Eventos Anais de eventos
ENCIT 2018
Brazilian Congress of Thermal Sciences and Engineering
TRANSIENT ANALYSIS OF A HEAT PUMP SOLAR EVAPORATOR THROUGH A TEMPERATURE STEP
Submission Author:
João Marcos Gomes Vieira , MG , Brazil
Co-Authors:
Neylor Makalister Ribeiro Vieira, Hélio Augusto Goulart Diniz, João Marcos Gomes Vieira, Oscar Ricardo Sandoval Rodriguez, Juan Jose Garcia Pabon, Luiz Machado
Presenter: João Marcos Gomes Vieira
doi://10.26678/ABCM.ENCIT2018.CIT18-0092
Abstract
The degree of superheat of a refrigerant fluid in a vapor compression cycle, applied in refrigerating and heating systems, is fundamentally important for the good operation of the compressor and consequently the good performance of the system. This work aims to analyse the degree of superheat control of the refrigerant fluid in the evaporator of a heat pump operating with vapor compression to heat water, when a temperature step is applied in its evaporator. For that, an evaporator coil was designed and built with an outside heat source due to an electric resistor with constant heat flux, simulating a direct expansion solar evaporator in clear and cloudy days. Physical and thermodynamic parameters behavior of the fluid is going to be analysed, besides system operation parameters. As inlet and outlet temperatures, mass flow rate and degree of superheat. As a predicted result, when the evaporator is heated it is expected that the mass inside of it decreases, because of the increase in the evaporation pressure. Concurrently, the compressor volumetric efficiency and the fluid specific mass increase, increasing the flux in the compressor suction side. Also, the flux imposed by the expansion valve decreases, due to an increase in the evaporation pressure. The degree of superheat is rised and the evaporator starts to deplete, until the thermostatic expansion valve actuates in the system and a new equilibrium state is reached, stabilizing the fluid fluxes at the evaporator inlet and outlet.
Keywords
heat pump, water heating, evaporator, electric resistor
