Calorimetry of ground source heat pump using direct expansion method : measurement of flow rate using PIV method

Abstract

The GSHP that use a direct expansion method is expected to have higher performance of energy-saving than the conventional type of the GSHP. We evaluated the quantity of heat by measuring temperature, humidity and flow rate at the indoor unit of the GSHP system. The purpose of this study was to improve the accuracy of the flow rate measured by hot wire anemometers using PIV method. The average of difference between the flow rate obtained by the hot wire anemometers and PIV method was 23.6% in the heating operation and was 24.0% in the cooling operation. We obtained the compensation formula which corrects the results of the hot wire anemometers using the results of PIV method. The average of difference between the compensated flow rate by the PIV method was reduced to 5.2% in the heating operation and 1.9% in the cooling operation. The compensation formula is used performance evaluation of the GSHP system. The COP obtained by conventional method was 3.4 in the heating operation. The compensated COP was 2.8.