Hi,
I am looking at performance curves for Boilers in eQUEST, specifically Heat Input Ratio as a function of Part Load Ratio, HIR-FPLR. Can anyone please explain to me exactly how this works?
The curve has the form Z=a+bX+cX^2, where X is the part load ratio. According to the help files Z "modifies the fuel consumption". In what way does Z modify HIR?
Is HIR(X) equal to Full Load HIR divided by Z(X)?
Thanks,
Brian Tysoe M.Sc., LEED AP
Brian,
If you haven't done so already, I'd recommend downloading the PDF files from
the DOE2 website. It is the source of information for the help available in
equest, so there isn't much in the way of new information; however, I find
that being able to see the information in context of the section sometimes
helps me to figure out where my errors are coming from.
In this case, though, what equest is doing is determining your part load
ratio (PLR) as your current load divided by your specified capacity.
Assuming that you have used your peak efficiency to determine your HIR, then
Z should a quadratic function of PLR that will be multiplied by the HIR you
input. Essentially, it is a penalty function that decreases the efficiency
of your equipment for not running at optimal load (which may or may not be
100%). I hope this helps answer your question.
-Doug