My company building is 35,000 SF single story located in Newburgh, IN as shown here:
After looking into residential solar for my parents in Florida, I've started to think what I can do to my building, so I am perhaps going slightly mad thinking about solar.
The building is 3 phase 208 VAC 800 amp service (288 KW) but we use a tiny fraction of that. All the lights are LED. The HVAC system is 9 ground source heat pumps. The building is well insulated such that we have mostly cooling loads so my usage is higher in the summer than in the winter. I heat and cool the entire building presently for about $250 in electricity per month (our electric bill is about $1200 month due to the other loads, I have a private meter on the HVAC panel just for curiosity). There are 4 miles of geothermal well pipe under the building (32 wells, each 300 ft deep).
Most electricity is used during the day time and during working hours (most employees have one laptop as their main computer and take it home, fewer have desktop PCs they leave running).
The basic idea would be to install one or more Sol-Ark 30K units which are 3 phase 208 VAC 30 KW (the 60K is 480 VAC so wouldn't work). The first unit would go on the subpanel that feeds the server room and thus serve as a big UPS for them. With ~35 KW of panels and perhaps 50 KWH of batteries, that might actually come close to meeting our local needs. A second unit could be on a different subpanel. I don't think I want to invest in the switch gear to intercept the 800 amp service. I don't really need backup power (thought the server room would be nice), it is mostly about grid up local generation.
We pay a "demand charge" which is a significant part of our bill. It is a charge per KW for the highest demand we've had in a 5 minute period in the last 3 months. So if by chance all the HVAC units line up and we're running a big machine (the test temperature chamber is the biggest load we got at about 5 KW), we can peak up and that costs us money over a long time.
I've got the land to do ground mount, but that big clear roof is really where the panels should go. They would be flat, unfortunately, but the cost for the structure to tilt them up would outweigh the cost of just having more panels. The cost of a ground mount would also favor the roof. I do hate having to put RSD devices on each panel, though. No need for optimizers, nothing to shade the panels. The roof is 1:12 slope with ridge going north/south, so splitting the pane string to each side of the ridge would be reasonable.
The local utility has instantaneous net metering and pays a fraction of retail on grid export, so the goal is to make use the power locally and only export when battery if full and local loads are satisfied. The load curve is favorable for solar, most usage is during daylight, so I hoping the battery size doesn't get too big. I'll have to model that.
Are there other options besides the Sol-Ark 30K for this job? I like that it is 3 phase and not having to parallel 3 single phase units, and I like that it is high voltage for the battery (48 volt current would be extreme). What else exists that can do the job? I figure this is about a $100K job to do right, so quality stuff is important over low cost. Payback maybe in 8 to 10 years.
I realize I am asking other inmates of the asylum if I am insane, but what do you think about making my building solar powered?
Mike C.
After looking into residential solar for my parents in Florida, I've started to think what I can do to my building, so I am perhaps going slightly mad thinking about solar.
The building is 3 phase 208 VAC 800 amp service (288 KW) but we use a tiny fraction of that. All the lights are LED. The HVAC system is 9 ground source heat pumps. The building is well insulated such that we have mostly cooling loads so my usage is higher in the summer than in the winter. I heat and cool the entire building presently for about $250 in electricity per month (our electric bill is about $1200 month due to the other loads, I have a private meter on the HVAC panel just for curiosity). There are 4 miles of geothermal well pipe under the building (32 wells, each 300 ft deep).
Most electricity is used during the day time and during working hours (most employees have one laptop as their main computer and take it home, fewer have desktop PCs they leave running).
The basic idea would be to install one or more Sol-Ark 30K units which are 3 phase 208 VAC 30 KW (the 60K is 480 VAC so wouldn't work). The first unit would go on the subpanel that feeds the server room and thus serve as a big UPS for them. With ~35 KW of panels and perhaps 50 KWH of batteries, that might actually come close to meeting our local needs. A second unit could be on a different subpanel. I don't think I want to invest in the switch gear to intercept the 800 amp service. I don't really need backup power (thought the server room would be nice), it is mostly about grid up local generation.
We pay a "demand charge" which is a significant part of our bill. It is a charge per KW for the highest demand we've had in a 5 minute period in the last 3 months. So if by chance all the HVAC units line up and we're running a big machine (the test temperature chamber is the biggest load we got at about 5 KW), we can peak up and that costs us money over a long time.
I've got the land to do ground mount, but that big clear roof is really where the panels should go. They would be flat, unfortunately, but the cost for the structure to tilt them up would outweigh the cost of just having more panels. The cost of a ground mount would also favor the roof. I do hate having to put RSD devices on each panel, though. No need for optimizers, nothing to shade the panels. The roof is 1:12 slope with ridge going north/south, so splitting the pane string to each side of the ridge would be reasonable.
The local utility has instantaneous net metering and pays a fraction of retail on grid export, so the goal is to make use the power locally and only export when battery if full and local loads are satisfied. The load curve is favorable for solar, most usage is during daylight, so I hoping the battery size doesn't get too big. I'll have to model that.
Are there other options besides the Sol-Ark 30K for this job? I like that it is 3 phase and not having to parallel 3 single phase units, and I like that it is high voltage for the battery (48 volt current would be extreme). What else exists that can do the job? I figure this is about a $100K job to do right, so quality stuff is important over low cost. Payback maybe in 8 to 10 years.
I realize I am asking other inmates of the asylum if I am insane, but what do you think about making my building solar powered?
Mike C.