Design, Build-up, And Performance Investigation Of A 35 kW (10 Ton) Military Environmental Control Unit Using Transcritical R744 Technology
Stefan W. Elbel, Pega Hrnjak · Purdue e-Pubs (Purdue University System) · 2010
Transcritical R744 technology was used to design and build a compact, lightweight unitary-type air-conditioner for military shelter cooling.The design focus was to achieve high energy efficiencies during operation in hot ambient temperatures.High performance prototype components were used to realize the target performance of 35 kW at the high ambient temperature rating condition (outdoor: 51.7 o C, indoor: 32.2 o C -50%RH).Experiments showed that the COP of this new R744 ECU is approximately 30% higher than that of a comparable R134a ECU and approximately 20% higher than that of a comparable R410A ECU (based on manufacturer data).ECU compactness was determined by calculating cooling output per ECU weight and volume.The new 35 kW R744 ECU was found to be 60% (cooling per weight ratio) and 40% (cooling per volume ratio) more compact than comparable R134a technology.The compactness levels of R744 and R410A technology were found to be approximately equal.