Energy saving through evaporatively cooled condenser air in conventional air-conditioning units

A theoretical study of the feasibility of evaporative cooling of the condenser air of a conventional vapour compression air-conditioning system to upgrade the rating of an air-cooled air-conditioning unit and consequent energy saving in the Delhi climate is presented. A brief review of the heat rejection option in an air-conditioning unit has been given and a theoretical background analysis for evaporative cooling of condenser air has also been presented. For illustration, one specific air-cooled package unit, whose performance characteristics as given by the manufacturers are available, has been used for calculations. Temperature variation data for New Delhi in the months of May and June 1991, obtained from the Meteorological Department, has been used. With the basic data, the upgradation of cooling capacity, power requirement and average energy consumption with and without evaporative cooling of condenser air has been calculated and the reduction in peak load and saving in the average energy consumption was predicted. Typical calculations of the water requirements for pre-cooling of condenser air were also predicted and compared with the corresponding requirements for water-cooled and evaporative condensers. It is concluded that there is an excellent and exciting possibility of reducing energy consumption (and consequent enhanced energy saving) in air-conditioning at national level.