Waste To Energy - Energy Recovery From Chillers

LOW GRADE WASTE HEAT RECOVERY FROM CHILLERS

Overview

Facilities like hospitals, hotels etc., spends considerable amount of energy is hot water generation through different conventional energy sources. These facilities also uses major portion of electrical energy for catering its entire cooling load. Maximum cases this cooling load is delivered by chillers through vapor compression technology. Around 30-40% of total energy involved in the vapor compression system is waste heat. Low grade waste heat recovery systems are available in the market which can recover heat from the refrigeration cycle and can produce hot water at almost zero conventional energy input.

Working

These low grade waste heat recovery systems extract heat energy from the high pressure vapor line going in to condenser through a simple modular heat exchanger.                           

Amount of energy recovery depends on the refrigerant type and its temperature.A good amount of waste heat can be recovered when the discharge temperature of the refrigerant is more than 55⁰C.Typical heat recovery will be around 15% of condenser load for ammonia based refrigeration system,10% for R22 based and 6 % for R134a based.

Case Study:

A large hotel in south India was using 250 TR, R134a based screw chiller for central air conditioning. Diesel boilers was used for hot water generation in the range of 45 – 520C.Double walled heat exchangers were installed in the high pressure line to recover heat energy from refrigerant and generate required hot water at almost no cost. Nearly 70 KW of heat has been recovered which reduced almost 80 % of the diesel consumption in boilers.

#Energy #Energyefficiency #Chiller #Wasteheat recovery #wastetoenergy