TO-82-03-1 -- An Evaluation of ASHRAE Standard 94.2 for Testing Electrically Charged Thermal Energy Storage Central Units

This paper describes research associated with performance evaluation of electrically charged thermal energy storage (TES) central units in accordance with ASHRAE Standard 94.2. A 30 kW central unit was used for conducting the experimental work. Two different arrangements were studied in regard to placement of the nozzle associated with the airflow rate measurement, and only one of those yielded valid test results. It was found that the presence of the nozzle decreased the flow rate by approximately 30%. Variation of the inlet air temperature level produced sizable changes in both the thermal discharge rate and the duration of the discharge period, but caused only small changes in the reported thermal performance of the TES device. The neglect of humidity level of the inlet air was found to result in errors no larger than 0.5%. Test results obtained with domestic olivine energy storage bricks were compared with corresponding test results obtained with English olivine bricks. The results indicate that the thermal performance of the TES unit was approximately the same for the two types of bricks.