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...

The TEWI analysis of residential heat pumps shows that it is sensitive to refrigerant emissions and mainly dependent on the seasonal coefficient of performance of the heating unit. Otherwise for countries where electricity is mainly produced by a combination of nuclear-power and hydro-power, the direct emissions become not negligible compared to the indirect emissions. Both direct and indirect ...

The capillary tube/suction line heat exchanger (SLHX) is widely used in small refrigeration systems. The refrigerant flowing in the SLHX experiences frictional and accelerational head losses, flashing, and heat transfer simultaneously. The simulation of refrigerant flow through SLHX is important since this will help engineers analyze and optimize the SLHX incorporated in a refrigeration system....

The present paper summarizes the activities at LTT-Erlangen on the field of thermophysical properties research for pure refrigerants and refrigerant mixtures. For the characterization of their thermophysical properties dynamic light scattering (DLS) has been intensively applied as a key tool during the past two decades. Beside a representation of the essential features of DLS for the determinat...

The Air conditioning system satisfies the various space conditions required for the comfort and industrial air conditioning. Now days demand for AC system applications are increasing and include the areas of application like apartment buildings, banks, office buildings, industrial plants, schools, restaurants etc. This growing demand for air conditioning system forced manufactures to develop su...

Kim, Woohyun. Ph.D., Purdue University, December 2013. Fault Detection and Diagnosis for Air Conditioners and Heat Pumps based on Virtual Sensors. Major Professor: James E. Braun, School of Mechanical Engineering. The primary goal of this research is to develop and demonstrate an integrated, on-line performance monitoring and diagnostic system with low cost sensors for air conditioning and heat...