|Abstract:||This work evaluates the performance and control of split system air conditioners
charged with a zeotropic, HCFC-22 alternative consisting of HFC-32, HFC-125, and
HFC-134a (23%,25%, and 52% respectively). The study involves the development of
two analysis tools: a split system air conditioner testing facility, and a mathematical system
model that predicts the performance of the facility. The experimentally validated system
model is used to analyze the potential system performance gains resulting from enhanced
evaporator air-refrigerant temperature profiles. In particular, six different evaporator
designs with varying tube arrangements are included in the system simulation to evaluate
the effects of increasing the number of evaporator rows on air conditioner efficiency.
Finally, the control of a system charged with the zeotrope is evaluated. Changes in system
capacity, sensible heat ratio, and system efficiency resulting from controlling evaporator air
flow rate, compressor speed, and expansion valve opening are quantified.