Evaporative cooling technologies for air-cooled chillers for building energy performance improvement

Abstract

Where water conservation is concerned, central air-conditioning systems in commercial buildings are installed with air-cooled chillers for comfort cooling. This study examines evaporative cooling technologies for air-cooled chillers to improve their energy performance. Two common devices for cooling air intake to condensers are evaporative coolers and mist generators. Depending on weather conditions and packing materials, evaporative coolers can enhance the refrigeration effect and chiller energy performance at various degrees. Yet, different configurations and designs for air-cooled condensers call for tailor-made design of the coolers. The coolers also impose additional flow resistance to condenser air and, in turn, additional fan power. Mist generated in front of the condensers brings no flow resistance to condenser air and allows the dry bulb temperature approach closely the corresponding wet bulb temperature. The cooling effectiveness can be maximized with lesser water consumption. The benefit of evaporative cooling for air-cooled chillers is more appealing in future climate scenarios in a subtropical climate, considering the higher difference between the dry bulb and wet bulb temperatures. Integration of control and optimization strategies with mist precooling has been discussed.

Experimental Investigation of a Split Air Conditioning Using Condensate as Direct Evaporative Cooling

“…Evaporative cooling technologies for air-cooled chillers for building energy performance improvement has been presented by Yu et al, [27], the cooling effectiveness can be maximized with lesser water consumption. Kabeel et al, [28] reported the performance evaporative Air-Cooled Chiller using cold mist water that cooled by a small amount of the chiller's chilled water.…”

Cooling effectiveness of mist precooler for improving energy performance of air-cooled chiller

“…22,No. 1A, fitted to existing air-cooled chiller systems to precool outdoor air and hence to enhance their energy performance [8,9]. To familiarize with the actual installation of a direct evaporative cooler and a mist precooler, please refer to [10] and fig.…”

“…2 in [11]. Mist precoolers are preferable than direct evaporative coolers, considering the ease of installation and the negligible air-flow resistance [9]. At present, there is no standard design for such evaporative cooling devices and no standard protocol to verify their cooling effectiveness.…”