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Re: Fwd: Enquiry on Type 4, Type60 and Type 66 modules

Dear TRNSYS users,

We now have a fix for both TRNSYS-EES problems with multiple units. It will be included in the next TRNSYS update but you can contact me if you need the fix before that.

Regards,

Michaël Kummert


Michaël Kummert wrote:


Dear Howard,

I was wrong, the current version of Type 66 allows you to use several units. It just does not work very well yet...

The first problem is that you will get errors and wrong results if the second unit has less inputs than the first one.

The second problem is that you may get a series of errors at the very end of the simulation (after you close the online plotter). Those errors seem to be operating system dependent but they have no influence on the results.

We currently have a fix for the first problem but we are still investigating the second one. Both problems should be fixed in the next TRNSYS update. Users who want to receive the first fix before that can contact me directly. As Dave mentioned it, you should also make sure you use a recent professional version of EES.


Regards,

Michaël Kummert




David Bradley wrote:


Dear Howard,
We recently completed a project that sounds quite similar to your proposed system. In it we had two vapor compression cycles and two storage tanks. Originally we were planning to put both vapor compression cycles into the same EES file until we found out that it is possible to use multiple instances of Type66 (my apologies for contradicting Michaël - if I hadn't tried this last week I would have said that only one Type66 instance was possible as well). We had some trouble getting it to run initially but found that it was a matter of some simple typos that we had made, which were causing stragne errors. Initially, we used extremely simple EES files; each one had only one input and one output. The first EES file simply added 1 to the input, the other added 2. Once we got that working, we then started adding the real equations to the EES files. One other thing that you need to do is make sure that you have a recent version of EES (within the past few months) because at one point, there was no way to completely turn off EES warnings about nearly singular equations and that message was not passed back to TRNSYS. We used tank models from our own libraries (Type524 specifically). With this model, one of the parameters is the number of isothermal nodes in the tank. You can look at the temperature of each node separately and see how well stratified your tank is. If the flow rates in and out of the tank are high, then you will see a lesser degree of stratification. Please let me know if you have any specific questions about the type of errors that you are seeing.
Kind regards,
David

At 01:46 PM 7/9/2003 -0500, you wrote:


From: "Howard" <howardbut@hkusua.hku.hk>
To: <trnsys@relay.doit.wisc.edu>, <bradley@tess-inc.com>
Subject: Enquiry on Type 4, Type60 and Type 66 modules
Date: Wed, 9 Jul 2003 22:07:55 +0800
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Dear all,

Currently I am trying to model a hot water storage tank for storing water heated by a heat pump. There are two similar models, the Type 4 and Type

60 in the TRNSYS and I would like to know:


- Any general guidelines to decide which Type of storage tank should be used?

- How do we define the number of stratification? Aren't the stratification is a natural phenomena?


On the other hand, I tried to write my own component in EES (such as the compressors, condensers) and would like to add them into the Trnsys project by Type66 module.

However, plenty of error popped up when I started the simulation if two or more Type66 module is used. I sorted out there may be some problem with the data transfer through CLIPBOARD but I cannot resolve it indeed. Does anyone have similar experience before which can share?


Regrads,


Howard But

The University of Hong Kong


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Thermal Energy System Specialists (TESS)
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--
_________________________________________________

Michaël Kummert

Solar Energy Laboratory - University of Wisconsin-Madison
1303 Engr Res Bldg, 1500 Engineering Drive
Madison, WI 53706

Tel: +1 (608) 263-1589
Fax: +1 (608) 262-8464
E-mail: kummert@engr.wisc.edu

SEL Web Site: http://sel.me.wisc.edu
TRNSYS Web Site: http://sel.me.wisc.edu/trnsys