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Problem of identifying heating EUI using DOE pre-1980 medium office building model

asked 2015-10-29 01:49:34 -0500

LELE gravatar image

updated 2020-01-27 18:47:33 -0500

I'm now doing a simulation using DOE medium office building,pre-1980 model. One important value I need to find out is the EUI for heating,but I came across some problems of identifying it. I'll be really appreciate if anyone could kindly help me on this.

In this model, heating is supplied only by gas. There is an item called 'Natural Gas End Use for Heating' in the results report (html file), and an item called 'Natural Gas Intensity for HVAC'. Shall I get the heating EUI by 'Natural Gas End Use for Heating/ Area', or shall I use 'Natural Gas Intensity for HVAC' as heating EUI?

What I really confused about is that 'Natural Gas Intensity for HVAC' is calculated from '(Natural Gas End Use for Heating+Natural Gas End Use for Water System)/Area' , but water system is not supposed to be part of HVAC system...Does anyone know why it's like that?

To be put into a separate question

One last point to add, I changed heating setpoints, found out that no matter how low the setpoint is(even 32 degree F), 'Natural Gas End Use for Heating' and 'Natural Gas Intensity for HVAC' are not equal to 0, they could not go down after reaching certain values (when the setpoint is approximately 60). It's another problem I need be helped with.

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Hi and welcome to unmet hours. I've removed the greetings as it is our convention. Also, please break your question in two. The one about the heating setpoint isn't related here.

Julien Marrec gravatar image Julien Marrec  ( 2015-10-29 03:52:35 -0500 )edit

Thanks for the advice! I'll break it to two.

LELE gravatar image LELE  ( 2015-10-29 18:18:30 -0500 )edit

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answered 2015-10-29 07:23:31 -0500

The major end use EUIs are contained in the LEED Summary section of the Summary Reports. It can be requested through the Output:Table:SummaryReports object. Below is an example in IP units from an OpenStudio model.

image description

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I found it! Thanks a lot!

LELE gravatar image LELE  ( 2015-10-29 18:17:54 -0500 )edit
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answered 2015-10-29 04:05:57 -0500

updated 2015-10-29 07:26:17 -0500

In order to get the heating EUI, you need to use the value of Heating, Natural Gas in the "End Uses" section of the summary report, and divide that by your floor area.

If you use the value for Natural Gas Intensity, HVAC, in the "Normalized Metrics", you are likely to get different results as this will for example include service hot water heating if you have any on natural gas.

Demonstration

I just ran a model where natural gas is used for heating and service hot water production. Here are the result from the model, as well as the calculated MJ/m² defined as:

$$\frac{Natural Gas [GJ]*1000}{Area}$$

eplustbl.htm

As you can see, the Normalized value for HVAC includes both heating and water systems (service hot water) production.

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Yes, that makes a lot of sense, thanks!

LELE gravatar image LELE  ( 2015-10-29 18:17:39 -0500 )edit

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Asked: 2015-10-29 01:49:34 -0500

Seen: 217 times

Last updated: Jan 27 '20