[Bldg-sim] the use of dynamic energy simulation tool

[김덕우]

I heartily thank you (Mr.Wetter and Mr.Jeff and Mr.Per) for your kind comments. 

 

It is very helpful to sort things out in my head. 

 

Best Regards, 
Deuk-Woo, Kim 



From: Per Sahlin [mailto:per.sahlin at equa.se] 
Sent: Friday, February 03, 2012 2:28 AM
To: 김덕우
Cc: bldg-sim at lists.onebuilding.org
Subject: RE: [Bldg-sim] the use of dynamic energy simulation tool

 

Hi,

 

I think we constantly underestimate the impact on society of this field. Let’s take some pride in what we do!

 

Most of the wealth of developed nations is in the value of buildings. That value is starting to be related to the actual performance of those buildings. (Funny this hasn’t happened before.) We have venture capitalists calling and asking about the validation status of our tool. They want to know if they can trust the performance numbers quoted by someone selling a property. This would hardly have happened a few years back.

 

Suppose an engineering-proficient company, perhaps like Toyota, was challenged with the task of developing a high performance building. Do you think they would look for the latest ISO standardized monthly hand calculation method for its optimization? No, they would look for the best possible engineering tools available for describing and experimenting with dynamical virtual models of buildings. (Actually, they might not do so well first because they would probably underestimate the pure technical challenges involved).

 

Even a  big ship, such as the AEC industry, will turn eventually in response to the challenges ahead. At that stage, real knowledge and engineering skills are likely to be more important than committee designed hand calculation methods.

 

Cheers,

 

Per

 

 

-----------------------------------------

Per Sahlin

EQUA Simulation AB   

 <mailto:per.sahlin at equa.se> per.sahlin at equa.se 

+46   8 546 20 111

+46 70 422 03 02   (mobile)

+46   8 546 20 101 (fax)

plurresahlin (skype)

Råsundavägen 100

169 57 SOLNA, Sweden

 <http://www.equa.se> http://www.equa.se     

-----------------------------------------

 

 

 

 

From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Michael Wetter
Sent: den 2 februari 2012 07:26
To: Jeff Haberl
Cc: 김덕우; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] the use of dynamic energy simulation tool

 

Deuk-Woo

 

To add to Jeff's answer of point 4), Modelica models that allow dynamic simulation of building energy and control systems are available from  <http://simulationresearch.lbl.gov/modelica> http://simulationresearch.lbl.gov/modelica, including source code. These models will run at sub-second time steps (when fast transients are present) and can model realistic representations of control sequences. 

 

The models can also be linked to hardware through BACnet and A/D converters using the Building Controls Virtual Test Bed,  <http://simulationresearch.lbl.gov/bcvtb> http://simulationresearch.lbl.gov/bcvtb.

 

See the papers, manuals and user guides at these web sites for more detailed information.

 

All the best,

 

Michael

 

2012/2/1 Jeff Haberl < <mailto:jhaberl at tamu.edu> jhaberl at tamu.edu>

Dear Deuk-Woo,

 

Here are a few comments on your questions:

 

1. To get energy efficiency incentives, such as LEED certificate. 

2. To compare alternatives (wall material, window, building design) in architect point of view. 

3. To compare alternatives (system type and configuration, COP, etc.) in mechanical engineer point of view. 

 

For Items #1 - 3, EQUEST, EP+ or TRNSYS will do. In the U.S. EQUEST is the most widely used by the AE community. Note, for most of these simulations an hourly simulation will do, which is not a true dynamic simulation.

 

4. To develop energy efficient control strategies and to test DDC controllers. (BEMS and emulation; maybe electric engineering field or ??)

 

For this you'll need MATLAB and a true dynamic simulation platform (i.e., it usually needs 1 sec or less time steps and true dynamic equations). Many of the U.S. controls companies have developed extensive tools for this, including Modelica/Dymola platforms. However, they do not distribute these outside their own companies. MATLAB is fast becoming a platform of choice, perhaps because most universities teach with it. There are other platforms as well, check with your local ME or EE controls Prof. Some that come to mind are HVACSiM+ (by George Walton at NIST).

 

5. To identify the system mal-function (such as AHU) comparing between “predicted” energy and “actual” energy in real-time. (BEMS, maybe electric engineering field??)

 

This is a tough one. LBNL and PNNL have been working on this for some time. PNNL has their AHU fault detection program, and other programs. LBNL has their controls test bed up and running. You might also check with the Chair of ASHRAE TC 7.5 to see what the latest RPs for controls simulation. This TC has most of the knowledgable folks on it (which does not include me). 

 

6. Building Simulator: which is used to training building managers or operators or learners (students) in HVAC system operation realistically (such as flight simulator)

 

Check out Joe Deringer's LEARNHVAC web page...just amazing...there is also other emulator work at LBNL that Phil Haves and Michael Wetter are doing.

 

7. To “JUST” verify Building behavior (HVAC operation, energy consumption, etc) over the whole year period with different whether conditions in IWEC and TMY. (to see "what could be")

 

This can be done with forward models (i.e., simulation) or inverse models (i.e., ASHRAE RP1050), or a combination of both. You can also use component models such as those available from ASHRAe (HVAC01 and HVAC02 toolkit, RP865, RP827, etc).

 

There are other proprietary tools that diagnose HVAC problems, some have published results, some not. You'll find lots of papers (apx., 3 - 5,000) on our Lab's web site about our commissioning work, which includes air-side simulation as a diagnostic. 

 

Hope this helps.

 

Jeff

 

 

8=!  8=)  :=)  8=)  ;=)  8=)  8=(  8=)  8=()  8=)  8=|  8=)  :=')  8=)8=?

Jeff S. Haberl, Ph.D.,P.E.,  <mailto:FASHRAE..............jhaberl at tamu.edu> FASHRAE..............jhaberl at tamu.edu

Professor............................................................Office Ph:  <tel:979-845-6507> 979-845-6507

Department of Architecture.............................Lab Ph: <tel:979-845-6065> 979-845-6065

Energy Systems Laboratory.............................FAX:  <tel:979-862-2457> 979-862-2457

Texas A&M University.....................................77843-3581

College Station, Texas, USA, 77843..................URL: <http://www.esl.tamu.edu> www.esl.tamu.edu

8=/  8=)  :=)  8=)  ;=)  8=)  8=()  8=)  :=)  8=)  8=!  8=)  8=? 8=)8=0

  _____  

From:  <mailto:bldg-sim-bounces at lists.onebuilding.org> bldg-sim-bounces at lists.onebuilding.org [ <mailto:bldg-sim-bounces at lists.onebuilding.org> bldg-sim-bounces at lists.onebuilding.org] on behalf of 김덕우 [ <mailto:deukwookim at skku.edu> deukwookim at skku.edu]
Sent: Tuesday, January 31, 2012 11:22 PM
To:  <mailto:bldg-sim at lists.onebuilding.org> bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] the use of dynamic energy simulation tool

Dear all, 

 

I have been thinking about the use of dynamic energy simulation tool (e.g. whole building simulation tool, such as E+, ESP-r, TRNSYS, SPARK, etc). 

 

The usage area of the tool would be classified into two, academic area and practical area.

 

But I really want to hear your high-level opinion on the practical areas.

 

The typical usage of energy simulation program in practice could be listed as follows (as far as I know), 

 

1.     To get energy efficiency incentives, such as LEED certificate. 

2.     To compare alternatives (wall material, window, building design) in architect point of view. 

3.     To compare alternatives (system type and configuration, COP, etc.) in mechanical engineer point of view. 

4.     To develop energy efficient control strategies and to test DDC controllers. (BEMS and emulation; maybe electric engineering field or ??)

5.     To identify the system mal-function (such as AHU) comparing between “predicted” energy and “actual” energy in real-time. (BEMS, maybe electric engineering field??)

6.     Building Simulator: which is used to training building managers or operators or learners (students) in HVAC system operation realistically (such as flight simulator)

7.     To “JUST” verify Building behavior (HVAC operation, energy consumption, etc) over the whole year period with different whether conditions in IWEC and TMY. (to see "what could be")

 

I think that the large portion of usage would be #1. 

 

But, the problem have been arisen due to the uncertainties and “too many” required input values of dynamic simulation tools. 

 

As far as I know in South Korea, many people say “these tools are not suited to assess building energy performance with acceptable speed. And there is no evidence it is helpful to achieve energy reduction actually. Something are missing. We (AEC) do not want to do full dynamic simulation. We just need a tool that is simple and faster and reliable”. 

 

These days, the government is willing to move their direction which requires architects just to submit a building energy analysis report using simple ISO toolkit. 

(many of my colleague agree to need of the normative performance method, ISO 13790 and DIN 18599.)

 

Now, in this situation, we have to rethink about the purpose of doing full dynamic energy simulation (E+, ESP-r, TRNSYS, etc) with practicality in mind.

 

I think that its usage would be more suitable for #4, #5, #6 rather than #1, #2, #3. Because #1,#2,#3 can be evaluated using ISO standards with acceptable speed and accuracy. 

(but I do not know well about the usage in the fields of #4, #5, #6)

 

I’m waiting your comments on my thoughts.

 

p.s. this topic was discussed in E+ user group before, and the contents are slightly revised for better discussions. 

 

Best Regards, 
Deuk-Woo, Kim 


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