Refrigerant-Side Instrumentation in Room Air-Conditioners

Jensen, A.C.

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https://hdl.handle.net/2142/11312 Copy

Description

Title

Refrigerant-Side Instrumentation in Room Air-Conditioners

Author(s)

Jensen, A.C.

Contributor(s)

Dunn, W.E.

Issue Date

1996-07

Keyword(s)

stationary air conditioning system analysis

Abstract

A refrigerant-side instrumentation system has been developed, installed, and utilized to obtain steady-state data from a 1.5-ton capacity room air conditioner for the continued validation of a simulation model. This report describes the design, in situ calibration, and verification of three venturi meters used to provide minimally intrusive measurements of refrigerant mass flow rate in the discharge, liquid, and suction lines. The specification and implementation of immersion thermocouples and pressure transducers used to directly measure refrigerant . temperatures, absolute pressures, and pressure drops is also described. Using companion data from thennocouples affixed to refrigerant tube surfaces, comparisons are made between surface and refrigerant-side instrumentation methods and recommendations are given regarding the simplest, cheapest, and most accurate methods for measuring refrigerant temperatures, pressures, and mass flow rate in room air conditioners. As well, the intrusive effects of refrigerant-side instrumentation on room air conditioner perfonnance are investigated. Lastly, perfonnance tests using R407C, a promising alternative to R22 in room air conditioners, are reported for the purpose of validating the simulation model with alternative refrigerants. The venturi meters provided refrigerant mass flow rate within ±2% and revealed that the discharge and liquid lines are best suited for venturi mass flow measurements. With the proper installation and insulation, surface thermocouples can be used to provide refrigerant temperatures within ±1-2 OF for the two-phase regions and outlets of the condenser and evaporator. Unavoidable intrusions on room air conditioner performance are introduced by the instruments themselves and the process of installing them (cutting open tubes, removing and reinstalling compressor, etc.). The effect of increased system volume can be controlled by increasing charge.

Publisher

Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign.

Series/Report Name or Number

Air Conditioning and Refrigeration Center TR-101

Type of Resource

text

Language

en

Permalink

http://hdl.handle.net/2142/11312

Sponsor(s)/Grant Number(s)

Air Conditioning and Refrigeration Project 69

Owning Collections