Operation control strategy and demonstration application of PV/T coupled dual source heat pump heating system

In response to achieve carbon peaking and carbon neutrality goals, reduce the energy consumption of traditional dual source heat pumps, optimize and accelerate the promotion of clean heating solutions, this paper proposed a solar photovoltaic thermal (PV/T) module coupled dual source heat pump heating system. The system consisted of four main parts: heat collection side, water source side, heating side, and power generation side. The collection side equipment included PV/T components and cooling tower, the water source side included heat storage tank, the heating side included dual source heat pump system, and the power generation side included power electronic devices such as inverter. Firstly, according to energy demand, rural buildings in northern China were divided into rural office buildings and rural living buildings, and the operating periods of dual source units were matched based on heating demand to maximize the COP of the units. Secondly, during the heating season, the heat collection side utilized the temperature difference between PV/T components and heat storage tank to achieve heat collection control and collect solar energy heat. During non heating season, use cooling towers to cool down PV/T components and control their temperature within a range with high photoelectric conversion efficiency. thirdly, the heat collected by the heat storage tank serveed as the primary heat source for the water source heat pump, converting low-temperature heat sources into high-temperature heat sources for end of pipe heating. When the temperature of the heat storage tank was low, switch to the air source heat pump for end of pipe heating. The most important thing was that when the temperature of the heat storage tank exceeds 45 ℃, the heat storage tank directly heated the end of the line without starting the dual source heat pump, minimizing power consumption to the greatest extent possible. The power generation side adopted the "self production and self use, surplus power grid connection" mode. During the heating season, the self generated part was given priority to supply power to the system equipment. During non heating season, power generation on the power generation side was integrated into the grid to increase system revenue. Finally, using Longzhai Village Committee and self built houses by farmers in Jinchang City as supply buildings, a demonstration project will be constructed to analyze typical daily heating and 72 hour continuous heating operation data. Data shows that from January to March, the Longzhai Village Committee had a total of 9 times of direct heating from the water tank, with an average heating power of 63.50kW and an average direct water supply time of 3.36 h. On typical days of direct supply, compared with the operation of air source heat pump units alone, this system increased heating capacity by 7.13%, reduced power consumption by 28.95%, and increased heating side energy efficiency by 27.98%. During the mid-term heating period of continuous operation for 72 hours, the average heat collection efficiency of public buildings is 44.42%, and the photoelectric conversion efficiency is 15.17%. The average heat collection efficiency of living buildings is 38.63%, and the photoelectric conversion efficiency is 15.46%. This system has good performance in heat collection, power generation, and heating, and has high engineering promotion value.