[Equest-users] Simple EEM question - HW Control

[Walker, Matthew]

In doing a little digging on this subject a came across some interesting info.  I found that EnergyPlus is also unable to model this EEM (Hot Water Fixed setpoint to Hot Water Reset setpoint based on OSA.)

In a document from the National Center for Energy Management, they stated: "EnergyPlus is unable to simulate the impact on energy consumption of the boiler due to a hot water reset. The program only applies a nominal efficiency and a part-load curve to determine the energy consumption of the boiler and also does not model any jacket losses. In addition, if piping losses are not specified in the program, the energy consumption of the boiler with and without a hot water temperature reset is unchanged and remains the same."

So now my question is if eQUEST has similar issues when modeling a hot water reset?  If it does, why is this EEM measure even available in the EEM wizard?

Thanks for any input on this.

- Matthew Walker

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Walker, Matthew
Sent: Friday, September 23, 2011 9:57 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Simple EEM question - HW Control

I feel like I must be missing something simple here.  I quickly modeled a building to show an energy savings through an EEM.  The baseline building is a VAV system with reheat.  The baseline HW System Control set-point is fixed, and the EEM is to change that set-point to an OA Reset. My simulation results in no savings.

I then quickly did a simple default building with the same mechanical system and the same Energy Efficiency Measure, only to find the similar result of no energy savings.  We have typically seen a 1% energy savings for every 4°F the boiler water is reduced for outdoor reset EEMs, but I cannot prove this result by modeling.

Can someone please either let me know if there is something in my models that are incorrect, or if I am wrong in assuming an energy savings from implementing a hot water reset from a fixed set-point?

Thank you!

- Matthew
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