Solar water heating

[csquared]

We are in the initial stages of researching the installation of solar water heating for combined use for our restaurant and brewing needs. The early numbers crunched made it seem that 75% of our water heating via gas would be eliminated. Obviously there are still many assumptions being made, and I'm looking for input regarding average percentages of brewery/restaurant gas bills, what portion is wort boiling vs. water heating, kitchen ranges and salamanders vs. water heating, etc. If anyone has info from a similar analysis, I'd love to compare it to the solar supplier assumed info.

The other big question is the feasibility of solar water heating for brewing application in the first place. Seen alot of photovoltaic brewery installs lately, but not as much water heating. Reasons for this, the latter is regarded as more efficient?

Any info/advice is greatly appreciated, either here on the forums or I can be contacted directly.

Cheers!

Caleb Staton
Head Brewer
Upland Brewing Co.
(812)336-2337 ext. 203

[canyon]

Solar sexiness?

For some reason, PV's(photovoltaics) get more attention. But solar hot water is a way better bang for the buck, hence way more efficient! I am in the process of getting mine online and am hoping others with existing systems might share their experience. I am going with flat plate collectors after years of consideration. They make more long term economic sense for my location. These systems are very location specific. If your brewery is in the sunbelt with limited freezing and you have reasonable exposure it is a grand slam. For me in the great white north I still think it will be a home run.

[brewbonghm]

Funny,
large groups of us seem to be flocking together from roost to roost.
We should try to exploit our purchasing power in some capacity, or at least cut down on engineering/professional/tooling costs.
I'm having a meeting this afternoon to try and share the expense of a solar system (not one w/a sun and planets).

[csquared]

FYI:
Our first proposal was for solar collector tubes, here's the manufacturer:

http://www.apricus.com

The claim is they are 57% more efficient than solar plates. My amatuer engineering design includes a vapor condenser off the kettle stack to additionally heat the water stream post solar heat exchanger before it hits hot water storage. Kunze reported for every hl evaporated wort, 0.8 hl of water would heat to 176 Fahrenheit. Hopefully I can get this portion partially covered by Vectren.

Any suggestions on multiple hot water storage containers vs. one large tank? For hot liquor tank filling, I am thinking the bigger the storage the better.

Hope you guys on the West Coast and the islands are looking into this stuff, lots of grant money available via the states and feds and you're right in sun alley! Indiana is around 3.5 kWh/m2/day.

[gitchegumee]

I've got two arrays of tubes on our roof. They are WAY more efficient at making hot water than photovoltaic/electric elements. The latter get the attention because they generate electricity, not hot water. And tubes are more efficient than plate collectors. Ours are the slant design with a 150 liter tank as a thermosyphon header. Our tubes get our water very close to boiling; we cycle the arrays to our HLT when the array temp gets to 87C. That's twice a day on a sunny day to yield 600 liters of free hot water every day. We got a screaming deal on the collectors at $300 each. Delivered. Anyway, solar water heating is the way to go. Just need a simple design to get your water cycled through the heating side to keep your HLT at required temperature; for us it's 80C and pumped with manual controls, but I have the capability to automate it easily. If you're fortunate enough to collect your heat at an elevation substantially lower than your HLT, then you would have an automatic, electric-free thermosyphon that would be ideal. Good luck!

[india_cmb]

water heating

Hey Phil,

what do you think of tankless water heaters? i am not able to find one for 400/3ph/50hz.

Any suggestions on a compact solar water heater instead? Where is the resevoir placed that stores the hot water? We have a space issue so the tankless water heater is ideal...

Cheers!
________
ACURA EL

[gitchegumee]

Hello Alex! I like tankless water heaters, but they don't compare with free heat! Our solar collectors are on the roof, each of the two have insulated 150 liter headers on them that store heat. Do you have clear, unshaded roof space that faces south? Otherwise, I'm sure you can find a tankless water heater for 220/1/50. I don't think the frequency matters (could be wrong here), and the permitted voltage should be a fairly wide range. Just out of curiosity, what are your electrical costs there? Cheers & good luck!

[india_cmb]

energy costs

even with sky high global fuel costs,
it is much more reliable and less expensive
to use LPG or CNG as an energy source as electricity
is expensive and supply can be unpredictable.

A 17kg LPG cyliner is less than $10 USD.
I would have to calculate the conversion
to how many Btus/Watts equivalent before
I could tell you exactly what the cost difference is.

What formula would you use to calculate this?
________
VAPORIZER REVIEWS

[gitchegumee]

That's cheap for propane. The conversion depends on the heating value of your propane. Usually around 90,000 BTU/gallon. And 3,414 BTU = 1kW*hr. If you don't have cheap & reliable electricity, and you don't have a sunny roof, then it sounds like you will want to use a simple propane burner & Hot Liquor Tank to heat & keep your hot water.

[csquared]

Wort heating/boiling vs. water heating

Punching more numbers on this project:

Does 70% of natural gas use for water heating vs. 30% for wort heating/boiling look comparable to your operations?

Quickly found out our 20 yr. old boiler is terribly inefficient, I'd say it runs less than 40% efficient. Gotta love used equipment.

[gitchegumee]

It's tough to get good efficiency from natural gas combustion in a small installation without economizers, feedwater heaters and other efficiency enhancers found in larger installations. Your efficiency will be lower because of things like heat loss to flue gas, excess air in combustion gas, incomplete combustion, heat loss to ambient, and many other operational factors. You'll be fortunate to get above 75% fuel-to-heat. And don't forget that your boil requires LOTS of BTUs to vaporize somewhere around 7% of your wort, too. So it's not just heating water, it's vaporizing it in a kettle. All the same, I think that properly designed, installed, and operated boilers are generally more efficient than comparable direct fire kettles. There is a whole range of tweaks to make your boiler run more efficiently. If you haven't done any boiler maintenance in a few years, then it will pay for you to hire a pro to get more out of your boiler for less fuel. Again, if you are just making hot water (or tempering it from cold before heating) for your HLT, then solar cannot be beat.

[gitchegumee]

It's tough to get good efficiency from natural gas combustion in a small installation without economizers, feedwater heaters and other efficiency enhancers found in larger installations. Your efficiency will be lower because of things like heat loss to flue gas, excess air in combustion gas, incomplete combustion, heat loss to ambient, and many other operational factors. You'll be fortunate to get above 75% fuel-to-heat. And don't forget that your boil requires LOTS of BTUs to vaporize somewhere around 7% of your wort, too. So it's not just heating water, it's vaporizing it in a kettle. All the same, I think that properly designed, installed, and operated boilers are generally more efficient than comparable direct fire kettles. There is a whole range of tweaks to make your boiler run more efficiently. If you haven't done any boiler maintenance in a few years, then it will pay for you to hire a pro to get more out of your boiler for less fuel. Again, if you are just making hot water (or tempering it from cold before heating) for your HLT, then solar cannot be beat.

[csquared]

Done!

Allright, 8 months later, grant wrote and approved, and some dollars later we're up and running.

Now if only the clouds would take a hike!

Pictures are here on facebook (I know, I know...):

http://www.facebook.com/photo.php?pi...id=54066034015

Cheers and thanks for the help guys!

Caleb Staton
Head Brewer
Upland Brewing Co.

[v2comp]

nice1

thats cool, I have such a small setup, I might build my own simple batch system.

[Sulfur]

heat

I'm a fan of solar power but I could only use it to heat the water NOT to boil of course (with a tube array). Also, if doing multiple batches with a heat exchanger setup I can collect most of my hot water when I cool my wort. I'm sure the costs of setting up a tube array would be amortized quickly especially if (in a brewpub setting) the restaurant and kitchen hot water is supplied this way but it's not a magic bullet.