4725 - Minimizing TEWI in a Compact Chiller for Unitary Applications PDF

A simulation model was developed to investigate strategies for reducing total equivalent warming impact (TEWI) in compact water chillers. The focus was on minimizing refrigerant charge while increasing efficiency, using R-410A as an example. Compact flat plate heat exchangers with refrigerant channels similar in scale to microchannels appear capable of reducing total system charge by about 80% compared to conventional air-air split systems. Results are also compared to those obtained for highly efficient air-to-air unitary systems, in which minimum-TEWI design strategies require larger heat exchangers having greater charge. Overall, the two approaches achieve comparable reductions in global warming impacts; the chiller depends more on reducing direct emissions, compared to unitary systems’ dependence on reducing indirect emissions through use of flat multiport tubes with folded fins.

Units: SI