Can you use eQuest for PMV calculations?

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Is it possible to use an eQuest model to do thermal comfort PMV (Predicted
Mean Vote) calculations per ASHRAE 55/RP884?

If not are there any recommendations?

JasonQuinn's picture
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Hi Jason,

I'm under the impression that eQUEST can't output surface temperatures which are needed to calculate PMV values.

I think an EnergyPlus based program might be a better place to look. I would ask on the Bldg-Sim list for recommendations as it has a broader user-base (this list is eQUEST specific).

Good luck,
Alex

Alex Krickx, LEED AP

John Dosmith's picture
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This is a topic that I have explored. Although DOE-2 (the core engine for eQUEST) does
not explicitly solve for the inside surface temperatures, researchers at EMPA in
Switzerland back in the late 90's added a routine to DOE-2.1E to back-calculate the inside
surface temperatures (think of it as doing a heat balance calculation in reverse). This
featured is documented in DOE-2.1E update package 2 (version 107), but I only have a hard
copy of the report. In 2003, I used this feature to do exactly what Jason is asking,
i.e., calculate
the PMV for naturally ventilated buildings in Egypt. Recently, I've also used the same
feature to estimate the amount of radiant heat
transfer from attics to the conditioned space, something that is ignored in the weighting
factor model in DOE-2.

The bad news, though, is that this feature has not been carried over from DOE-2.1E to
DOE-2.2, although I've had some discussions
with members of the development team about resurrecting it.

Joe

Joe Huang

Joe Huang's picture
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DOE-2 Supplement Version 21E
December 1993
Appendix A
Hourly Report Variables
Page A10

LOADS
Variable-Type = u-name of EXTERIOR-WALL
Variable List Number 5 Q Heat transfer from wall to the zone un-weighted (Btu/hr)
Variable List Number 6 T Outside surface temperature (Rankine)

The outside surface temp was used to calculate the inside surface temp in this example
http://bepan.info/contents
http://bepan.info/proj-doe21e/p22_kuwait-shell-mrt
?Proj-22 - Kuwait-Envelope-Temps-MRT-Systems-Study?

Varkie Thomas's picture
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Alex, ASHRAE sells a Thermal Comfort program which will do these calculations for you based on temperature, humidity, air speed, etc. It doesn't cost much and is easy to use. Check the ASHRAE website for things to purchase.

Kathryn Kerns's picture
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I'll second the suggestion to purchase the Thermal Comfort tool. It is easy to use. I believe that a newer version was recently released - we're still using the 1994 version.

However, I'm not sure that it solves Jason's problem - it still requires a user-entered Mean Radiant Temperature which I don't believe eQUEST gives as an output.

When we use the tool (specifically for perimeter comfort analysis understanding the impact of different glazing options on comfort) we make some assumptions on wall/floor/ceiling temps, some calculations on glass-temperatures, and some further assumptions on the ratio of glass-to-other surfaces from the occupant's perspective. Based on that we can calculate the PMV for that single point time with those conditions.

I've used software in the past that was able to calculate PMV for every hour of the year (so every hour it would combine air temp, a calculated MRT based on surface temps, humidity, etc) and then give an output for how comfortable the space was throughout the year (with hourly outputs of PMV for different spaces). I don't believe that eQUEST gives the necessary information (surface temps) to do this type of analysis.

I included Jeremiah's response below which suggests that Energy Plus can do these calculations. This was my impression, however I have never used E+ to do them.

Kind regards,
Alex

Alex Krickx, LEED AP

John Dosmith's picture
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I use both Energy Plus and eQuest, and try to choose between the two for
features not preference.

Energy Plus can produce many comfort calculations, including PMV, eQuest
can not.

I spent a moment and went through an Energy Plus file I am working on and
copied most of the possible variations of comfort objects, and published
them to this google spreadsheet:
https://docs.google.com/spreadsheet/ccc?key=0Ak5Rfmjyon9idHJLUW8tbjhHOWpNUE9nMkhrdDdBTGc

Hope this helps, and if you decide to use and need some help with Energy
Plus please let me know.

*Jeremiah D. Crossett*

CleanTech Analytics's picture
Joined: 2012-02-09
Reputation: -1

Varkie,

That's interesting, so at least there are three people who've used the the EMPA surface
temperature calculation in DOE-2.1E (EMPA, you, and me) :-)

In case anyone's interested, I'm attaching some more information on this feature in 2.1E:
(1) original documentation by Markus Koschenz of EMPA from the 2.1 Update, Version 107
(2) my description of the comfort calculator that I implemented in 2003 as a User
Function to 2.1E.

Call me old style, but I really like the User Function in DOE-2.1E, because it allowed me
to add features and tweaks to the program to get the information that I need, instead of
just waiting for
the next release of whatever program you're using.

Joe

Joe Huang

Joe Huang's picture
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Alex you are correct, eQuest does not know the surface temperatures required to calculate the Mean Radiant Temperature. eQuest /DOE2 uses the Cooling Load Temperature Difference (CLTD) method to arrive at heat loads in a space. This approach makes approximations of the radiant component of heat transfer and does not directly calculate radiant gains or losses. Because of this, any DOE2 based software at best can predict air temperature and moisture needed for a PMV calc.

EnergyPlus or IES are the only engines that can produce hourly surface temp information and therefore, mean radiant temperature averages.

If you are interested in providing comfort feedback of envelope changes and not HVAC changes, learning EnergyPlus using OpenStudio from NREL is well worth the time and effort. Their workflow takes some practice to adopt but once you get the hang of things, creating buildings is very easy. Their youtube channel is best for explaining this, search for OpenStudio and NREL.

Neil Bulger

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Neil,

eQUEST/DOE-2 does not use the CLTD method, which is a quasi-steady state method from the
late 70's for calculating heat gain through the envelope. It uses Weighting Factors (also
known as Room Response Factors) that characterize the dynamic response of a space for a
given input of heat flow. Envelope heat flows are similarly calculated using Response
Factors that are also dynamic, i.e., they capture the thermal lag and capacitance of the
materials. Radiant heat
gains are taken into account in both response factors (using the sol-air temperature
method) and weighting factors (there are different weighting factors for different types
of heat gain). However, radiant heat gains are ignored in interzone heat transfer.
Although DOE-2 doesn't compute inside surface temperatures, they can be output (in
DOE-2.1E at least) and I've that little-known feature to do PMV calculations. Lastly,
DOE-2 has always been able to model the humidity of the indoor air. What it doesn't do
(which may be what you're thinking) is that it doesn't model the absorption/desorption of
moisture in the building fabric.

Joe

Joe Huang

Joe Huang's picture
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8760 hourly inside zone wall surface temp and MRT at a point in space is not very useful. It might be useful in Loads program based on design day conditions in summer and winter. See http://bepan.info/engg-calcs - 3a - Design-Weather-Generator
DOE2.1E uses the Transfer Function method to calculate envelope heat transfer. I think Trane-TRACE and Carrier-HAP use the same method. The CLTD-SCL-CLF method is still very useful for teaching envelope heat transfer. See http://bepan.info/class-notes/e4-project-loads The Total Equivalent Temperature Difference (TETD) method is also useful for teaching. See - http://bepan.info/hvac-prog/x1-apec-hccv-loads It is difficult to explain the heat storage capacity and time lag concepts of the envelope with the other methods although all Loads calculations are done by computer today.
The APEC (Automated Procedure for Engineering Consultants) HCC-V Loads program can be downloaded and used. If you don?t know what the ?decrement factor? is, use 0.5 since the range is between 0 and 1. An estimate for ?time-lag? depends on the type of bldg. In design loads calculation for commercial buildings it is important NOT to underestimate the loads.
The hourly Fortran Variable report of the DOE2 based programs include outside wall surface temp. In the DOE2 Loads section choose (1) Variable-Type = u-name of EXTERIOR-WALL (2) Variable List Number 5 Q Heat transfer from wall to the zone un-weighted (Btu/hr) (3) Variable List Number 6 T Outside surface temperature (Rankine). Transfer the values of Q and T to an Excel spreadsheet and calculate the inside wall surface temps.
Examples of calculating inside surface temp using outside surface temp.
http://bepan.info/proj-doe21e/p22_kuwait-shell-mrt
Proj-22 - Kuwait-Envelope-Temps-MRT-Systems-Study?
I have found the hourly Fortran Variable report by the DOE2 program very helpful. Transfer the hourly data to an Excel spreadsheet and do the rest yourself.
Example of using hourly solar data is:
http://bepan.info/proj-doe21e/p21_beijing-solar-pv
Proj-21 - Beijing-Solar-Radiation-PV-Study - PDF-Report?
Example of using cooling coil data is:
http://bepan.info/proj-doe21e/p27_dubai-condens-recov
Proj-27 - Dubai- Cooling-Coils-Condensate-Recovery
Files recently added to the website: 4b ? Tall-Bldgs - Stack Effect, Wind Press and 4c - High-Rise-Apt-Bldgs-Pressurization
Varkie

Varkie Thomas's picture
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Thanks for letting me know about the problems of installing and running the APEC-HCCV program. I added a folder HCCV.zip? containing the executable program HCCV.EXE. http://bepan.info/hvac-prog/x1-apec-hccv-loads . Let me know if it works.
It runs in Windows 7 32-bit computer or earlier hardware, but it will not run on a 64-bit computer. You have to install Windows XP Virtuual Mode on 64-bit.
The same applies for the DOE2.1E program http://bepan.info/doe2inp
http://www.microsoft.com/windows/virtual-pc/download.aspx
How to install Windows XP Mode on Windows 7 Home Premium or lower
http://www.youtube.com/watch?v=CbEK0jD6GlE&feature=related
Windows Virtual PC Windows XP Mode For Windows 7
http://www.youtube.com/watch?v=8RcSZqAnYLo
How to Install Windows XP on Virtual PC
http://www.youtube.com/watch?v=n24oQdgTdZs&feature=related

Varkie Thomas's picture
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