A Novel Solar Photovoltaic- Heat Pump Composite Building Energy Systems Analysis

As the growth of the economy and the improvement of productivity, coal, oil, gas and other traditional fossil energy consumption sharply, causing worldwide energy crisis and the increasingly serious environmental pollution, in total energy consumption, building energy consumption accounts for a large proportion, therefore, develop and utilize renewable energy and improve the utilization rate of existing energy is the main way to solve the energy crisis. Solar energy is the basic energy of renewable energy, can be directly for transformation and utilization, it is universal, harmless, durability and huge reserves. But a factor exists in utilizing solar energy photovoltaic systems that high temperature leads energy conversion efficiency to low. Heat pump is a kind of technology that the high grade heat can be used by people be obtained from the low grade heat energy like air, water and soil, work through the power of electricity. Air source heat pump is widely used because of the advantages of simple,convenient installation, however, the outdoor environment affect the air source heat pump observably, performance fell sharply when outdoor air temperature is low, so combined solar energy technology and heat pump by solar energy as the low heat source of heat pump, can solve the heat pump performance fell sharply in the low temperature, improve the performance and the efficiency of PV/T by decrease the temperature of solar photovoltaic system, it can also realize year-round heat water supply, heating, cooling, other building required functions.First of all, summarizing the predecessors’ research results, this paper present a composite building energy system based on a novel type of water-cooling PV/T collector with micro heat pipe array(MHPA- PV/T) combined with dual heat source heat pump, finish the preliminary design of the composite building energy system and establish the experimental platform, and explain the main components of the system(a novel type of water-cooling PV/T collector with micro heat pipe array system, dual heat source heat pump system, the cooling and the water pipe system, control operation system, Measurement system, etc.).Design a variety of complex function system operation mode and control strategySecond,the composite building energy system operation performance and the actual effect of energy saving has carried on the experimental study by six typical operation mode of the system, including heating condition by PV/T cooperate the dual heat source heat pump, heating condition by PV/T cooperate the water source heat pump, heating condition by air source heat pump, PV/T cooperate air source heat pump hot water condition, refrigeration and air conditioning in summer, refrigeration and air conditioning meanwhile hot water condition in summer. It has been Analyzed the relationship between power generation, power generation efficiency and instantaneous thermal power of heat pump vary with solar irradiance and running time. It is also has a comprehensive evaluation to the heat pump COP, the photoelectric efficiency and thermal efficiency of PV/T, and the comprehensive efficiency of the whole system. For PV/T thermal efficiency, the PV/T cooperate water heating operation mode than PV/T cooperate double heat source heating operation mode increased by 16.6%, two models of PV/T power generation efficiency, high power generation efficiency is about 15%. For COP, PV/T cooperate water heating operation model than double heat sources model increased by 17.6%, 39.1% higher than that of air source model. The experimental results show that the composite building energy system can not only realize all design conditions, but also satisfy the functions which building needs such as heating, cooling, power supply, hot water, and etc. The system can make full use of renewable energy, and maximizing the comprehensive utilization efficiency of system with smaller equipment operation cost. The PV/T cooperate water heating operation mode is the best match, can make full use of the heat absorption by the PV/T, to achieve maximum use of renewable energy, reducing energy waste. And at a low temperature for PV/T system set of heat and power generation. The model for the system preferred.Finally, mathematical model of the composite building energy system is established. The results show that the mathematical model of the system has certain feasibility, but still needs to be further improved to lay the foundation for system optimization.