[TRNSYS-users] Deactivate battery

Fri Jul 15 07:53:49 PDT 2016

Benjamin,

   Probably you have to be a little careful how you implement the 
switch. If you implement a switch that is on a timer so that no matter 
what, the inverter sees that there is no power available from the 
renewable source at certain times of day then there should be no reason 
for there to be convergence problems. However, if your switch is 
watching the state of charge of the battery or something else that might 
change then the switch needs to have some hysteresis in it. I don't know 
what your exact situation is but pretend that the switch is watching the 
battery SOC and stops charging the battery if the battery SOC gets above 
0.9. If you implement this switch with a simple equation then charging 
will stop when the SOC gets to 0.9000000000001 and allow charging as 
soon as the SOC falls back to 0.9000000000000. You need to use one of 
the thermostat controllers to provide a deadband on the SOC so that 
charging stops when SOC reaches 0.90 and stops until the battery falls 
back to 0.85 (or something)

   The inverter/charge controller model isn't all that complicated. It 
looks at a load, at the power available from renewables and at the 
battery SOC and makes a decision as to how the power should flow. If 
you're trying to effectively remove the battery without deleting it you 
need to figure out how to make the inverter/charge controller think that 
the battery should never be charged and can never provide power to the 
load. You might look at some of the inverter/charge controller 
parameters that set up when the battery can and cannot be charged based 
on its SOC. If you set those values close to each other and start the 
battery somewhere outside that range you may be able to effectively 
prevent the battery from having an influence on the system.

kind regards,

  David

On 07/15/2016 02:58, Manrique Delgado Benjamin via TRNSYS-users wrote:
>
> Thanks for the reply. I have used that strategy successfully with 
> other Types, but unfortunately the inverter just ignores the switch. A 
> message in the List file says ”The input to the listed units have not 
> converged at this timestep. The values at the last iteration will be 
> used and the simulation will proceed”.
>
> *From:*Ben Heymer [mailto:bheymer at gmail.com]
> *Sent:* Thursday, July 14, 2016 9:43 PM
> *To:* Manrique Delgado Benjamin <benjamin.manriquedelgado at aalto.fi>; 
> TRNSYS users mailing list at OneBuilding.org 
> <trnsys-users at lists.onebuilding.org>
> *Subject:* Re: [TRNSYS-users] Deactivate battery
>
> I'm not familiar with that component (Type 47a) but its usually 
> possible to use equations to effectively disconnect the links to and 
> from any Type.
>
> You can zero out inputs to the type with something like this:
>
> input1 = datapoint1 * switch  ! (where "switch" = 1 for "on" or 0 for 
> "off")
>
> You can choose to use outputs from one type or another type with 
> something like this:
>
> output1 = output1a * switch + output1b * (1 - switch)  ! (where 
> "switch" = 1 for "on" or 0 for "off")
>
> This will take a bit of time to set up and it's not very elegant, but 
> the freedom to hack is what makes TRNSYS great!
>
> On Thu, Jul 14, 2016 at 9:54 AM, Manrique Delgado Benjamin via 
> TRNSYS-users <trnsys-users at lists.onebuilding.org 
> <mailto:trnsys-users at lists.onebuilding.org>> wrote:
>
>     Dear all,
>
>     Is there a way to deactivate a battery (Type 47a) without having
>     to delete it from a model? I want to do an optimization that
>     includes options with and without battery, so I need to find a way
>     to give the battery zero capacity or stop the inverter from
>     charging/discharging it. I have tried different values for High
>     and Low limit on FSOC but the inverter basically ignores them when
>     the value doesn’t converge. Any suggestions?
>
>     Cheers,
>
>     Benjamin Manrique D.
>
>     Aalto University
>
>     Finland
>
>
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>
>
>
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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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