Determination of heat requirement in greenhouses and evaluation of precautions to be taken for energy efficiency

The thermal energy demand during the production period in greenhouses is important for determining the production economics and feasibility studies to be carried out. This is because evaluating future investments in the greenhouse sector requires accurate estimates of energy demand and costs. For this purpose, the heat energy required in the greenhouse and the heating costs were calculated, taking into account the meteorological conditions of the region, the optimum temperature demand of the plants and the technical specifications of the greenhouse. Two different cover materials were used to determine the heat energy requirement: polyethylene sidewalls and roof (PE) and polycarbonate sidewalls + polyethylene roof (PC+PE). In addition, calculations were made for 8 different greenhouse combinations, including different insulation statuses (poor, medium and good insulation) of these greenhouses without thermal screen and with thermal screens. As a result of the study, it was calculated that the amount of energy consumed was reduced by 4.5% when PC covering material was used instead of PE covering material as covering material for the greenhouse side walls. In greenhouses covered with PE and PC+PE covers, if well-insulated thermal screens are used, the amount of energy consumed will decrease by 23.1%-22.4%, respectively, compared to PE and PC+PE greenhouses without thermal screens. Heating energy and fuel costs that can be saved with low heat transfer coefficient cover materials and well-insulated thermal screens could be reduced by 25.8%. The results of the study will guide greenhouse producers in regions with similar climates in determining the energy consumed, greenhouse design, investment evaluation and also greenhouse sector policies.