Our heat exchangers have been carefully developed over the past 30 years.
When we started building tanks, the common wisdom was to use 3/4" Type L copper tubing as a heat exchanger for domestic hot water or other heat input/output needs.
The reality is that in most cases, 3/4" tubing does not work as well as other sizes and configurations. We discovered this through lengthy research and development with technical support from the University of Maine's Mechanical Engineering Department. Using the results of our research, we were able to develop more compact heat exchangers that cost less money and actually perform better than filling the tank with masses of less efficient 3/4" tubing or finned stainless steel or copper.
We recently performed more testing on our Domestic Hot Water heat exchanger that includes an antiscald valve.
In the late 1980's, we had tested it thoroughly ourselves and also had a local electric utility test its performance, but felt it was appropriate to update our data.
We heated the 180 gallon Heat Bank storage tank in our shop to 180˚F. Then, we set the antiscald valve to deliver a steady stream of 110˚F water at 3.25 gallons per minute. THe system delivered 224 gallons of 110˚F water. When the test was over, the tank temperature was within a few degrees of 110˚F, which was our cutoff temperature for the test; the limit of usable domestic hot water. Our findings show that all of the useable heat was delivered to the faucet with the highest efficiency.
We have tested our space heat exchangers and found similar results.
We have always and will continue to develop the most cost effective ways to store and move heat in unpressurized storage tanks and offer them to you at competitive prices.