Optimization, Design and Fabrication of a Prototype 5-Ton ECU Using Hydrocarbon Refrigerants

Mainstream has a long history of investigating the use of hydrocarbon refrigerants in heat pumps and air conditioners. Experimental data has demonstrated the performance of some hydrocarbon refrigerants to be about 7% better than R-410A and 10% better than HCFC-22. Experiments have also demonstrated that hydrocarbon blends can be formulated to match the saturation temperature/pressure behavior of HCFC-22. Compressor tests have shown that the hydrocarbons are compatible with conventional mineral-oil refrigeration oils. This Phase I effort proposes to: A) evaluate the performance of various hydrocarbon refrigerants and mixtures using our in-house heat pump models, B) select the optimum hydrocarbon working fluid for this Lightweight ECU application, C) experimentally determine the flammability characteristics of the potential hydrocarbon refrigerant, D) Design and Build a full-scale prototype 5-Ton Lightweight ECU, E) measure the performance of this improved ECU, and F) compare the performance, size and weight benefits to Mainstream's existing ECU which uses R-410A. Phase I also includes the delivery of the prototype 5-ton Lightweight hydrocarbon-refrigerant ECU. Our accelerated schedule not only reduces the risk to the government and provides more value, it also allows the follow-on Phase II to focus on Military Field Tests, Life Tests, and more extensive performance testing.