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Simplified Models Of Fault Effects On Unitary Air-Conditioning Equipment For Use In Building Simulation Tools, David Yuill, Mehdi Mehrabi
Simplified Models Of Fault Effects On Unitary Air-Conditioning Equipment For Use In Building Simulation Tools, David Yuill, Mehdi Mehrabi
David Yuill
Building performance models most typically do not account for equipment faults, even though such faults are believed to significantly impact performance. One reason is that fault effects on performance are not very well understood, and can be quite complex to model. To address this situation, the current paper provides a summary of known empirical studies of fault effects on air-cooled unitary equipment. The summary includes three important performance parameters – capacity, efficiency, and sensible heat ratio – for three common fault types. Statistical analyses have been used to provide simplified models that can be programmed into building simulation software
Generalized Effects Of Refrigerant Charge On Normalized Performance Variables Of Air Conditioners And Heat Pumps, Mehdi Mehrabi, David Yuill
Generalized Effects Of Refrigerant Charge On Normalized Performance Variables Of Air Conditioners And Heat Pumps, Mehdi Mehrabi, David Yuill
David Yuill
Several laboratory experiments have studied the effect of faults on vapor compression cycle air-conditioning systems. There has been a particular focus on refrigerant charge variation, which is believed to be quite common in air conditioners. The current paper summarizes the effects on several normalized performance variables for all of the results available in the literature for refrigerant charge variation, and provides generalized relationships. The generalizations were developed for operation at ANSI/AHRI 210/240 standard test conditions and are provided separately for fixed orifice and thermostatic expansion valve equipped systems in both cooling and heating mode. The level of variation found in …