Brewery Upgrade: Heating 8,000 gallons a day on Solar?

[magnet creek]

Solar thermal seems like the way to go here. That is ~75% efficient vs ~15% with Solar PV and heat pump. I do not know why these systems are not popular in the US. Every residential development built in the last 10 yrs in Spain and Israel has a solar thermal collector and you can buy them for a couple of hundred bucks at Costco (no actually a Costco but you get the idea). Even small systems here are > $1500 and not widely available. For a whole roof I would order a 40ft full in China. Probably pays for itself quickly for your crazy gas bills. https://www.alibaba.com/product-det...yofferlist.p_offer.d_title.1235473aBEw9KR&s=p
@OzSolar I did not see any links working in your post, would be interesting to see local availability in the US.

 

[AntronX]

Grid-tie 550w solar panels on the roof. NEM agreement with power utility. Resistive "tankless" water heaters in line with gas boiler controlled by PLC or some other logic controller. Most simple approach. 30k s.f. roof space can fit about 300 kW of solar panels. Depending on your climate that's anywhere between 3 - 6 solar hours per day or 27 - 54 MWh per month. 3500 CCF = 102.58 MWh * 90% boiler efficiency = 92.3 MWh(t) delivered to equipment per month. So it looks like going solar can displace 30 - 60% of your gas usage. Cost of 300kW solar at $1.50/watt minus 30% tax credit = $315k. Payback time 4 - 8 years not including electric water heaters.

 

[Doggydogworld]

Solar thermal seems like the way to go here. That is ~75% efficient vs ~15% with Solar PV and heat pump.

PV+heat pump should be 35-50% efficient. About half of solar thermal.

I do not know why these systems are not popular in the US. Every residential development built in the last 10 yrs in Spain and Israel has a solar thermal collector and you can buy them for a couple of hundred bucks at Costco

How do $300 units handle freezing temps?

 

[OzSolar]

Solar thermal seems like the way to go here. That is ~75% efficient vs ~15% with Solar PV and heat pump. I do not know why these systems are not popular in the US. Every residential development built in the last 10 yrs in Spain and Israel has a solar thermal collector and you can buy them for a couple of hundred bucks at Costco (no actually a Costco but you get the idea). Even small systems here are > $1500 and not widely available. For a whole roof I would order a 40ft full in China. Probably pays for itself quickly for your crazy gas bills. https://www.alibaba.com/product-det...yofferlist.p_offer.d_title.1235473aBEw9KR&s=p
@OzSolar I did not see any links working in your post, would be interesting to see local availability in the US.

It's all about scalability. What few residential scale solar thermal systems available in the US aren't meant to be scaled up to an application like this.

EG: pretty much anyone can fake thier way to building a 25 kW, 50 kW or 100 kW PV system. Electrons are far easier to move around than BTUs. If you want to design and build a solar thermal system capable of collecting, storing and delivering that sort of equivalent energy it's an entirely different skill set.

I sound like a broken record but there's still not been a single response to my request to supply a real world example of a similar system, successful or not. There's a reason for that.

Not sure what missing links you are referring to.

 

[magnet creek]

Maybe the lack of real-world examples for a large-scale solar has more to do with the lack of use cases. Giant hot water demands are not that common and in that scenario, a more industrial solution would be more appropriate rather than a consumer product at scale. That said, (and I am not a mechanical engineer) it seems like the technology is pretty simple. These Vaccum tubes operate on low pressure (also helps for frost protection) You would create little low-pressure loops. Simply make a low-pressure loop with a small circulation pump ($50) and run it through a small heat exchanger ($60 or so) and connect to a normal water pressure hot water loop. You could create a series of loops like you would with radiant floor heating or one big loop with temperature-controlled actuators. The system does not have to be complicated imho (but some level of management over flow rate and temperature would be nice). It really is similar to a radiant floor system albeit the temperature flow is reversed and the temps are likely to be a bit higher. You would run the warm end of the hydronic loop through the cold side of whatever boiler situation you have now, that way you do not to change a lot on your output side. The gas boilers would simply only heat 5 degrees rather than 50.
I system like that should be easy and cheap to DIY, You can just divert the cold side of the current system, and run it through a single solar thermal 30 tube water heater, and scale as you sell more beers. It's all low capital simple off the shelve stuff.





@OzSolar in your post you say :"
-Flat Plate - follow the below link
-Evacuated Tube - follow the below link" but there are no links

 

[Doggydogworld]

I sound like a broken record but there's still not been a single response to my request to supply a real world example of a similar system, successful or not. There's a reason for that.

Here's a very small brewery in Massachusetts with a correspondingly small solar thermal system (PDF). The financial numbers don't look so hot (ha).

 

[AntronX]

Here's a very small brewery in Massachusetts

$2.8/W(t) equivalent and relatively small 30 kW(t) system. OP needs a system at least 10x as large. PV electric system can be done for $1.50/W and electric water heaters remove the need for plumbing, heat exchangers and water storage tank. And having it grid-tied allows to export excess power on the weekend when shop is closed.

 

[magnet creek]

You can of course generate energy using PV's as well as Solar Thermal; I have no dog in this fight. But a back-of-the-envelope comparison in scale:
You would need around 700kW of solar PV which translates to a whooping 1400 panels @500W each.... ~3800m2 (40K SqFt) of solar panels. That is a whole roof and a bit. ~$1m of capex investment (with 30%fed credit)
You would need around 1990 m2 of Solar Thermal to generate the hot water required (around 1.44kWh/day/m2). That is still 420! Solar Thermal babies, but they retail for $200 each in CY. With this type of gas bill, I would order 10 of these puppies and put them on the parking lot, pipe them up with a heat exchanger and a circ pump and test them. A couple of months of gas bill worth of investment that should pay back pretty quickly.
And this is NOT new or sophisticated technology; it is just not popular in this country (and obviously this is a Solar PV forum). Does anybody want to start a solar thermal import business here? I think there is a market.
I think a solar thermal system should come in at less than half the cost of PV. Damn, now I am tempted to order a system for my house to test!

 

[OzSolar]

@OzSolar in your post you say :"
-Flat Plate - follow the below link
-Evacuated Tube - follow the below link" but there are no links

The sentence below that text has a hyperlink it it.

You can use hyperlink tool at the top to turn a long link into hyperlinked text. Most people do this rather than copying and pasting links.

Something like this unfurl="true"]https://www.alibaba.com/product-det...ferlist.p_offer.d_title.1235473aBEw9KR&s=p[/U

turns into

Here's an example of a solar water heater on alibaba.