Investigation Of A Cogeneration Of Cooling/Heating Heat Pump System Based On PV/e Roof Module

A novel PV/e roof module has been recently proposed to act as the roof component by the prefabrication technique, electricity generator and the evaporator of a heat pump system. The modules, in conjunction with a heat pump, are able to provide heat and power supply to building with an enhanced efficiency resulting in a saving of construction space and initial investment. It could also reduce the reliance on the fossil fuel and therefore improve the environmental quantity. Solar power has been widely used into life since the coming energy crisis. Thus how to improve the efficiency of solar apparatus is becoming a crucial issue.In order to achieve the high working efficiency of solar instruments, it's important to reduce the loss to the environment, including reflection, absorption, and thermal dissipation and so on. Both reflection and absorption losses could be decreased by the replaced material of component. However thermal loss is not only determined by the property of explosive material but also affected by the air temperature, air velocity, temperature of component and other factors. The lower temperature of solar apparatus would lead to the higher solar efficiency and the less thermal loss.The conventional solar equipment could only supply hot water or process pre-heating action but directly supply heat or cooling to construction. The PV/e roof module based heat pump system could not only provide heat and cooling to buildings strait way, but enhance the solar efficiency with a lower working temperature of apparatus. This system could then be widely utilized in other fields.First in this report, the modules, in conjunction with a heat pump, were able to provide heat and power supply to building with an enhanced efficiency resulting in a saving of construction space and initial investment. Two different heat pump systems were introduced to provide heat and cooling to buildings respectively in winter and summer. Different design parameters were assumed in details, such as roof tilt and 1 effective areas of module, the evaporation temperature and condensation temperature as well as the system mass flow rate.Second, thermal performance of the PV/e module was analyzed and its optimum structure and operating characteristics were recommended. The PV/e based heat pump system was further investigated, and its energy supply potential over a typical climate year was evaluated by computer software. The results conclude that the average attained solar efficiency is about 71.7% under the winter condition of Shanghai, China. The ideal evaporation (0～10℃) and condensation (50～70℃) temperatures are respectively recommended. Borosilicate cover performs better than other two glazed materials and mono-crystalline photovoltaic cell is able to generate better electricity output.Then taking the one typical building located in Shanghai, China as an example, the daily and seasonal energy demand of the building and energy supply of the PV/e system was compared. This report refers to the solar thermal and photovoltaic energy storage systems, which were supposed to provide timely and completely energy management to the energy-poor duration and reserve thermal energy at energy-rich period by overcoming the main difficulty of match the discrepancy between energy demand and output. It provided a preliminary study of the performance of the proposed PV/e system and thus formed a base for further development of such a system and aided in its future application in buildings.Finally the prospection and practicality of PV/e solar assisted heat pump system were proposed through the analysis of its economy and affection to the environment. It was pointed out that the integration of the PV and evaporation coil into a prefabricated roof would lead to large saving in both capital and running costs over separate arrangements and could also reduce the reliance on the fossil fuel and therefore improve the environmental quantity.