[Bldg-sim] [Equest-users] Process Equipment Power Consumption

Wed May 5 11:55:10 PDT 2010

The schedule, with multipliers (fractions), as found in DOE-2 for example, will have in fact already accounted for both run time and diversity.

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Demba NDIAYE

From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Carol Gardner
Sent: Wednesday, May 05, 2010 2:04 PM
To: Yuvaraj Saravanan
Cc: eQUEST Users List; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] [Equest-users] Process Equipment Power Consumption

I do not believe we are double discounting. Try this: think of when you turn your computer on and off however you do so during the day, lets say on at 9 am off at noon on at 1 pm off at 5 pm. That is your schedule. Now think of how when you walk away from your computer for any length of time and it goes into sleep mode, that's your diversity.

Comments, thoughts are welcome. Is this what you were maybe getting at with the multiplier, Nick.

Waiting to learn more,
Carol
On Wed, May 5, 2010 at 10:02 AM, Yuvaraj Saravanan <Yuvaraj.Saravanan at arup.com<mailto:Yuvaraj.Saravanan at arup.com>> wrote:
Hi Carol,
This question is not specific to equest. Would you apply a diversity as well as a schedule for process load? I thought by applying a schedule we are accounting for diversity. By applying a diversity and then a schedule are we not double discounting the load?
Regards,
Yuvaraj

From: equest-users-bounces at lists.onebuilding.org<mailto: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 Carol Gardner
Sent: Tuesday, May 04, 2010 11:15 PM
To: Gaurav Mehta
Cc: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>

Subject: Re: [Equest-users] Process Equipment Power Consumption

Whenever you have an equipment, aka process, load it is proper to apply first a diversity factor, aka % on at one time, and then a schedule. Whether your building is new or existing doesn't matter. This is an Art not a Science. Experience is the primary teacher. You can always ask us old farts. We are relevant and have information that one only can get with time. Yours to chose to listen to or not.

Peace out,
Carol
On Mon, May 3, 2010 at 9:20 PM, Gaurav Mehta <gmehta75 at gmail.com<mailto:gmehta75 at gmail.com>> wrote:
Please refer to the Chapter 18, Nonresidential Cooling and Heating Load Calculations of the 2009 ASHRAE Handbook of Fundamentals.

Best regards,

Gaurav Mehta

Stantec

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From: "Walson, Kristy" <kristy.walson at tlc-eng.com<mailto:kristy.walson at tlc-eng.com>>
Sent: Monday, May 03, 2010 11:29
To: <omoltay at mimtarch.com<mailto:omoltay at mimtarch.com>>; <equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>>
Subject: Re: [Equest-users] Process Equipment Power Consumption

Hi Omer,

On recent projects, I have had to pay more attention to the process loads for the types of equipment you mentioned below.  In the past, I would just ensure that my process energy cost was 25% of the total energy cost because I knew that the types of buildings I was modeling (commercial offices, mostly) would never have an actual process load even close to 25%.

However, recently I have been modeling process loads in a more exact way. What I do is I take the kW rating of the equipment, then I talk to the electrical engineer to get an idea of whether that equipment will ever run at its rated load and, if not, I apply the appropriate reduction to it based on what the electrical engineer says.

Once I have this maximum energy use for process loads in the building, I then create a custom schedule for this process energy.  Sometimes I need to create more than one custom schedule based on the type of equipment in the space.  This can become very tedious if you get too far into the weeds, so I try to keep the schedules realistic, but simple and I keep the number of different custom schedules I create to a minimum.  As we all know, you can never know the actual occupancy and use schedule of a building until it is occupied for a certain period of time, so keep your assumptions simple and logical.

I'd love to hear what other folks are doing if it differs from my process.

Kristy Walson, PE, LEED AP
Mechanical Engineer / Sustainable Design

-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org<mailto: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 omoltay at mimtarch.com<mailto:omoltay at mimtarch.com>
Sent: Monday, May 03, 2010 1:46 PM
To: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: [Equest-users] Process Equipment Power Consumption

Dear All,

One of the things that cause most trouble for us in modelling is the power
consumption of equipment such as dishwashers, ovens, food warm-up
equipment and so on that have varying levels of power consumption during
operation (even PCs and laptops). We are sometimes using nameplate
installed kW values, but deep inside we know that this is quite wrong -
but we have no other more reliable source / guideline for such equipment.
I would appreciate any feedbacks on how others are modelling such
equipment.

Thank you,

Omer Moltay, LEED AP
Mimta

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