Evaporation of nonazeotropic mixture of refrigerants R143a and R124 flowing inside smooth and corrugated tubes

Conference · Sat Aug 01 04:00:00 EDT 1992

OSTI ID:10167408

Hinton, D L ^[1]; Conklin, J C; Vineyard, E A ^[2]

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1. Tennessee State Univ., Nashville, TN (United States)
2. Oak Ridge National Lab., TN (United States)

Because heat exchanger thermal performance has a direct influence on the overall cycle performance of vapor-compression refrigeration machinery, enhanced heat transfer surfaces are of interest to improve the efficiency of heat pumps and air conditioners. We investigated a nonazeotropic refrigerant mixture (NARM) of 75% R143a and 25% R124 (by mass) to study its thermal performance in an evaporator made of conventional smooth tubes and another evaporator made of corrugated, or spirally indented, tubes. We investigated the evaporating heat transfer and pressure drop characteristics in an experimental test loop model of a domestic heat pump system employing a variable speed compressor. The refrigerant circulates inside the central tube and the water circulates in the annulus. At a refrigerant mass flux of approximately 328 kg/m{sup 2}s, the measured irreversible pressure drop of the corrugated surface was 100% higher than that of the smooth surface, and the measured heat transfer coefficient was 11% higher than that of the smooth surface.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 10167408
• Report Number(s): CONF-921110--15; ON: DE92018994
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320106
320303
42 ENGINEERING
420400
AIR CONDITIONERS
BUILDING EQUIPMENT
EQUIPMENT AND PROCESSES
EVAPORATION
HEAT EXCHANGERS
HEAT PUMPS
HEAT TRANSFER
HEAT TRANSFER AND FLUID FLOW
MIXTURES
PRESSURE DROP
REFRIGERANTS
REYNOLDS NUMBER
THERMODYNAMIC CYCLES
TUBES
VAPOR COMPRESSION REFRIGERATION CYCLE