Articles by John Siegenthaler, P.E.

The measure of a heat pump’s heating performance is called coefficient of performance (COP). It’s the ratio of useful heat output divided by required energy input, where both the output and input are expressed in the same physical units.

Most of the modern hydronics technology used in North America for residential and light commercial buildings is for heating. 

One of the most fundamental principles used in all areas of science and engineering is the first law of thermodynamics. 

The heating output and coefficient of performance (COP) of any hydronic heat pump is very dependent on the water temperature leaving the heat pump’s condenser. 

Although the market for gas-fired boilers continues to track toward those that can modulate and operate with sustained flue gas condensation, conventional boilers (e.g., those not designed to operate with sustained flue gas condensation) still represent a significant portion of the market. 

As global energy planning moves away from fossil fuels and toward electricity, an increasing number of hydronic heating systems are being supplied by heat pumps. 

Heat pumps are incredibly useful devices. 

Hydronic heating professionals often promote the concept that current generation mod/con boilers can operate with AFUEs in the range of 95% and above. 

I’m sure everyone reading this column has heard the adage “a picture is worth a thousand words.”  

Whenever a hydronic system is divided into several zones, it’s worth considering a buffer tank between the heat source and distribution system.