Research on the Application of PVT in Agricultural and Greenhouse Heating: Empowering Technology to Build a "Warm Defense Line" for Modern Agriculture

Research on the Application of PVT in Agricultural and Greenhouse Heating: Empowering Technology to Build a "Warm Defense Line" for Modern Agriculture

In the development process of modern agriculture, temperature is one of the core factors affecting crop growth, yield and quality, especially in the greenhouse planting model, which has higher requirements for the stability, energy efficiency and environmental friendliness of the heating system. Traditional greenhouse heating mainly relies on coal-fired, gas-fired boilers or electric heating equipment, which not only have problems of high energy consumption, high operating costs and large carbon emissions, but are also vulnerable to fluctuations in energy supply and difficult to precisely match the temperature requirements of different growth stages of crops. Against this background, the photovoltaic-thermal integrated technology (Photovoltaic-Thermal, abbreviated as PVT), with its unique dual function of "power generation + heating", has gradually become a key technology to solve the pain points of agricultural and greenhouse heating, injecting new impetus into the green transformation and efficient development of modern agriculture.

The core principle of PVT technology is to integrate an absorber layer, heat transfer medium channels and insulation layer on the basis of traditional photovoltaic power generation components, achieving a highly efficient utilization mode of "one input of solar energy, simultaneous output of electricity and heat" - the photovoltaic components convert solar energy into electricity to meet the power supply needs of lighting, ventilation and water and fertilizer irrigation equipment in the greenhouse; the absorber layer absorbs the waste heat generated during the power generation process of the photovoltaic components (about 60%-70% of solar energy is converted into heat energy and wasted in traditional photovoltaic components), and transfers the heat to the greenhouse heating system through heat transfer media such as water and air, providing a stable heat source for crop growth. Compared with the "separate application" of traditional heating and independent photovoltaic systems, the energy comprehensive utilization rate of PVT technology is increased by more than 30%, not only solving the problem of power generation efficiency decline of photovoltaic components due to high temperature, but also avoiding the shortcomings of high energy consumption and high pollution of traditional heating, perfectly matching the development concept of modern agriculture of "energy conservation, environmental protection and efficiency".

The application of PVT technology in agriculture is not limited to greenhouse scenarios, but also extends to multiple links such as insulation in large-scale field planting, heating in livestock and poultry breeding, and preservation of agricultural products in storage, providing full-process protection for agricultural production from "planting end" to "storage end". In large-scale field planting, the low temperature in winter and the cold snap in spring in northern regions are the main problems restricting the emergence rate and stress resistance of crops such as wheat and corn. Traditional cold protection measures mainly rely on covering plastic film and spraying anti-freezing agents, which have limited effects and are difficult to be promoted on a large scale. However, the PVT system can provide continuous heat to the buried heating pipes in the field through the combination mode of "electricity-driven + heat supply", stabilizing the soil temperature at 10-15℃, which is suitable for crop germination. At the same time, it uses the power generation function to supply power to soil moisture sensors and automatic irrigation equipment, achieving "temperature regulation + precise management" integration. Taking a wheat planting base in Northeast China as an example, after introducing the PVT large-scale field heating system in 2023, the spring wheat emergence rate of the base increased from 82% in previous years to 95%, the average yield per mu increased by 12%, and no coal was consumed during the winter heating period, reducing carbon emissions by about 80 tons per year and reducing operating costs by 40% compared with traditional electric heating methods, truly achieving the triple benefits of "increased production, energy conservation and carbon reduction".

In the field of livestock and poultry breeding, stable temperature directly affects the survival rate, growth rate and disease resistance of livestock and poultry - the suitable growth temperature for piglets is 28-32℃, and for chicks is 33-35℃. Traditional breeding heating mainly uses coal stoves and hot air stoves, which not only have large temperature fluctuations (errors can reach ±5℃), but also easily produce pollutants such as carbon monoxide and dust, increasing the risk of respiratory diseases in livestock and poultry. The application of PVT systems in the aquaculture scenario, through the design of "centralized heating + zonal temperature control", can precisely adjust the heating intensity according to the temperature requirements of different aquaculture areas (breeding rooms, brooding rooms, fattening rooms), and at the same time utilize the power generation function to supply power to temperature control sensors, ventilation fans, and manure treatment equipment, creating a "constant temperature, clean, and intelligent" aquaculture environment. Data from a large-scale pig farm in Shandong shows that after introducing the PVT heating system, the survival rate of piglets increased from 90% to 98%, the fattening pig's marketable period was shortened by 7 days, and the annual coal consumption was reduced by 150 tons. The dust concentration in the breeding workshop decreased by 60%, and the incidence of diseases dropped by 35%. This not only reduced the breeding cost but also improved the quality of livestock and poultry products, providing technical support for green breeding. In the core scenario of greenhouse planting, the application of PVT technology has demonstrated the advantages of "customization, precision, and long-term effectiveness". According to the growth cycle and temperature requirements of different crops (vegetables, fruits, flowers), a mature heating solution has been formed. The core pain point of greenhouse planting lies in the significant differences in temperature requirements for different crops and different growth stages - for example, the suitable temperature for tomato seedlings is 20-25℃, and it needs to be raised to 25-28℃ during the fruiting period; the suitable temperature for Phalaenopsis during the growth period is 18-25℃, and it needs to be stabilized at 20-22℃ during the flowering period. Traditional heating systems are difficult to achieve "zonal and time-based" precise control, and the operating costs are high, especially in cold winter regions, where the heating cost of greenhouses can account for 30%-50% of the total planting cost. The PVT greenhouse heating system, through the "photovoltaic power supply + waste heat heating + energy storage peak shaving" three-in-one design, perfectly solves this problem. Firstly, the system converts solar energy into electricity through PVT components installed on the roof, prioritizing the real-time power demand of greenhouse equipment such as lighting, water and fertilizer integration machines, and circulation fans. The remaining electricity is stored in batteries for use at night or on cloudy days, achieving "self-generation and self-use, with excess electricity stored", reducing the consumption of purchased electricity. Secondly, the waste heat generated by the PVT components is transported to the heat sinks, buried pipes, or fan coil units inside the greenhouse through a water circulation system, providing a stable heat source for the greenhouse. At the same time, the temperature sensors monitor the internal temperature of the greenhouse in real time. When the temperature exceeds the set value, the system automatically reduces the heating intensity and stores the excess heat in the insulation water tank. When the temperature is lower than the set value, the system automatically releases the stored heat to ensure that the temperature fluctuation in the greenhouse is controlled within ±1℃, precisely matching the growth requirements of the crops. Finally, to address the problem of insufficient light and heat supply in winter, the system can be linked with a small amount of auxiliary gas heating equipment (only activated in extremely cold weather), forming a "PVT heating as the main, auxiliary heating as the supplement" mode, minimizing energy consumption. Taking a smart greenhouse strawberry planting base in Jiangsu as an example, the base built a total area of 5,000 square meters of PVT greenhouse heating system in 2022, achieving an autonomous cycle of "power generation + heating" through the installation of 2,000 square meters of PVT components on the roof. Data shows that the system's average daily power generation in winter can reach 800 kWh, fully meeting the power demand of greenhouse equipment, and the remaining electricity can be stored in energy storage batteries for use at night for heating. The average daily heat supply can reach 12,000 MJ, stabilizing the greenhouse temperature at 22-25℃, fully meeting the temperature requirements of the strawberry fruiting period. Compared with traditional gas heating, the base reduces gas consumption by 2,000 cubic meters per year, lowers heating costs by 45%, increases the average yield per mu of strawberries by 18%, and improves the fruit sweetness by 1.5 percentage points. It also reduces carbon emissions by approximately 1.8 tons per year, achieving the unification of "economic benefits, environmental benefits, and social benefits". In addition, the application of PVT technology in greenhouse heating also has the advantages