Hot water system coupled with water source heat pump loop?

[carlosgw]

Water Source heat pump system – I have used a boiler for direct heat add (boiler used only for heat add). I have used a boiler for an indirect heat add (heat exchanger). I don’t think I had a system the hot water system was directly coupled to the heat pump loop (hot water used for entry unit heaters and heating ventilation air). I can’t think of any reason I can’t have the loops directly coupled as long as I have a heat trap. Am I not thinking of something?

(I am talking about a regular water source heat pump loop - not a ground source).

 

[EnergyProfessional]

what exactly do yo mean by heat trap? and you also have a cooling tower, or is this a heat-only solution?

and it seems you use the boiler to directly heat hydronically, and also to heat the loop? So you need two temperatures, one lower one for the heatpump loop (since you also need to cool it can't be too warm), and a high temp loop for heating directly.

not sure what you actual question is?

 

[carlosgw]

Heat trap is just a loop of piping to keep hot water (180 deg) from moving by gravity to the heat pump loop (80ish deg). I'm not sure I need if the heat pump loop runs continuously.
The tricky thing is expansion and where to put the expansion tank.

 

[EnergyProfessional]

Each loop needs its expansion tank (if you have a heat exchanger, you have a second loop requiring its own expansion tank).

I'm not sure what your question is, are you designing a new system, or retrofitting an existing one?

And why run a boiler at 180°F? Especially if you use a heatpump. So you operate the boiler very inefficiently at 180°F, then you blend the water to lower temps (~60°F or so) for the heatpump, and put electricity in to get 120°F air temperature.