[TRNSYS-users] Control of Type 927 Water-Water heat pump

[Mattias Ericsson]

Thank you David!

I managed to solve it by using the proportional controller and an equation that takes the control signal from the controller and multiplies it by the number of heat pumps, truncates the result and passes it to the heat pump model. I will look at your suggestions and see if I can find a smoother solution!

Best regards

Mattias

Från: David BRADLEY [mailto:d.bradley at tess-inc.com]
Skickat: den 13 april 2015 22:41
Till: TRNSYS users mailing list at OneBuilding.org; Mattias Ericsson
Ämne: Re: [TRNSYS-users] Control of Type 927 Water-Water heat pump

Mattias,
  The tools you need are definitely there! first off, yes, there are two components that can store the value of an input and keep it for one or more time steps before "releasing" it. Utility: Input Value Recall: Type93 and Controllers Library (TESS): Delayed Inputs: Type661)

  Second, you may already have noted that some of the TESS HVAC Library heat pump components allow you to specify that there is more than one identical heat pump in parallel among the parameters and to control how many of them are currently on among the inputs. Type927 is one of these.

  I would recommend that you look at the components available in the TESS Controllers library; you may find a staged controller in that library that does what you want without having to write your own controller model.
kind regards,
 David

On 4/10/2015 9:02 AM, Mattias Ericsson wrote:
Dear TRNSYS users!

I am running a Type 927 water-water heat pump with a borehole field as source. The heat pump heats a storage tank which in turn supplies several secondary heating systems.

Now I want to model 4 identical heat pumps and determine the number of heat pumps on depending on the return temperature from the storage tank to the heat pump. If the temperature is below a certain set point I want to start another heat pump and if the temperature is too high I want to switch one off.

I tried to write a short code in the w-interpreter but my problem is that the heat pump component can't tell another component how many heat pumps that are already running. Therefore the option "start one more heat pump"  is not available. Is it possible to let another component store the input variable to Type 927 so it can be available in the next time step? Or do anyone have any idea on how to achieve what I want to do?

Best regards
Mattias Ericsson







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