[TRNSYS-users] Controling Heatpump system

Amdi Worm amdiworm at gmail.com
Tue Jan 15 02:33:41 PST 2013


Thanks a lot for the quick answers.
I have been trying to use the equation-method, but im not able to make it
work, could you by any change mail me a screen dump of the MAX OR -
sentences you recommended? Im also having a hard time figurering out how to
integrate a hysteresis when using the functions since they just retur "0"
or "1".

Sorry to question you again, I would just really like to make this work.

Best Regards
Amdi Worm

2013/1/15 Richard Thygesen <richard.thygesen at mdh.se>

> Amdi.
> I'm simulating a system like yours and I use a equation to allow two
> control signals to control the heat pump.
> One which is based on the return temperature from the heating system and
> one based on the temperature in a certain place on the DHW tank.
> A max or or equation should work. Play around with equations a bit and
> read chapter 6 in the manual to see which arguments that can be used.
>
> Almost all heat pumps in Sweden prioritize the DHW production.
>
> Richard
>
>
> ----- Reply message -----
> Från: "Amdi Worm" <amdiworm at gmail.com>
> Till: "trnsys-users at cae.wisc.edu" <trnsys-users at cae.wisc.edu>
> Rubrik: [TRNSYS-users] Controling Heatpump system
> Datum: tis, jan 15, 2013 10:16
>
>
>
> Dear All
>
> I am simulating a heatpump system as attached in the PDF file.
> My heatpump system is supplying both roomheating and DHW. As it is for now
> the heatpump (type 927) is controlled by the temperature in the returnpipe
> to the heatpump (as it is in many practical cases with a hysteresis) and
> the temperature in the returnpipe where the heatpump is turned on, depends
> on the outdoor temperature (lower outdoor temperature = demand for higher
> return temperature).
>
> But as my system is connected, the DHW system gets the same temperature as
> the room-heating system, and in summertime due to the outdoor dependence,
> the temperature is not sufficient for the DHW system. I need the outdoor
> dependence according to danish law so it is not a solution just to turn it
> off.
>
> Instead I would like to model the system so that the heatpump turns on if
> the temperature in the returnpipe in the roomheating curcuit goes below a
> certain values, and in the same way for the DHW circuit, but here the
> heatpump must turn on at another value in the returpipe of that circuit.
> Is it possible to give the heatpump 2 control signals, so that it runs if
> one (or both) of the criterias is met? Which controller could be used in
> this case? Is it possile to create an "if / else" equation and thereby give
> the heatpump a control-signal or maybe a Type 108 with roomheating as stage
> one and DHW as stage two.
>
> It is not an option for me to choose a 2 stage heatpumpe, since I haven't
> been able to get sufficient cataloge-data as input.
>
> I hope one is able to help.
>
> Best regards
> Amdi Worm
>
> Esbensen A/S
>
>
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