[Equest-users] Process Load & LEED Documentation

[Sami, Vikram]

First off - 3.7 is high, but not unreasonable for an office. It depends on what you are doing in the space. I would recommend trying to get a good representation of power loads on a space by space basis rather than spreading a uniform power intensity across the whole building - this makes a big difference with CAV & VAV systems - especially with reheat issues. If you assume 50 ft2 per workstation and around 175 W per station - that's  over 3w/ft2. Remember - connected peak power and actual peak power are different - you need to factor in some level of diversity in your usage schedules. If you have any kind of server room - I would definitely model that as a separate space with its own system and equipment load.

Relative to the GBCI & LEED - if you document your equipment assumptions properly and can make the case that you have modeled this close to reality (I would provide a space by space table along with a usage profile), you should be fine. The 25% is a minimum unless you can reasonably document otherwise.

Hope this helps


Vikram Sami, LEED AP BD+C
Sustainable Design Analyst
1315 Peachtree St. NE, Atlanta, GA 30309
t: 404-443-7462    f: 404.892.5823       e: vikram.sami at perkinswill.com   www.perkinswill.com<http://www.perkinswill.com/>
Perkins+Will.  Ideas + buildings that honor the broader goals of society


From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Daniel Kaler
Sent: Friday, March 02, 2012 10:04 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Process Load & LEED Documentation

Hello All,

My question is regarding the 25% process load as required by LEED online. I'll give a little background on the building first...

The building is located in northern Minnesota, rendering it a heating dominate building. Our HVAC system is a geothermal water-to-air heat pump system with an electric back up boiler. There will be no gas usage. For this scenario, system type 4 was used for the baseline case. Since a majority of the winter will be spent below the heat pump operating temperature, in heating mode, electric resistance is the main source of heating. This being said, my baseline system has a very large annual heating consumption.

Now to my dilemma. With the large heating consumption in the baseline design, the process load was below the 25% threshold. I was advised to increase the plug load until I was able to surpass the 25%. After multiple iterations, I came to a value of 3.7 W/sqft for the office spaces (the building is primarily offices). Obviously this is much greater than anticipated for offices spaces.

Initially the process load was 30% with my proposed design, but after the modifications the process load was roughly 50% of my total energy consumption. To my knowledge the only other option we have to is document each piece of equipment contributing to the process load.

Has anyone encountered the problem before and have advice on a solution?

Thanks in advance.

Daniel Kaler
Energy Engineer, EIT


MEP ASSOCIATES
engineers  |  consultants  |  commissioning
MEP Associates, LLC | 2720 Arbor Court | Eau Claire, WI 54701
Phone: 715.832.5680 | Fax: 715.832.5668 |www.mepassociates.com

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20120302/0f99923b/attachment-0002.htm>