Aspects Regarding the Optimal Insulation Thickness, the Cost and Energy Savings for Cold Storage in Romania

The paper presents a technical and economic analysis regarding the sandwich panels with polyurethane insulation layer (PUR) used in cold stores’ construction. The authors determine the optimal thickness of the insulating layer (OIT) corresponding to the 5 climatic zones in Romania. The operating and investment costs for cold and frozen storage in these 5 climatic zones have been assessed. The results obtained from the analysis show that regardless of the climatic zone, the OIT for cold storage is 150 mm and for frozen storage is 180 mm. The investment cost increases by 41% and the expenditure on operating energy decreases by 8.3% for 180 mm for cold storage in comparison to OIT. Moreover, this tendency is maintained as well in the other case of frozen storage, where, by increasing the thickness above OIT at 200 mm the investment cost is increased by 20% and the expenditure in operating energy is decreased by 6.7%. The SEC has an average value of 54.83 kWh·m3/yr for cold storage and 74.55 kWh·m3/yr for frozen storage respectively. The average values obtained in the paper were compared with those presented in the literature and resulted in deviations of about 1.58% for refrigeration, and hence 4.1% for freezing.