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Re: [TRNSYS-users] type107 or 680 data file

Jochen,

What I did to create the .dat file is as follows:

I used your algorithm.

I calculated the 'cooling required' for the rated 5.5 C
temperature change.  The spreadsheet says 70.287 kW but
I could have just used the stated capacity of 70.3 kW.

Then I calculated the 'available cooling capacity' given
hot, cool and chilled water inlet temperatures. I followed 
the Yazaki cooling capacity formula and multiplied rated
capacity by heat flow correction and cooling capacity
factor.

Then I divided 'cooling required' by 'available cooling
capacity' to get the capacity fraction.  This value is
the fraction that runs down the left side of the page
starting at the 5th line of the .dat file.  I did this
for different inlet hot and cool water temperature.
(The column G label in the spread sheet should say
cooling available.)

To calculate the design energy input fraction, I
first used the Yazaki heat input equation to calculate 'required 
heat' given operating conditions.  I multiplied the 'rated
heat input' by heat flow correction and heat input factor.
I divided 'required heat' by the 'rated heat input' to calculate the design energy input fraction. This is the second column of 
numbers that run down the left side of the .dat file.
Let me reference the comment "fraction of design load" from the 
.dat file.  This is the line that has 1.0 and 0.8.  The
fractions calculated in the previous paragraphs are for the fraction of design load of 1.0 (full load). The capacity fraction is the same for 1.0 and 0.8. The design energy input fraction for 0.8 is the the design energy input fraction for 1.0 multiplied by 0.8. I suppose this represents the case where only 80% of the rated delta T is required so 80% of the heat is need to remove it. By inspecting the example .dat file is where I figured out how to get the different fraction of design loads from the calculated data at 1.0. It seems to be the pattern. I must state that I did not test any TRNSYS output below full load capacity,,, yet.
So that s what I did. I have had no complaints. About 7 or 8 
people all over the world have the files.

Now differentiating between "fraction of design load" and
"fraction of full load capacity".
There is a fraction of design load comment in the .dat file as described above. I take this to mean the required heat input divided 
by available heat input.
To confuse matters, in the documentation for type 680 there is a symbol f^designload where f^designload = Q^remove / capacity^rated. 
This formula is similar or the same as the formula used
to calculate the capacity fraction above.
Then there is fraction of full load capacity in the documention represented by f^fullloadcapacity. I am going to take a guess and say that that represents the fraction of design load in the 
.dat file.
How do you like that a full circle of confusion. Terms in the .dat file seem to be mixed up. Either that or I am mixed up. Probably 
both and more so the later.
Like I said. The tests I ran for 9 operating conditions at full load match hand calculations of delta T within the range of 0.03 oC. 
That where I am at.

Thank you,

Mario Ortiz




On Mon, 28 Jul 2008 09:21:36 +0200
 Jochen Doell <jochen.doell@ise.fraunhofer.de> wrote:

Dear Mario,

thank You for Your .dat files on the SH20.
I experience all the same trouble with ANY manufacturer. My opinion is that they just underestimate the possibilities (and the necessity) of accurate simulation before installing a system.
Anyway, can You explain to me how You set up the data file? I had problems with the definition of the parameters, especially the difference between "fraction of design load" and "fraction of full load capacity" is not clear to me.
Following I added the question I sent to the user forum (including an example). Maybe You can give a brief answer. 

Best regards,
Jochen



Dear TRNSYS users,
I have problems setting up the input file required by type 107 from 
manufacturers data.
To make this easier I would like to ask You to look up the following 
example and correct it if necessary:

I have a chiller with
Rated capacity = 35kW
Rated Energy Input = 50,2kW


One exemplary operation point:
T_hot_in=70°C
T_medium_in=27°C
T_cold_setpoint=7°C
P_hot_in=20,3kW
P_cold_out=13,5kW


Calculated fraction of design load:
f_design_load=(m_cold*cp_cold*(T_cold_in-T_cold_setpoint)/Capacity_rated
                         =(1,53kg/s*4,20kWs/kgK*2,1K)/(35kW)
                         =0,386

Calculated fraction of full load capacity:
F_full_load_capacity=13,5kW/35kW=0,386

Calculated fraction of design energy input:
F_design_energy_input=20,3kW/50,2kW=0,404
The following numbers would form one row in the input file. 
T_hot_in=70°C
T_medium_in=27°C
T_cold_setpoint=7°C
f_design_load=0,386
F_full_load_capacity=0,386
F_design_energy_input=0,404
I doubt that the "fraction of design load" and "fraction of full load 
capacity" should be the same....
So what is the difference between the two. If the latter is the maximum chilling capacity I could get from the machine (what I suppose right now) how is it defined? As far as I know manufacturers do not deliver that number... 


Mario Leroy Ortiz schrieb:

Absorption Chiller Users,

I have not recieved and data from Yazaki.  It has
been about 2 or 3 weeks since I asked for it.  We should
have asked for it before we paid them.
Either way. I think I have created a few absorption chiller data files that model the Yazaki SH20. I am getting TRNSYS to output changes in temperature for hot and chilled water flows very close to the tempertures changes calcultated by hand calculations like the examples on the yazaki web site.
Attached are 4 .dat files a TRNSYS project file and an Xcell spread sheet. The 4 .dat files are for 100%, 120%, 65% and 55% of rated flow. The project file is what I used to test the output.
In the spread sheet, the left side of the sheet is where I calculated the fractions and the right side is where I compared hand calculations to TRNSYS results. I was very surprised that they are so close after 
I was so confused trying to create the data files.
The data files are for the range of temperatures given in the Yazaki website. To give TRNSYS some data to work with I put data in each .dat file for a chilled water set temperatures of 7 C and 7.1 C. However, the 7.1 C data is simply the 7 C data repeated. I got that 
idea from Sebastien.
I did not get to try your new type Sebastien. I do not know what to do with the files you gave me in order to get an instance of the new 
type into a project.  One day I ll figure it out.

Hope this helps.

Mario Ortiz


--
_________________________________________________

Dipl.-Ing. (FH) Jochen Döll
Dept. Thermal Systems and Buildings

Fraunhofer-Institut für Solare Energiesysteme ISE
Heidenhofstrasse 2, 79110 Freiburg, Germany

Phone:	+49 (761) 4588-5527
Fax:	+49 (761) 4588-9000
Mail:	jochen.doell@ise.fraunhofer.de
Web:	www.ise.fraunhofer.de
_________________________________________________