selection of water heater
selection of water heater
(OP)
Normally for apartment building, should we select water tank for a domestic water heater? (for example there are 70 suits inside)
As I read in Ashrae handbook, 2 data are used to select heater and tank, recovery rate GPH and size of storage capacity Galon.
While my boss always selects a heater with a huge gas input but a very small storage capacity without providing additional storage tank. Is this the new design concept or is he wrong?
THX
As I read in Ashrae handbook, 2 data are used to select heater and tank, recovery rate GPH and size of storage capacity Galon.
While my boss always selects a heater with a huge gas input but a very small storage capacity without providing additional storage tank. Is this the new design concept or is he wrong?
THX





RE: selection of water heater
In the absense of storage, you have to run the process/machine even if you have only one user point requiring it.
RE: selection of water heater
Also, since there's a sawtooth temperature profile, there will also be variations in the delivered water temperature.
TTFN
RE: selection of water heater
Why not look into the new condensing boilers that give excellent effeciencies going to smaller storage that is over 160deg F and then mixing back down to operating temperature??
RE: selection of water heater
The scenario I see is somebody in an apartment a long distance from the heater complains that he doesn't have enough hot water. The maintenance guy, without really diagnosing the problem, goes in and turns the thermostat up either on the water heater or the mixing valve. Now the system is outside its design parameters which usually means that an apartment close to the heater gets water that is way too hot, possibly 160.
Also, at least in the apartments I have seen, the showers/tubs do not have thermostatic mixing valves to prevent or limit the above problem from escalating, so scalding water is now in the tub or the shower. If the occupants are elderly or have younger children, the results can be deadly.
For a residential application, I would never have the system produce water above 130. While it can still scald, the exposure time is much less before damage occurs.
RE: selection of water heater
RE: selection of water heater
RE: selection of water heater
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RE: selection of water heater
RE: selection of water heater
So, for domestic HW applications, the condensing boilers get pretty much the full rated efficiency, and for heating applications the efficiency goes down because of the higher return temperature.
Look at:
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RE: selection of water heater
RE: selection of water heater