Waste heat heated greenhouses

Sammanfattning: Large industrial units, electrical generating stations and nuclear power plants all produce waste heat during different processes generally in the form of flue gases or warm water. The high or medium temperate waste heat can be used for many applications, however low temperature waste heat has a few usages such as space heating, water heating or preheating in different industrial processes. Heating is one of the main costs for greenhouse especially in the cold regions like Sweden, so it is very clear that the use of waste heat for greenhouse space heating can bring economical and environmental friendly benefits both for industries and greenhouse owners.This report investigated both technical and economical possibilities to start new greenhouses in the region close to the industries to make use of their waste heat. Case study of 300 m2 polycarbonate twinwall greenhouse selected and peak power demand, annual heat energy and operational electricity requirement for it calculated. This study showed that each square meter of greenhouse requires around 233 W and 270 kWh per year. Case study of Sorption Company could support 656 m2 greenhouse.Economy calculations investigated investment and annual cost and by using an online calculating program, pay-off time and profitability of investment has been studied. Pay-off time counted for 3.1 years, which can be considered as a good investment for such a projects.