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Re: [EnergyPlus_Support] Boiler Efficiency modeling
A new boiler model is scheduled for the next release of Energyplus. The
current model does not have a sufficient inputs to correctly model new
condensing boilers. I will discuss remaining issues with you through
direct email communication.
JV Dirkes II wrote:
>
> Dear E+ Forum,
>
> I am reviewing the E+ boiler simulation objects for their ability to
> model "real world" energy usage. My past experience with boiler
> energy use indicates that there are a number of factors, such as
> jacket and blowdown losses, which cause a boiler to be dramatically
> less efficient at part load than at full load. Some ASHRAE studies of
> actual installations show that a well-maintained boiler may achieve a
> seasonal average efficiency of less than 60%!
>
> Over 10 years ago, when reviewing some DOE2 engineering documentation,
> I took notes of the "part load factor" used by DOE2 for gas unit
> heaters and boilers, and have used that in BIN analyses. I suspect
> that new boiler control methods have made my DOE factors obsolete, so
> I am asking for information that you may have which discusses creation
> or use of part load factors in E+ that are appropriate for
> new-generation boilers.
>
> In addition, condensing boilers seem to represent a special case,
> since their efficiency varies not only with part load ratio, but also
> with the entering water temperature.
>
> Finally, a condensing boiler which has a setpoint which is reset
> according to outdoor temperatures, is even more complex.
>
> Does anyone out there have experience with modeling boilers in E+
> which account for these factors?
>
> Thanks in advance!
>
>
--
Richard A. Raustad
Senior Research Engineer
Florida Solar Energy Center
University of Central Florida
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