Modeling and technical-economic analysis of the combined cooling, heat & power systems (CCHP) based on a gas engine for use in a greenhouse in Tehran

Providing electrical, thermal and cooling energy in greenhouses is a very important issue. Due to the low efficiency of most of the conventional systems in greenhouses, the use of simultaneous production of electricity, heat and cooling (CCHP) systems has been highly considered in recent years. The main purpose of this article is the technical and economic feasibility of CCHP technology for use in a greenhouse in Tehran. In this research, a cucumber greenhouse with an area of 1 hectare, which consists of two structures of 0.5 hectare, has been analyzed and investigated. In order to analyze the technical-economic system used, calculations for four scenarios including the basic and conventional system, CCHP with absorption chiller and selling electricity to the grid, CCHP with absorption chiller and self-supply and CCHP with compression chiller and self-supply accepted. According to the results obtained for each scenario as well as the comparison of the selected scenarios, the greenhouse considered for the implementation of the CCHP system is not economical. The results of the research show that in case of using the CCHP system with absorption chiller and selling electricity to the grid, in order to make the system economical, the minimum rate of buying electricity from these units should be 3223 Rials per kilowatt hour. In the CCHP system with absorption chiller and self-supply, if the location of the greenhouse is such that 176 kilometers of transmission line is needed, this scenario becomes economical.