[TRNSYS-users] Control strategy

[David Bradley [SEL]]

Maurizio,
  It looks from what you describe as though your best option would be to 
write a new controller component. You cannot directly implement the 
IF..THEN..ELSE structure using EQUATIONS in an input file.Often times 
you can fake an IF..THEN..ELSE statement using one of the Boolean 
functions as a multiplier on the variables that you wish to set. For 
example, if your condition were:

IF (T_supply_air < T_set_supply - dT_dec) THEN
  mode = -1
  mode_status = 0
ELSE
  mode = 1
  mode_status = 0
ENDIF

then you could get the same effect by putting the following in your 
input file:

EQUATIONS 3
ModeCheck = LT(T_supply_air,(T_set_supply - dT_dec))  !ModeCheck has a 
value of 1 when T_supply_air is less than T_set_supply-dT_dec and 0 
otherwise
mode = -1*ModeCheck + 1*(ModeCheck-1)
mode_status = 0

however, the control scheme that you describe below is too complex for 
such tricks I think. The other alternative is that you might be able to 
implement your control strategy in Type40.

> In addition, does exist a manual for the equation tool?
>
The Simulation Studio equation tool is described in section 2.7 of the 
Simulation Studio manual (volume 2 of the TRNSYS 16 documentation set). 
There is additional information about the functions that can be 
implemented in equations in section 7.6.8 of the 07-TRNEdit manual.

Kind regards,
  David

-- 
David BRADLEY
TRNSYS Engineer
Solar Energy Laboratory - University of Wisconsin, Madison
1500 Engineering Drive
Madison, WI  53706  
United States

ph: +1 608 263 1589
fax: +1 608 262 8464
email: dbradley at engr.wisc.edu

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