RE: [EnergyPlus_Support] define schedule compact for infiltration to reach convergence results

Hi, Mohammad

I think, the topic is now not on infiltration alone. It is on how to simulate a customized zone condition to match a real condition..

Based on the photo and the IDF, I think you are trying to control the test cell temperature to what you have measured on the same day, using EPlus simulation, so that the output variables on the partition should give you the same information as the measured values for the test sample.

What you are trying to do is to modify the zone condition resulted from a simulated OD and solar condition, to match that to a real zone environment with measured values.

If this is what you want, you are on the right track. You did not get the result, because infiltration object is not easily control. It depends on the OD temperature and wind velocity.

As you are blowing air into the two zones, the two zone temperature values changed in the same direction and may be with a different magnitude.

With the lighting and other equipment method below, one heat and one cool the zone. Therefore, it is easier for you to adjust the resultant value.

First record the experiment date and should try to record the OD temperature at the same time as the measurements indoors.

Dry bulb temperature is the temperature at 2 pm, the difference is the temperature between 2 pm and 5 am. Wet Bulb temperature can be read from a psychromatic chart. (a few degree below the dry bulb. Same value as dry bulb in Winter, when the two values are the same for 0 degree as difference)

The date on the DesignDay object is used to calculate the solar angle on the windows.

Run the simulation and note the window heat gain, and zone heat gain/loss conditions and the zone air temperature, without any additional control. People, lighting, and equipment should be there, if applicable.

If the zone temperature in the two zones are not too far from your measured values, the building envelop entries can be assumed correct.

Compare the values and note the values for night time, morning, sun rise, noon, afternoon, sun set. If the difference indoor and outdoor are in the same direction and general over all shape, the building information is probably good.

Now, if the measured temperature is lower than the simulated temperature in both zones, you may want to try reduce the dry bulb temperature in the DesignDay object to make a correction downwards. After that, use light power to increase, and a negative value power in the other equipment object to reduce the simulated temperature. Both of these can be changed by a multiplier schedule, and you can try different schedule values on the same compact schedules for different days, i.e., Sunday, Monday, ... etc.

Repeat the DesignDay object with a different name and a different day type (say

Hello Dr. Li,

Thanks again for wide spread information,

In my case,we did experimental tests that in detail:

A test cell which created a wall inside it we put sensors in two parts(north and south ambient part of cell) for measuring temperate changes and i try to simulate it by E+(attached pictures). when i put infiltration such as .idf file i can obtain good results in simulation,but i am not sure that is correct or not ...because infiltration can be exist in real. could you please put comment for me? how can i evaluate my simulation.

regards

From: YuanLu Li <yli006@xxxxxxxxxxx>
To: EnergyPlus_Support <energyplus_support@xxxxxxxxxxxxxxx>
Sent: Tuesday, March 13, 2012 11:47 PM
Subject: RE: [EnergyPlus_Support] define schedule compact for infiltration to reach convergence results

There is no problem with your IDF, except that you do not have DesignDay sizing.

The air infiltration rates to the zones were very high, 0.5 to 3.5 ACH.

You can add the followings to display them.
============================

Output:Variable,*,Zone Mean Air Temperature,Timestep;

Output:Variable,*,Outdoor dry bulb,Timestep;

Output:Variable,*,Schedule Value,Timestep;

Output:Variable,*,Zone Infiltration Air Change Rate,Timestep;

==============================

Output:Table:TimeBins,
*, !- Key Value
Zone Mean Air Temperature, !- Variable Name
, !- Interval Start
, !- Interval Size
20, !- Interval Count
, !- Schedule Name
Temperature; !- Variable Type
============================
I do not know what this is for and was not simulated.
Dr. Li

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: mohammadkheradmand@xxxxxxxxx
Date: Tue, 13 Mar 2012 10:31:59 -0700
Subject: [EnergyPlus_Support] define schedule compact for infiltration to reach convergence results

Hello,

Could you please explain to me this point in

schedule compact:

Field: Value

Finally, the value field is the schedule value for the specified time interval.

what is meaningful of it? and is it true that i did in .idf file till now?

regards,

From: saleh saadi <salehsnjsaadi404@xxxxxxxxx>
To: "EnergyPlus_Support@xxxxxxxxxxxxxxx" <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Sent: Thursday, March 8, 2012 7:33 PM
Subject: Re: [EnergyPlus_Support] what can i do for convergence the result ?

Does the simulation underestimate or overestimate your experimental results?

You might need to consider the infiltration in your model. try to use simple convective heat transfer coefficient algorithm.

Use real weather data measured at site.

what is the uncertainty in your measurements equipment. ? your results need to be within 1 deg difference. (3-4) degree difference is large.

regards,

From: Mohammad Kheradmand <mohammadkheradmand@xxxxxxxxx>
To: "EnergyPlus_Support@xxxxxxxxxxxxxxx" <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Sent: Thursday, March 8, 2012 11:06 AM
Subject: [EnergyPlus_Support] what can i do for convergence the result ?

I simulate my model for coldest and hottest a day of August, for comparing results between experimental and simulation results, i got reasonable result for hottest day(almost 4-5 degree differences ), but for coldest day i have difference almost 10-12 degree ...what is my problem?

regards

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