Greenhouse Solar Heating System And Boiler Joint

Solar energy has become a hot topic studied by more and more people due to the increasingly serious energy crisis and environmental pollutions. Chinese greenhouse has been heated mainly based on small-scale coal-fired boiler, which needs high costs to keep it running well. However, with the growing prices of energy, the expenditure of heating is becoming a major problem. The Chinese government carried out relevant policies to promote energy efficiency and develop new energy. Under these beneficial conditions, the development of solar thermal technology has brought a new direction of the greenhouse heating. Because of the heterogeneity and instability of solar, the way to provide heat should be combined with boiler and solar energy for the sake of ensuring the reliability of providing heat throughout the year.This paper firstly introduced the utilization status of greenhouse solar and knowledge of greenhouse heating technology. Based on this, the resource distributions about solar energy in China, as well as the climate zones of greenhouse were divided in the paper. In addition, the basic theory including calculation method of the solar radiation was analysed. The performances of solar collector, heat storage tank, boiler, as well as the cooling system were thermodynamically analysed through explaining the structure of the combined heating system. Further design work including designing the entire system and each important part of the system was conducted. Finally, the dynamic heat load of the greenhouse was also simulated by DeST-h simulation software.Besides, tests and analyses including solar collector system, insulation properties of heat storage tank and heating performance of the greenhouse have been done under Kunming’s climate conditions. Furthermore, effectiveness of the greenhouse including energy conservation, economic efficiency, as well as environmental benefit was evaluated in the paper. The study indicated that the greenhouse system can theoretically save about153.12tons of standard coal per year, which is equivalent to122496yuan. According to the test results, the system can actually save about146tons of standard coal per year, which equals116800yuan. The investment cost can be recovered within8.2years theoretically and8.6years practically. The carbon emissions reductions of the system reach10190.04tons in20years on the premise of totally converting the amount of solar radiation in Kunming per year. And the average annual amount of emissions reductions of carbon dioxide is about509.5tons under this premise. Benefit evaluation of the system show this system has a very good energy efficiency, economy and environmental protection, and should be widely applied.Project summary and outlook of this research have been done at the end of the paper. As a new greenhouse heating method, solar energy has capabilities to save energy, obtain economic benefits and protect environment, which possesses broad prospects in the field of greenhouse heating.