[TRNSYS-users] DEGS in hydrogen systems

[Amir Hossein Rahmanzadeh]

Thank you much David, it makes much more sense now.
Kindest regards
Amir
________________________________
From: David BRADLEY <d.bradley at tess-inc.com>
Sent: Thursday, March 5, 2020 10:05:28 PM
To: TRNSYS users mailing list at OneBuilding.org <trnsys-users at lists.onebuilding.org>
Cc: Amir Hossein Rahmanzadeh <amir_rahmanzadeh at mecheng.iust.ac.ir>
Subject: Re: [TRNSYS-users] DEGS in hydrogen systems


Amir,

 The fuel cell model is a little different than most components in TRNSYS in that you tell it how much current it needs to provide and it computes the voltage at which the stack has to operate in order to provide that amount of current. I think the error is badly worded. It should specify that the power being demanded from (not generated by) the fuel cell is too great for the fuel cell (as presently sized) to generate. When you remove the DEGS, the fuel cell has to provide power if the wind turbine cannot. You may need to add some controls into the system so that if the needed current gets too high or if the hydrogen supply gets too low then the fuel cell stops operating (i.e. isn't asked for power it can't provide).

kind regards,

 David



On 02/29/2020 03:36, Amir Hossein Rahmanzadeh via TRNSYS-users wrote:
Hi everyone
I'm trying to simulate a stand alone power system, I went through the example provided by trnsys itself, there is a Diesel engine generator system which as far as I get will be used when the input power is not sufficient to keep the electrolyzer working ( am I right?) but I don't want it to do such a thing, I just want to turn off the whole hydrogen system when the power input is not enough, so I deleted it's component and set the minimum and maximum number of DEGSs to 0 in type 105 controller, but after doing that I faced this issue:

"The fuel cell power is too high, add more DEGS or decrease the FC size."

What I get from this massage is that DEGSs were consuming power and now when they are gone the power through fuel cell is too high.

So what's the role of them after all? How can I delete them and just turn the whole thing off when power is not enough?

Thank you very much for your time and support

Kindest regards

Rahmanzadeh

Mechanical engineering at Iran university of science and technology
Interested in fields of energy consumption, renewable energies , IT & programming.



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