New method for applying solar energy in greenhouses to reduce fuel consumption

Abstract: Renewable energies (especially solar energy) are globally suitable alternatives for fossil fuels. On the other hand, greenhouses, as a main part of agriculture industry, use a significant amount of fossil fuels annually to provide the required heat for the under-cultivation crops in the greenhouse. Currently this heat demand is provided by a heater which burns gas oil as its main fuel. The main problem with these heaters is fuel hyper-consumption. That is why feasibility of utilizing a solar energy storage system in greenhouses is studied here. As the low temperature heat is required for preheating the air in the greenhouse, a solar collector array is proposed to be utilized in order to displace heating demand of the heater and to reduce amount of fuel consumption. To evaluate the proposed system effectiveness, an economic survey has been done on the proposed system based on Net Present Value (NPV) method. The optimum capital cost for the project is found based on economic methods. The economic analysis showed that 85 flat plate collector modules and an 8.5 cubic meters of storage tank are optimum selection of the project. The results showed that, by employing the proposed system, 7 735 USD benefit as well as 11 050 litres of fuel providence is obtainable annually. Economic evaluation based on NPV method resulted in the payback period of ten years.