How to model an off-grid building?

asked 2019-03-03 23:46:20 -0500

audunbul
81 ●3

updated 2019-03-05 10:13:02 -0500

__AmirRoth__

4436 ●5 ●17 http://bleedinggreenna...

I have added Generator:Photovoltaic, ElectricLoadCenter:Generators,ElectricLoadCenter:Inverter:Simple, ElectricLoadCenter:Storage:Battery and ElectricLoadCenter:Distribution. Since it is an off-grid building, I was surprised that the HTML report in results showed that there is "Electricity coming from utility" and "Surplus Electricity going to utility". What can I do to define that it is not grid-connected?

answered 2019-03-05 16:29:06 -0500

MJWitte

9670 ●6 ●10 http://www.gard.com/

I am not completely sure this can be done. All electric demands must be met. If the PV plus storage cannot meet the current electric demand then power will be taken from the utility unless DemandManager* objects are used to shed load. It should be possible to avoid exporting power to the utility, but I cannot say that I've tested that. Start with example file LrgOff_GridStorageDemandLeveling.idf and look at the utility demand fields in ElectricLoadCenter:Distribution.

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Thanks for the reply! I read that IORef says the same as you: "All demand not met by available generator capacity (or storage) will be met by purchased electrical." I tried to look at the possibility of using DemandManager* objects, but it seems like they can only be used to shed load above a set limit in Watt. It would have been good if DemandManager also could have shed load in case the PV produciton and the battery was not enough to cover the load. I also looked at ElectricLoadCenter:Distribution, but I think it only limits power demand drawn from the utility service to a prescribed level.