[TRNSYS-users] logic controls for DHW and buffer tanks

[Jeff Thornton via TRNSYS-users]

Use a few simple equations in the calculator component. Let's call the thermostat signal for the DHW tank Y_DHW and the thermostat signal for the buffer tank Y_BUFFER.  One of the signals has to be one and the other zero at all times. So we then have the signals for the diverting valve as:

Y_Diverter_1 = Y_DHW
Y_Diverter_2 = 1-Y_DHW

And the pump signal would be:

Y_PUMP = MAX(Y_DHW , Y_BUFFER)

Jeff - TESS

Sent from my iPhone

> On Jul 1, 2017, at 11:53 AM, Dashamir Marini via TRNSYS-users <trnsys-users at lists.onebuilding.org> wrote:
> 
> Dear TRNSYS user,
>  
>  
> I’m trying to model an heat pump system that should charge a DHW and a buffer tank (please see the diagram below).
> The idea is that heat pump always first  (when there is demand) should charge  the DHW tank and later the buffer tank for space heating.
> How I can build a logic expression like this:
>  
> Let say that I have two signals coming from tank 1 and tank2 .
> The logic control should be:
>  if the signal from tank1  = 1 (tank1 temp < t setpoint) then the diver valve (Type647)  circulate all water flow at tank1;
> if the signal from tank1 =0 and signal from tank2 =1 ((tank2 temp < t setpoint) then the divert valve circulate all water flow at tank2;
>  
> so the logic is that heat pump through diverting valve Type 647 first should charge the DHW tank  (tank534 coiled 2 ) and after if there is no need to charge DHW tank then the divert valve should sent all water flow rate to the  buffer tank Type534.
>  
> How it can be developed that control logic in TRNSYS?
>  
> Thank you in advance
>  
> D Marini
>  
> <image001.jpg>
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