Evaluation of the efficiency of steam compression heat pumps of the "air-water" type as part of a combined heat supply system

Abstract

Every year, increasing attention is paid to the use of unconventional and renewable energy sources for heating. Promising sources of heat supply are steam compression heat pumps, for which soil, atmospheric air, groundwater, ventilation emissions, etc. are used as low-potential heat sources. Due to its accessibility, air is one of the most common sources of heat for such installations. The efficiency of air heat pumps depends significantly on climatic conditions, and in practice they are used in conjunction with an additional energy source. This study evaluates the efficiency of such a combined system using the example of a heat supply system for a residential building under various climatic conditions in Russia. The coefficient of performance (COP) of a heat pump is considered as the main indicator of its efficiency. The load on the heating system for each region was determined using the thermal balance method. The study utilized the values of the COP obtained from testing. It is established that the average annual COP of the heat pump for the considered climatic conditions ranges from 1.76 to 1.98 when operating the heat supply system with a temperature schedule of 80/60°C, and it functions effectively at this temperature schedule down to an outdoor air of no lower than – 16°C; at lower temperatures, the load is covered by an additional source. In addition, the annual energy costs for operating the heat supply system are calculated, and the distribution of this component between the heat pump (48% – 97.6%) and the additional source is determined. The feasibility of using heat pumps in non-gasified areas is determined by the electricity tariff.