Heat Distribution Systems

Heat distribution systems are more commonly termed as central heating systems. These are systems that provide, as the term implies, heat or warmth to the whole interior (or portions) of a building. Heat usually originates from only one source and is then conducted to different parts of the building. Examples of heat distribution systems include the forced air heating system and the hydronic heating system.

The forced air heating system uses an intricate connection of ducts and vents to transfer heated air into the different parts of the building. It also utilizes an air handling unit or AHU. AHU is a large metal box containing a blower, air filters and filter chambers, dampers, heating and / or cooling elements and sound attenuators. The AHU is usually situated in the basement of a building, and is controlled separately by room thermostats.

Forced air heat distribution system basically works this way: air is “forced” or pushed into the ductworks from the central AHU. A plenum (a receiving chamber underneath the floor or a space above the ceiling) directs the heated air into the pre-designated rooms. Cooled air is then redirected back into the plenum, back to the AHU and re-circulated after it has been heated again. That is why the forced air heating system is also called as the “warm air” system, and it employs expendable energy sources like: fuel-based combustibles (like natural gas, oil and propane,) electricity and heat pumps with refrigeration-like cycles.

The hydronic heating system, on the other hand, is a broad term given to any heat transferring medium that utilizes water. Hot-water radiators and steam radiators are the most common and oldest examples of the hydronic heating system. Unlike the forced air system where its energy source is expendable, this one works in a closed loop; the same fluid in the pipes are heated and reheated many times over. The equipments necessary for the hot-water system include a boiler, distribution piping, hot water circulating pumps, and a radiator unit.

Another system, called the hydronic radiant floor system, uses plastic pipes to circulate heated water all over the building. These pipes are usually installed in concrete slabs embedded on the floor. The heated water in the pipes radiates into the pre-designated rooms from the ground up.

Lastly, the hydronic coil heating system uses both forced air and the hydronic system to produce and distribute heat. Hot water is produced by the hydronic coil or heat exchanger using fuel-based combustibles as energy source. The heated water is then “forced-air” delivered through pipes.