Study on the Effect of Storing the Solar Heat Energy under the Ground of Greenhouse

Zhang Hailian 1, Xiong Peigui 2, Zhao Limin 1 and Xu Haiqin 2 (1 Hanzhong Normal College, Shaanxi Hanzhong 723000, 2 Qinghai Academy of Agricultural Science, Xining 810016)

The solar heat energy; Greenhouse; Storing heat under ground; Effects of temperature rising; Temperature curves

Measurement, analysis and study were conducted on the efficiency of the system of storing the solar heat energy under the ground of a vegetable greenhouse, located in Xining in the QinghaiTibetan Plateau. A total of 18 measuring temperature points was set inside and outside the greenhouse, at the air,the surface of the ground,and 5,10,15,20,40,60,80 cm deep under the ground respectively. The temperature at each point was measured every day for a whole year. Correlation coefficients, regression equations and other parameters were calculated, with results indicating (in the order of points mentioned above) that: 1. the indoor annual average temperatures rose to 17.9,20.2,19.1,18.7,18.5,18.7,18.7,18.9,18.3 ℃ respectively, 2. the indoor temperature increments were 12.2, 9.2, 10.8, 10.7, 10.7. 11.1, 11.0, 11.2, 10.3 ℃,compared with the outdoor annual average temperatures, 3. the dynamic equilibrium of the heat stored under the ground by the system reached to 5.68 GJ. After both the earth and the air temperatures inside the greenhouse rose, many kinds of vegetables grew in and kept it green all the year, and therefore, definits economic benefits were produced.