My domestic hot water is heated via my oil fired boiler. I'm thinking about installing a "tempering tank" so my well water reaches ambient temperature before reaching the boiler water heating jacket. Is it a reasonable assumption that this will save fuel? Any advice on the type of tank to use. I wonder if a hot water tank with the insullation removed may be a reasonable choice???
Tempering Tank
- Thread starter deep wood
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You'd get more mileage out of it if you actively heat the preheat tank - perhaps with a sidearm. A steel tank with ice cold water in it will also sweat, and rust. That having been said, it's a great idea and should save you a bunch on hot water.
If you do go the preheat route, you'll want to install a mixing valve on your DHW outlet to make sure you don't scald anyone. See the writeup on my site - link in my signature below.
If you do go the preheat route, you'll want to install a mixing valve on your DHW outlet to make sure you don't scald anyone. See the writeup on my site - link in my signature below.
going back to the original question about whether a tempering tank will save fuel (presumably the oil is what you're referring to)- I'd say maybe- but maybe not- here's why- if your tempering tank is warming well water, it's doing that by absorbing heat out of its surrounding space.
That means, even if it is not heated actively/ directly, then it is imposing a heat load that has to be "made up"
with other energy. If that other heat energy is supplied by wood or solar, you may save oil, though you'll be using part of your available "other source".
If that other heat energy is supplied by the oil boiler, you have no way to get any "free lunch" and probably will use more oil than heating the same amount of water directly, just because of general losses and inefficiencies in conversion from one spot and mode to another.
That means, even if it is not heated actively/ directly, then it is imposing a heat load that has to be "made up"
with other energy. If that other heat energy is supplied by wood or solar, you may save oil, though you'll be using part of your available "other source".
If that other heat energy is supplied by the oil boiler, you have no way to get any "free lunch" and probably will use more oil than heating the same amount of water directly, just because of general losses and inefficiencies in conversion from one spot and mode to another.
I agree. I wondered about saving fuel during the winter months when I'm actively heating the space where the boiler is located. I assume the water will warm to ambient temperature with no heat loss during the summer months. I didn't consider the rust factor on the exterior of the steel tank. I will see if I can locate a plastic tank......thanks!
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