Frost deposition and refrigerant distribution in microchannel heat exchangers

Sumin Song; Clark W. Bullard; Predrag Stojan Hrnjak

Frost deposition and refrigerant distribution in microchannel heat exchangers

Sumin Song, Clark W. Bullard, Predrag Stojan Hrnjak

Mechanical Science and Engineering

Research output: Contribution to journal › Conference article › peer-review

Abstract

This paper investigates frosting and refrigerant distribution in the outdoor coil of a 10 kW CO₂ (R-744) split system in heating mode. Experimental results are presented from a well-instrumented prototype, operating under frosting conditions. Photographs record frost buildup over time, and reveal nonuniform patterns of surface temperature distribution at carefully selected operating conditions (air inlet temperatures at 4.5°C; air inlet humidity 55%; 0.10 and 0.30 inlet vapor qualities). Parallel heat exchanger modules exhibited different frosting patterns, so they were tested individually. Results indicated that such frosting tests can be an inexpensive and efficient way to identify severe refrigerant maldistribution problems and to suggest a possible cause.

Original language	English (US)
Pages (from-to)	944-953
Number of pages	10
Journal	ASHRAE Transactions
Volume	108 PART 2
State	Published - 2002
Event	ASHRAE Transactions 2002 - Honolulu, HI, United States Duration: Jun 22 2002 → Jun 26 2002

ASJC Scopus subject areas

Building and Construction
Mechanical Engineering

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title = "Frost deposition and refrigerant distribution in microchannel heat exchangers",

abstract = "This paper investigates frosting and refrigerant distribution in the outdoor coil of a 10 kW CO2 (R-744) split system in heating mode. Experimental results are presented from a well-instrumented prototype, operating under frosting conditions. Photographs record frost buildup over time, and reveal nonuniform patterns of surface temperature distribution at carefully selected operating conditions (air inlet temperatures at 4.5°C; air inlet humidity 55%; 0.10 and 0.30 inlet vapor qualities). Parallel heat exchanger modules exhibited different frosting patterns, so they were tested individually. Results indicated that such frosting tests can be an inexpensive and efficient way to identify severe refrigerant maldistribution problems and to suggest a possible cause.",

author = "Sumin Song and Bullard, {Clark W.} and Hrnjak, {Predrag Stojan}",

year = "2002",

language = "English (US)",

volume = "108 PART 2",

pages = "944--953",

journal = "ASHRAE Transactions",

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publisher = "Amer. Soc. Heating, Ref. Air-Conditoning Eng. Inc.",

note = "ASHRAE Transactions 2002 ; Conference date: 22-06-2002 Through 26-06-2002",

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TY - JOUR

T1 - Frost deposition and refrigerant distribution in microchannel heat exchangers

AU - Song, Sumin

AU - Bullard, Clark W.

AU - Hrnjak, Predrag Stojan

PY - 2002

Y1 - 2002

N2 - This paper investigates frosting and refrigerant distribution in the outdoor coil of a 10 kW CO2 (R-744) split system in heating mode. Experimental results are presented from a well-instrumented prototype, operating under frosting conditions. Photographs record frost buildup over time, and reveal nonuniform patterns of surface temperature distribution at carefully selected operating conditions (air inlet temperatures at 4.5°C; air inlet humidity 55%; 0.10 and 0.30 inlet vapor qualities). Parallel heat exchanger modules exhibited different frosting patterns, so they were tested individually. Results indicated that such frosting tests can be an inexpensive and efficient way to identify severe refrigerant maldistribution problems and to suggest a possible cause.

AB - This paper investigates frosting and refrigerant distribution in the outdoor coil of a 10 kW CO2 (R-744) split system in heating mode. Experimental results are presented from a well-instrumented prototype, operating under frosting conditions. Photographs record frost buildup over time, and reveal nonuniform patterns of surface temperature distribution at carefully selected operating conditions (air inlet temperatures at 4.5°C; air inlet humidity 55%; 0.10 and 0.30 inlet vapor qualities). Parallel heat exchanger modules exhibited different frosting patterns, so they were tested individually. Results indicated that such frosting tests can be an inexpensive and efficient way to identify severe refrigerant maldistribution problems and to suggest a possible cause.

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VL - 108 PART 2

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JF - ASHRAE Transactions

T2 - ASHRAE Transactions 2002

Y2 - 22 June 2002 through 26 June 2002

ER -

Frost deposition and refrigerant distribution in microchannel heat exchangers

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