Abstract: A heat transfer system having a a radiant source, a first heat exchanger configured to permit a first fluid to flow therethrough, and a thermal shield configured to provide controlled radiative heat from the radiant source to the first exchanger. The radiant source is a flame. The thermal shield is a second heat exchanger configured to permit a second fluid to flow therethrough or a non-contact thermal shield fabricated from a material arranged to provide controlled radiative heat exposure from the radiant source to the first exchanger. Oxy/coal combustion systems are also disclosed.

Abstract: A boiler furnace avoids NOx and increases thermal efficiency with a small boiler. The boiler furnace has an outer water wall and an inner water wall with flared top and bottom portions.

Abstract: A solid fuel burning stove having a hot water heating means. A water containing chamber open at the top for communication with room air serves the dual purpose of providing a heat sink for preheating water while at the same time providing a means for humidifying the room air. Domestic water heating coils are positioned so that cold water flows first through coils located at the water containing reservoir where it is preheated and then passes into the combustion chamber where it is heated to a high temperature before flowing into a hot water tank. The stove is preferably also provided with a small baking oven.