Estudo da viabilidade do uso de válvulas de expansão termostática para bomba de calor de pequeno porte utilizando evaporador solar

Abstract

With the increase in demand for energy consumption, as well as the difficulty in supply and due to restrictions of non-renewable inputs. The development of equipment that supplies energy in a clean and sustainable manner is necessary. This work uses an evaporator heat pump that harnesses solar energy, generating energy for residential water heating. In order to analyze the behavior of the equipment in the face of sudden changes in the radiation received, and to analyze the financial viability of using a thermostatic expansion valve, instead of an electronic expansion valve. Operating parameters such as evaporation temperature, evaporation and condensation pressures, volumetric flow rate and performance coefficient were analyzed in the face of external changes. The values found were compared with other studies, showing a good approximation. A step in the amount of heat incident on the evaporator was promoted from 90 to 900 KW / m². The evaporation pressure took about 23 s to increase. The response time of a thermostatic expansion valve to the step was around 57.4 s. Even with variations in system operating speed, the machine operated at an average overheat of 11 ° C, which enhances reliability in a thermostatic expansion valve. Financial feasibility studies have shown that the use of a thermostatic expansion valve is feasible for residential heat pumps with a heating capacity of less than 1000L compared to an electronic expansion valve.