Tvårörssystemet

Tvårörssystemet is a Swedish term referring to a two-pipe heating and cooling system. This type of system is commonly found in buildings where a single set of pipes is used to distribute either hot water for heating in the winter or chilled water for cooling in the summer. The direction of flow determines the function of the system at any given time.

In a tvårörssystem, two pipes are installed: one supply pipe and one return pipe. During the heating season, the supply pipe carries hot water from a central heating plant or boiler to radiators or fan coil units throughout the building. The cooler water then returns to the source via the return pipe. When cooling is required, the system is switched to circulate chilled water through the same pipes. The chilled water absorbs heat from the building, and the warmed water returns to the chiller.

The primary advantage of a tvårörssystem is its cost-effectiveness in terms of installation, as it requires less piping than a four-pipe system, which has separate pipes for heating and cooling. However, a key limitation is that heating and cooling cannot be provided simultaneously to different zones within the building. If one area requires heating and another requires cooling, the entire system must be set to one mode or the other, potentially leading to discomfort in some areas. This makes tvårörssystem best suited for buildings with relatively uniform heating and cooling demands or where simultaneous zoning is not a priority.