What Is Delta-T?

A Forced Hot Water (FHW) Heating System is designed to provide appropriate energy distribution to a living space, and do it efficiently. This is done by combusting a fuel in a boiler and moving the heated water through radiation to warm the environment.

However, to accomplish this most efficiently requires:

  1. A correctly sized and fired boiler.
  2. Properly sized and positioned radiation for each heated area.
  3. Idealized, simultaneous energy delivery of heated water to all radiation, irrespective of its demands.

Practically, none of these elements are absolutely correct, nor can they be. Boilers and radiation are almost never idealized for efficiency, but the third (energy delivery) is typically the most poorly executed of all. You must deliver heated water at an ideal rate for maximum heating transfer efficiency. Common distribution systems consist of:

  1. Dedicated circulators for each zone, or
  2. A common circulator with a zone valve for each zone.

Neither of these configurations performs efficiently in practice, in particular zone valves.

Enter the Delta-T Continuously Variable Speed Circulator, found at this link: http://www.taco-hvac.com/uploads/FileLibrary/100-101.pdf

“Delta-T” is a technical connotation. “Delta” (from the Greek letter ∆) is difference, or differential. “T” designates temperature. Thus Delta-T (∆T) is “temperature differential”.

The Delta-T Circulator does this by measuring and controlling the temperature differential of heating water between the supply (output) and the return lines near the boiler by using sensors. It then continuously adjusts its speed (water delivery rate) to match the heating load. This method significantly reduces electric power consumption, and even more so when using the new low energy zone valves, found at this link: http://www.taco-hvac.com/uploads/FileLibrary/100-82.pdf

This system also smoothes the performance of your existing radiation by usually eliminating hydronic whistle from over-sped, heating lag and imbalance from under-sped zones.

There is no costly control system employed. Just finitely adjust the Delta-T (∆T) on the circulator (shipped preset @ 20°F) if necessary.

So, be rid of all those restrictive “hot head” valves and misapplied circulators while reducing your entire energy bill, including electricity!