Improving the efficiency of heat exchanger using spray evaporative cooling

点击翻译按钮获取中文摘要

In a water cooled air handler, which cools and heats the air supplied to a building, the cooling coil typicallyruns below the dew-point temperature of the incoming air in order to maximize sensible cooling capacity aswell as to provide dehumidification. The condensate that forms on the fins of the cooling coil is typicallycollected in a drainage system and is removed using sloped piping or a condensate pump. Since the temperatureof the condensate is close to the temperature of the coil fins, this scenario represents an untapped opportunityfor additional cooling. This is typical for heat exchanger units manufactured by Price industries Ltd, a Heating,Ventilation and Air-Conditioning (HVAC) company headquartered in Winnipeg, Manitoba. The objective ofthe company is to reuse the cold condensate in spray/evaporative cooling application to pre-cool the warm airbefore it reaches the cooling coil for additional cooling.It is expected that this approach would increase the cooling efficiency of the air handling unit. However, theimplementation of this concept requires a comprehensive optimization study with respect to the pertinentvariables of the spray flow (e.g., airflow velocity, water flow rate, droplets formation (spray) and distribution,etc) in order to maximize the amount of pre-cooling that can be achieved with the condensate. Quantifying theeffect of this evaporative pre-cooling on the latent capacity of the cooling coil would be another beneficialcomponent of this study/project.The objective of the proposed research is to develop an efficient spray cooling strategy to maximize liquid/airheat transfer of HVAC precooling systems. The resulting improvement in the efficiency of these units will helpincrease and strengthen the market share of Price Industries Ltd and consequently the Canadian HVACindustry.