DESIGN AND ECONOMIC ANALYSIS OF HEAT RECOVERY WHEEL USED IN HVAC SYSTEM OF A BUILDING

Abstract

Heat Recovery Wheel is a type of heat exchanger positioned between the supply and exhaust air streams of an air handling system of a building. It is also known as a rotary heat exchanger or a rotary air to air enthalpy wheel. This heat exchanger pre cools the fresh air entering the building by removing the heat from the return air stream and providing the same to the fresh air stream. This reduces the load on the central chillers. The aim of the project was to evaluate the payback period of the heat recovery wheel in an office building in Kolkata by doing an economic analysis with respect to the conventional system. In order for the Payback period to be less and economically feasible, the operational costs of the Heat Recovery Wheel should be significantly less in comparison to the conventional system so as to offset its high capital cost. Below are the various costs of both the systems and the Payback period associated with the Heat Recovery Wheel: Capital Cost with Heat Recovery Wheel 66 Lakhs Capital Cost without Heat Recovery Wheel 23 Lakhs Operational Cost with Heat Recovery Wheel 72 Lakhs Operational Cost without Heat Recovery Wheel 93 Lakhs Therefore from the above data the Payback Period comes out to be 2.1 years which is economically feasible and after which the Heat Recovery Wheel would continue to give substantial energy and electrical savings for the rest of its life. The result shows significant potential that Heat Recovery Wheels have in modern day mechanical ventilation of buildings and why they should be promoted an building regulations.