Performance characteristics of a residential air conditioning system with subcooling control
Bruno Yuji Kimura de Carvalho1, Pega Hrnjak2,3.
1University of Illinois at Urbana-Champaign, Urbana, United States; 2University of Illinois at Urbana-Champaign, Urbana, United States; 3Creative Thermal Solutions, Inc., Urbana, United States
Superheat control of refrigerant flow using thermostatic expansion valves (TEV) has been widely employed in residential air conditioning and heat pump (RAC&HP). Subcooling control is an alternative for refrigerant flow metering focusing on maximizing COP/HPF or capacity. An electronic expansion valve (EEV) adjusts subcooling while an accumulator prevents liquid return.
The paper provides an experimental analysis on the performance of a RAC system with subcooling control.
Performance of the system was evaluated at different conditions, at nominal charge. Superheat and subcooling control are compared. Refrigerant charge was also optimized at a single condition for both superheat and subcooling control.
Results show a 10.1% increase in COP using subcooling control for indoor/outdoor temperatures of 20°C/40°C. Subcooling control provides a balance between the increase in specific compression work and the increase in specific refrigerating effect.
