unmet load hours

Elisabetta Annoni

Building engineer

LEEDuser Basic Member

11 thumbs up

April 5, 2011

Hi, for the unmet load hours test there is a throttling range to be defined. As I understand from ASHRAE 90.1 there is no fixed value for this range, how shuold it be defined? Is it linked to any other setting of the system? Which could be standard/accepted values? thank you

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Christopher Schaffner

CEO & Founder

The Green Engineer

LEEDuser Expert

630 thumbs up

Wed, 04/06/2011 - 18:59

You are correct that there is no fixed value in 90.1. Only requirement is that it is identical in both Baseline and Proposed cases. Many modeling programs use 2 deg F as a default - that is usually where I start. I'll only adjust it if I see funny results such as high of unmet load hours, or big reheat loads.

Elisabetta Annoni

Building engineer

LEEDuser Basic Member

11 thumbs up

Thu, 04/07/2011 - 06:16

Thanks for your reply and advice.

SIG - Sustainability Main Account

Sustainability Consultants

Sustainable Investment Group (SIG)

LEEDuser Premium Member

63 thumbs up

Tue, 11/03/2020 - 18:24

Would increasing the throttling range then be acceptable to resolve UMLH in both the proposed and baseline models?

Marcus Sheffer

LEED Fellow

7group / Energy Opportunities

LEEDuser Expert

4454 thumbs up

Tue, 11/03/2020 - 19:01

Possibly. The settings must be idential in both models and should represent reasonable values based on the likely occupancy. Procedures for reducing UMLH are contained in Section G3.1.2.2.