Image.47 – Daily Load Matching

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20 ARC6780 Building Environment Simulation Analysis

Potential Renewable Energy Sources:

Renewable energy is about using natural sources to create energy so that the dependence on electricity is

lesser. These natural sources usually include the sun, water, wind, and geothermal sources. A net zero-

energy building (ZEB) is a building which depends less on energy through efficiency gains such that the

balance of energy needs can be supplied with renewable technologies [Torcellini et al. 2006].

Apart from Solar panels on the roof, other techniques are ensuring passive ventilation by stack method

and cross ventilation. This will increase the cooling in the interior spaces and reduce the energy

consumption for cooling. All interior paints should be low VOC to improve the standards of the

interiors. The materials chosen for the house are also locally available such as brick and insulation

materials. This reduces the carbon footprint of the materials.

Alternately, the solar energy can also be utilised to heat hot water in insulated solar thermal tanks (see

image 52). As Delhi receives adequate rain water, rain water collection is required to conserve and reuse

water. New Delhi also has the potential of being benefitted by the hydroelectric power generated by the

dams on the Chambal River. Off-site renewable Energy Sources can also benefit the accumulation of

energy.

Image.49 – Solar panels Energy Calculations

Image.50 – Solar panels Yearly Power Calculations

Image.51 – Solar panels laid on the roof

Available at http://www.millennialliving.com/content/up-your-

solar-panel-roof

Image.52 – Solar thermal heaters-operation

Available at http://mapawatt.com/tag/solar-thermal-schematic/

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21 ARC6780 Building Environment Simulation Analysis

ECO HOUSE- Montreal, Canada

Site Analysis and Location:

LOCATION DATA

Location Montreal

Latitude 45.47⁰

Longitude -73.75⁰

Altitude 9.1m

Time Zone -5.0 hours

Climate Humid continental

(US Department of Energy)

Montreal is one of the largest cities in

Canada. Montreal is located in between the

St. Lawrence River on its south, and by the

Rivière des Prairies on its north. The climate

is classified as humid continental or

hemiboreal. Summers are warm with average

temperature being around 26°C. Winters in

Montreal are often very cold, snowy and

windy at times. Typical winter daytime

temperatures brings between -2 to -6°C and

overnight temperatures between -10 to -15°C.

Montreal receives plenty of snow throughout

the winter season. Average yearly snowfall is

218 cm (86 inches). Despite plenty of snow

during winter, Montreal still sees plenty of

days with sunshine. The maximum

temperature recorded is during July

(36.1°C).The hottest months are June, July

and August. The lowest temperature recorded

is -33°C in January. Annual precipitation is

218 cm of snowfall. The wind direction is

from the south west.

Image.53 – Montreal Location, Google maps

Image.54 – Montreal Wind direction-Ecotect

Image.55– Degree Hours-Montreal, Canada

Image.56– Climatic data, Montreal (Wikipedia)

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22 ARC6780 Building Environment Simulation Analysis

Design Considerations:

Factors Analysis Solutions Image.

Building

orientation

Optimum building orientation

will increase direct solar

ingress into the house

Building will be oriented in the

East-West axis so that only the

so that the front faces the south.

(165⁰ from North).

59,60

Construction wall

elements

Right choice of materials can

retain heat in the interior

spaces.

Timber clad masonry is selected

with insulation in walls.

62

Prevailing Breeze From the West direction,

cooler evening breezes

The living space is on the west,

which will enjoy the breeze in

summers, but ample planting

will be provided to deflect the

harsh breeze in winter.

66

Fenestration

design

Design of windows and openings increase solar ingress

into the building.

Double glazed windows with

timber frames.

More windows facing South and

smaller windows on the north

side to reduce heat losses.

67

Precipitation Excess snowfall Sloped and pitched roofs

provided.

67

Image.57– Monthly Diurnal Temperatures and

comfort levels- Ecotect

Image.58– Psychrometric Chart- showing comfort

level

Page 24: Building Simulation

23 ARC6780 Building Environment Simulation Analysis

Orientation:

Ideal orientation for Montreal is the East-west Orientation where larger part of the building

faces south. The southern facade has the potential for more solar ingress during winters and lesser

during summers. Also, the living spaces oriented in the west and is shaded by an extended terrace. The

roof is a pitched is made sloping to prevent accumulation of snow on rooftops. A greenhouse is also

added on the southern façade to increase the heat in the evening times.

From the images above it is seen that that the northern faces receive very little sunshine. Hence it

is better to locate bedrooms in the north. These rooms will rely on artificial lighting.

Construction elements:

• External walls - Timber clad masonry with insulation provided in the air gap. The

external walls consist of the following layers: 25mm white wood fir +75mm air

gap+80mm polystyrene foam as insulation + 110mm brick masonry+ 75mm air gap

+110mm brick masonry +10mm internal plaster. The u-value attained is 0.28 W/m2K.

Admittance is 4.97 W/m2.K.

Image.59– Optimum Orientation-Ecotect Image.60– Building facing South

Image.61 (a), (b), (c)- Sunshine hours calculation on each facade

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24 ARC6780 Building Environment Simulation Analysis

• Internal walls – The internal walls are brick plaster whose U value is 2.64 W/m2.K and

admittance is 4.38 W/m2.K.

• Floor Slab on Ground- Timber floor on Concrete Slab consisting of 50mm white wood

oak flooring + 75 mm Urea Formaldehyde cellulose+ 200mm Plain cement concrete+ 25

mm Vapour barrier+ Compacted soil 1500mm. U value achieved is 0.37 W/m2.K and

admittance is 3.48 W/m2.K.

• Floor Slab of first floor- Suspended Timber floor consisting of 15mm carpet + 5 mm

carpet underlay+10mm plywood+ 50mm Polystyrene as insulation+ 200 mm air gap+

Plaster board 10mm. U value achieved is 0.70 W/m2.K and admittance is 1.44 W/m

2.K.

Image.62– External Walls Layers and properties-Ecotect Materials tab

Image.63-Floor Slab Layers and properties-Ecotect Materials tab

Image.64-Floor Slab (F.F) Layers and properties-Ecotect Materials tab

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25 ARC6780 Building Environment Simulation Analysis

• Roof Slab – Clay tiled roof that consists 30mm Clay tiles+ 0.6mm aluminium

foil+50mm fibre quilt+150mm Reinforced concrete slab+75mm air gap+ 10mm plaster.

U value achieved is 0.59 W/m2.K and admittance is 0.98 W/m

2.K.

• Glazing – Double glazed with timber frame with cellulosic insulation. U value is 1.65

W/m2.K and admittance is 0.87 W/m

2.K.

Prevailing Breeze:

Since the prevailing breeze direction is from the south west, this can be used as an advantage in

summers. Hence, the living room is on the western side. However, planting on the west side can deflect

the harsh winds in the winter.

Image.65-Roof Slab (F.F) Layers and properties-Ecotect Materials tab

Image.66-Prevailing wind direction and Design interventions

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26 ARC6780 Building Environment Simulation Analysis

Other Interventions:

Thermal Analysis:

For calculation of the thermal performance of the eco house, certain considerations made are:

• The model was simplified in terms of zones namely the Ground floor (zone 1), first floor (zone

2), garage and store as services (zone3) and greenhouse (zone 4).

• The ground, first floor and services were assigned as- ‘Heating only’ system which is the same

as the air conditioning system with only heating being calculated(help file).

• The green house, although being a zone, is not given any conditioning being an external space.

• All the thermal zones were given the following values- activity as sedentary-70W, clothing as

2.0 clo, Air speed as 0.3 m/s, Humidity as 60%, lighting level as 300 lux, Occupancy 6 persons.

• The comfort band was set between18-22⁰C.

Image 67(a), (b), (c)-Design

Interventions

Image.68-Zone settings in Zone Management

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27 ARC6780 Building Environment Simulation Analysis

The thermal calculation was run and displayed the following result for the Average coldest day in

and average hottest day in Montreal, Canada.

Image.69- Thermal Analysis for Coldest day Average, 17th

January, in Montreal, Canada

It can be seen from the graph that the ground and first floor and service rooms have achieved the lower

bands of comfort at 18⁰C for most part except at night, according to the operation of the heating system.

A passive strategy of having a greenhouse that dissipates heat into the house at night is proposed but

due to the limitation of the software to detect it, it cannot be displayed in the graph. Zone 4(greenhouse)

is not given any system of operation as it an external element. The average temperature is 18.7⁰C.

Image.70- Thermal Analysis for Hottest day Average, June 27th

, in Montreal, Canada

It can be seen from the graph that the ground, first floor and services (zone 1, 2 and 3) are within the

higher level of the comfort range at 20-22⁰C. Night time temperatures drop in small increments, but are

still within the comfort level. All the zones are below the external temperatures. The green house

however accumulates the heat in the mornings and will release it in the evenings. The average

temperature of all zones is 20.6⁰C.

During the average coldest day in Montreal (see image 71), 1 56 5614Wh of losses occur by the fabric.

The maximum solar gain is 16 2575Wh. The maximum gain occurs by the penetration through opaque

Total Conductance (AU): 2051 W/°K

Total Admittance (AY) : 11 534 W/°K

Total Conductance (AU): 2051 W/°K

Total Admittance (AY) : 11 534 W/°K

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28 ARC6780 Building Environment Simulation Analysis

surfaces of wall and roof in the mornings (around 7:00 am to 12:00 pm). The maximum direct gains by

the windows and openings occur in July around 19 033 Wh at 12 pm, from the south faces of the

building.

The graph for the average hottest day average (see image 74) shows that although the inter-zonal heat is

nearly constant, the gains by HVAC are highest at mid day to maintain comfort. Minimum conduction

takes place during the day and increases during midday. The maximum gain through the opaque surface

of the fabrics is 17 2716Wh and gains by the HVAC system is 56 3080Wh. The maximum direct gain

through the windows is 4 8730Wh at 11 am in July.

Max Heating: 10 9171 Wh at 03:00 on 18th January

The distribution of temperature annually is between 16- 20⁰C. The most attained temperature level is

18⁰C (see image 76). The building is in comfort for 6729 Hrs totally, throughout the year.

Image.71-Hourly Gains- Coldest day

Image.72-Sun path-Coldest day

Image.73-Direct Solar Gains

Image.74-Hourly Gains- Hottest day Average Image.75-Sun path-Hottest Day Average

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29 ARC6780 Building Environment Simulation Analysis

While comfort has been achieved in most cases, a few limitations of the software prevent accurate

results displaying the performance of the building with the effect of the greenhouse in dissipating heat

into the interiors. In this case, Ecotect has just assumed the effect of the orientation and building fabric,

for calculating the thermal performance of the building.

Lighting Analysis:

A comparative tabulation of the lighting analysis was made:

Space Required (CIBSE) Achieved Accepted Refer

image. Daylight

Factor

(%)

Illuminence

(Lux)

Daylight

Factor (%)

Illuminence

(Lux)

Living rooms

and Dining

rooms

1.5 5-200 33.27 1135 Yes 82,83

Bedrooms 1 100 GFa-1.28

FFa-39.82

FFb-1.17

FFc-4.65

GFa-150

FFa-950

FFb-250

FFc-450

Yes 84

Kitchen 2 300 16.57 400 Yes 85

Bathroom - 100 GFa-0.7

FFa- 1

GFa-100

FFa- 95

Yes 88

Zone Comfort(hrs) Comfort (%)

Ground 5315 90.2

First 5362 91

Services 5522 93.7

Greenhouse 2274 41.8

Image.76-Temperature Distribution Graph

Image.77-Comfort Chart- Each zone

The percentage value of the design sky using the latitude

is 7200 lux (see image 78). But for this analysis Tregenza

Formula is used which states the design sky value to be

7215 Lux. All calculations are taken at 85cm from the

ground. Image.78-Design Sky calculations- Latitude

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30 ARC6780 Building Environment Simulation Analysis

FFb- 0.8 FFb- 115

Office 2-4 300 4.23 400 Yes 88

The following images show the light analyses for the ground and first floor respectively. The spaces on

the south are better lit than the rooms on the north. The day lighting analysis for individual spaces will

be discussed in detail. The bedroom on the north east corner is benefited with an extra window to

improve the Illuminence levels. Enabling the ‘Show Average Value’ displays the average daylight

factor which is 27.43% for the first floor and 22.56% for the ground floor. The Analysis grid was set at

850 mm from floor level in all cases.

All artificial lamps are 40 watts of Compact fluorescent lamps and the parameters of the lamp

fixtures are specified in the materials as shown in the image 79.

The following analyses were made by exporting the data to ‘Radiance’. The settings selected were-

Overcast sky settings, Using Ecotect’s sun angles and design sky which generates images according to

the camera settings in the following spaces:

Image.78-Daylight Analysis- Ground floor

Image.80-Daylight Analysis- First floor

Image.79-Artificial lamps- Materials Tab

Image.81-Daylight Analysis- First floor after Intervention

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31 ARC6780 Building Environment Simulation Analysis

Living room- Lighting Analysis shows that when the overcast sky conditions are set, the living room

does not have enough illuminence (fig1). Hence, artificial lighting in the form of low energy compact

fluorescent lamps (CFLs) is recommended. The ‘False colour’ settings enable to give a more uniform

result of the space. More than 950 Lux of illuminence is achieved uniformly. The Average daylight

factor achieved is 33.27%.

Bedroom 1 (GF) - Average Daylight Factor is between 1.28% which is sufficient for bedrooms.

Master bedroom (FF) - Average Daylight Factor is 39.82% which is sufficient for bedrooms, mainly

because of its southern orientation (see image 85).

Image.82-Lighting analysis Living room-Before and after adding artificial lighting

Image.83-Lighting analysis for Living room

Image.84-Lighting analysis for Bedroom (GF)

Image.85-Lighting analysis for Master Bedroom (FF)

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32 ARC6780 Building Environment Simulation Analysis

Pantry (GF) – Two artificial lamps are provided to improve the ADF of

the pantry which is 2.05% with artificial lighting (see image 86).

Lounge - Average Daylight Factor first floor lounge is 4%.

Kitchen (G.F.) - Average Daylight Factor is 16.57% which is more than the required 2%.The

illuminence varies between 350-550 lux.

Bathroom (G.F.) - Average Daylight Factor is 0.7% for bathrooms in the ground floor.

Image.86-Pantry (GF)

Image.87-Lighting analysis for Lounge (FF)

Image.88-Lighting analysis for Kitchen (GF)

Image.89-Lighting analysis

for Bathroom (GF)

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33 ARC6780 Building Environment Simulation Analysis

Other spaces:

Ground floor lobby-between 90-570 lux First floor bathroom-1% ADF Office/Study-4.23%

The analyses conducted in the eco house helps to understand the illuminence within the house of

various spaces for different sky conditions. As the Eco house is assumed to exist in an open site with no

surrounding obstructions, the overshadowing of surrounding structures has not been taken into

consideration. However, as choosing an overcast sky condition means analysing the lighting levels in a

much restricted scenario, and after achieving the required standards, it can be deduced that the spaces

are adequately lit. The overall consumption of the electric loads due to artificial lamps will be discussed

under resource consumption.

Resource Consumption:

The resource consumption calculation is essential in understanding how much energy is consumed by

the building in order to maintain comfort and achieve everyday activity. Resources include electricity,

water, gas, petrol, diesel and oils. At the moment, only solar collection and water are considered as

production resources (Ecotect Help).

To supplement the load of the HVAC system and the electric loads, photovoltaic panels are added. The

system chosen is a mixed mode system with 100% efficiency. The maximum heating is required in

January. The monthly heating loads (see image 88) indicate that 29 38 0136 Wh is required for heating

and 12 57 9360Wh load is consumed by electricity (appliances, light fixtures). To reduce the impact on

Image.90 -Lighting analysis for Bathroom (GF)

Image.91 (a), (b), (c) -Lighting analysis for other spaces

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34 ARC6780 Building Environment Simulation Analysis

the environment, Compact fluorescent lamps are suggested, which are energy efficient as compared to

ordinary lamps. A 40 Watt lamp (specified for lamps in the project) generates same illuminence as a 150

Watts ordinary lamp. Hence, more energy can be conserved.

The image below illustrates the monthly heating loads consumed by the building. During winters 29 38

0136Wh of heating is required by the building. The maximum head loads consumed is 12 0976 W at

19:00 on 4th February.

Photovoltaic cells are used to generate energy and supplement the loads of the building. The panels

occupy a total area of 80.4 m2. According to the formula Optimum angle (in degrees) = (your latitude x 0.9) + 29, the

optimum orientation for solar panels mounting is 70⁰ tilt towards the southern direction. The solar panels

will be placed on the sloped roof. The efficiency of the solar collectors was set 100% for efficiency and

100% for space heating efficacy. During the summers, when there is maximum sunshine, the solar panels

can collect 16 14 7293 Wh of energy which is roughly a third of the energy consumption of the building.

When part of the resources is derived from renewable sources, the Eco house is closer to attaining a low

energy standard. The graphs below describe the solar energy generation (16 14 7293 Wh) and the loads

generated within this building is (29 38 0136 Wh). The size of each panel is 0.9x0.95 m.

Image.92 –Resource

Consumption- Daily Energy Use

Image.93 –Monthly Heating loads

Image.95 –Total Energy Collected Image.94 –Resource usage- Hourly Electrical Usage

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35 ARC6780 Building Environment Simulation Analysis

Potential Renewable Energy Sources:

.

As Montreal receives very less sunshine during

peak winters and the hazard of snow accumulation

on rooftops cannot be ignored, the Eco house will

have to depend on an alternate source of

renewable energy as well. Apart from the solar

panels which can cater to the electric loads of the

building, the Eco house will rely on the potential

of the wind to generate electricity by providing

wind turbines. From the charts below the

character of the winds can be determined. The

direction of the prevailing breeze is south west.

The highest temperature that the wind achieves is

around 20⁰C. A building mounted wind turbine is

around 1-2kW in size, much smaller than pole

mounted wind turbines. A 6kW turbine is capable

of generating around 10,000kWh per year. For the

Eco house in Montreal, around 300 kW will be

generated with a 2kW size of Turbine placed on

the roof (Energy Savings Trust, 2012). This will

supplement the power requirements of the Eco

house.

Image.96 –Daily Load Matching Image.97 –Solar panels placed on roof

Image.98 –Annual Wind Analysis

Image.99 –Wind Turbine Operation

www.windenergy7.com (online).

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36 ARC6780 Building Environment Simulation Analysis

DETAILED COMPARISON

FACTORS Eco house- India Eco house- Canada

Climate Composite- warm humid summers, cold

winters

Humid Continental- cold most of the

time

Climatic discomfort Overheating in summers, excess solar

ingress, cool winters

Too cold

Building orientation East west- to avoid harsh summer sun East-west- to gain solar ingress from

south face.

Building parameters

Total Building area 724.168 m2 531.345 m

2

Total opaque exposed surface area 869.880 m2 450.349 m

2

Total glazing area 42.590 m2 92.818 m

2

Materials

Walls External- Brick Cavity Wall

Internal-Brick plaster

External- Timber clad hollow masonry

Internal-Brick plaster

Floors Concrete slab with tiles, insulation

provided

Suspended Timber carpeted floor

Roofs Suspended concrete Ceiling with

insulation provided

Clay tiled sloped roof with insulation

Glazing Double Low E glass with aluminium

frame.

Double Glazed with timber frame

Thermal Analysis-Hottest day Average

Average temperature achieved 24.4⁰C 20.6⁰C

Heat Flow(Fabric) 11 0404Wh 17 2716Wh

Heat flow(Glazing) 3 2425 Wh 4 8730Wh

By HVAC 50 3250Wh 0

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37 ARC6780 Building Environment Simulation Analysis

Thermal Analysis-Coldest day Average

Average temperature achieved 13⁰C 18⁰C

Heat Flow(Fabric) -8 7800 Wh -1 56 5614Wh

Heat flow(Glazing) 3 0235 Wh 19 033 Wh

By HVAC 11 1472 Wh 56 3080 Wh

Building Design

Passive Techniques Thermal mass of walls, Stack effect Greenhouse

Ventilation Cross ventilation in living spaces Well sealed envelope.

System adopted Mixed Modal system-95% Heating only-100%

Shading External Sun shades an internal blinds -

Energy

Needed by HVAC 3 55 7304 Wh - heating

17 14 0620Wh – cooling

29 38 0136 Wh

Electricity 15 01 8696 Wh 12 57 9360Wh

Solar collected 19 84 1492 Wh 16 14 7293 Wh

Collection point and area Roof- 70.7 m2 On sloped roof- 80.4 m

2

Potential renewable Energy Source

To Supplement the loads of the

building

Solar panels

Hydroelectric power

Solar Panels

Wind Turbine

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38 ARC6780 Building Environment Simulation Analysis

Conclusion:

The performance of the Eco house was analysed in two different climatic conditions. By

understanding the climate of each location, the behaviour of the entire building in response to the

climate was known. Then appropriate solutions were suggested to achieve the standards of thermal and

lighting. In order to make the building more energy efficient and consume lesser energy for operation,

alternate energy sources were recommended from renewable sources like the sun and the wind.

By understanding the demands that climate makes on the building, appropriate solutions were

made. For example, the Eco house in New Delhi, was sensitive to the maximum solar ingress from the

west direction and hence the building was oriented to curb excess soar ingress. Also considering the

impact of increased humidity in the home, cross ventilation was suggested. The heavy thermal mass of

the walls with its cavity and insulation prevents the ingress of heat in summers and at the same time

brings in the heat during the winters by slowly dissipating it into the interiors. The southern surfaces also

help to keep the building warm during winters but tend to accumulate heat during summers and hence a

lawn is proposed in front of the living room on the South, to disintegrate the solar rays.

In Montreal, the northern side receives lesser sunshine and hence the spaces are rearranged in

such a way that only the bedrooms are on the north side. As more heat losses occur from the northern

side, the size of the openings is reduced in the north side. Also to avoid the impact of the harsh breeze

from the south west direction, suitable planting of conifers and deciduous trees in the western side will

significantly help maintain comfortable interior conditions. The materials on the building envelope also

help considerably in achieving thermal comfort.

To achieve the best practice of construction, the U value standards were consulted and then

appropriate choice of materials that attain those target values were selected. By understanding the

properties of these materials and how low U values can prevent heat transfer into interiors and at the

same time even prevent heat losses, it was possible to maintain optimum comfort in the interiors.

Further, the choice of material is also governed by the context and easy availability in a particular

region. For example the abundance in oak wood in Canada, was related to specifying it as a façade

material.

Lighting analysis for India proved that all spaces were adequately lit naturally during daytime. In

Montreal, the rooms in the north required certain alterations to meet adequate standards. Further,

artificial low energy CFLs were suggested to achieve adequate illuminence. Since winters in Montreal

receive lesser sunshine especially the facades, it is wiser to provide skylights on the roof to cater to

natural lighting. Since, New Delhi suffers from excess glare of sun in the evenings in summers and the

high solar incidence, it is better to provide illumination by shaded windows on the wall surfaces instead

of skylight.

It is always better for a building to derive benefits from the passive environmental system for

heating and cooling systems. By doing this the building will depend less on mechanical methods of

achieving comfort. Having done the analysis for both thermal and lighting, and proposing relevant

solutions, the performance of the building and its loads will help realise how energy efficient the Eco

house is.

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39 ARC6780 Building Environment Simulation Analysis

References:

• CIBSE concise handbook / [Chartered Institution of Building Services Engineers,(2001), London

• Energy Savings Trust.(2012). Available at http://www.energysavingtrust.org.uk/Generate-your-

own-energy/Wind-turbines. (Accessed on 22/12/2012).

• Green Building Guide.(2012) Available at http://www.greenbuildingadvisor.com/green-

basics/structure-exterior-walls. (Accessed on 22/01/2012).

• Indian Green Building Council.(2012) Available at http://www.igbc.in/site/igbc . (Accessed on

22/01/2012).

• McMullan, R. (2002) Environmental Science in Building. 6th Edition. United States, Palgrave.

• Natural Frequency. Ecotect Community (1994 - 2011) Design Sky, available at

http://wiki.naturalfrequency.com/wiki/Design_Sky. (Accessed on 22/01/2012)

• Torcellini,P., Pless, S. et al. (2006) Zero Energy Buildings:A Critical Look at the Definition.

Conference Paper at National renewable Energy Laboratory, Pacific Grove. California.

• Solar panel orientation.(20120. Available at http://24volt.co.uk/info/SolarPanels/Mounting

SolarPanels. (Accessed on 22/01/2012).

• US Department of Energy (2012) available at http://apps1.eere.energy.gov/buildings/energyplus

/cfm/weather_data.cfm

• WIKIPEDIA (2012) New Delhi, India climate available at http://en.wikipedia.org/wiki/Acapulco

(Accessed on 22/01/2012)

• WIKIPEDIA (2012) Montreal, Canada climate at http://en.wikipedia.org/wiki/Rome (Accessed

on 22/01/2012)