Abstract: A heat pump system has a separate outdoor coil which is mounted below the primary outdoor coil and connected in parallel with it by valves. On system start up in the heating mode, the inlet of the auxiliary coil is closed, and the outlet is opened so that compressor vacuum will boil off the more volatile, high pressure components thus filling the system. The outlet valve is then closed trapping the low pressure component in the auxiliary coil. In a second embodiment, the accumulator is utilized to assist the auxiliary coil in vacuum separation of the refrigerant blend. Variants include blocking flow through the expansion valve on start up.

Abstract: A method of combusting a hydrocarbon fuel includes mixing the fuel with a first air stream to form a fuel/air mixture having an equivalence ratio of greater than 1 and partially oxidizing the fuel by contacting it with an oxidation catalyst to generate a heat of reaction and a partial oxidation product stream. The partial oxidation product stream is mixed with a second air stream and completely combusted in a main combustor at a condition at which appreciable quantities of thermal NO.sub.x are not formed to generate an effluent gas stream, thereby generating an effluent gas stream containing decreased amounts of thermal and prompt NO.sub.x. A system for combusting a hydrocarbon fuel includes, in combination, means for mixing the fuel with a first air stream, a catalytic oxidation stage containing an oxidation catalyst, means for mixing the partial oxidation product stream with a second air stream, and a main combustor capable of completely combusting the partial oxidation product stream.