During the process of refrigerant alternative, R290 (propane), as a nature refrigerant used in Room Air Condition (RAC) system, is thought as a long-team substance and has attracted great attention. This paper simply introduced the characteristics and standard demands of R290 application, then, based on a 1HP R290 DC INV. RAC system at first, then finished the comparison test when a one-cylinde...

Modern lifestyle, industrialization and economy thrive on energy which is getting expensive overtime. Thermosyphon based systems are getting attraction for their promising heat transfer efficiency and zero energy utilization. Refrigerants having ozone depletion potential (ODP) and high Global Warming Potential (GWP) have been banned or under time bared permission under Montreal (1987) and Kyoto...

An important issue for optimal operation and plantwide control is to find the degrees of freedom available for optimal operation. A previously published systematic approach to determine the steady state degrees of freedom is expanded to take into account the active charge as a possible degree of freedom in cyclic processes. Additional degrees of freedom related to the composition of the circula...

We have developed a new CO2 heat pump water heater compressor with a single rotary mechanism in practical use for the first time in the world. CO2 refrigerant doesn't destroy the ozone layer, and the global warming potential (GWP) is less than 1/1000 in comparison to hydro-fluorocarbon refrigerants. However the operating pressure of CO2 refrigerant is approximately three times as high as that o...

According to the results of the international testing program AREP, the most likely replacements for HCFC-22 refrigerant will be blends of HFCs. However, as concerns about their global warming potential increase, other options should also be considered. As a naturally occurring substance, propane would be an ideal refrigerant, except for its flammability. When dealing with a flammable refrigera...

Refrigerant mass migration and redistribution have been regarded as factors influencing the performance of air conditioning and refrigeration systems. This paper presents a dynamic model of an R134a automotive A/C system that is able to capture the shut-down and start-up cycling dynamics including the refrigerant mass migration transients. Building upon recent work (Li and Alleyne, 2010), the h...

Variable refrigerant flow (VRF) systems are easily subjected to performance degradation due to refrigerant leakage, mechanical failure or improper maintenance after years of operation. Ideal VRF systems should equip with fault detection and diagnosis (FDD) program to sustain its normal operation. This paper presents the fault diagnosis method for refrigerant charge faults of variable refrigeran...

Using identical mechanical hardware used in an automobile, a stationary test bench has been developed for an automotive air conditioning system (AACS). However, a number of additional sensors have been used in the system for an accurate assessment of its performance. The steady state performance of the system has been investigated for three independent variables, namely the refrigerant charge l...

Heat pump technology has been rapidly developed recently as a clean and efficient heating method. Continuous capacity modulation of heat pumps is necessary for enhancing room thermal comfort and reducing start-stop losses. A novel capacity modulation method for the scroll compressor heat pump system based on refrigerant injection and refrigerant release is proposed. The experiments indicate the...