[TRNSYS-users] Max. time points of Type 14 in TRNSYS 16

Fri Oct 26 02:27:38 PDT 2012

Dear all,

I'd like to ask you whether or not max. time points of Type 14 is only 20
in TRNSYS 16?
If I need more than 20 points, how could I solve this problem?

Many thanks in advance!

Br

wang

2012/10/26 <trnsys-users-request at cae.wisc.edu>

> Send TRNSYS-users mailing list submissions to
>         trnsys-users at cae.wisc.edu
>
> To subscribe or unsubscribe via the World Wide Web, visit
>         https://mailman.cae.wisc.edu/listinfo/trnsys-users
> or, via email, send a message with subject or body 'help' to
>         trnsys-users-request at cae.wisc.edu
>
> You can reach the person managing the list at
>         trnsys-users-owner at cae.wisc.edu
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of TRNSYS-users digest..."
>
> Today's Topics:
>
>    1. Re: Type energy balance (David BRADLEY)
>    2. Re: Type energy balance (Micha?l Kummert)
>
>
> ---------- 已转发邮件 ----------
> From: David BRADLEY <d.bradley at tess-inc.com>
> To: PARTENAY Vincent <vincent.partenay at cstb.fr>
> Cc: "trnsys-users at cae.wisc.edu" <trnsys-users at cae.wisc.edu>
> Date: Thu, 25 Oct 2012 16:34:28 -0500
> Subject: Re: [TRNSYS-users] Type energy balance
>  Vincent,
>   When you perform an energy balance on a tank, you need to take into
> account its change in temperature between the beginning and the end of the
> simulation (output 7 of your Type4). If the tank ends up hotter at the end
> of the simulation than it was at the beginning, it has stored some energy.
> If it ends up colder, then it has given up some energy. I would imagine
> that with 10 nodes, there is some stratification developing in the tank
> that is not modeled when you have a fully mixed tank (1 node)
> Best,
>  David
>
>
> On 10/25/2012 09:40, PARTENAY Vincent wrote:
>
>  Dear all,****
>
> ** **
>
> Typ4a (Storage tank) allows to model a stratified tank with several
> temperature nodes. The problem I noticed is that the energy balance of both
> sides on the tank can vary depending on the chosen timestep :****
>
> ** **
>
> In the attached file, a simplified example, the tank is coupled to an
> energy production and energy consumption model (very simple in an
> equation). Thermal losses of the tank is set to zero.****
>
> When I run a simulation with one node (1m height for 0.5m3) for the tank
> and a timestep of 0.1hr, I get the same energy on both side (see plotter
> “”Power&NRJ”, Esource = 2659kWh and Eload = 2666kWh), slight difference
> maybe explained by initial charging period to setpoint temperature.****
>
> When I run it in the same conditions but with 10 nodes (each 0.1m), these
> two energy are different ! While I still have 2666kWh for Eload I have
> 3146kWh !****
>
> When I run it again reducing the timestep from 0.1hr to 0.001 hr, still
> with 10 nodes, I get 2666kWh, the energy balance is ok…****
>
> ** **
>
> So, my question is : is it necessary to check before every bigger
> simulation (that can include lots of tank models) the energy balance of
> this model for one defined timestep and boundary conditions to the model or
> is there some rules to predefine adapted discretisation for one given
> timestep ?****
>
> ** **
>
> Kind regards,****
>
> ** **
>
> ** **
>
> *Vincent PARTENAY*
>
> Energies Renouvelables - Département ESE****
>
>  ****
>
> *Centre Scientifique et Technique du Bâtiment*
>
> 290 Route des Lucioles BP 209 – F 06904 Sophia Antipolis Cedex****
>
> Tél : +33-(0)4-93-95-67-21****
>
> Fax : +33-(0)4-93-95-64-31****
>
> *Évitez d’imprimer vos emails inutilement. Respectez l’environnement*****
>
> ** **
>
> ** **
>
>
> _______________________________________________
> TRNSYS-users mailing listTRNSYS-users at cae.wisc.eduhttps://mailman.cae.wisc.edu/listinfo/trnsys-users
>
>
> --
> ***************************
> David BRADLEY
> Principal
> Thermal Energy Systems Specialists, LLC
> 22 North Carroll Street - suite 370
> Madison, WI  53703 USA
>
> P:+1.608.274.2577
> F:+1.608.278.1475d.bradley at tess-inc.com
> http://www.tess-inc.comhttp://www.trnsys.com
>
>
>
> ---------- 已转发邮件 ----------
> From: "Michaël Kummert" <michael.kummert at gmail.com>
> To: <trnsys-users at cae.wisc.edu>
> Cc:
> Date: Thu, 25 Oct 2012 18:19:39 -0400
> Subject: Re: [TRNSYS-users] Type energy balance
>
> If the energy (de)stored between the initial and final state cannot
> explain the differences, I think there is another possible cause: Type 4
> can have quite large energy balance errors when the nodes are “flushed out”
> during one time step. ****
>
> ** **
>
> Here is my understanding: ****
>
> If you have 10 nodes and a total volume of 500 L, that means each node
> holds 50 L of water. Using 0.1 h time steps you cannot have a flowrate
> through the tank higher than 500 L/h, otherwise you will replace the entire
> volume of a node within a time step, and the equations used by Type 4 are
> not valid anymore. This would explain that it works again when you reduce
> the timestep (with 0.001 h you would need a flowrate of 50000 L/h to
> “flush” a node out).****
>
> ** **
>
> To my knowledge this problem is specific to Type 4, i.e. it does not
> affect the Storage tanks in the TESS libraries (Type 534 etc.) – if you
> have access to them that may be a more practical solution than running
> 0.001 h timesteps…****
>
> ** **
>
> Michaël Kummert****
>
> Polytechnique Montréal****
>
> ** **
>
> *From:* trnsys-users-bounces at cae.wisc.edu [mailto:
> trnsys-users-bounces at cae.wisc.edu] *On Behalf Of *David BRADLEY
> *Sent:* Thursday, October 25, 2012 17:34
> *To:* PARTENAY Vincent
> *Cc:* trnsys-users at cae.wisc.edu
> *Subject:* Re: [TRNSYS-users] Type energy balance****
>
> ** **
>
> Vincent,
>   When you perform an energy balance on a tank, you need to take into
> account its change in temperature between the beginning and the end of the
> simulation (output 7 of your Type4). If the tank ends up hotter at the end
> of the simulation than it was at the beginning, it has stored some energy.
> If it ends up colder, then it has given up some energy. I would imagine
> that with 10 nodes, there is some stratification developing in the tank
> that is not modeled when you have a fully mixed tank (1 node)
> Best,
>  David
>
> ****
>
> On 10/25/2012 09:40, PARTENAY Vincent wrote:****
>
> Dear all,****
>
>  ****
>
> Typ4a (Storage tank) allows to model a stratified tank with several
> temperature nodes. The problem I noticed is that the energy balance of both
> sides on the tank can vary depending on the chosen timestep :****
>
>  ****
>
> In the attached file, a simplified example, the tank is coupled to an
> energy production and energy consumption model (very simple in an
> equation). Thermal losses of the tank is set to zero.****
>
> When I run a simulation with one node (1m height for 0.5m3) for the tank
> and a timestep of 0.1hr, I get the same energy on both side (see plotter
> “”Power&NRJ”, Esource = 2659kWh and Eload = 2666kWh), slight difference
> maybe explained by initial charging period to setpoint temperature.****
>
> When I run it in the same conditions but with 10 nodes (each 0.1m), these
> two energy are different ! While I still have 2666kWh for Eload I have
> 3146kWh !****
>
> When I run it again reducing the timestep from 0.1hr to 0.001 hr, still
> with 10 nodes, I get 2666kWh, the energy balance is ok…****
>
>  ****
>
> So, my question is : is it necessary to check before every bigger
> simulation (that can include lots of tank models) the energy balance of
> this model for one defined timestep and boundary conditions to the model or
> is there some rules to predefine adapted discretisation for one given
> timestep ?****
>
>  ****
>
> Kind regards,****
>
>  ****
>
>  ****
>
> *Vincent PARTENAY*****
>
> Energies Renouvelables - Département ESE****
>
>  ****
>
> *Centre Scientifique et Technique du Bâtiment*****
>
> 290 Route des Lucioles BP 209 – F 06904 Sophia Antipolis Cedex****
>
> Tél : +33-(0)4-93-95-67-21****
>
> Fax : +33-(0)4-93-95-64-31****
>
> *Évitez d’imprimer vos emails inutilement. Respectez l’environnement*****
>
>  ****
>
>  ****
>
>
>
>
> ****
>
> _______________________________________________****
>
> TRNSYS-users mailing list****
>
> TRNSYS-users at cae.wisc.edu****
>
> https://mailman.cae.wisc.edu/listinfo/trnsys-users****
>
>
>
> ****
>
> -- ****
>
> *******************************
>
> 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****
>
>
> _______________________________________________
> TRNSYS-users mailing list
> TRNSYS-users at cae.wisc.edu
> https://mailman.cae.wisc.edu/listinfo/trnsys-users
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/trnsys-users-onebuilding.org/attachments/20121026/6e3295b1/attachment-0005.htm>