2013/1/18 王洋 <wanghongyang1767@gmail.com>2013/1/8 <trnsys-users-request@cae.wisc.edu>Send TRNSYS-users mailing list submissions to
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Today's Topics:
1. Re: 2 independet + 1 dependent variables in look-up files
(David BRADLEY)
2. Re: Type94a - multi array will be wrongly calculated
(David BRADLEY)
3. Hybrid dessicant dehumidifier (Graham S. Wright)
---------- 已转发邮件 ----------
From: David BRADLEY <d.bradley@tess-inc.com>
To: leen peeters <l.f.r.peeters@gmail.com>
Cc: "trnsys-users@cae.wisc.edu" <TRNSYS-users@cae.wisc.edu>, vanreeth.b@bxl.daikineurope.com
Date: Tue, 08 Jan 2013 09:10:04 -0600
Subject: Re: [TRNSYS-users] 2 independet + 1 dependent variables in look-up files
Leen,
Unless I am misunderstanding what you want to do, the solution is quite easy as long as you are able and willing to write a new Type; TRNSYS has a built-in kernel subroutine called InterpolateData (formerly called DynamicData) that performs exactly the function that you are looking for. The subroutine is called from a Type with the values of as many as 6 independent variables. The subroutine looks through an external file, finds and returns the values of as many as 10 dependent variables that correspond to the input values. The subroutine interpolates linearly between values but cannot extrapolate beyond the range of values that is given in the data file.
Before you go too far down the path of writing a new heat pump model, I would recommend that you look through the TESS HVAC Library documentation on existing heat pump models and also take a look at the code of some of those models. Most of them stay away from energy rate control (in which a precalculated load is imposed on the heat pump) and stick with temperature level control (in which case heat pump capacity and fraction of full load power are computed based on inlet and ambient conditions.) Those models may be what you are looking for or could be modified with little effort to better suit your needs.
Best,
David
On 1/8/2013 06:35, leen peeters wrote:
Hi all,We are trying to model more accurately a heat pump for which the performance should ideally be read out from a text or excel file.The data depend on 3 parameters (outdoor and indoor air temperature, requested output).Part load ratios are hard to define, as the actual capacity depends on the model type and the outdoor conditions. So it seems logic to use excell. However, values are not a function, but should be looked up in the excell table, potentially interpolated, ... and to make it more challenging, the final SPF does depend on PLR, outdoor and indoor temperature. So it is not just using the external temperature and required capacity to calculate PLR and consequently use that PLR plus indoor temperature to calculate SPF.Calling 6 different excell files in a simulation of 8760*4 steps will take considerable time. The current standard TRNSYS look up model allows two independent parameters defining the output ... so insufficiently accurate.any suggestions on how to solve that?thanks,leen
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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@tess-inc.com http://www.tess-inc.com http://www.trnsys.com
---------- 已转发邮件 ----------
From: David BRADLEY <d.bradley@tess-inc.com>
To: Olaf Scholz <olaf.scholz@online.de>
Cc: trnsys-users@cae.wisc.edu
Date: Tue, 08 Jan 2013 09:16:30 -0600
Subject: Re: [TRNSYS-users] Type94a - multi array will be wrongly calculated
Olaf,
I have used multiple instances of Type94 to compute the output of differently oriented PV arrays a number of times and have gotten good results so I suspect that there may be a problem in the way the model has been defined. One complexity of Type94 is that it has two power outputs; one that gives the power at the maximum power point (and therefore assumes that the array is equipped with a maximum power point tracking (MPPT) device) and another that gives the array power at a particular load voltage. This second output is used for direct-connected systems that do not have an MPPT and in this case, the load voltage is an input to the model. Make sure that you are looking at the maximum power point power when you compare the output of the three arrays; otherwise, the problem may be that the load voltage on the array is so low that the power output of the array is minimal no matter what its orientation. If you are unable to find the solution then I would recommend that you send your project to your distributor for further assistance.
Best,
David
On 1/8/2013 03:12, Olaf Scholz wrote:
I created a PV collector field consisting of three fields (type 94a) for 3 incident directions (east, south, west) all 94a- modules are connected tot o a type109 weather generator. The total incident radiation for the three directions seems to be calculated correctly (output of type109 for three different surfaces). But the power output of the PV modules seems to be always the same, which is not correct. Do you have a solution for that ?
It seems to be the used input variable in type 94a is always the same, so that only the last value is used for the calculation.
Olaf
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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@tess-inc.com http://www.tess-inc.com http://www.trnsys.com
---------- 已转发邮件 ----------
From: "Graham S. Wright" <graham@wrightonsustainability.com>
To: trnsys-users@cae.wisc.edu
Cc:
Date: Tue, 8 Jan 2013 09:20:31 -0600
Subject: [TRNSYS-users] Hybrid dessicant dehumidifier
Hello,
I am wondering if some one has made a TRNSYS component for this thing, or if there is a way to model it with existing ones. The DryCool HD dessicant dehumidifier by Munters. See screenshot below from the manual.
Thanks,
Graham S. Wright
Passive House Institute US
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