Heating Water

[Curtis]

Anybody out there know how efficient it would be to use the steam from a boiler through a heat exchanger for heating mash water rather than using a HLT?

Thank You

[MG Thermal Consulting]

Heat transfer would be great, having the steam boiler already is the part that has the greatest cap expense.

Looking at some of these options for a proposed distillery in VA.

I'll let you know how the numbers crunch out.

[seventh son]

Curtis, I'm in the process of incorporating a similar process next week. I had been heating my mash water overnight by circulating hot water (180-190deg)through the outer jacket of the mash tank. Due to a recurring leak in the outer jacket I will be filling the tank and recirculating the water through a heat exchanger overnight to get it up to 180deg by morning. It will use a little extra energy with an extra pump running overnight, but its still cheaper than replacing my mash tank!

[Stills Crossroad]

My brewery uses a loop inside of the boiler for instant hot water. It is an "optimizer" designed to preheat the boiler feed water. We use it as instant hot water to sterilize the filter. In theory it will heat 40 gallon per minute 100 degrees. Since I do not have enough flow for it I get a mixture of boiling water and steam. You can use a small brazed plate heat exchanger with a pump and a holding tank for hot water and it will work very well. At another brewery we used that system and since the return entered the hot liquor tank from the spray ball the effect of the aeration while heating dropped the pH of the water some as well as being able to heat the hot liquor about 1 degree per minute.

[Natrat]

We use a combination glycol/steam tank for our hot water. Glycol, you ask? Yes, we have an array of solar tubes on the front of the distillery that cycle sun-heated glycol through a loop in the hot water tank (made by Stiebel Eltron). Once the tank is up to 185F, a wax valve on the array shunts the glycol to an air heat diffuser on the roof (I've seen the glycol hit 420 F!)

For days with no sun, or when I have multiple mashes, there is a steam loop through the same hot water tank. Full steam at 15 psi heats it from 80F to 195F in about 17 minutes (I average about 6 degrees a minute, but it accelerates near the end) We have a relatively small distillery, and my mash tun only holds about 400-500 lbs of malt, so our 168 gallon hot water tank is plenty.

The solar array ended up costing less than the tax credits we were eligible for...made more sense than two tankless hot water heaters inline...which is what we would have needed for sufficient flow and delta T in the winter.

A steam coil/calandria in an insulated vessel works great, but if you plan to use a heat exchanger to heat your water, I would recommend a tube and shell type over a plate HX if your application is strictly heating water.

I have the luxury of a lot of excess steam, so we used that.

[MG Thermal Consulting]

Like many, the steam boiler usually has excess capacity, so a steam/water heat exchanger does the trick.

Not as much steam in SE USA (not as many pipefitters either)but in the northern states the reuse of water as a preheater is valuable, but solar is tough- hard to get good quality sun.

For the rural distilleries, better value if a water source heat pump/chiller/underground piping grid is an option for the cooling and heating loop.

[Natrat]

Not as much steam in SE USA (not as many pipefitters either)but in the northern states the reuse of water as a preheater is valuable, but solar is tough- hard to get good quality sun.

I'm not sure what you mean about "good quality sun." These are not photovoltaics (although we use those, too) but vacuum tubes. Essentially, it is a vacuum flask that is half-silvered to filter out most visible wavelengths and allow red and infrared to pass through. Infrared passes readily through light cloud layer (which is why cloudy summer days are so warm)...so "quality" sunshine is not really needed.

I think that condensate re-use and any kind of passive preheating is valuable. Any way you can reduce your delta T in your boiler, bain-marie, or whatever you use is energy saved. As a matter of fact, I lament the fact that I cannot use the excess heat from the solar array to pre-heat our boiler water, but the cost of piping and insulation would be prohibitively expensive as it is well over a 100' run. Certainly we have condensate traps and return that is fully insulated here. Maybe I could run a glycol coil inside my condensate return tank...hmmmm.

I really really agree that geothermal or similar is underused technology. Here in NC almost no one is familiar with geothermal or radiant floor technology, while back in the PNW it's relatively ubiquitous. We have a very high water table where I am, making a liquid/liquid heat transfer easy with shallow loops, yet no one seems to want to invest in this type of technology.

Even in a community with as much "quality sunshine" as we have, we are the only facility of any type with solar ANYTHING.

However, I am not sure if geothermal or heat pump can generate enough energy to run the needs of a production distillery for hot water or bain marie distilling, unless you are situated near a hot spring or other geothermal event horizon. Wouldn't a geyser powered still be cool? Does anyone in Iceland distill with geothermal?

Haha...I wonder if Smoogdog ever considered placing an alembic on an A'a flow...!!

[rumfarmer]

No A'a on Oahu, or I would give it a go! Ocean Vodka now claims to be fully solar on Maui. Not sure if it's true or not. I would really like to use more solar. LP is crazy expensive in Hawaii. Was looking a parabolic solar arrays using Sopogy MicroCSP, but just seems like another expense at the moment. Need to get the process working on the grid before moving off of it.