PERFORMANCE AND CONTROL STRATEGIES ANALYSIS OF A CO_2 TRANS-CRITICAL BOOSTER SYSTEM

摘要

This research paper theoretically studies the performance and control strategies of a CO_2 trans-critical booster system. A computer simulation with field measurement-based inputs is used to analyse the performance of the system. Energy usage/efficiency indicators including cooling-heating loads, electricity use and COPs are presented and discussed for an entire year. Subsequently, some of the controlled parameters are varied to evaluate their significance in energy saving.rnAccording to the results, in the warm months, medium temperature cooling demand is 30-35% higher than cold months and the entire heat is rejected in the gas cooler while half of the dissipated heat is recovered in the de-superheater in cold months, following the suggested heat recovery control strategy. Considering the system as a heat pump, a high seasonal performance factor of 4 is achieved.rnStudying the control parameters shows that lowering the gas cooler approach temperature and increasing evaporation temperature in cabinets and freezers are the most efficient methods for energy saving.rnCO_2 trans-critical booster system with proper control strategies can provide the entire refrigeration and heating demands with high energy efficiency in relatively cold climates.