Energy Saving Potentials of Desiccant-enhanced Evaporative (DEVap) Cooling System with District Heat Source

Abstract

The purpose of this study is to estimate energy saving potentials of a desiccantenhanced evaporative (DEVap) cooling system with district heat source based on a combined heat and power (CHP) system. The DEVap cooling system is an alternative to a vapor compression system. A DEVap cooler is comprised of an internally cooled liquid desiccant dehumidifier and a dew point evaporative cooler and is possible to operate the two devices independently. The liquid desiccant unit of the DEVap requires heat source in the process of regenerating diluted liquid desiccant solution. For that reason, the DEVap, a thermally driven cooling system, has an advantage of using heat energy in cooling season. In this study, district heat source based on the CHP system is applied to the DEVap as a heat source. A cooling coil and a terminal reheating coil are installed auxiliarily to meet supply air temperature set point. Supply air flow rate is modulated according to cooling demand as a variable air volume (VAV) system. This study compared to energy consumption of the DEVap cooling system with the VAV system based on an absorption chiller to evaluate energy saving potentials of the DEVap cooling system. The absorption chiller is also thermally driven cooling system unlike electric chiller. An energy simulation is conducted during the cooling season that performance of cooling system is expected to show biggest difference. The result of this study is predicted the DEVap cooling system with district heat source saves energy compared to VAV system with district heat source in the cooling season.