Design charts for sizing CC/DV system aided with personalized evaporative cooler to the desired thermal comfort

Abstract

This work extends chilled ceiling displacement ventilation (CC/DV) design charts to a wider operation range of DV supply temperatures and flow rates when aided with personalized evaporative cooler (PEC) at typical office of peak load of 70W/m2. The overall thermal comfort (OTC) of the occupant can be read off from the chart at different operating conditions of DV/CC-PEC system. The charts simplify the sizing procedure of the CC/DV-PEC system by specifying the operational design parameters which include temperatures of DV supply and CC surface, PEC airflow rate, the ratio of total load over DV airflow rate named displaced air parameter (P), and the CC cooling load. In producing the charts, extensive simulations were performed using a multilayer space thermal model to determine the human microenvironment conditions and local comfort models to determine occupant thermal comfort.The use of the charts is demonstrated through case studies. It is found that the addition of PEC at flow rate of 10l/s provided acceptable thermal comfort up to DV supply temperature of 26°C. In such conditions, the CC/DV heat removal is about 83% of the space baseline load in design conditions which leads to energy savings while maintaining comfort.