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Today's Topics:
1. Re: controller type 2 (David Bradley)
2. Re: Type 56- Restaurant's example (David Bradley)
3. Model batterie (Chehal, Samir)
---------- Forwarded message ----------
From: David Bradley <bradley@tess-inc.com>
To: tchanche fankam bertrand < tfb_tchanchef@yahoo.fr>, TRNSYS USERS <trnsys-users@engr.wisc.edu>
Date: Thu, 10 May 2007 10:06:55 -0500
Subject: Re: [TRNSYS-users] controller type 2
Betrand,
I think you are going to need to use two controllers. The first controller will determine the flow rate of your collector loop in order to maintain a collector outlet temperature of 70C. The other controller will determine the flow rate on the load side of your heat exchanger in order to maintain source side outlet temperature of 60C. I am also not sure that Type2 is an appropriate controller model; Type2 models a differential controller that has only two states: ON and OFF. In order to modulate your flow and maintain an outlet temperature, you will need to use a proportional or a PID controller. There are some solar collector models in the TESS Solar Library that combine a variable speed pump, controller, and collector and modulate the required inlet flow rate in order to maintain an outlet temperature.
Kind regards,
David
At 01:50 5/10/2007, tchanche fankam bertrand wrote:
Dear all,
i am simulating a system that comprises a subsystem made of a colector loop(ETC collector, pump, flat plate heat exchanger ). i need to to keep the inlet temperature of the collector at 60C and the outlet temperature at 70C.
I would like to know if it is possible to control the system with type 2 and how.
Thank in advance for your help.
yours,
------------------------
TCHANCHE FANKAM Bertrand
C/O SUH Christopher
22 kadmeas-BOTANIKOS
11855 Athens, GREECE
mobile:+30 694 295 5952
office: +30 210 529 4046
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Thermal Energy System Specialists (TESS), LLC
David BRADLEY 2916 Marketplace Drive - Suite 104
Partner Madison, WI 53719
Phone: (608) 274-2577 USA
Fax: (608) 278-1475
E-mail: bradley@tess-inc.com
Web Pages: http://www.tess-inc.com and http://www.trnsys.com
"Providing software solutions for today's energy engineering projects"
****************************************************************************************
---------- Forwarded message ----------
From: David Bradley <bradley@tess-inc.com>
To: MERIEM SOUSSI <soussi_meriem2005@yahoo.fr >, trnsys-users@engr.wisc.edu
Date: Thu, 10 May 2007 10:20:49 -0500
Subject: Re: [TRNSYS-users] Type 56- Restaurant's example
Meriem,
1- In type 56, When you calculate the response factors of the walls, which properties do you take for the inside and the outside air layers?? Do you take the ASHRAE standard library (I mean the layer A0 for the outside surface resistance and the layer E0 for the inside surface resistance).
How does this interfeer with the indicated values of (hc)int?
The convection and radiation from the inside and outside surfaces of Type56 walls are calculated internally based on the user specified values of front side and back side solar absorptance and inside and outside convection coefficient. These values are specified in the wall type manager in TRNBuild. TRNBuild displays a wall u-value that includes estimated values of front and back side surface resistance but these values are for display only. The actual values are calculated during the simulation and are a function of current ambient conditions.
2-How to calculate response factors with variable values of convective heat transfer coefficient of wall (inputs/shedule values)??
in order to see the time dependent, calculated values of the wall u-value, you need to choose the appropriate Type56 output NTYPE by clicking on the "outputs" button in the TRNBuild project window.
3-In the example "Restaurant" ; the convective heat transfer coefficient (back)of the wall "outside" is defined as = 1*HOUTSIDE; where HOUTSIDE is an input of type 56, and HOUTSIDE is not connected to any other type, that means that during the simulations, this parameter is equal to zero?? Why is that input not connected properly??
you are quite correct; that is an error in the example. There should be an equation that sets the value of HOUTSIDE and that equation should be connected to Type56's input. The equation should have the form:
(AA+BB*WindVel+CC*WindVel**2)*3.6
where AA, BB, and CC are empirical coefficients that depend on the exterior surface material and WindVel is the wind speed. The AA, BB and CC coefficients (from ASHRAE) would be:
AA BB CC
Stucco 11.58 5.894 0.0
Brick 12.49 4.065 0.028
Concrete 10.79 4.192 0.0
Wood 8.23 4.00 -0.057
Smooth plaster 10.22 3.1 0.0
Glass 8.23 3.33 -0.036
Thanks for finding that error.
David
Thank you for clarifying my doubts.
Best regards
Meriem
Découvrez une nouvelle façon d'obtenir des réponses à toutes vos questions ! Profitez des connaissances, des opinions et des expériences des internautes sur Yahoo! Questions/Réponses.
_______________________________________________
TRNSYS-users mailing list
TRNSYS-users@engr.wisc.edu
https://www.cae.wisc.edu/mailman/listinfo/trnsys-users****************************************************************************************
Thermal Energy System Specialists (TESS), LLC
David BRADLEY 2916 Marketplace Drive - Suite 104
Partner Madison, WI 53719
Phone: (608) 274-2577 USA
Fax: (608) 278-1475
E-mail: bradley@tess-inc.com
Web Pages: http://www.tess-inc.com and http://www.trnsys.com
"Providing software solutions for today's energy engineering projects"
****************************************************************************************
---------- Forwarded message ----------
From: "Chehal, Samir" <Samir.Chehal@jacobs.com>
To: <trnsys-users@engr.wisc.edu >
Date: Thu, 10 May 2007 17:28:12 +0200
Subject: [TRNSYS-users] Model batterie
Dear trnsys' s users,
I must model cool and heat battery.
I use type 32 (cooling coil) to model cool battery and I don' t know how model heat battery.
Best Regards
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