At my workplace there's a new school building that's under construction and nearing completion. The power monitor system was commissioned a few days ago. Attached are some screen captures of it's web interface. I've been testing the system and learning how to use the software. The building has two main electrical service panels. Add the meter one and meter two plots together for the total. When the building HVAC system started up this morning, the peak power was about 350 Kilowatts! The total energy use for this Friday was about 3.1 megawatt hours!
Would you like to have this electricity bill in your mailbox
The power monitoring system has 19 three phase power monitors connected using an RS-485 bus. Two monitors in the main electrical panels and 17 more in the sub panels. You can see some missing data points on the plots. The data logs also show random missing data points from the power monitors. After talking with tech support, it seems that the most likely problem is noise on the RS-485 bus. I agree with that. You have low voltage RS-485 network cables in the same electrical panel that has conductors carrying up to 150A at 277V. And, very little space to keep the network cables separated from the power cables. This may be an application where a fiber optic network would be a great idea.
Also, this building is heated and cooled using electric heat pumps. The supply air to the heat pumps is preheated during cold weather with natural gas-fired air handling units. The energy use shown in these plots does not include the many BTU's of gas heat needed to preheat the air supplied to the heat pumps. Add this gas heat and it's even more amazing how much energy it takes to heat a large building!
Finally, this school building is located in Brooke County West Virginia. It's a large building here. It's designed for about 1000 students. In a big city, this would be a small building. I can't even imagine how much energy a really large building could use.
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