Consumers who live in areas with no district heating have to use their own boiler to produce central heating. Placed in a boiler room with a boiler circulating pump, a boiler installation has the following components: burner, nozzles, boiler casing, hot-water tank (integrated or separate) and a chimney.
Smaller boilers are usually made of cast iron or steel plate. Larger systems often use fire-tube boilers to reduce the flue gas temperature, resulting in optimal heating efficiency. In some cases, a boiler shunt is fitted to avoid too low supply water temperature to the boiler. This is to avoid unwanted condensation inside the boiler and to ensure, that the temperature between the top and the bottom of the boiler is not too high. A high temperature difference can cause tensions in the material and thus reduce the life of the boiler.
The fuel's chemical potential energy is converted to heat energy via combustion inside the boiler. Heat is transferred to the water by thermal radiation from the flame and convection from the flue gas. In condensing boilers, energy in the water content of the flue gas can be utilized. Thereby a thermal efficiency close to 100 % is achievable. Non-condensing boilers can improve their efficiency significantly by having economizers fitted onto the system. These cool the flue gases as they transfer heat to the boiler's feed water.
Various types of fuels are used in boiler systems: Domestic fuel oil (smaller systems), heavy fuel oil (larger systems), natural gas and solid fuel (straw, wood, pellet, wood chip, coal). The efficiency of a boiler system is affected by heat loss through the chimney, as well as heat loss from the boiler’s surfaces.
Grundfos offers a broad range of circulating pumps that integrate fully into a boiler room installation.