In greenhouses, crop production is dependent on soil and air temperature as well as humidity and solar radiation. Greenhouse operators face many challenges, among them increasing energy costs, security of energy supply, and customer expectations for more sustainable operations, which means a reduction in carbon footprint and the transition to carbon-free production processes. At the same time they need to ensure the production of food for the increasing needs of the community. Solar thermal as an energy source enables the greenhouse operator to tackle many – if not all – these challenges.
Flat plate collector-based solar plants provide competitive sources of heat for applications requiring heat at below <100 °C, and are especially competitive for temperature levels used in most greenhouses, e.g. 40–60 °C. Solar thermal heated water can satisfy several purposes in greenhouses, such as feeding rails and growing pipes, central heating and dehumidification.