Savings resulting from coupling the PV with the space cooling system

Warsaw University of Technology, Institute of Heat Engineering, Division of Refrigeration and Energy in Buildings, Nowowiejska St. 21/25, 00-665 Warsaw

^* Corresponding author: bartosz.chwieduk@itc.pw.edu.pl

Abstract

The paper presents results of analysis of possible cooperation of a photovoltaic system with the space cooling devices. The size of the photovoltaic system was determined on the basis of electricity demand of the selected single family house. The demand for the electricity use for cooling and air conditioning had not been taken into account while calculating the size of PV system. On the basis of the heat balance of the building, the demand for cooling in the following hours of a year was determined. The demand for cooling and heating is affected by the heat transfer through walls, windows, floor, roof, and air exchanged through ventilation. Also solar and internal gains were taken into account. Based on Next, a cooling unit was selected. A cooling device was selected to provide enough energy to maintain the thermal comfort of the building in summer. Taking into account parameters of the selected device, the demand for electricity was determined. Based on time and hours of operation of electrical appliances in the building, a chart of electricity demand was created. The demand for cooling was included. Calculated values of the energy demand required to power all devices in the building were compared with the energy gains from the photovoltaic system. In order to calculate the energy generated by the PV system (in following hours of a year) the isotropic model of solar irradiation was used. The input solar radiation data on horizontal surface were downloaded from the website of the Ministry of Investment and Economic Development. In the last paragraphs, savings obtained in result of using the energy generated by the PV system to drive the space cooling system were determined and conclusions from the calculations were presented.