[Equest-users] Can you use eQuest for PMV calculations?

[Joe Huang]

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
White Box Technologies, Inc.
346 Rheem Blvd., Suite 108D
Moraga CA 94556
yjhuang at whiteboxtechnologies.com
www.whiteboxtechnologies.com
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"


On 4/13/2012 1:19 PM, Neil Bulger wrote:
>
> 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*
> Project Engineer
>
> *________________________________*
>
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>
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> nbulger at integralgroup.com <mailto:nbulger at integralgroup.com>
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> *DEEP GREEN Engineering. *
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> *________________________________ *
>
> *From:*equest-users-bounces at lists.onebuilding.org 
> [mailto:equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Alex Krickx
> *Sent:* Thursday, April 12, 2012 9:13 AM
> *To:* Kathryn Kerns
> *Cc:* equest-users at lists.onebuilding.org
> *Subject:* Re: [Equest-users] Can you use eQuest for PMV calculations?
>
> 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
>
> Building Energy Specialist
>
> Serious Energy, Inc.
>
> 1250 Elko Dr, Sunnyvale, CA 94089
>
> (t) 408.541.8124
>
> akrickx at seriousenergy.com
>
> /The information contained in this e-mail and any attachments may be confidential, 
> proprietary and/or privileged. If you are not the intended recipient then you have 
> received it in error and any review, distribution or copying of this message and any 
> attachments is prohibited and you are to notify the sender immediately by reply e-mail 
> and delete immediately this message and any attachments./
>
> Energy Plus does PMV and inside surface temperatures as well...
>
>
> /Jeremiah D. Crossett/
>
> /CleanTech Analytics/
>
> /503-688-8951/
>
> /www.cleantechanalytics.com/ <http://www.cleantechanalytics.com>
>
> *From:*Kathryn Kerns [mailto:kathryn.kerns at bceengineers.com]
> *Sent:* Thursday, April 12, 2012 8:58 AM
> *To:* Alex Krickx
> *Cc:* equest-users at lists.onebuilding.org
> *Subject:* RE: [Equest-users] Can you use eQuest for PMV calculations?
>
> 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.
>
> *From:*equest-users-bounces at lists.onebuilding.org 
> <mailto:equest-users-bounces at lists.onebuilding.org> on behalf of Alex Krickx
> *Sent:* Wed 4/11/2012 3:42 PM
> *To:* Jason Quinn; equest-users at lists.onebuilding.org 
> <mailto:equest-users at lists.onebuilding.org>
> *Subject:* Re: [Equest-users] Can you use eQuest for PMV calculations?
>
> 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
>
> Building Energy Specialist
>
> Serious Energy, Inc.
>
> 1250 Elko Dr, Sunnyvale, CA 94089
>
> (t) 408.541.8124
>
> akrickx at seriousenergy.com <mailto:akrickx at seriousenergy.com>
>
> /The information contained in this e-mail and any attachments may be confidential, 
> proprietary and/or privileged. If you are not the intended recipient then you have 
> received it in error and any review, distribution or copying of this message and any 
> attachments is prohibited and you are to notify the sender immediately by reply e-mail 
> and delete immediately this message and any attachments./
>
> *From:*equest-users-bounces at lists.onebuilding.org 
> <mailto:equest-users-bounces at lists.onebuilding.org> 
> [mailto:equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Jason Quinn
> *Sent:* Wednesday, April 11, 2012 3:36 PM
> *To:* equest-users at lists.onebuilding.org <mailto:equest-users at lists.onebuilding.org>
> *Subject:* [Equest-users] Can you use eQuest for PMV calculations?
>
> 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?
>
>
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