Cycle performance testing of nonazeotropic mixtures of HFC-142a/HCFC-124 and HFC-32/HCFC-124 with enhanced surface heat exchangers

Conference · Tue Jun 01 00:00:00 EDT 1993

OSTI ID:10162849

Vineyard, E A; Conklin, J C; Brown, A J

In an effort to improve the efficiency of residential heat pumps using altemative refrigerants, two nonazeotropic refrigerant mixtures (NARMs) were tested over a range of heat exchanger capacities to determine their cooling mode performance at US Department of Energy (DOE) heat pump rating conditions of 82{degrees}F (27.8{degrees}C). The two mixtures, 30% HFC-32/70% HCFC-124 and 75% HFC-143a/25% HCFC-124, were selected on the basis of a previous study that screened refrigerant pairs using such factors as boiling point, stability, ozone depletion potential (ODP), and coefficient of performance (COP) to determine suitable candidates for residential heat pump performance. Three refigerant-side heat transfer enhancements were tested to determine improvements to overall system performance. Comparisons were made on the basis of the COP as a function of capacity. The results for one of the heat exchanger combinations, a segmented evaporator and finned condenser, were quite promising. Improvements in COP, relative to that for HCFC-22, were from 9 to 17% for the 30% HFC-32/70% HCFC-124 mixture and from 5 to 9% for the 75% HFC-143a/25% HCFC-124 NARM. Another combination, a smooth tube evaporator with a perforated foil insert and finned condenser, had similar gains at low capacities but experienced decreased performance at the higher capacities. The final combination, a smooth tube evaporator with a perforated foil insert and smooth tube condenser with a benttab insert resulted in poor performance.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 10162849
• Report Number(s): CONF-930675-4; ON: DE93015215
• Resource Relation: Conference: 1993 American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) annual meeting,Denver, CO (United States),26-30 Jun 1993; Other Information: PBD: [1993]
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
54 ENVIRONMENTAL SCIENCES
36 MATERIALS SCIENCE
REFRIGERANTS
PERFORMANCE TESTING
FLUORINATED ALIPHATIC HYDROCARBONS
THERMODYNAMIC PROPERTIES
HEAT EXCHANGERS
HEAT PUMPS
AIR POLLUTION ABATEMENT
COEFFICIENT OF PERFORMANCE
320107
540120
360606
BUILDING SYSTEMS
CHEMICALS MONITORING AND TRANSPORT
PHYSICAL PROPERTIES