Abstract: A heating system combines a heat source for applying heat energy to a supply of heat transfer fluid including a polyol having five or less pendant hydroxyl groups and a polydimethylsiloxane and a pump that moves the heat transfer fluid through conduits to a heat exchanger. In one configuration, the heating system has a primary circuit including the heat source, delivery line, pump, heat exchanger and return line, and a sub-circuit including a bypass line interconnecting the delivery line and the return line to provide a flow path bypassing the heat source. The sub-circuit includes the bypass line, a portion of the delivery line, the pump, the heat exchanger, and a portion of the return line. Control valves and a control mechanism direct the flow of fluid between the primary and sub-circuit. The heat transfer fluid is a blended mixture of 5-15% glycerin, 20-40% propyl glycol and 45-75% silicone.

Abstract: A heating system combines a heat source for applying heat energy to a supply of heat transfer fluid including a polyol having five or less pendant hydroxyl groups and a polydimethylsiloxane and a pump that moves the heat transfer fluid through conduits to a heat exchanger. In one configuration, the heating system has a primary circuit including the heat source, delivery line, pump, heat exchanger and return line, and a sub-circuit including a bypass line interconnecting the delivery line and the return line to provide a flow path bypassing the heat source. The sub-circuit includes the bypass line, a portion of the delivery line, the pump, the heat exchanger, and a portion of the return line. Control valves and a control mechanism direct the flow of fluid between the primary and sub-circuit. The heat transfer fluid is a blended mixture of 5-15% glycerin, 20-40% propyl glycol and 45-75% silicone.