Wood fired boilers that are housed outside of a home are called outdoor furnaces.
The heat source and the place to be heated are located a hundred yards apart.
The furnace can heat either glycol or water. The glycol or water is pumped through insulated pipes to your home. There are three different processes by which the heated liquid can be delivered. These three processes are liquid to liquid heat exchanging, direct heat, and through a hot air radiator. In a liquid-to-liquid heat exchanging system, the heated liquid enters a huge storage tank containing coils of copper tubing. Water in the tubing is heated and this flows through the hot water baseboard system in your home and supplies all of the hot water that your home needs. A direct heat process is when heated liquid enters the home and goes directly into the home’s hydronic system and indirectly heats the overheated water in a separate system. When using a hot air radiator, heated liquid can be pumped through inside the plenum of a forced-air system. Using the ductwork of an existing heating and A/C system, the radiator transfers the heat to the air which is then distributed by the fans of the furnace when the system turns on and starts running. All outdoor furnace systems are closed loop systems. This means that the cooled liquids return to the heat source via a return tube and are reheated again. Remember that these three outdoor heating systems exist and choose the correct one based on your home and your needs.