head loss caused by wrong inlet /outlet connection of heat exchanger ?
head loss caused by wrong inlet /outlet connection of heat exchanger ?
(OP)
What mey be typical head loss of an AHU heating coil being fed at bottom in comparison to one fed at the top ? The medium being water.





RE: head loss caused by wrong inlet /outlet connection of heat exchanger ?
wrong direction of control valve is another story, but you are not mentioning control valve.
RE: head loss caused by wrong inlet /outlet connection of heat exchanger ?
RE: head loss caused by wrong inlet /outlet connection of heat exchanger ?
Mixing valve being connected correctly.
RE: head loss caused by wrong inlet /outlet connection of heat exchanger ?
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RE: head loss caused by wrong inlet /outlet connection of heat exchanger ?
Such an effect has influence on distribution heating pipework calculation in high-rise buildings.
RE: head loss caused by wrong inlet /outlet connection of heat exchanger ?
RE: head loss caused by wrong inlet /outlet connection of heat exchanger ?
going back to practical probabilities - if you change direction of waterflow it is possible that your control valve will receive flow in wrong direction, and whil i cannot be certain, i can suspect that could be cause of problem - if your problem only exists when you swap connections.
you mentioned in your previous post that "mixing valve is connected correctly", but correctness of mixing valve connection can directly depend on water flow, i.e what is correct in one flow direction can be incorrect in opposite flow direction.
mixing valves normally have symbols on their bodies which, first show whether they do hydraulic mixing or hydraulic diverting, second they show what are inlet and what are outlet port(s).
RE: head loss caused by wrong inlet /outlet connection of heat exchanger ?
RE: head loss caused by wrong inlet /outlet connection of heat exchanger ?
RE: head loss caused by wrong inlet /outlet connection of heat exchanger ?
RE: head loss caused by wrong inlet /outlet connection of heat exchanger ?
What do you mean ?
I am sorry that I cannot post the picture I drawn. The installation have performed some absolute morones, that is the problem.
RE: head loss caused by wrong inlet /outlet connection of heat exchanger ?
What I meant was that a typical coil might have 3/4 inch piping to and fro, but reduce to 3/8 inch at the inlet and outlet fittings. This is by design, as a velocity increase lessens the laminar boundary layer and provides better heat transfer. For a 3 gpm coil (as an example), our 2.2 feet per second velocity would increase to about 9 fps through the coil tubing. The water then turns 180° a few times before exiting.
So with this hot water, the big rise in velocity, and the bends through a coil, gases can tend to leave solution.
RE: head loss caused by wrong inlet /outlet connection of heat exchanger ?
The heat exchangers in AHU's have two vertical collectors (possibly, one such HE may have 3/4 pipe collectors) feeding between them a dozen or so coils (maybe, one HE having them of 3/8 diameter). But as there are many of them, water velocity in them should rather decrease.
RE: head loss caused by wrong inlet /outlet connection of heat exchanger ?
To clear, I described in my previous post not the idiotic installation I mentioned, but AHUs in general.