I have a 36 story office building that I am trying to model the current energy usage in and have run into a question about losses in a steam distribution system. Not having much experience modeling large office buildings using a steam distribution system, I was wondering what to use for my supply losses for the system. I know that it is hard to make a generalization on a typical supply loss Delta T because so many factors come into play depending on the system, but I just want to make sure I'm in the right ball park on my estimate. I'm currently using a 1?F temperature loss. The pipe is insulated pretty well and all the traps were replaced about 10 years ago. I don't really know the total length of steam piping, but it is distributed to 36 floors for perimeter heating only. Any suggestions or advice would be helpful. Thank you.

Thanks,
Landon Streed, EIT