Sadhan Mahapatra

ABSTRACT Thermal comfort study provides crucial information about thermal performance of naturally ventilated buildings. Humphreys and Auliciems comfort model uses indoor and outdoor temperatures to predict comfort temperatures. It is found that the comfort temperatures obtained by using these methods do not take into account the occupant behavioral adaptability to a particular climatic zone. This demands development of new set of comfort models based on local environmental parameters, socio-cultural setup and behavioral action. Analysis shows that four major variables like indoor and outdoor temperature, relative humidity and clothing pattern plays an important role in defining comfort and greatly influence the occupant's perception and acceptance on thermal comfort. In this study, comfort models are developed based on these variables. The computed neutral temperatures based on the models are compared with the comfort temperatures obtained through comfort survey. The models are developed using the measured data of January and July months and validated with the measured data of April and October months. This study also concludes that it is not possible to obtain a generalized thermal comfort model for all climatic zone because adaptation process, expectation and perception of people are region specific and governed by local socio-cultural requirement.

Climate responsive building design is determined by the local micro-climate and the ability of the building envelope to regulate the indoor thermal environment. The building envelope characteristics are based on the available/accessible building materials and technology. Studies on vernacular architecture across the world showed that wall configurations and the thermo - physical properties of the building materials are used intelligently to maintain comfortable indoor comfort across the seasonal weather variations. Vernacular buildings of North-East India are naturally ventilated. Hence, it is important to find out an optimum wall configuration which will provide enough time lag, reduced discomfort hours as well as optimum thermal performance of these buildings. Various studies on building simulation/modelling show that building dynamic simulation tool can be effectively used to study the building envelope characteristics. In this study, a typical vernacular building in warm and hum...

Vernacular buildings are evolved through trial and error method over the period of time. These buildings are constructed more on ‘design-based approach’ suited to a particular climatic condition and socio-cultural setup rather than emphasizing technological solutions or prescriptive requirements. However, in recent times, due to quest for better thermal comfort, energy consumption is increasing in these naturally ventilated buildings. So, it is an urgent need to analyse the present level of thermal comfort and the occupant’s expectation in these buildings. In case of design based approach, passive solar design, ventilation, insulation on the building envelope, shading and glazing area, proper orientation of buildings etc. are the key parameters for optimization process. In this study, a vernacular building of warm and humid climatic zone of North-East India is considered. Thermal performance study has been done by carrying out year long measurements of environmental parameters both ...

ABSTRACT The study presents an analysis aimed at choosing between off-grid solar photovoltaic, biomass gasifier based power generation and conventional grid extension for remote village electrification. The model provides a relation between renewable energy systems and the economical distance limit (EDL) from the existing grid point, based on life cycle cost (LCC) analysis, where the LCC of energy for renewable energy systems and grid extension will match. The LCC of energy feed to the village is arrived at by considering grid availability and operating hours of the renewable energy systems. The EDL for the biomass gasifier system of 25 kW capacities is 10.5 km with 6 h of daily operation and grid availability. However, the EDL for a similar 25 kW capacity photovoltaic system is 35 km for the same number of hours of operation and grid availability. The analysis shows that for villages having low load demand situated far away from the existing grid line, biomass gasification based systems are more cost competitive than photovoltaic systems or even compared to grid extension.

Abstract:[en] Energy and Built Environment are closely related, the more is the energy consumption the worse is the environment degradation. The use of natural lighting and the use of solar energy for heating and cooling as well as enhanced natural ventilation not only reduce the commercial energy demand but minimize the impact on environment too. Traditional buildings constructed long back in the different climatic zones of the region have a number of passive features which help in controlling the indoor environment mostly by ...

ABSTRACT This paper is based on the studies made on a numerical model for calculating the turbine characteristics at low tip speed ratio for a Horizontal Axis Wind Turbine. The turbine characteristics are analysed for different configurations over the total operating range ie from tip speed ...

Four out of five people without electricity live in rural areas of developing countries, mainly in South Asia and sub-Saharan Africa. Most of these households use kerosene lamps for lighting. The light outputs of these devices are very poor and vary from about 10 to 100 ...

This paper represents the very basic work of bio-climatic classification of north-east India into warm and humid, cool and humid and cold and cloudy zones. This classification is extremely useful to the building design for wide range of objectives such as climate responsive building design, building energy conservation, thermal comfort, out door design conditions, etc. This classification is based on the meteorological data collected over a period of more than 30 years, from Regional Meteorological Centre, Guwahati, India from ...