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International Journal of Civil Engineering and Technology (IJCIET) Volume 7, Issue 6, November-December 2016, pp. 523–535, Article ID: IJCIET_07_06_058

Available online at http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=7&IType=6

ISSN Print: 0976-6308 and ISSN Online: 0976-6316

© IAEME Publication

PERFORMANCE EVALUATION OF THE DESIGNED

SOLAR PASSIVE ARCHITECTURE INCORPORATED

RESIDENCE IN WARM HUMID CLIMATE

C.V. Subramanian

Associate Professor, Department of Architecture, Periyar Maniammai University, Tamilnadu, India

N. Ramachandran

Professor, Department of Architecture, Periyar Maniammai University, Tamilnadu, India

S. Senthamil Kumar

Professor, Department of Civil Engineering, Periyar Maniammai University, Tamilnadu, India

ABSTRACT

The modern day construction practice depends much on electromechanically devices for

thermal comfort of the buildings increasing the demand for already fast depleting energy

resources. The solar passive architecture concepts incorporated in the design of the building uses

minimum or no energy for keeping the building comfortable naturally. So, an attempt has been

made by constructing a modern building using solar passive architecture techniques in Thanjavur,

Tamilnadu for warm-humid climate. Performance evaluation of the designed building is studied

during the peak summer during the month of May and peak winter during the month of December.

During summer and winter, the air temperature inside the building ranges from 24.6 to 30.8˚ C and

relative humidity ranges from 46 to 74%. It is found that the building is well within the thermal

comfort as predicted by Tropical Summer Index & National Building Code of India Standards and

bioclimatic chart. The analysis shows that thermal comfort model as suggested by Humphreys and

Nicol (2000) is the model of best fit for the designed building. It is also evident from the analysis

that the naturally ventilated building with solar passive architecture provides a thermally

comfortable environment during summer and winter seasons.

Key words: Bioclimatic chart, Solar passive architecture, Summer and winter, Thermal comfort

model, Warm-humid climate.

Cite this Article: C.V. Subramanian, N. Ramachandran and S. Senthamil Kumar, Performance

Evaluation of the Designed Solar Passive Architecture Incorporated Residence in Warm Humid

Climate. International Journal of Civil Engineering and Technology, 7(6), 2016, pp.523–535.

http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=7&IType=6

1. INTRODUCTION

The modern day building construction is not giving importance to climate conscious design measures and

solar passive architecture techniques. The buildings of modern style use electromechanical devices such as

fan, air coolers or air-conditioners to achieve the required indoor thermal comfort. This results in high

energy utilization that leads to global warming.

Performance Evaluation of the Designed Solar Passive Architecture Incorporated Residence in

Warm Humid Climate


On contrast, traditional architecture has close linkages to nature, climate conscious designs with greater

adaptability to climate and hence the comfort zone is wider. Qualitative and quantitative analysis carried

out on traditional buildings to assess the passive environment control designs have proved that traditional

architecture has provided a comfortable indoor environment even during summer which is considered to be

the most unpleasant time of the year [1-5].

Solar Passive Design (SPD) strategy varies according to climatic conditions. These designs help to

achieve energy efficiency and thermal comfort by using natural energy sources and techniques. Such

passive and low energy climate responsive buildings can improve human comfort and human condition in

all parts of the world [6]. SPD features are employed since Indus valley civilization. Climate responsive

design techniques employed in the houses of Mohenjo-daro and Harappa are historical examples for the

present day designers to design houses comfortable for living [7]. Such energy efficient designs provide

comfortable and healthy indoor environment apart from reducing the environmental impact of buildings

moving towards sustainable habitat.

In the modern building construction, with the restrictions available in the site and existing bye laws and

regulations, people tend to make use of the site economically with the modern materials available at

reasonable cost without any consideration for energy efficiency. Hence architects, engineers and other

building designers should focus on the ways and means to increase thermal comfort by incorporating solar

passive architecture techniques in the contemporary houses designed with an aim to demonstrate the

technologies needed for sustainable house design [8, 9].

Literature survey reveals that no attempt has been made so far in Thanjavur district, Tamilnadu, to

construct a modern residential building with SPD strategies. So, a modern style house is constructed

incorporating solar passive architecture principles in Thanjavur district, Tamilnadu and the performance of

the designed building is evaluated during peak summer and winter in the month of May & December

respectively. The main objective of the study is to evaluate the importance and outcome of incorporating

SPD strategies to achieve thermal comfort.

2. MATERIALS AND METHODS

2.1. Area of Study

Figure 1 Location showing Thanjavur

C.V. Subramanian, N. Ramachandran and S. Senthamil Kumar


The site is geographically located at 10.75˚ N, 79.10˚ E in Thanjavur, Tamilnadu. Thanjavur is located

in Cauvery delta region, about 320 kilometers from the state capital Chennai and 56 kilometers from

Tiruchirapalli. The city falls under warm and humid climate zone as per the classification of National

Building Code (NBC) of India 2005 [8-10]. The city has an elevation of 57 metres above mean sea level.

The mean maximum temperature is 37.48˚ C during May - July with maximum temperature at times

exceeding 40˚ C. Similarly the mean minimum temperature is 20.82˚ C during November – January [11].

The monthly mean temperature for the hottest month May is 32.2˚ C and for the coolest month December

is 24.6˚ C [12]. The location of Thanjavur is shown in Fig. 1.

2.3. Orientation and Planning

Site area available for construction of residence is 3200 sq. ft. The site is north facing with a slight tilt of

20˚ in which the modern style house of size 55’x33’ is constructed. The orientation is little away from the

climatic recommendations due to site limitations. The building plan is arrived based on golden ratio 1:1.6.

The golden rectangle of size 55’x33’ forms the overall plan layout. The building plan is inward looking as

in the traditional courtyard houses both for the climatic reasons and privacy. Simplicity and minimalism in

forms are planned in design. Proper care is taken to locate buffer spaces, shading devices, shading trees

and proper fenestrations in the building plan. The plan of the building designed is shown in Fig. 2.

Figure 2 Plan of the designed building

2.4. Design of the Building

The building is designed with main door openings on the central axis facing North and South directions.

During the construction process, shallow foundation is used according to the soil condition. Framed

structure with columns, beams and concrete slabs with 12cm are used in construction. Exterior 9” thick

brick walls and internal partition 4.5” thick brick walls are used for construction. Vitrified tiles are used for

flooring. Tinted glasses with timber frames are used for windows of size 4’x5’ or 4’x3’ as per the positions

shown in the plan of the building. Floor to roof height of 10’ is followed. Living room is raised to double

floor height of 18’. The mezzanine floor introduced adjacent to living room is diagonally connected with

the dining space located in the ground floor. Courtyard, shading device projection, toilet spaces and


Warm Humid Climate


external staircase act as buffer spaces along east and west directions protecting habitable rooms. The front

view of the designed building is shown in Fig. 3.

Earth sheltered thermal mass of around 4000 cubic feet of soil is filled below the building up to plinth

which has a capacity to retain the coolness inside the building during varied thermal conditions of outdoor.

This can contribute coolness inside the building during day time.

Figure 3 Front view of the designed building

For warm and humid climate, the design approach for SPA incorporated house should have 3 major

focuses:

• Avoid heating of the building elements to reduce cooling demand.

• Promote adequate ventilation / heat loss.

• Maximise the usage of daylight to reduce artificial lighting demand.

Towards the aim of achieving thermal comfort, various Solar Passive Architecture design features

incorporated in the design of the building are:

• Courtyard design and stack effect

• Atrium design / Solar chimney effect

• Nocturnal radiation effect

• Heat reflecting roofing tiles

• Roof level ventilators and high ceiling

• Shading elements

• Landscaping for microclimate

• Light coloured building exterior

• Day lighting

2.4.1. Courtyard Design and Stack Effect

Courtyard is an unroofed area that is partially or completely enclosed by walls of building. A courtyard of

size 3’ x 10’ is designed on the eastern part of the house as shown in Fig. 4.



Figure 4 View of buffer courtyard with dry garden in the designed house

This courtyard is the main source of energy providing better ventilation, lighting and thermal comfort

as it acts as a buffer space avoiding heat gain on the wall exposed to solar radiations. This narrow

courtyard allows view of sky making a perfect blend with nature allowing rain water inside. The rain water

is drained through the sunken pebble bed. The hot air rises up through the narrow courtyard due to heat

convection. When this stack effect takes place, a low pressure is created, which helps to draw more cool air

inside the building through the openings.

2.4.2. Atrium Design / Solar Chimney Effect

A covered courtyard cum atrium space of size 1m x 2m is designed in the central part of the house as

shown in Fig. 5. It is elevated to 6’ and is covered with translucent roofing sheet with adequate space

below for ventilation and day lighting. Since the atrium covered with translucent roofing sheet is at an

elevated level, the air heated just below roofing sheet exhausts out through the ventilator gaps. It creates a

stack effect pulling the air from room within and below. Air rushes through roof level ventilators designed.

Figure 5 View of the atrium cum solar chimney


Warm Humid Climate


2.4.3. Nocturnal Radiation Effect

The heat absorbed throughout the day is radiated out through the courtyard during the night. The courtyard

acts like a thermostat which can control the temperature inside the house. The inward looking plan

focusing towards the courtyard enables ventilation and light entering the house throughout the day.

Nocturnal cooling takes place as displacement ventilation with the connectivity of atrium opening at the

top of high ceiling towards the narrow courtyard at lower level.

2.4.4. Heat Reflecting Roofing Tiles

Figure 6 Heat reflecting roofing tiles

Light coloured roofs have Solar Reflectance Index (SRI) of 50% or more. Dark coloured weathering

roofing tiles have SRI in the range of 5 to 20%. Cool roofs with high emissivity can remain at a

temperature 10-16˚ C lesser than other roofs [13]. Hence white roofing tiles with high reflectance are used

in the present building instead of weathering course and are shown in Fig. 6. This reflects the heat radiation

back thereby minimizing the heat gain into the building through roof.

2.4.5. Roof Level Ventilators and High Ceiling

Figure 7 Roof level ventilators



From the literature study it is inferred that a drop of 10

C can be obtained for each 20cm increase in

ceiling height. High ceilings also provide more volume of spaces in which stratification of air provides the

occupants to use the cooler lower levels [14, 15]. Roof level ventilator of size 2’ x 5’ as shown in Fig. 7

and vented skylight are provided along with high ceiling. This acts as an opening for hot air to escape out

through buoyancy ventilation strategy. This augments the air flow through the openings provided just

below the translucent roofing sheets by stack effect.

2.4.6. Shading Elements

Figure 8 Side view of the designed building

The building plan has a slight tilt though it is facing north. On the North West direction and South East

direction, roof overhangs completely shade the walls apart from shading devices for all other fenestrations.

The side view of the designed building is shown in Fig. 8, which shows roof projection at the front and

other shading devices.

2.4.7. Microclimate through Landscaping

Figure 9 Front lawn of the building


Warm Humid Climate


In the designed building, trees and plants are used to shade South East walls and North West walls.

Shrubs and creepers are used as ground cover in the front lawn which reduces heat generation from

concrete surfaces and barren land. Thus, landscaping enhances the microclimate of the site condition. The

front lawn of the building is shown in Fig. 9.

2.4.8. Light Coloured Building Exterior

The external finish of the building envelope determines the amount of heat gain. A smooth and light

coloured surface finish reflects more light and heat as compared to any other coloured building. So, the

building exterior is coloured white due to its high emissivity and reflectivity. The building interior surfaces

are also coloured white so as to provide good daylight inside the building.

2.4.9. Day Lighting

The building is designed in a way that daylight is ensured everywhere inside the residence in order to

reduce artificial lighting. This can save power and reduce the exploring energy demand. Windows in all

habitable rooms, Courtyard and atrium satisfies the daylight requirement in the designed building. The

depth of the building from the openings is kept as minimum for adequate daylight to penetrate inside the

building. Fig. 10 shows day lighting inside the building.

Figure 10 Day lighting inside the building

The measurements taken in all the rooms have proved that lighting level of minimum 100-260 lux

exists in all the habitable areas of the house throughout the day avoiding any artificial lights both in

summer and winter.

3. PERFORMANCE ANALYSIS OF THE DESIGNED BUILDING

To analyse the thermal performance of the designed building, temperature, relative humidity, air velocity,

day lighting and solar radiations are measured on hourly basis during summer and winter in months of

May and December respectively.



3.1. Instrumentation and Methods

The study is carried out in living cum dining area as this space of the house is utilized maximum.

Calibrated HTC data logger is used to monitor outdoor temperature, indoor temperature and relative

humidity. The indoor and outdoor air velocities are measured using the anemometer MASTECH

MS6252B. A solar meter TES 1333 is used to measure the solar radiations of the location. The day lighting

is measured using HTC LUX meter [16].

The thermal comfort conditions given in National Building Code (NBC) of India are based on

ASHRAE & Tropical Summer Index (TSI). According to NBC 2005, the thermal comfort limit of a person

ranges from 25º C to 30º C. The comfortable indoor relative humidity ranges from 40% to 70% and the

comfortable indoor air flow is in the range of 0-2 m/s. According to TSI, temperature between 30º C and

34º C is classified as comfortably warm which can be managed with sensible air movement of 1.5m/s

[6,17,18].

3.2. Performance and Analysis of the Designed Building in Summer

The performance of the designed building is studied during peak summer in the month of May. From the

study it is observed that the ambient outdoor temperature varies from 23º C to 38.2º C with a diurnal swing

of 15.2º C. During the study period, the solar radiation is found to vary from 470 W/m2 to 1280 W/m

2 with

10 hours of sunshine each day.

Indoor air temperature in the designed building corresponding to ambient outdoor temperature during

summer season is shown in Fig. 11. The indoor room temperature of the designed building ranges from

27.4º C - 30.8º C showing a diurnal variation of 3.4º C. The relative humidity of the outdoor varies from

41.9% to 89.3% whereas the relative humidity inside the building ranges from 46.4% to 74% during the

study period. The indoor air temperature of the modern building designed with SPD is observed to be

much lower than the outdoor temperature

Figure 11 Indoor air temperatures in the designed building corresponding to ambient outdoor temperature during

summer

Variation of relative humidity inside the designed building and outdoor during summer season is

shown in Fig. 12. When outdoor temperature drops down and humidity raises very high, adequate comfort

is attained in the designed building. This is due to the solar passive design features courtyard design and

stack effect, Atrium design / Solar chimney effect, nocturnal radiation effect, Heat reflecting roofing tiles,

Roof level ventilators and high ceiling, Shading elements, Landscaping for microclimate, Light coloured

building exterior incorporated in the building.


Warm Humid Climate


Figure 12 Variation of relative humidity inside the designed building and outdoor during summer

It is also found that indoor air temperature and relative humidity inside the designed building are well

within the comfort zone during summer season according to TSI & NBC (25-30º C). The design of the

building has minimized the use of electromechanical devices thereby contributing to energy conservation.

3.3. Performance and Analysis of the Designed Building in winter

The performance of the designed building is studied during winter in the month of December. Fig. 13

shows the variation of indoor air temperature of the designed building with SPD for corresponding ambient

outdoor temperature. It is observed that the ambient outdoor temperature ranges from 20.8º C to 31.6º C

with a diurnal swing of 10.8º C. Solar insolation varies from 180 W/m2 to 755 W/m

2 during the study

period. In the designed building, the indoor room temperature varies from 24.6º C to 27.1º C showing

diurnal variation of 2.5º C. The graph shows that the indoor air temperature of the modern building

designed with SPD is well within the comfort zone during winter season according to TSI & NBC

standards (25-30º C).

Figure 13 Variation of air temperature inside the designed building for the ambient outdoor temperature during

winter



Fig. 14 shows the relative humidity of the designed building with SPD for the corresponding outdoor

relative humidity during winter. The relative humidity of the outdoor varies from 45% to 98% during the

study period. By incorporating SPD aspects the designed building brings down the relative humidity which

ranges from 61% to 70.7%. This is also well within the comfort zone during winter season according to

TSI & NBC standards.

Figure 14 Relative humidity of the designed building with SPD for the outdoor relative humidity in winter

Thermal comfort is attributed due to solar passive design incorporated in the building which helps to

maintain the required indoor air temperature and relative humidity.. The occupants in the designed house

with SPD are comfortable even without electrical gadgets during winter. This helps in saving energy

consumption which is the need of the hour.

3.4. Comfort Zone using Bioclimatic Chart

Bioclimatic chart developed by V Olgyay [19] can be used as a tool for analyzing the performance of the

building. The chart helps to locate the comfort zone using dry bulb temperature and relative humidity. The

mean maximum and minimum temperature during the study period and its corresponding relative humidity

are marked on the chart for both summer and winter which is shown in Fig. 15.

It is observed that the thermal comfort parameters lie within the comfort zone for the designed building

in both summer and winter. This ensures the proper design of the building.

Figure 15 Bioclimatic charts for the designed building for summer and winter [19].


Warm Humid Climate


3.5. Thermal Comfort Models

Various thermal comfort models have been proposed to predict the comfortable indoor temperature based

on the monthly mean temperature. The monthly mean temperature To for Thanjavur during the month of

May and December are 32.2 ºC and 24.6 ºC respectively [12]. Comfortable temperature for the designed

building during summer and winter has been calculated for different models and is given in Table 1

Table 1 Thermal comfort models and the predicted comfort temperature [6, 20-24]

No. Thermal comfort models Model Equation

Predicted Comfortable

temperature (ºC)

Summer Winter

1 Humphreys (1978) Tc = 12.1 + 0.53 To 29.17 25.14

2 Nicol and Roaf (1994) Tc = 17.0 + 0.38 To 29.24 26.35

3 Auliciems and de Dear (1978) Tc = 17.6 + 0.31 To 27.58 25.23

4 Humphreys and Nicol (2000) Tc = 13.5 + 0.54 To 30.88 26.78

The observed indoor temperature in the building ranges between 27.4º C and 30.8º C during summer

and from 24.6º C to 27.1º C during winter which is close to the predicted value for all the models.

Observations show that model proposed by Humphreys and Nicol (2000) is most suitable than other

models for the designed building.

4. CONCLUSION

A modern residence has been constructed with solar passive designs such as courtyard, atrium, roof level

ventilators, light coloured exterior, reflective white coloured roofing tiles, landscaping, shading and buffer

spaces in Thanjavur district and the thermal comfort in the building is studied during summer and winter. It

should be noted that the techniques used are highly site specific and climate specific. The study proves that

the temperature and relative humidity are well within the comfortable limits ranging very close from 25-30

º C for both the seasons as per TSI and NBC standards. Bioclimatic chart also indicates that the parameters

of designed building lie in the comfortable zone. Different thermal comfort models are studied and it is

found that the predicted comfortable temperature given by Humphreys and Nicol (2000) is the best fit for

the building under study.

Thus, coupling of techniques adopted in traditional buildings into the present day constructions with

available modern materials will certainly be an example towards sustainable development. The results will

certainly be an eye opener for Architects and Engineers to adopt solar passive designs in modern

constructions and also to modify and retrofit in already executed modern buildings to make it climate

responsive to achieve energy efficiency and comfortable.

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PERFORMANCE EVALUATION OF THE DESIGNED SOLAR … › MasterAdmin › UploadFolder › IJCIET_07_06_058 › ... · 2016-12-29 · model, Warm-humid climate. Cite this Article: C.V