[Bldg-sim] Boilers sized by eQuest

[David S Eldridge]

Try running the simulation with one boiler to get the auto-sizing.  Then enter your own sizing for each when you add the second boiler, whatever that percentage would be.

> -----Original Message-----
> From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-
> bounces at lists.onebuilding.org] On Behalf Of yizhao1 at vt.edu
> Sent: Friday, July 11, 2008 2:10 AM
> To: bldg-sim at lists.onebuilding.org
> Subject: [Bldg-sim] Boilers sized by eQuest
>
>
> Hi -
> My model let eQuest to size the boiler capacity based on 'secondery' demand
> to
> see how large the size of the boiler will be. There are 2 equally sized
> boilers. I made the capacity and capacity ratio of each boiler default
> (blank).
> The output report shows the rated capacity for each boiler is 4.037 MBtu/h,
> and
> boiler A works at all spectrum of part load for most hours when heating is
> needed, while the boiler B only work several hours at very low part load
> percent. The peak load for boiler A is 4.125 MBtu/h, the peak load for
> boiler B
> is only 0.058 MBtu/h.
>
> Since boiler B works less efficiently, I try to downsize the boiler
> capacity to
> reduce equipment cost and heating energy use. If I input a capacity ratio
> of
> <0.5 for each boiler, eQuest will give out a warning that the hot water
> loop
> heating capacity is less than the secondary demand. However, the percent of
> hours outside throttling range was not affected.
>
> Is the warning a concern? Or any alternative way to reduce the size of the
> boiler and make them 'work' more efficiently in eQuest?
>
> Many thanks in advance.