Fahri,
This is a problem in actual heat pump systems, not a problem in your
simulation. I have seen two approaches. You can either store very hot
water (60C or so) in the tank and then use valves to mix some of the
water that returns from the floors with some of the hot water that is
being stored in the tank (supplied by the heat pump) so that the actual
supply temperature is lower than the stored water temperature (maybe
28C). Or you can store water in the tank at your distribution (supply)
temperature of 28C. In this case, a thermostat sits watching the tank
temperature and turns on the heatpump when the tank drops below the set
point. Of course the heat pump still delivers 60C water to the tank but
it then turns off as soon as the thermostat in the tank sees that the
temperature has risen back above 28C
Best,
David

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David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI 53703 USA

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d.bradley at tess-inc.com

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