Water Boilers that don’t boil water?
Nuke
| Posted in Energy, Heating & Insulation on
Do water boilers really boil water? I mean, in the modern sense of the phrase, water boiler.
What got me thinking about this was the Manchester, MA TOH project from a year or two ago in which temporary heating was setup using an air handler being fed by a water boiler. I’m still surprised that the damaged (only slight, and to the cabinetry of the handler) air handler cost $100, and was fed by PEX with quick-connects for the heated water.
Replies
It depends.
Steam boilers do boil water. The term 'boiler' probably comes from the steam era, when the whole nation ran on steam.
Regular hot water 'boilers' typically have a max design output temp of about 190 degrees. They can go a bit higher, but this is uncommon (and generally less efficient). 180 degrees was the standard output design temp for many years since you needed to keep the return temps high enough to avoid condensing (around 130 degrees).
Modern heating systems with condensing 'boilers' can have very low output temperatures, and are in fact more efficient at low temps. A modulating/condensing boiler supplying radiant floors on outdoor reset may output as low as 75-80 degree water (just for example), but can be set even lower. An ice melting system may have return temps below freezing, for example.