Vinay,
In numerical solutions, the relaxation factor (or weighting factor) is used to either speed up the convergence (over relaxation, a factor >1) or slow down the convergence (under relaxation, a factor <1). This technique is used in iterative numerical scheme such as Gauss?Seidel method. During the time step, many iterations are done to reach the solution. So relaxation factor is used during the iteration process to reduce/increase # of iterations to reach your solution.
Now in E+, the relaxation factor is used to adjust your current solution (nothing to do with iterations discussed above). It is a weighting factor that takes the previous time step
solution and current time converged-solution before you go to next time step.
So in Numerical solutions, it is used within the iteration loop and in E+ is implemented outside the iteration loop.
regards
From: Vinay Devanathan <vinay.devanathan@xxxxxxxxx>
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Sent: Friday, March 23, 2012 9:15 AM
Subject: Re: [EnergyPlus_Support] Convergence issue-- does this matter?
Saleh,
Please tell me what do you refer to as the relaxation factor?
THank you.
On Wed, Mar 21, 2012 at 3:30 PM, saleh saadi <salehsnjsaadi404@xxxxxxxxx> wrote:
No problem.regardsSent: Tuesday, March 20, 2012 10:14 PM
Subject: Re: [EnergyPlus_Support] Convergence issue-- does this matter?
Saleh, Again thank you for your help!Thought I had tried that, but must not have..Thanks again!Jeremiah D. CrossettCleanTech AnalyticsThis document may contain valuable information proprietary to CleanTech Analytics which is private and confidential. It may not be shared, copied, stored or transmitted in any form without the prior written consent of CleanTech Analytics
On Tue, Mar 20, 2012 at 9:07 PM, saleh saadi <salehsnjsaadi404@xxxxxxxxx> wrote:Jeremiah,I ran your file on my machine on Denver weather file after changing the relaxation factor to 1 and increasing the # of max warm up period to 100 and set the min warm up period to 6.
E+ version 7 (32 bits) your is 64bits.Here is what I got:Program Version,EnergyPlus-32 7.0.0.036, 3/20/2012 9:43 PM,IDD_Version 7.0.0.036
************* Beginning Zone Sizing Calculations
************* Testing Individual Branch Integrity
************* All Branches passed integrity testing
************* Testing Individual Supply Air Path Integrity
************* All Supply Air Paths passed integrity testing
************* Testing Individual Return Air Path Integrity
************* All Return Air Paths passed integrity testing
************* No node connection errors were found.
************* Beginning Simulation************* Simulation Error Summary *************
************* EnergyPlus Warmup Error Summary. During Warmup: 0 Warning; 0 Severe Errors.************* EnergyPlus Sizing Error Summary. During Sizing: 0 Warning; 0 Severe Errors.
************* EnergyPlus Completed Successfully-- 0 Warning; 0 Severe Errors; Elapsed Time=00hr 11min 7.11sec
So, it might be the relaxation factor that gave those warnings. Try 0.5 or 1.regards,saleh
From: CleanTech Analytics <jeremiah@xxxxxxxxxxxxxxxxxxxxxx>
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Sent: Tuesday, March 20, 2012 7:36 PM
Subject: [EnergyPlus_Support] Convergence issue-- does this matter?
Dear List,I have been working on this file for many a days, attempting to have a warning free run.The simulation is for a Phase Change Material, and is producing good results so far as energy savings, heat flux reduction, HVAC size reduction, and Peak load reduction. The file is to be used in a climate study of various melt temperatures, so determine best product for each ASHRAE climate.There are no errors without the PCM, and I have all three convergence settings, and relaxation at max values (the file did not work with lower)
I realize I could ignore this, but would like to figure out the issue and fix it if at all possible... Thanks
Program Version,EnergyPlus-64 7.0.0.036, 3/20/2012 4:37 PM,IDD_Version 7.0.0.036************* Beginning Zone Sizing Calculations** Warning ** Inside surface heat balance did not converge with Max Temp Difference [C] =1.344E-002 vs Max Allowed Temp Diff [C] =1.000000E-002** ~~~ ** During Sizing, Environment=COOL, at Simulation time=08/21 05:16 - 05:18** Warning ** Inside surface heat balance did not converge with Max Temp Difference [C] =1.288E-002 vs Max Allowed Temp Diff [C] =1.000000E-002** ~~~ ** During Sizing, Environment=COOL, at Simulation time=08/21 07:28 - 07:30** Warning ** Inside surface heat balance did not converge with Max Temp Difference [C] =1.199E-002 vs Max Allowed Temp Diff [C] =1.000000E-002** ~~~ ** During Sizing, Environment=COOL, at Simulation time=08/21 09:56 - 09:58** Warning ** Inside surface heat balance did not converge with Max Temp Difference [C] =1.106E-002 vs Max Allowed Temp Diff [C] =1.000000E-002** ~~~ ** During Sizing, Environment=COOL, at Simulation time=08/21 12:08 - 12:10** Warning ** Inside surface heat balance did not converge with Max Temp Difference [C] =1.005E-002 vs Max Allowed Temp Diff [C] =1.000000E-002** ~~~ ** During Sizing, Environment=COOL, at Simulation time=08/21 15:16 - 15:18** Warning ** Inside surface heat balance did not converge with Max Temp Difference [C] =1.170E-002 vs Max Allowed Temp Diff [C] =1.000000E-002** ~~~ ** During Sizing, Environment=COOL, at Simulation time=08/21 18:44 - 18:46** Warning ** Inside surface heat balance did not converge with Max Temp Difference [C] =1.018E-002 vs Max Allowed Temp Diff [C] =1.000000E-002** ~~~ ** During Sizing, Environment=HEAT, at Simulation time=02/21 09:46 - 09:48** Warning ** Inside surface heat balance did not converge with Max Temp Difference [C] =1.401E-002 vs Max Allowed Temp Diff [C] =1.000000E-002** ~~~ ** During Sizing, Environment=HEAT, at Simulation time=02/21 15:46 - 15:48** Warning ** Inside surface heat balance did not converge with Max Temp Difference [C] =1.421E-002 vs Max Allowed Temp Diff [C] =1.000000E-002** ~~~ ** During Sizing, Environment=HEAT, at Simulation time=02/21 17:32 - 17:34************* Testing Individual Branch Integrity************* All Branches passed integrity testing************* Testing Individual Supply Air Path Integrity************* All Supply Air Paths passed integrity testing************* Testing Individual Return Air Path Integrity************* All Return Air Paths passed integrity testing************* No node connection errors were found.************* Beginning Simulation** Warning ** Inside surface heat balance did not converge with Max Temp Difference [C] =1.347E-002 vs Max Allowed Temp Diff [C] =1.000000E-002** ~~~ ** Environment=COOL, at Simulation time=08/21 05:16 - 05:18** Warning ** Inside surface heat balance did not converge with Max Temp Difference [C] =1.288E-002 vs Max Allowed Temp Diff [C] =1.000000E-002** ~~~ ** Environment=COOL, at Simulation time=08/21 07:28 - 07:30** Warning ** Inside surface heat balance did not converge with Max Temp Difference [C] =1.199E-002 vs Max Allowed Temp Diff [C] =1.000000E-002** ~~~ ** Environment=COOL, at Simulation time=08/21 09:56 - 09:58** Warning ** Inside surface heat balance did not converge with Max Temp Difference [C] =1.105E-002 vs Max Allowed Temp Diff [C] =1.000000E-002** ~~~ ** Environment=COOL, at Simulation time=08/21 12:08 - 12:10** Warning ** Inside surface heat balance did not converge with Max Temp Difference [C] =1.005E-002 vs Max Allowed Temp Diff [C] =1.000000E-002** ~~~ ** Environment=COOL, at Simulation time=08/21 15:16 - 15:18** Warning ** Inside surface heat balance did not converge with Max Temp Difference [C] =1.170E-002 vs Max Allowed Temp Diff [C] =1.000000E-002** ~~~ ** Environment=COOL, at Simulation time=08/21 18:44 - 18:46************* Simulation Error Summary *************************************** ===== Recurring Error Summary =====************* The following recurring error messages occurred.************************** ** Warning ** Inside surface heat balance convergence problem continues************* ** ~~~ ** This error occurred 459 total times;************* ** ~~~ ** during Warmup 0 times;************* ** ~~~ ** during Sizing 0 times.************* ** ~~~ ** Max=5.370517E-002 [C] Min=9.900995E-003 [C]************************** EnergyPlus Warmup Error Summary. During Warmup: 0 Warning; 0 Severe Errors.************* EnergyPlus Sizing Error Summary. During Sizing: 9 Warning; 0 Severe Errors.************* EnergyPlus Completed Successfully-- 474 Warning; 0 Severe Errors; Elapsed Time=00hr 26min 21.93secJeremiah D. CrossettCleanTech AnalyticsThis document may contain valuable information proprietary to CleanTech Analytics which is private and confidential. It may not be shared, copied, stored or transmitted in any form without the prior written consent of CleanTech Analytics
Vinay Dev