[TRNSYS-users] Type743’s power coefficients parameter setting

Tue Nov 17 01:51:12 PST 2015

Dear Alastair,

Thank you for your patient reply. Now I can understand the relationship
between the coefficients and the parameters. And, I tried to understood the
Fortran code although my poor knowledge about it.

But it sees that the pump’s power drawn result is not right according to
the setting as the following, Which is much lower than the equation curve I have
attached the simple project(.tpf and.txt file) and the fitting equation(.xls)
data file. 

For example, I has fitted a pump power curve equation as followings

p = 56877 + 49714(m/m rated)
+ 1094.3(m/m rated) ^2  (R² =
0.9959), So the setting is :

power coefficient-1 = a0=56877 (Parameter 6 for TYPE 743)

power coefficient-2 = a1=49714
(Parameter 7 for TYPE 743)

power coefficient-3 = a2=1094.3(Parameter 8 for TYPE 743)

 May you tell me the
reason? Thank you very much for your time!with best regards
yours sincerelyWeiweiChongqing University
From: xiaoweiweiwu at hotmail.com
To: trnsys-users at lists.onebuilding.org
Subject: Type743’s power coefficients parameter setting
Date: Mon, 16 Nov 2015 13:49:52 +0800

Dear all,        In the type743’s document, there is an equation743.1 about P, which is power drawn the pump, as following:P=a0+a1(m/mrated)+ a2(m/mrated)2+ a3(m/mrated)3+………..In the type743’s parameter setting, parameter number 5 is set to“number of power coefficients”,if I input “3”then the parameter number6、7 、8 is as following：power coefficient-1power coefficient-2power coefficient-3And the explanation about the coefficient is “The value of the polynomial multiplier for the relationship between normalized pump power and normalized pump flow rate”.My question is:1)whether a1、a2 a3 is correspond to power coefficient-1、power coefficient-2 and power coefficient-3 respectively? if yes, how to set the value a0? or i just need fitting an equation that a0 is zero?2)If not ,what is the right relationship between them?In addition, I referred to an example named “pumps with flow rate known” in Tess models of TRNSYS software, the type743’s parameter 5 is set to 3, and the parameter6 and 7 (power coefficient-1、power coefficient-2) are  both  0, while parameter 8 is set to 1. The similar situation setting could be found in other types such as TYPE510’s power coefficient.Thank
you very much help me out of this issue.
With best regards
Yours sinscerelyWeiwei
Chongqing university

Thank you very much help me out of this issue.  		 	   		   		 	   		  
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temperature(c)	fluid flow rate(kg/hr)             
26	0
26	272500
26	1428.062986
26	411.2671769
26	412
26	95.42000473
26	95.42000473
26	95.42000473
26	162.8229907
26	291.3515393
26	515.3536052
26	816.3867389
26	1188.812221
26	1629.100815
26	2132.495628
26	2694.385669
26	3310.339016
26	3976.002224
26	4687.142171
26	5439.612918
26	6229.375654
26	7052.546089
26	7905.373301
26	8784.250604
26	9685.638667
26	10606.2077
26	11542.76175
26	12492.15509
26	13451.33061
26	14417.46804
26	15388.0293
26	16360.38064
26	17331.98101
26	18300.54096
26	19264.10823
26	20220.7465
26	21168.47184
26	22105.3515
26	23029.67749
26	23940.14874
26	24835.50433
26	25714.30133
26	26575.14388
26	27417.22139
26	28239.626
26	29041.5795
26	29822.41425
26	30581.25659
26	31317.54747
26	32031.15858
26	32721.80414
26	33388.95537
26	34032.41532
26	34652.05705
26	35247.8131
26	35819.68878
26	36367.7572
26	36892.15362
26	37393.07305
26	37870.76135
26	38325.5109
26	38757.65937
26	39167.58578
26	39561.53769
26	39941.79438
26	40304.67486
26	40650.60506
26	40979.98526
26	41293.40659
26	41591.22674
26	41873.41682
26	42140.71464
26	42393.55355
26	42631.93313
26	42856.63174
26	43068.11454
26	43266.40333
26	43452.30007
26	43626.28331
26	43788.37814
26	43939.39285
26	44079.80836
26	44210.09202
26	44330.72309
26	44442.17133
26	44544.89603
26	44639.34676
26	44725.9603
26	44805.16391
26	44877.82507
26	44943.94822
26	45003.90333
26	45058.12832
26	45106.97303
26	45151.2349
26	45191.37694
26	45227.84799
26	45261.09101
26	45291.06615
26	45318.03697
26	45342.69877
26	45365.39087
26	45386.44659
26	45405.74225
26	45423.45658
26	45440.20213
26	45456.23818
26	45471.82045
26	45487.20557
26	45502.62727
26	45518.30012
26	45534.42234
26	45551.17725
26	45568.73184
26	45587.23648
26	45607.28491
26	45629.12944
26	45652.55191
26	45677.65694
26	45704.52247
26	45733.19649
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