Hello,
I'm currently working with two (600,000 Btuh, 130 Gallons, 97 EF) boilers for a dormitory building. From my interpretation of Table 7.8 the equation I'm suppose to use is 80%Et(Q/800 +110sqrt(V)) SL, Btuh. From I've what I've read, I'm suppose to disregard the 80% Et and that leaves me for the remainder of the equation to get 2004 Btuh as my standbyloss for my baseline water heater. A few questions I had were:
1. Should I leave this number in the service water heating section as what I calculated asfor the SL or do I need to convert this to an EF ?
2. Is there a way to convert to this to an efficicency (EF)?
In previous projects my co-worker worked on they always left as a % EF and used that to calculate an energy usage in MBH/hr for each water heater. The then plugged that energy usage into Trace 700 for the base utilities for the water heaters.
Tyler Thumma
7GroupLEEDuser Expert
61 thumbs up
April 5, 2024 - 10:49 am
I would suggest you model the water heater with the 80% thermal efficiency, and add the calculated standby loss (2,004 Btu/h in your case) to the hourly water heating load. However, you would also need to do the same for the Proposed water heater.