THERMODYNAMIC PERFORMANCE ENHANCEMENT OF AN AIR CONDITIONER WITH DEW POINT EVAPORATIVE COOLER

Abstract

The vapor-compression based conventional split air conditioners (CAC) consume a large portion of total electrical power and pose an alarming threat to global environment. The present work aims to reduce cooling load and power consumption of CAC by employing a dew point evaporative cooler (DPEC). DPEC consists of a counter flow type heat and mass exchanger with alternate layers of dry and wet channels. The intake air is sensibly cooled before entering the cooling room through the evaporator coil of the air-conditioner. Also, the working air (a part of outlet air in dry channel), after absorbing sensible heat of intake air and water vapors from the wet channel surface, is allowed to pass across the condenser coils. The intake dry bulb temperature (T0 = 29-44°C) and specific humidity (ω0 = 6-22g/kg) are taken as input parameters. While the cooled air entering the evaporator decreases the cooling load on the conditioned space, the compression work is also reduced due to increased heat transfer in the condenser. The maximum reductions in cooling load and monthly energy consumption at T0 =44°C and ω0 = 6 g/kg are found as 59.54% and 340kWh, respectively. The average energy savings with the DPEC system for hot-dry climate (from April to June) and hot-humid climate (from July to September) of New Delhi, India are observed to be 479.6kWh and 79.1kWh, respectively. The proposed system is found to payback in about 2.7 years.