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

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@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

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