|Title:||Minimizing TEWI by Charge Reduction in a Compact Chiller
|Author(s):||Barnes, P.R.; Bullard, C.W.
|Subject(s):||stationary air conditioning system analysis
|Abstract:||A simulation model was developed to investigate strategies for reducing total equivalent
warming impact (TEWI) in compact water chillers. The focus was on minimizing R-410A
refrigerant charge while increasing efficiency. Compact flat plate heat exchangers with
refrigerant channels similar in scale to microchannels (Dh= 0.7 mm and 0.8 mm for the
condenser and evaporator, respectively) appear capable of reducing total system charge 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
multi-port tubes with folded fins. These results are tentative, because the simulations did not
include detailed analysis of possible opportunities for improving the chiller technology by
optimizing the air and water pumping requirements in the secondary loop. The primary benefit
of the chiller technology, relative to air-air unitary, appears to lie in its compatibility with the use
of toxic or flammable refrigerants.
|Publisher:||Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign.
|Series/Report:||Air Conditioning and Refrigeration Center TR-176
|Sponsor:||Air Conditioning and Refrigeration Project 69
|Date Available in IDEALS:||2009-05-29