Designing and Optimizing Systems for Compressor Rapid Cycling

Uribe, T.; Bullard, C.W.; Hrnjak, P.S.

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https://hdl.handle.net/2142/12179 Copy

Description

Title

Designing and Optimizing Systems for Compressor Rapid Cycling

Author(s)

• Uribe, T.
• Bullard, C.W.
• Hrnjak, P.S.

Issue Date

2003-12

Keyword(s)

compressor short-cycling

Abstract

The purpose of this project is to explore the system design implications of compressor rapid cycling. An earlier project yielded promising results for a typical 2-ton residential split system. It showed that cycle periods as long as 10-25 seconds should be able to produce COP’s comparable to those achievable with variable speed compressors. This project builds on those results and aims to develop ways of designing heat exchangers and other components to fully capitalize on this technology. Even though the experimental program only includes residential systems, most findings all are also relevant for automotive applications where clutch-cycled open compressors are used. This project assumes that rapid cycling is possible by many means, some of them already in the market, and some still to be developed. Earlier work identified the four most important factors that account for the difference between cycle efficiencies of systems with continuous (variable speed) and rapid-cycling compressors: 1) refrigerant-side temperature difference (heat transfer resistance); 2) refrigerant-side pressure drop; 3) heat exchangers thermal capacitance; and 4) refrigerant backflow through the compressor during off-cycle. Results suggested that microchannel heat exchangers may offer significant advantages for rapid cycling systems This project was designed to test that hypothesis. Several system configurations were conceived and tested, namely: 1) direct expansion (DX); 2) flash gas bypass (FGB) 3) high side receiver and 4) high side receiver with suction line heat exchanger (SLHX) all with a microchannel evaporator. Also different alternatives for minimizing each of the loss terms have been analyzed, analytically and experimentally. The results of those experiments and analyses are the subject of this report.

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-220

Type of Resource

text

Language

en

Permalink

http://hdl.handle.net/2142/12179

Sponsor(s)/Grant Number(s)

Air Conditioning and Refrigeration Project 134

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