[TRNSYS-users] (no subject)

[David BRADLEY]

There are any number of ways that you can accomplish the control that 
you want. In general Type2 controls based on a relative temperature 
difference. If the difference becomes large then the controller turns 
on. If the difference becomes too small, the controller turns off. There 
are other controllers that will watch a set point temperature and turn 
on or off if a monitored temperature falls below (or rises above) a 
desired absolute set point. There are also equations that you can write 
in order to combine control signals together.

I am a bit confused by Type668 and 674 in your diagram. I assume that 
the GHSP can either heat the house or the tank based on your description 
but I am not sure that is how the arrows in the links are set up. Also, 
is there a situation where if the tank is hot and the collector is still 
producing energy but the house is cold that you would want to directly 
heat the house with solar?

I am not sure if this will entirely solve the problem but I would start 
by defining two equations:

tankWant is 1 if the tank is cold and the GSHP should send water to it. 
tankWant is 0 if the tank is already hot enough. You could have tankWant 
be the result of a thermostat model that watches the tank temperature 
and compares it to a set point or you could do many other things; the 
important thing is to have an equation whose result is 1 if the tank 
wants energy from the GSHP.

houseWant is similar. It has a value of 1 if the house wants heat from 
the GSHP and it has a value of 0 otherwise.

the equation for your diverter valve is going to determine the fraction 
of incoming water that should go to the tank:

toTank = (tankWant)/MAX((tankWant+houseWant),0.001)

by this, the tank will get all the flow if the tank wants heat and the 
house is satisfied. It will get half the flow if both the tank and that 
house want heat. It will get no flow if the tank is already satisfied.

kind regards,

  David




On 06/20/2018 04:54, berkane ahlem via TRNSYS-users wrote:
>
> Hello sirs,
> I simulate a solar cycle is separate from GSHP cycle for heating a
> building and DHW and i have some problems about */_a solar cycle 
> control_/*
> ,if  the collector temperature exceeds the tank temperature, GSHP will
> not heat the tank and control signal of the solar cycle is set to 1.
> In this case, as all of the fluid flow steer by Type 11f as a
> controlled diverting valve to the solar collector  and  Type 647-3
> will send all of the GSHP heat to the house .If water storage tank,
> collector and the building are cold simultaneously, Type 647-3 will
> send half the flow through house and half to tank. I use controller  
> type 2b
> , *how can i coupled the collector and storage tank with conroller type*
> *2b , should i use 2 controller ( tank and collector) or can i use one*
> *controller between the tank and collector as the output signal for*
> *equation written for diverter*
> Tank- fraction = Max(0, (*/_Tank_cold_/*-0.5 House_cold), how can i chose
> the control signal */_Tank_cold_/*
> thank you so much
>
>
>
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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com

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