An adaptive thermal comfort model for hot humid South-East Asia

in Building & Environment (2012), 56

The present paper presents a full procedure to develop an adaptive comfort model for South-East Asia. Meta-analysis on large number of observations from field surveys which were conducted in this region ... [more ▼]

The present paper presents a full procedure to develop an adaptive comfort model for South-East Asia. Meta-analysis on large number of observations from field surveys which were conducted in this region was employed. Standardization and bias control of the database were fully reported. Statistical tests of significance and weighted regression method applied in the analyses strengthened the reliability of the findings. This paper found a great influence of ‘Griffiths constant’ on the establishment of adaptive comfort equation and proposed an appropriate value. The adaptive comfort model generated is applicable to naturally ventilated building under hot and humid conditions of South-East Asia. The mean neutral comfort temperature (operative temperature, effective temperature, standard effective temperature) in naturally ventilated and air-conditioned building was compared and the differences have been discussed. The similar neutral standard effective temperature in both naturally ventilated and air-conditioned building proposes a new idea to implement SET* into building simulation tools to assess thermal comfort without the attention of building classification. Through the analysis, the effectiveness of behavioral adaptive actions on occupant’s thermal perception has been argued. The extended PMV-PPD model for hot humid conditions was examined and its applicability was recommended. Other comfort related issues, the differences and similarities between various adaptive comfort models were also addressed. [less ▲]

THERMAL ACCEPTABILITY ASSESSMENT IN VERNACULAR BUILDINGS OF COLD AND CLOUDY REGION OF NORTH-EAST INDIA

in 30th ISES Biennial Solar World Congress 2011, SWC 2011 (2011, September 02)

Thermal performance study is one of the critical aspects of the natural ventilated vernacular buildings. Thermal comfort studies of built environment mainly focussed on two different approaches, one is ... [more ▼]

Thermal performance study is one of the critical aspects of the natural ventilated vernacular buildings. Thermal comfort studies of built environment mainly focussed on two different approaches, one is heat balance approach and the other is adaptive approach. Thermal comfort survey has been carried out in 50 houses covering over 100 occupants of cold and cloudy climatic zone of North East India. This comfort study has been done in the form of long term thermal monitoring at outside and inside of a house, comfort survey based on ASHRAE thermal sensation scale for different seasons of the year. Comfort temperatures are calculated based on Humphreys and Auliciems comfort model. Neutral temperatures at which people feels comfortable in this natural ventilate buildings are obtained from the comfort survey. It has been found that the comfort temperature obtained from the Humphreys and Auliciems comfort model differs with the neutral temperatures obtained from comfort surevy. There are four major indicator like outdoor and indoor temperatures, relative humidity and clothing pattern of the peoples has direct impact on the peoples perception and acceptabilty on comfort situtaion. In this study, thermal comfort equations are developed based on these four indicator and validated with the neutral temperature obtained from comfort survey. It has been found that the comfort equation developed with all these four indicators has highest co-relation coefficient and provide the neutral temparture values very close to thermal comfort survey results. However, these equations are valid only for similar kinds of natural ventilated buildings and also for similar kinds of building functioning management of this climatic zones. It is also not appropriate to obtaine a genralized thermal comfort model as the adpation process and the expectation and perceptation of the peoples are region specific and also differs with socio-cultural norms. [less ▲]

Adaptive thermal comfort model for different climatic zones of North-East India

in Applied Energy (2011), 88(7), 2420-2428

Thermal comfort standards ISO 7730 and ASHRAE 55-2004 are based on the experimental results conducted in climatic chambers and the adaptive opportunities are usually limited in these experiments. However ... [more ▼]

Thermal comfort standards ISO 7730 and ASHRAE 55-2004 are based on the experimental results conducted in climatic chambers and the adaptive opportunities are usually limited in these experiments. However, in naturally ventilated buildings, adaptive opportunities are not fixed and occupants always have the liberty to modify the opportunities in order to feel comfortable. A comfort survey has been carried out in three different climatic zones of North-East India in four different seasons of a year. Climatic parameters corresponding to actual mean vote (AMV) are recorded during the survey and the values are used to calculate the predicted mean vote (PMV) using ISO 7730 calculation procedures. Results show that the PMV deviates from AMV values. A corrective term ‘adaptive coefficient’ is calculated based on PMV and AMV values and least square method to assess the different adaption used for thermal comfort. Theoretical adaptive models of thermal comfort have been developed based on these adaptive coefficients for the region. The adaptive coefficient values are varying for different seasons and also for different climatic zones. This reflects the various levels of adaptation in different seasons in a particular climatic zone. This adaptive coefficient can be used as a reference to thermal comfort assessment of the buildings and also can be used as dynamic control of the set temperature in the air conditioning system, which will results enormous energy saving. Result of this study also contributes towards the debate over the applicability of PMV model to naturally ventilated building. [less ▲]

Thermal performance study and evaluation of comfort temperatures in vernacular buildings of North-East India

in Building & Environment (2010), 45(2),

Solar passive techniques are being used in vernacular buildings throughout the world. Researchers have done extensive study on thermal performance of vernacular buildings in the different parts of the ... [more ▼]

Solar passive techniques are being used in vernacular buildings throughout the world. Researchers have done extensive study on thermal performance of vernacular buildings in the different parts of the world. Vernacular architecture of North-Eastern India represents the principle of climate-responsive architecture, which still lacks experimental validation and quantitative analysis. Thermal comfort not only makes the occupants comfortable but also governs energy consumption in the building. Detailed field studies on thermal performances of typical traditional vernacular dwellings in different bioclimatic zones have been undertaken. This field study includes detailed survey of 150 vernacular dwellings, field tests and thermal sensation vote of 300 occupants on ASHRAE thermal sensation scale. Field test includes measurement of temperature, humidity, illumination level and building design parameters. Thermal performances of these vernacular dwellings were evaluated for winter, pre-summer, summer/monsoon and pre-winter months of the year 2008. This evaluation is based on ‘adaptive approach’, which is the outcome of the field studies and is now part of ASHRAE standard 55/2004 for predicting comfortable temperature of naturally ventilated buildings. This study also tried to find out the range of comfort temperature in these vernacular buildings for different season of the year. It has been found that these vernacular dwellings perform quite satisfactorily except in the winter months and the occupants feel comfortable in a wider range of temperature. [less ▲]

Bioclimatism and vernaculat architecture of North East India

in Building & Environment (2009), 44(2), 878-888

Vernacular architecture based on bioclimatism concepts was developed and used through the centuries by many civilizations across the world. Different civilizations have produced their own architectural ... [more ▼]

Vernacular architecture based on bioclimatism concepts was developed and used through the centuries by many civilizations across the world. Different civilizations have produced their own architectural styles based on the local conditions. This study is carried out on the vernacular buildings of north-east India across all the bioclimatic zones. A survey of 42 houses, more than 70 years old was carried out at representative locations across all bioclimatic zones. The study has yielded findings relating bioclimatism, socio-economic status and cultural setup to the vernacular architecture of the region. Also, different solar passive features are available in most of these houses, related to temperature control and promoting natural ventilation. These houses are constructed using locally available materials like wood, cane, bamboo, stone, mud, jute, lime and represent unique examples towards sustainable building design. [less ▲]

Comfort Status in Naturally Ventilated Buildings of North-East India

Scientific conference (2008, December 11)

A field study has been carried out to evaluate the thermal comfort perception of the occupants in naturally ventilated buildings at different bioclimatic zones of North-East India. The survey also ... [more ▼]

A field study has been carried out to evaluate the thermal comfort perception of the occupants in naturally ventilated buildings at different bioclimatic zones of North-East India. The survey also examined the adaptive behavior of the occupants in the usage of climatic control such as windows and fans to modify the indoor environment. The survey was performed in naturally ventilated buildings during the winter, pre-summer season in 2008. There were 220 occupants from 75 vernacular buildings who participated in this study and 200 questionnaire responses were collected. This study is primarily concerns on human thermal comfort from the physiological, adaptive and social convention aspects. The data collected include temperature, humidity and lighting level, as well as results from questionnaires on the occupant’s sensations of thermal comfort. This study also looks into the occupants social and cultural requirements in the vernacular buildings. Thermal acceptability assessment reveals that the indoor environment in naturally ventilated buildings are widely varied across the three bio-climatic zones and also influenced by visual, social and cultural aspects of respective zones. The upper and lower range of acceptable temperatures in naturally ventilated buildings is varied by 2 0C from neutral vote for each climate zone in both winter and pre-summer. The study also attempts to define the comfort status and suggestions are made to improve the comfort status in naturally ventilated buildings of the region. [less ▲]

Climate-responsive Building Design in North-East India

in Emerging trends in Energy Efficiency Opportunities and challenges (2008, October 17)

Energy, environment and architecture are closely related, the more is the energy consumption the worse is the environmental degradation. With rapid economic growth and improvement in people’s living ... [more ▼]

Energy, environment and architecture are closely related, the more is the energy consumption the worse is the environmental degradation. With rapid economic growth and improvement in people’s living standard, the building sector will continue to be the key energy end user. Hence energy conservation becomes a necessity rather than an option in both commercial and residential buildings and hence it becomes desirable to design climate responsive buildings by incorporating appropriate solar passive features. Climate responsive building design is a concept that integrates the micro-climate and architecture with human thermal comfort conditions. This concept takes into account the solar passive techniques, micro-climatic conditions and thermal comfort conditions that improve the building artificial energy efficiency. This fact is well supported by various studies on vernacular architecture as well as on modern architecture throughout the world. Thermal comfort not only makes the occupants comfortable but also decides the energy consumption in the building and thus its sustainability. Throughout the world, from ancient times people have used solar passive techniques that have evolved through generations. These structures got attention for detailed study among the researchers at present times. Different researchers had done extensive study on thermal performance of vernacular buildings in the different parts of the world. However, vernacular architecture of North-Eastern India which perfectly represents the principle of climate-oriented architecture still lacks experimental validation and quantitative analysis. A field study has been carried out to evaluate the thermal comfort perception of the occupants in naturally ventilated buildings at different bioclimatic zones of North-East India. The survey was performed in naturally ventilated buildings during the winter, pre-summer season in 2008. There were 220 occupants from 75 vernacular buildings who participated in this study and 200 questionnaire responses were collected. The data collected include temperature, humidity and lighting level, as well as results from questionnaires on the occupant’s sensations of thermal comfort. We came across some interesting findings related to bioclimatism, socio-economic status, cultural setup and sustainability in this vernacular architecture. We also found different solar passive features available in most of these houses related to temperature control and promotion of natural ventilation. These houses are constructed using locally available building materials. Since these materials have low embodied energy and are from the same climatic zone. Henceforth, they fit into the local environment perfectly and represent a unique example towards achieving sustainability. [less ▲]

Bio-Climatic Chart for Different Climatic Zones of North-East India

in S K, Dube; T, Muneer; G N, Tiwari (Eds.) et al Proceedings of 3rd International Conference on Solar Radiation and Day Lighting : (SOLARIS 2007) (2007, February)

This article examines and analyses the climates of Northeast India with respect to building design parameters: temperature, relative humidity, wind velocity/direction and solar radiation, with a view to ... [more ▼]

This article examines and analyses the climates of Northeast India with respect to building design parameters: temperature, relative humidity, wind velocity/direction and solar radiation, with a view to providing passive solar design potential for the achievement of physiological comfort. It presents the work on development of bio-climatic zones for the region. The major climatic types of the region are warm and humid, cool and humid and cold and cloudy zones. A bio-climatic approach is adopted in which the comfort zone and 12 monthly climatic lines are determined and plotted on the psychrometric chart for each climatic zone. From these bioclimatic charts, the potential use of passive design strategies such as solar heating, natural ventilation, thermal mass, thermal mass with night ventilation and evaporative cooling are assessed. A total of five passive design strategies are considered. It is expected that this study will help in explaining the different passive features, which are present in traditional buildings of the region and also help the architects to design modern climate responsive energy efficient buildings in the region. [less ▲]