I am trying to design a system that will power off grid 4 apartments.
I sure could use some typical power consumption spreadsheets for single and 2 bedroom units. Or typical loads and run times that could give me a start.
or some ideas that others have used in sizing their own systems.
What real world data could someone help with?
Please anything would be helpful
Assuming firstly that you have no electric resistance heat loads such as electric furnace, electric clothes dryer, or electric stove (which would make the project unfeasible), the largest consumers of electricity will be first a well pump, secondly a septic pump, and thirdly any compressors -- refrigerator, freezer, air conditioner. If you're on city water and sewer, you can eliminate the first two. That makes your choice of (EnergyStar or DC) refrigeration appliances extremely important in your calculations of load. Most other loads are fairly negligible assuming you use LCD televisions and LED light bulbs versus the energy hog alternatives.
You also have to consider peak usage -- what if all four apartments decide to use a hair dryer, or toaster, or vacuum at the same time? You need to size your battery bank, cables, and inverters to handle that peak load even if the average load is much, much lower.
Also, is someone going to be monitoring this system or is it just supposed to work no matter what? If someone will be keeping an eye on it, then you can plan to accommodate average input conditions and start a backup generator (perhaps automatically) if the batteries get too low. But someone has to make sure it stays fueled, unless perhaps you have a city gas hookup or a large propane tank with regular deliveries. If this is not the case, then you would have to oversize the system to account for low energy input (a string of overcast days if using solar, a string of calm days if using wind).
Also, will all loads be running off an inverter or will you have some DC loads as well? Remember that conversion takes 5-10% right off the top and certain loads such as compressors or motors may be significantly less efficient on AC (power factor) than DC.
Also, are the people living in these apartments expected to follow certain guidelines, such as don't use a hairdryer or only do your laundry during the middle of the day? Also, no super-powered gaming computers or window air conditioners.
There are a lot of considerations. One size does not fit all. That said, if you just want to over-kill it, go with 4kW of solar per apartment and 1500Ah of battery capacity per apartment (still no electric resistance heat loads or other huge loads!). That will be significantly more expensive than it likely needs to be though if some of the considerations mentioned above favor efficiency and flexibility. The low side would probably be around 1.5kW of solar per apartment and 600Ah of battery capacity per apartment. That's a range I would feel comfortable settling somewhere in between.
