Window Air Conditioners: Performance Evaluation and Energy Conservation

Abstract

The paper presents the results of performance evaluation of window air conditioners (mainly units of capacity 1.5 TR) which use R22 as the refrigerant and electrical power (230 V, 50 Hz) as the actuating energy source. The results pertain to two types of studies-field studies, wherein over 100 units are routinely tested for their cooling load and power input (as a part of the energy audit in a number of locations all over India); and laboratory studies wherein the cooling load and daily energy consumption are monitored under stabilized conditions. The power input to window A/Cs is 10-30 per cent more than state-of-the-art systems. The daily specific energy consumption (kWh/m³/d) is higher by six to seven times than those in the developed countries and can be reduced by logic based controls and by minimizing heat in leaks in the conditioned space. The laboratory tests indicate that the daily energy consumption of conventional window A/Cs are in the range 17-23 kWh/d/NTR. Logic based energy savers can reduce the energy consumption by 11-20 per cent. Use of state-of-the-art developments in compressors, motors and heat exchangers can minimize the electrical power input by as much as 30 per cent. In the long run, R22 needs to be replaced by more eco-friendly refrigerants.