During winter, greenhouses face a particular challenge: on sunny days, the indoor air can become excessively warm, and part of this heat is released through ventilation. At night, however, gas or electricity must be used again to maintain the required temperature. In other words, surplus heat accumulated during the day is lost, only for additional energy to be consumed a few hours later to produce heat again.
One way to address this problem is to capture surplus daytime heat, store it, and reuse it at night. Heat from the greenhouse air is transferred to water through a heat exchanger. The heated water is then stored in an insulated tank. At night, when the air temperature drops, the stored thermal energy is used to heat the greenhouse with the help of a heat pump. In this way, heat that would otherwise be lost during the day becomes an additional source of energy at night. Because the system operates together with ventilation, it can also help regulate excess humidity and maintain a more stable greenhouse microclimate.
This approach was tested under field conditions in an operational greenhouse in Pinggu District, Beijing, China. Winter observations were conducted from 16 December 2023 to 20 January 2024, while the study results were published in 2026. During the day, the system captured and stored surplus heat and released it back into the greenhouse at night.
The coefficient of performance (COP) in heating mode reached 4.8. In simple terms, for every 1 kWh of electricity consumed, the system delivered approximately 4.8 kWh of thermal energy. At night, the greenhouse temperature was on average 4.4°C higher than under conditions without heating. According to the authors’ calculations based on local energy tariffs, operating costs were 47.5% lower than with coal heating and 64.8% lower than with gas heating. In summer mode, the system reduced the indoor air temperature by an average of 3°C compared with natural ventilation.
For Uzbekistan, the technology is particularly relevant because it could make use of the temperature difference between sunny winter days and cold nights. Storing surplus heat accumulated during the daytime could reduce demand for gas or electricity during the evening and nighttime hours. Presidential Resolution of the Republic of Uzbekistan No. PP-371, dated 13 October 2026, also provides support mechanisms for the introduction of energy-efficient and environmentally friendly heating technologies.
The technology could therefore first be tested through a pilot project at a modern vegetable greenhouse in Tashkent Region. The pilot should compare gas and electricity consumption, nighttime temperature, humidity levels, energy costs per square metre, crop yield, and the investment payback period with those of a conventional heating system. If the results confirm the technical and economic feasibility of the solution, its wider application in other greenhouse facilities could be considered.
Alisher Azizov
Chief Specialist, NGO “Center for Sustainable Development”