Technical evaluation for a solar absorption cooling system to be applied for greenhouse climate control

The management of the greenhouse environment depends on the manipulation of the climat-ic parameters, such as solar radiation, air temperature, relative humidity and carbon dioxide concentration, in order to guarantee suitable growing condition for the crop, safety condition for the workers and energy savings. Evaporative systems are generally used in warm regions for commercial greenhouse cooling, however such systems require large quantity of water that is often a scarce natural resource in Mediterranean areas. Solar absorption cooling sys-tems can be applied for greenhouse climate control in regions with high values of solar irra-diation as alternative to evaporative systems by exploiting renewable energy sources. The solar cooling system could provide significant energy-saving opportunities for cooling green-houses in hot climates allowing the reduction of electricity and water consumption by exploit-ing the contemporaneity between the cooling requirements and the solar energy availability. The paper presents the technical considerations on the application of a solar absorption cool-ing system to a Mediterranean greenhouse. The aim of the research was to define the poten-tial of the system in terms of energy absorption and the solar collector surface related to the greenhouse cultivated area. The simulation study was realized based on the experimental data collected at the experimental centre of the University of Bari, Southern Italy, in order to control the air temperature of a greenhouse covered with plastic film; the greenhouse was characterized by a surface of 300 m2. The cooling system was designed by adopting suitable technologies of energy saving, in order to reduce cooling energy needs. The designed sys-tem consists of an absorption chiller having a cooling capacity of 18 kW fed by 60 m2 of evacuated-tube solar collectors coupled to a new distribution system which provides the cooling power only for the air volume surrounding the crop and not for the whole greenhouse