COPING WITH THERMAL STRESS IN TROPICAL HOT CLIMATES

Prof. Dr.S.Kumar.a and Ar.M.V.Janardhan Rao.b

aDepartment of Architecture, SPA, JNAFA University, Masab Tank, Hyderabad.

bPhD Research Scholar, SPA JNAFA University, Masab Tank, Hyderabad.

Abstract

Building is man’s device for controlling his environment against extremes of weather

and coping with thermal stress. The building envelop consisting of opaque elements

such as walls, roofs and floors and transparent elements such as windows and

ventilators has a strong influence on thermal behavior and energy needs.

Traditional building in our country managed thermal stress effectively by

incorporating thick and dense materials with high thermal capacity and medium

thermal resistance. On the other hand contemporary buildings with structural framing,

thin walls and large areas of glazing are clearly failing to meet the thermal criteria. As

the demand for comfort during hot conditions goes up, the building becomes

thermally stressful to the inhabitants due to the high indoor temperature. So what can

we do to reduce thermal stress and its harmful effects? The easy way out is to use

readily available energy consuming devices such as air conditioning. This paper

however emphasizes the importance of passive design and thermal insulation in

tropical hot climates for effective thermal stress management and energy

conservation.

In the selection of wall and roof materials and their thickness due consideration

should be given to their thermal properties, i.e. thermal resistance (R) and thermal

capacity (C). Thermal capacity depends on its mass and determines time lag and

decrement factor, while thermal resistance reduces the heat flow rate.

This paper discusses how these two properties are to be balanced according to

climatic needs by discussing aspects such as heat flow mechanisms, thermo-physical

properties of building materials, steady and periodic thermal characteristics of wall

and roof sections, thermal performance evaluation for building sections, use of radiant

barriers, low emissivity wall papers etc.