Good morning,
I'm in the process of carrying out a simulation using a budget building based on ASHRAE 90.1-1999. In the proposed building, 75% of the annual heating load is met by single zone, gas-fired, constant volume roof top units (with DX cooling). The remaining 25% of the annual heating load is met using electric baseboard heaters. The budget building uses system types 11 (packaged rooftop air conditioner, CV, DX, fossil fuel furnace). I'm wondering what to do with the electric baseboards in the budget building. Do I keep them in just as they are in the proposed building (I.e. same capacities), or do I delete them altogether and force the rooftop units to meet 100% of the annual heating load? ASHRAE 90.1-1999 appears to be silent on this issue.
Thanks and kindest regards,
Greg Leskien, C.E.T.
Yes you include them. 90.1-1999 11.4.3.k.(2) round about page 59 says if you have two sources use the primary source to determine your system type but the secondary one stays the same between the two models.
Now I have to get back to office bingo. Happy modeling.
Paul Riemer, PE, LEED AP
Thanks Paul! I looked up that clause and its very clear that I keep the electric baseboards in. When they say they "shall be modeled identically", I assume they also mean keep the capacities that same, correct?
Greg
I would take 'identical' to mean same type, capacity, schedule, zone depth, and control method. I do not read 'identical' to mean the absolute same electrical heating consumption values on your ECB form. If you have thermostatic control of your baseboards, the numbers won't match.
Paul Riemer, PE, LEED AP