Qiu Z.,The Branch of Agri. Science and Technology of Gansu Science and Technology Association with Retired Experts |
Song M.,Gansu Academy of Agricultural science |
Wang J.,The Branch of Agri. Science and Technology of Gansu Science and Technology Association with Retired Experts |
Zhang X.,Gansu Province Economic Crop Technology Exten sion Station |
And 3 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2014
In order to solve the common problems in existing solar greenhouses such as simple equipment, poor environmental regulation and cold prevention ability, as well as low land utilization rate and labor productivity, a new type of greenhouse, the assembly type solar double effect greenhouse was built and researched. There are two kinds of structures for the assembly type of the solar double effect greenhouse: internal insulation greenhouse and external insulation greenhouse. Internal insulation warehouse has two layer frames with single layer film covering each layer frame, in addition, one layer of heat preservation quilt is placed between the two layer frames to insulate and preserve heat energy during the night. The external insulation greenhouse has a structure of transparent Polycarbonate sandwich plate as its back half roof and back wall. In winter time, thermal insulation material is filled in the interlayer to preserve heat, in the meantime, the heat preservation quilt is covered on the front half roof, it changed the old way of an opaque back wall and an opaque back half roof in the previous greenhouse. Both the internal and the external insulation greenhouses are fully transparent greenhouses with galvanizing steel structures as framework. A solar energy source heat pump system is assembled in the greenhouse, it includes a solar heat collector, thermal storage pool and the heat pump, with water as its medium, it uses the solar heat collector to convert solar energy into heat energy and it is stored in thermal storage pool. When it is cold, the solar heat collector converts the heat energy stored in the heated water to the greenhouse. When the stored heated water is too cold to provide heat energy, the heat pump is started to convert the low grade heat energy to high grade heat energy, to provide heat energy to the greenhouse. The heat pump can also convert the steam and redundant heat energy in the air into heated water and it is stored in the thermal storage pool, so as to adjust the air temperature and moisture in the greenhouse automatically thus achieving double effects. In this paper, insulation moisture performance and the yield increasing effect are mainly researched for the assembly type of the solar double effect greenhouse. The test was processed from Dec. 2012 to Jan. 2013. The main test indexes are, air minimum temperature, daily average temperature, light intensity, relative air humidity, crops yield per plant and yield per unit area. The test results show: For the internal insulation greenhouse, the minimum temperature of the testing greenhouse was always over 9℃. Compared to the reference greenhouse, during Jan. 2013, the average temperature increased 3.4℃, the monthly average minimum temperature increased 4.0℃, and the monthly average relative air humidity was below 80%, thus achieved a 70% reduction in the incidence of vegetables. For the external insulation greenhouse, the average minimum temperature of the testing greenhouse was 12.5℃, the relative air humidity was below 80%, and the average temperature increased 3.8℃ compare to the reference greenhouse. The temperature was 27.7℃ higher than outside of the greenhouse (-15.2℃), the yield of the planting vegetables increased 19% - 55%. The conclusion is, the assembly type of the solar double effect greenhouse improved environmental conditions greatly, and improved the capacity of both cold and disease prevention, and increased both production and income. The research and application of this new type of greenhouse are referenced for similar areas in northern China.