Analysis of factors affecting the performance of a novel micro-channel heat pipe PV-Trombe wall system for space heating

Abstract

Building energy consumption accounts for about 1/3 of the world's total energy consumption. Photovoltaic Trombe wall (PV-TW) is an effective way to reduce a building's energy consumption, but it still has disadvantages such as low energy efficiency and uneven indoor temperature distribution. To address these issues, a novel system with a PV-TW and a micro-channel heat pipe (MCHP) was initially presented in this research. By cooling the PV cell with both air and refrigerant, the system can reduce its surface temperature and improve its electrical performance. To promote thermal performance and user comfort, an air-cooled condenser is also employed to regulate the room's heat transfer. This paper establishes the system's dynamic mathematical model for winter and theoretically evaluates its performance. Besides, the key factors influencing the system’s performance were examined. In winter, the total power generation and average daily electrical efficiency are 3.12 MJ and 13.52%, respectively, with a maximum indoor temperature of 21.46 °C and a daily average thermal efficiency of 56.76%. The system’s performance is all improved with the incremental change of the factors besides the size of the micro-channel flat tube (MAFT), and the performance is not sensitive to the change of the air channel width. The optimal number and width of the MAFT in the evaporator section are 11 and 45 mm. The indoor air-cooled condenser should have about 10 rows of tubes and an ideal air volume of 540 m3/h. The recommended airflow channel thickness is between 5 cm and 10 cm.