A study on the performance of photovoltaic Trombe wall in Mashhad residential buildings

Recently, new combinations of passive solar systems are introduced to enhance their performance. Trombe wall is one of the popular passive solar systems which has been studied with different forms and in combination with various materials. The aim of the current research is to investigate the Trombe photovoltaic wall in residential buildings in Mashhad. The study was carried out using energy simulation by Energy Plus software. The vents of the Trombe Wall are open from eight in the morning to four in the afternoon and closed for the rest of the day. Brick and concrete Trombe walls with photovoltaic coating panels are studied in three different positions, air gaps, and different vents for the whole year. The variables are simulated in an integrated way. First, two rooms with 20 centimeters thick brick and concrete Trombe walls were considered, then, the dimensions of the vents (18 percent of the Trombe wall surface and 3/20 of the Trombe wall height), air gap (0.1 meters) and with different photovoltaic coverages with two and four square meters were attached on the mass wall, in the next stage by keeping the size of the vents fixed (18 percent of the surface of the Trombe wall) and changing the air gap (0.05 meters) the simulation was performed. Then, the performance of photovoltaic panels on the glass and in the air gap were simulated. The dimensions of the room have been selected according to the dimensions of a living room in common residential buildings in Mashhad. The results show that for a room with a volume of 120 cubic meters with brick and concrete Trombe wall and 18% vent area, an air gap of 0.05 meters, and a coverage area of four square meters of photovoltaic panels, the received heat, electricity production, and thermal comfort significantly increase. The amount of received heat, electricity production is 257652.3, 307963.6, and 1975482 kilojoules, respectively. In October, thermal comfort was rated as cold. The heat received by the concrete Trombe wall is more than that of the brick one. The more the coverage of the photovoltaic panels on the Trombe wall, the lower the received heat and the temperature of the room would be. The greater the surface of the vents, the more heat is received in the room, and the temperature of the room increases. The temperature of the inner surface of the photovoltaic panels and the heat received due to internal convection increases from bottom to the top of the Trombe wall. Photovoltaic panels on the massive wall perform better than those on the glass or in the air gap in terms of received heat thermal comfort and electricity production. Therefore, positions of photovoltaic panels on the massive wall, on the outer glass, and on the blind slats respectively are suggested in the cold period of the year, while it would be the opposite for the hot period of the year.