Efficiency of Operation of Air Heat Pumps with Evaporators of Various Designs

Abstract

Resume. The development of the heat pump market ensures the growth of energy prices, the fight against global warming and the stimulation of the growth rates of countries in transition to "clean energy sources". the most environmentally friendly and energy efficient, taking into account the cost of their installation and the impact of air source heat pumps compared to geothermal ones. However, their use in countries with cold climates is limited by the formation of frost on the evaporator unit heat exchanger, which significantly increases their heating capacity and conversion efficiency.Purpose of research. The purpose of this work is to compare the efficiency of heat pumps with an evaporative circuit heat exchanger manufactured by MITSUI (Japan) and a heat exchanger with a MOVEBIT defroster manufactured by ALTEC (Russia).Methods. The research methodology is based on large laboratory tests of an evaporator with an oscillatory circuit of the MOVEBIT system (ALTEK - Russia) and an industrial heat exchanger MITSUI (Japan), a graphical analysis of the operation of a heat pump with common evaporators, and a theoretical substantiation of the transformation ratio. To compare the main standardized performance indicators, the transformation coefficient (COP – coefficient of performance) is used, showing the ratio of received energy to applied work.Results. The analysis of the results of the heat pump operation showed that while maintaining the humidity at a constant level of φ ≈ 65% and lowering the temperature from +10°C to +5°C, a decrease in the heat output of the unit is observed, regardless of the type of MOVEBIT and MITSUI heat exchanger, which is explained by the formation of condensate. With a further decrease in temperature to zero and below, ice forms on the evaporator of the heat exchanger. Taking into account the cost of removing ice on the MITSUI heat exchanger, the transformation ratio of the heat pump unit (HPU) is 2.08. The removal of ice by the MOVEBIT system practically does not require additional costs and the transformation ratio of the installation is 4.45, which is similar to the operation of an air source heat pump at positive temperatures.Conclusion. Our studies show that the best prospect for de-icing is the application of mechanical oscillations with the use of magneto-constrictive transducers. The COP of the air source heat pump with the MOVEBIT system exceeds the COP of the heat pump with the MITSUI standard evaporator by 2 times at a temperature of 0°C and below.