“To solve the problems of insufficient rhizosphere temperature, severe fluctuations in thermal environment, and high energy consumption of traditional heating methods in solar greenhouses during winter, a gravity driven rhizosphere water cycle heat exchange system (WCHES) was constructed. Field comparative experiments and energy analysis methods were used to study the rhizosphere temperature regulation performance, thermal buffering characteristics, and energy efficiency of the system under clear and cloudy winter conditions. This provides important technical support and equipment reference for improving the winter rhizosphere thermal buffering capacity of solar greenhouses in northern China and achieving green and low-carbon production in facility agriculture.”