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diy solar

Hybrid Solar System for Multi-Tenant Residential Buildings

b1gf00t

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Aug 28, 2022
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3
Hello,
A common problem that residential building habitants face is the lack of rooftop space to provide enough solar power to each household.

In simplistic terms, not enough Horizontal space to cover the Vertical needs.

Say, we are talking about short building, max of 20 stories with 40 apartments + common facilities, and would like to invest in solar power to reduce electrical bills, provide more sustainable power solutions etc..

So the idea came to mind, and dont shoot me please, but why not install as much PV Panels possible on the roof, invest in some multi MPPT (currently looking at Sungrow, Deye) inverters with high enough AC output and that can take the load from the DC panels ... Store the power into a central Lithium LifePO4 storage (ie: 200Kwh) and then distribute AC power to the tenants whereby each tenant would have daily energy quota to distribute the stored power fairly.

Reason its hybrid is to have the ability to charge the batteries from multiple sources, PV/AC

Is this too crazy to accomplish?

Looking forward for your comments.

TIA
 
Years ago I worked on some larger buildings like you are describing. Once you get over 5 stories high the regulations get quite strict. I can’t imagine the cost of components or the hoops you would need to jump through to get appoval for such a system. In theory anything is possible but I can’t imagine how long it would take to pay back. You would need some form of electrical engineer as a consultant just for initial planning.
 
Years ago I worked on some larger buildings like you are describing. Once you get over 5 stories high the regulations get quite strict. I can’t imagine the cost of components or the hoops you would need to jump through to get appoval for such a system. In theory anything is possible but I can’t imagine how long it would take to pay back. You would need some form of electrical engineer as a consultant just for initial planning.
regulations isnt of concern right now, the buildings are in an area where no grid exists .. and they purely run over Deisel generator. Lets say am doing a study to check the feasibility of the whole thing.

Challenges I have faced so far is there isnt big enough hybrid inverters to do this .. so I was thinking to either connect parallel hybrids to cover the need, or go with separate charge controllers and big inverters to handle the AC loads ...

More importantly if you are storing energy on central Lithium .. am looking for smart energy meters that has tariff quotas.

then we can minimize the Deisel consumption and charge the batteries when needed...
 
I worked as an advisor a few year ago on a large building that had a mix of solar and combined heat and power to run the house loads. If there was a disaster, the house loads could be islanded from the grid to keep the basic function of the building's common spaces operational. There was a lot of capacity that was underused most of the time with the house loads so I proposed connecting the house loads to the electrical riser of the building and let the tenants take advantage of the lower cost of site generated power. It was a fairly low cost change as the each unit was submetered for each tenant off the riser. I thought it was a great "green idea" that could be expandedl later with additional solar but the owner was adamant that he would not spend a dime on anything green for the tenants. He was forced to put the solar on the house loads by local regulations and was obviously not a fan of renewables. The group we were advising ended up backing down so an opportunity was lost.
 
regulations isnt of concern right now, the buildings are in an area where no grid exists .. and they purely run over Deisel generator. Lets say am doing a study to check the feasibility of the whole thing.

Challenges I have faced so far is there isnt big enough hybrid inverters to do this .. so I was thinking to either connect parallel hybrids to cover the need, or go with separate charge controllers and big inverters to handle the AC loads ...

More importantly if you are storing energy on central Lithium .. am looking for smart energy meters that has tariff quotas.

then we can minimize the Deisel consumption and charge the batteries when needed...
That’s an entirely different scenario than I had imagined. The biggest trick will be to create an incentive for the tenants to decrease their electrical use to the point where the solar has the biggest benefit. If you can successfully manage a battery bank of that size it will greatly reduce the amount of generator time you need even if you had no solar at all. It seems to me that you would want inverter chargers that can do load sharing or a dc generator to charge the batteries. On small scale I have seen setups where 2 AIOs were used with one dedicated primarily to battery charging to get around the ac input requirements for the pass through features of these units. But the idle power consumption of the inverters might be a big problem. Sounds like an exciting project I hope you can find a solution that starts saving you a ton of fuel.
 
Pretty simple, in dense urban areas int he Northeast where I work on occasion, big batteries have a bad rep with fire departments and the FDs keep piling on restrictions to the point where most owners and insurance companies want nothing to do with them. I have 1.6 MW unit on one project and it has to set away from any buildings with a minimum 20 foot buffer on all four sides. It cant be mounted on top of anything. No doubt in my mind that the recent switch in battery chemistry in the Tesla Megapacks was partially driven by the restrictions being placed on their old battery tech. Fireman have real long memories and they can really slow down a job if they dont like something.
 
Hello,
A common problem that residential building habitants face is the lack of rooftop space to provide enough solar power to each household.

In simplistic terms, not enough Horizontal space to cover the Vertical needs.

Say, we are talking about short building, max of 20 stories with 40 apartments + common facilities, and would like to invest in solar power to reduce electrical bills, provide more sustainable power solutions etc..

So the idea came to mind, and dont shoot me please, but why not install as much PV Panels possible on the roof, invest in some multi MPPT (currently looking at Sungrow, Deye) inverters with high enough AC output and that can take the load from the DC panels ... Store the power into a central Lithium LifePO4 storage (ie: 200Kwh) and then distribute AC power to the tenants whereby each tenant would have daily energy quota to distribute the stored power fairly.

Reason its hybrid is to have the ability to charge the batteries from multiple sources, PV/AC

Is this too crazy to accomplish?

Looking forward for your comments.

TIA
A "short" 20 story building (around 200ft tall) with only 40 apartments? In an area where the grid does not exist? I do not know if the solar part of your proposal has any realistic path forward but I question the basis.

However once you get into multi residential you get into the realm of architects and engineers and I would bet they do not advise for free.
 
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