RE: [EnergyPlus_Support] Re: Setting the HVAC ON/OFF cycle

Hi,

Are you using a third party software to run the IDF?

Try the attached IDF, which was expanded from my previous IDF.

I am using EPlus ver.6.0.0.037. You seems to have an extra line in the template that the expandIDF cannot handle. I did not change the template.

Dr. Li

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: adityaravi87@xxxxxxxxx
Date: Tue, 16 Aug 2011 09:58:12 -0700
Subject: Re: [EnergyPlus_Support] Re: Setting the HVAC ON/OFF cycle

Dr.Li,

I ran the file you had sent me but there seems to be a severe error and hence the simulation was incomplete. Following was the error message I got:

Program Version,EnergyPlus 6.0.0.023, 8/16/2011 12:55 PM,IDD_Version 6.0.0.023

** Severe ** Output:PreprocessorMessage="ExpandObjects" has the following Fatal conditions:

** ~~~ ** SEVERE: Too many fields were found for the object: HVACTemplate:Zone:PTAC

** ~~~ **

** ~~~ ** Number expected=[27]

** ~~~ ** Number found=[28]

** Fatal ** Preprocessor condition(s) cause termination.

...Summary of Errors that led to program termination:

..... Reference severe error count=1

..... Last severe error=Output:PreprocessorMessage="ExpandObjects" has the following Fatal conditions:

************* Warning: Node connection errors not checked - most system input has not been read (see previous warning).

************* Fatal error -- final processing. Program exited before simulations began. See previous error messages.

************* EnergyPlus Warmup Error Summary. During Warmup: 0 Warning; 0 Severe Errors.

************* EnergyPlus Sizing Error Summary. During Sizing: 0 Warning; 0 Severe Errors.

************* EnergyPlus Terminated--Fatal Error Detected. 0 Warning; 1 Severe Errors; Elapsed Time=00hr 00min 1.31sec

I am not sure what changes I need to do to correct them.

Also by the output what I meant was, if I could see the zone temp fluctuate between the set point and the set back of say 1 deg C. So when we reach the set point the compressor should go OFF and I should be able to monitor how the room/zone temp varies. Then once again on reaching the set point, compressor kicks ON and then I should be able to see the variations in the zone temp.

Regards,

Aditya

From: YuanLu Li <yli006@xxxxxxxxxxx>
To: Linda Lawrie <energyplus_support@xxxxxxxxxxxxxxx>
Sent: Monday, August 15, 2011 4:48 PM
Subject: RE: [EnergyPlus_Support] Re: Setting the HVAC ON/OFF cycle

Hi, Aditya

If you are not an experienced software program, I do not think you can handle the EMS in EPlus. It is a software debugging tool modified for variable viewing and changing.

If you run the exercises in the Getting Started Document, you will have learned how to use theremostat and other schedules.

ON/OFF in HVAC is done using a theremostat control. There is nothing special about it. The part that is confusing is that the VAV system does not use the zone thermostat cirectly. Three or four more parameters are used to allow the zone thermostat to control the variable damper in the zone, and turning on the reheat system and adjust the OA damper. So stay away from VAV.

The part that is difficult for a beginner to do is to want the ON/OFF at a precise setback of 1 or 2°C.
=========================
Theremostat type 1 is for heating with SB, Type 2 is cooling with SB.
Tpye 3 is one set point for both heating and cooling. Because these types do not have a dead band, you cannot activate them at the same time. In another word, you will have a Summer and Winter period defined for these schedules to be active.

Thermostat type 4 defines two bands, one for cooling and one for heating. They do not overlap. The space between the band is the dead band where neither cooling nor the heating system would be turned ON. This is very useful for places where the transition from Summer to Winter is not well defined. You may want heating at the night and cooling during the day time.

Run any example without the VAV will provide you with a running model.
======================
The zone occupancy and equipment schedules are independent of the thermostat schedules.

I do not know what you meant by "to get the simulation output in the format I had written in this post".

If you are referring to a building green certificate report. You have to do a lot more than just simmulating a system. I know how to do it, but I do not want to be involved to write one, because I do not have the reference documents.
=================
If I can retrieve your earlier IDF, I will correct it and mail it to you.

Dr. Li

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: adityaravi87@xxxxxxxxx
Date: Mon, 15 Aug 2011 17:08:49 +0000
Subject: [EnergyPlus_Support] Re: Setting the HVAC ON/OFF cycle

Dr.Li,

Thank you for the time.

Well I had some schedules put up for the equipment and Lights. Also I have included some occupancy schedule in my idf. So the warnings are now associated with these inputs only. I changed my CLGSP sch and HTGSP sch to the simple example one which you have suggested. If you can now tell me what is type4 Thermostat and how I can use it and also how to choose or set the on/off fan instead of the constant fan, I can make the changes and run the simulation.

Like I mentioned my final motive is to achieve a ON/OFF schedule for the HVAC. I was also given a suggestion to look into EMS documentation which I am doing right now.

It will be of great help if you can modify my IDF and send me the file with pointers explaining how the schedule works. I need to get the simulation output in the format I had written in this post. Please guide me through it.

Sincerely,

Aditya

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@...> wrote:

>
>
> >
> Previous mail removed.

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