EVALUATION OF THE EFFICIENCY OF USING THE THERMAL POTENTIAL OF THE ENVIRONMENT AND THE TOP LAYERS OF THE LAND OF UKRAINE
An assessment of the effectiveness of the combined use of low-potential soil heat and atmospheric air for the operation of a heat pump heat supply unit has been carried out. The analysis of the main provisions of the EU regulatory documents and legislative acts of Ukraine in terms of attributing heat pumps to equipment that uses renewable energy sources and choosing the criterion for such attribution. The minimum permissible value of the average calculated seasonal efficiency is considered. The influence of the duration of air temperatures of various gradations on the heat pump heat output is analyzed and the time intervals for the effective operation of each of the low-potential sources are determined. To increase the efficiency of the two-circuit heat pump system, a scheme for extracting low-potential heat using a soil heat pipe and an air heat exchanger based on a two-phase gravitational thermosyphon is proposed. The initial data and assumptions for assessing the thermal potential of the upper layers of the Earth, which can be used for geothermal heat supply using heat pumps, are considered. The comparison of the energy characteristics of the geothermal and air heat pump during their autonomous and combined operation throughout the year in the climatic conditions of Kiev is carried out and it is shown that the combined use of low-potential heat of atmospheric air and soil allows to increase the annual heat output of the heat pump system by 1.2 times. Based on the studies carried out, it has been established that the advantage of air as a heat carrier is that air heat pumps can operate almost everywhere and do not require a low-temperature circuit. A promising way to increase the efficiency of a heat pump with an annual cycle of its operation is the combined use of low-potential heat of soil and air. The heat pump system with two energy sources provides high heat pump performance throughout the year and has a higher energy efficiency than traditional solutions. Bibl.11, tab.2, fig.4.
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