(GIST OF YOJANA) GREEN TECHNOLOGIES IN AFFORDABLE HOUSING
GREEN TECHNOLOGIES IN AFFORDABLE HOUSING
Increasing population along with the paid urbanization has led to a
significant shortfall of housing in the country. The housing shortage for
2012-17 is estimated to be 18.78 million units in the urban areas and 43.90
million units in the rural areas (Goyal, 2014; NBO, 2012). The residents in
Lower Income Group (LIG), and Economically Weaker Sections (EWS) are facing more
than 95 percent of the urban housing shortage. Similarly, below poverty line (BPL)
resident are facing more than 90 percent of the rural housing shortage. Hence,
affordable housing has been of the paramount importance to the policy makers of
the country (NHB, 2015).
Over the past decades, India has adopted multiple policies at the central,
state and Urban Local Bodies (ULB) levels to deliver affordable housing to LIG,
EWS, and BPL residents (Sarkar, Dhavalikar, Agrawal, & Morris, 2016). More
recently, Government of India (GOI) proposed several ambitious schemes to
address the housing shortage in the country. They include Housing for all
(Urban) by 2022 Mission, Atal Mission for Rejuventiion and Urban Transformation
(AMRUT), and Smart Cities (Ministry of Housing and Urban Poverty Alleviation
Government of India, 2015; NHB, 2015,
Ministry of New and Renewable Energy (MNRE) offered capital subsidy
incentives for purchase and installation of solar water heating and solar
lighting equipment in house.
Better housing enhances the equality of life of the resident and leads to
higher productivity as well as income generating capabilities. Hence, the
affordable housing design should aim to provide a healthy and comfortable
environment to the residents. The design philosophy of affordable housing should
incorporate key performance metrics such as indoor air quality, thermal comfort,
and energy performance index (energy use per unit area of the house.
Energy-efficient buildings are typically designed using one of the two
approaches – prescriptive-driven of performancedriven. Prescriptive approach
specifies requirements for each building components. The builders, developers,
or designers can choose the most suitable option from the possible combinations
to design and construct the building.
Definition of Thermal Comfort for India
A comprehensive research study, India Model for Adaptive Comfort (IMAC),
indicates that Indians can be comfortable at higher temperatures and wider
temperatures bands than those prescribed by the international standards (Manu,
Shukla, Rawal, Thomas, & Dear, 2016). Recently, NBC and ECBC 2016 have also
incorporated IMACas a design method of the new buildings. IMAC provides an
opportunity to design houses with broader temperature bands and design suitable
active and passive technologies to achieve the same.
The envelope of the affordable housing should be designed to minimize the
heat gain inside the building. High reflectance roof (also known as the cool
roof) is one of the cost-effective technologies to reject solar radiation
falling on the building.
Further, wall, window, and roof materials with the higher thermal resistance
(lower thermal conductance), commonly known as R-value, will significantly
reduce heat gain inside the building. The Higher thermal capacity of the roof
and wall materials commonly known as the thermal mass further dampens and delays
heat gain inside the building.
External Shading Devices
External shading devices, fixed or movable, can be a very cost-effective
approach for affordable housing to reduce direct solar radiation and heat gain
from the windows. Traditional buildings often incorporate fixed external
shadings (awnings and overhangs) in their design. However, the use of movable
external shading devices (external louvers) is relatively new in the Indian
The primary purpose of the ventilation is to maintain indoor air quality in
the buildings. However, the well-designed ventilation can also use outdoor air
to provide space cooling whenever the environmental conditions are favorable.