INTERIORS: Secondary loop and heat pump climate control under evaluation once more

摘要

Is secondary loop climate control about to make an engineering splash? It got a close look for A/C when the industry was considering low-global-warming alternatives to R-134a, because it permitted confining a system using a refrigerant with safety/environmental issues to a safe underhood area. But once R-1234yf was seen as a safe albeit mildly-flammable choice, usable with under-dash circulation in a direct expansion cycle with existing technology, secondary loop went into mothballs. However, at the recent SAE Thermal Management Systems Symposium (TMSS) it was once again identified as a promising alternative.