Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
DESIGN OF AN EMBEDDED SYSTEM FOR WATER TEMPERATURE CONTROL IN A SOLAR ASSISTED HEAT PUMP
Submission Author:
Tiago de Freitas Paulino , MG
Co-Authors:
Tiago de Freitas Paulino, Euler Fonseca, Antônio Maia, Luiz Machado, Ricardo Koury
Presenter: Tiago de Freitas Paulino
doi://10.26678/ABCM.COBEM2017.COB17-1176
Abstract
The heat pump is considered as one of the alternatives to achieve greater efficiency in heating water for bath. The control of heating water is necessary in a direct expansion solar assisted heat pump (DX-SAHP) for proper operation. One of the alternatives to make the control effective would be an embedded system. In this study, it is presented a low cost embedded system which is developed to set the hot water temperature in 60°C in a DX-SAHP. The hardware of the embedded system has a microcontroller, an optocoupler for separating power and control circuits, a Mosfet for high frequency switching and a Schottky diode for attenuating the reverse current. The software has as its main functions getting temperature throughout an interruption generated by timer, the calculation of the error by comparing the current temperature with the set-point, the calculation of the PID, the generation of PWM signal and finally, the data is displayed on the LCD and sent by USB port. The system performance was verified with a solar radiation variation between 154 W/m² and 1154 W/m². During this test the maximum absolute error (MAE) and the root mean square error (RMSE) were 1.25 and 0.028, respectively. The volumetric flow rate varied between 0.26 L/min and 0.55 L/min during the solar radiation variation to keep the hot water temperature in the correct value.
Keywords
control water temperature, embedded system, heat pump, solar assisted
