Energy and Economic Analysis of an R744 Cooling System as a Replacement for an R404A System

Abstract

      High consumption of energy in HVACR industry need to be reduced according to intense fossil fuels usage. It is dangerous for our climate and then for our health and life quality of next generations. The main aim of the study is to compare two cooling systems with the same cooling capacity but with different working refrigerant. One of them is R404A (fluorinated gas) and another is R744 (carbon dioxide). The question is, which of the systems uses lower amount of energy and which of them has lower LCC. The ‘carbon path’ – CO₂ emmision is considered too. In the paper the configuration of the systems were established. The cycle with R404A is straight one stage compressor refrigeration system compare to supercritical compression refrigeration system with R744. The calculation process was done in Pack Calculation Pro software. It gives some databases with climate data which helps to find exploitation energy usage and energy cost with ‘carbon path’ calculations. For a system based on the use of R744 refrigerant, electricity consumption is lower than when using R404A refrigerant. Particularly large savings are generated in winter. Annual savings can be estimated at 28%. This is due to the difference in average annual EER of 1.15. Then, calculation introduced that total emission for the system with R404A is nearly 32% higher than in case of R744 supercritical compression system. The comparison done in this paper shows that supercritical compression systems with R744 is good alternative technology for those with fluorinated gases. However, some technical problems should be improved to make this technology much more efficient, cheaper and safe.