Evaporation characteristics of R22 flowing inside a corrugated tube

Technical Report · Wed Jul 01 04:00:00 EDT 1992

OSTI ID:10150181

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. As part of a larger program investigating nonazeotropic refrigerant mixtures for replacement of chlorofluorocarbon compounds, we investigated the performance of R22 (chlorodifluoromethane) in conventional smooth tubes and enhanced heat transfer tube geometries as a base case. This paper presents the results of this initial investigation for a smooth tube and a tube with a commonly available enhanced heat transfer surface, called corrugated or spirally indented. We investigated the evaporating heat transfer and pressure drop characteristics in an experimental apparatus consisting of a variable-speed compressor and two sets of counterflow concentric-tube heat exchangers having both smooth and corrugated enhanced tubeside surfaces. The refrigerant circulates inside the central tube and water circulates in the annulus. The measured pressure drop and the heat transfer coefficient for the evaporation of the R22 are presented as a function of heat flux, quality, and mass flux for both heat transfer surfaces. Both the heat transfer coefficient and the pressure drop of the corrugated surface are higher than those of the smooth surface at any given refrigerant condition. The heat transfer enhancement is most notable at low mass qualities.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 10150181
• Report Number(s): CONF-920804--11; ON: DE92015104
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320106
320302
42 ENGINEERING
420400
AIR CONDITIONERS
BUILDING EQUIPMENT
CHLOROFLUOROCARBONS
EFFICIENCY
EVAPORATION
EXPERIMENTAL DATA
FLOW RATE
HEAT EXCHANGERS
HEAT PUMPS
HEAT TRANSFER
HEAT TRANSFER AND FLUID FLOW
MATERIALS
PRESSURE DROP
REFRIGERANTS
TUBES