The usage of the renewable energy sources and their application for greenhouse heating

In this study the usage of renewable energy sources in greenhouse heating is mentioned. Generally, it requires a heat pump application. The usage of the ground as an energy source is more attractive than air and water in cold climates as well because of its almost permanent properties during year. Consequently, ground source heat pumps and ground heat exchangers are mentioned primarily in our thesis. In addition, the usage of solar energy in greenhouse heating applications are included in our thesis. However, the times of obtaining the solar energy and the time that the high thermal loads exist do not coincide, because of that the thermal energy storages which allow solar energy to be stored and used when it is needed are mentioned. The properties of the ground change in time. In addition the heat transfer from the ground to the water which circulates in the ground heat exchanger changes the properties of the ground. Because of these reasons thermal performance of the ground decreases in time. Therefore heating the greenhouse with ground source heat pump system causes high electricity loads especially during nights when thermal loads increases so high. To decrease these high loads, solar and thermal energy storage assisted ground source heat pump system was projected. In order to obtain sufficiently precise results, hourly heat losses of the greenhouse, hourly heat gains from ground and solar energy and hourly energy quantity stored in thermal energy storage were calculated and given in the tables. The investment costs and operational costs of the system and the storage?s additional compressor work supply ratios were calculated for different ground heat exchanger module pipe lengths, module quantities and burying debths, different solar collector surface areas and thermal energy storage volumes. The pay-back periods were calculated comparing the total of the investment and operational costs of the system with the total of the investment and operational costs of a conventional heating system and the results were shown as charts and tables. Keywords: Greenhouse heating, heat pump, ground heat exchanger, solar energy, thermal energy storage