Assessment of using energy recovery from a sustainable system including a pyramid-shaped photovoltaic cells and batteries to reduce heating energy demand in the ventilation section

Buildings should reduce their carbon dioxide emissions by 95 % from 2020 to 2050. The cooling and heating system of the building is one of the most important parts of the building in CO2 production. In this study, thermal analysis of a building that was heated and cooled using the radiant pipe within the floor was investigated in the climate region of Riyadh (latitude 24.7, longitude 46.73). The floor of the building with an area of 200 m2 with a thermal resistance of 0.713 m2W.K was located over a parking space. To decline the heat loss or heat gain of the floor, phase change material (PCM) at the thickness of 3, 6, 9 and 12 cm was installed inside the floor. Owing to installing PCM of A25 with a melting point temperature (MPT) of 25 degrees C, heat transfer through the roof declined by 15.8 % (at a thickness of 3 cm) to 46.7 % (at a thickness of 12 cm). Several PCMs such as A23(MPT = 23 degrees C), A24, A25, A26, A27 and A29(MPT = 29 degrees C) were examined. In heating mode, A23by recording the energy demand reduction of 345.4 kWh was the best while in cooling mode, A25 was the best by recording the energy saving of 476 kWh. Moreover, in the heat recovery section, the use of heat from batteries and solar cells to preheat the ventilation air lead to an energy consumption reduction of 1.8 %.