CO2 Employment as Refrigerant Fluid with a Low Environmental Impact. Experimental Tests on Arugula and Design Criteria for a Test Bench

In order to define design criteria for CO2 refrigeration systems to be used for agricultural products and foodstuff storage, a variable geometrical system was realized, with the goal of meeting a wide range of environmental and process conditions, such as producing low environmental impact and maintaining the highest Coefficient of Performance (COP), at the same time. This test-bench, at semi-industrial scale, was designed as a result of experimental tests carried out on Arugula. The storage tests showed that all samples stored in cold rooms with R.H. control showed a slight increase of weight but also small rot zones in all the boxes due to an excessive accumulation of water condensation; thus, the system may not have achieved conditions that RH requires in a given range, without reaching saturation condition. At the same time, the use of CO2 must be adequately tested along its thermodynamic cycle, during steady state and/or transient conditions, imposing variable working conditions that can simulate plant starting phase or some striking conservation process, like those that characterize sausages. The designed plant will allow studying these specific performances and evaluate COP variation, according to environmental and plant operating conditions.