Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
EFFECTS OF SOLAR RADIATION IN A DIRECT EXPANSION SOLAR ASSISTED CO2 HEAT PUMP
Submission Author:
Tiago de Freitas Paulino , MG
Co-Authors:
Raphael Nunes Nunes de Oliveira, Luiz Machado, Ricardo Koury, Tiago de Freitas Paulino
Presenter: Tiago de Freitas Paulino
doi://10.26678/ABCM.COBEM2017.COB17-0401
Abstract
The superheat in the evaporator outlet, in a direct expansion solar assisted heat pump for water heating, is affected by the modification of solar radiation. In the present work, the mathematical model of the heat pump was used to show the effects of solar radiation in the system. When the model achieves a steady state, the solar radiation was reduced in 5% (simulation 1) and in 15% (simulation 2), consequently the superheat decreased. Ten seconds after the reduction of the solar radiation, the internal area of the expansion device was reduced in 3.5% (simulation 1) and in 9.4% (simulation 2) so that the superheat could return to the initial condition. The reduction of the internal area of the expansion device implies a decrease in the amount of refrigerant mass in the evaporator. Around 50 seconds after the valve step, the superheat had practically returned to the initial condition. It was possible to see that a small modification in solar radiation produces relevant effects on the superheat. Consequently, the expansion device needs to be adjusted almost at the same time for the superheat return to the correct value and the system requires an expansion device with a low response time, as an electronic expansion valve.
Keywords
distributed model, solar assisted, direct expansion, superheat, CO2 heat pump
