Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
I've done a lot of electrical design for commercial / residential buildings and can affirm, there likely isn't any clear line to be drawn in most cases between electrical distribution/service calculations and trended electrical load profiles. Electrical distribution design (per NEC in the USA, at least) has a lot of safety built into the standard loads & sizing factors we attribute to receptacles, motors, lights, etc. We depend on those guidelines and upsizing factors to ensure we do not undersize our systems and cause a life/safety hazard (i.e. fires).
More productively (kinda?), I suppose you could walk a path of using the associated feeder/circuit over current protection (fuses, circuit-breakers) to determine a ceiling on sustained (this is a loaded word - in electrical design terms I'm thinking minutes, not seconds) amperage draw, for the purposes of gut-checking the order of magnitude that your simulation's inputs produce for a peak demand interval... but if you polled 100 electrical designers I expect 99+ would sincerely hope that real world measurements would bear out some distance in peak sustained draw from what they sized up, else somebody is in hot water!
Long story short: No, I don't believe you can use electrical power distribution calculations to productively estimate something like a plug load density or a plug load usage profile.
Your electrical designer's calculations / specifications concerning large motor efficiencies, lighting, the likes of VFD's however are probably of much interest to the typical building simulation, so you should still buy him/her a beer when you have the opportunity!
| | 2 | No.2 Revision |
I've done a lot fair amount of electrical design for commercial / residential buildings and can affirm, there likely isn't any clear line to be drawn in most cases between electrical distribution/service calculations and trended electrical load profiles. Electrical distribution design (per NEC in the USA, at least) has a lot of safety built into the standard loads & sizing factors we attribute to receptacles, motors, lights, etc. We depend on those guidelines and upsizing factors to ensure we do not undersize our systems and cause a life/safety hazard (i.e. fires).
More productively (kinda?), I suppose you could walk a path of using the associated feeder/circuit over current protection (fuses, circuit-breakers) to determine a ceiling on sustained (this is a loaded word - in electrical design terms I'm thinking minutes, not seconds) amperage draw, for the purposes of gut-checking the order of magnitude that your simulation's inputs produce for a peak demand interval... but if you polled 100 electrical designers I expect 99+ would sincerely hope that real world measurements would bear out some distance in peak sustained draw from what they sized up, else somebody is in hot water!
Long story short: No, I don't believe you can use electrical power distribution calculations to productively estimate something like a plug load density or a plug load usage profile.
Your electrical designer's calculations / specifications concerning large motor efficiencies, lighting, the likes of VFD's however are probably of much interest to the typical building simulation, so you should still buy him/her a beer when you have the opportunity!
