Cooling Tower Build

[beermanpete]

I am building a cooling tower for use with my wort heat exchanger. Here are a few photos mid-build.

 

[beermanpete]

I got the blower installed today. I still need to install a baffle to prevent the air and water from bybassing the wet deck. Hopefully I can get it ready for a brew day next weekend.

 

[day_trippr]

Holy cow. Looking at the size of that blower I'd wear a rain coat
You definitely need to shoot a video of this beast in action!

Cheers!

 

[beermanpete]

Yeah, I have a feeling the blower is larger that necessary. It does pick up the water and blow out the top. If it still blows out a lot of water after I add the baffles I will have to see if I can slow it down a bit or perhaps block the air duct some.

 

[StuckSpargeSarge]

That fan should have a low speed. Make sure you wire your hot to that tap and it should slow down substantially. I’m an HVAC contractor and can help you with the wiring if you haven’t figured the taps out yet.

 

[beermanpete]

That fan should have a low speed. Make sure you wire your hot to that tap and it should slow down substantially. I’m an HVAC contractor and can help you with the wiring if you haven’t figured the taps out yet.

Cool, thanks for the tip. I will take a look at the wiring and see if there are any unused taps.

 

[StuckSpargeSarge]

From the looks of it that is a three speed motor. You obviously hook your white wire from supply power to the neutral on the motor, then you will hook your black from the supply power to either one of those taps to select the speed. Black is typically high-speed. If it is not label on the motor you might have to try switching your hot from the supply voltage between those leads to figure out which one is low speed.

 

[day_trippr]

fwiw I have a couple of big blowers like that and they're both two speed.
On mine the black wires are for the high speed winding while the low speeds use red wires.
Running both windings doesn't make them go any faster...

Cheers!

 

[Rhaop]

This is a cool ideal, thermodynamics at work!

 

[StuckSpargeSarge]

fwiw I have a couple of big blowers like that and they're both two speed.
On mine the black wires are for the high speed winding while the low speeds use red wires.
Running both windings doesn't make them go any faster...

Cheers!

I don’t think faster would fix his issues of water coming out the top. It definitely needs to be slowed down. As far as 2 speed blower motors, I haven’t seen one in a long time for a furnace if that is where it is from. The fan setting for AC uses the high speed(Black like stated) and the Heating speed is usually on medium speed and the motor usually has a low speed that is “parked” on the board.

 

[ancientmariner52]

I like it!

Looks if you had another barrel, you could cut one end out just as you have here, and cut the other where it tapers to full diameter. Then set it over this barrel to serve as a stack. Might help get the splashing under control.

Hey electrical guys? Is there an add-on speed control that would work on this motor?

 

[ancientmariner52]

Oops. Shoulda thought about that a bit more. Water will run down the inside of the stack and collect in the gap between the barrels. Maybe some drain holes to direct it back inside?

 

[Rairdog]

The EF I built is a HVAC blower. It has 4 speeds/wires. I used a 3 gang box with a single pole switch and 2 double pole switches. The single pole is low/off, the next double pole is med and the last double pole is high. I don't use the med-high wire. There are some youtube vids on dust collection blowers to show the wiring diagram. Much cheaper than 3 or 4 speed switches and I had all the parts laying around.

 

[StuckSpargeSarge]

The EF I built is a HVAC blower. It has 4 speeds/wires. I used a 3 gang box with a single pole switch and 2 double pole switches. The single pole is low/off, the next double pole is med and the last double pole is high. I don't use the med-high wire. There are some youtube vids on dust collection blowers to show the wiring diagram. Much cheaper than 3 or 4 speed switches and I had all the parts laying around.

Sweet! So you ended up using the different speeds. Super cool. Does it still spit water out using the low speed?

 

[Rhaop]

Will probably have water droplets no matter what speed just part of evaporative cooling, could extend the top of the barrel a little higher maybe with a half a barrel section


Or a removable section to force the air in a directional change to help the water drop out

 

[ancientmariner52]

Maybe some window screen over the top, like a splatter screen in the kitchen? Or just stand upwind.

 

[MaxStout]

Build some baffles to restrict airflow.

BTW, you could get one of these to make it easier to move around.

 

[SleepyCreekBrews]

Have you done any testing yet? I'm curious what the cooling delta is.
I don't know how the big ones operate, but don't they cool near-boiling temps down to something like 100 degrees?

 

[FourSwitch]

One thing that may be useful, is the more dry the climate is the better these will work, and inversely if you have a very humid climate you may find a horrible approach on the tower. i am curios how it'll work though, for me in canada i just use our near freezing ground water

 

[Rhaop]

Commercial cooling towers on a chilled water system are cooling condensing water in the area of 85* F and lowering it about 10* to about 75* F in a perfect world, there are other systems obviously like in the power generation field hopefully someone with more experienced can chime in

 

[FourSwitch]

I'm no expert, but i have been servicing them for the last five years [terribly gross things, bacteria and usually a dead pigeon floating in them.... gross......] on the evaporative cooling side of things, they usually hold a temperature requested to maintain a chillers high side condensing refrigerant pressure, via a VFD on the fan and or pumps for the water... but if you were to run the fans and pumps across the line, assuming you get 970 BTU of useful cooling for 1 lb of water evaporated --[reference - it takes 1 btu to change 1 lb of water 1 F degree] -- id assume you can do some pretty good cooling to the loop assuming you have a dry climate.

everything else comes down to engineering honestly, and they are very uncomplicated units, ether blow through, or pull through, depending on fan location and everything else is the same essentially.

dunno if that helps or not but hopefully it does


--edit --
also don't forget to have a form of make up water (a hose or what not) you'll be impressed how much water can evaporate sometimes

 

[day_trippr]

[...]also don't forget to have a form of make up water (a hose or what not) you'll be impressed how much water can evaporate sometimes

Float valve to the rescue!

 

[beermanpete]

Thanks for all the suggestions. Yes, an extension is likely necessary so I can add a drift eliminator. I have run the water pump and the fan at the same time but not with any heat input. There is too much water coming out the top to leave it on very long. It is funny to watch but not usefull. After I get a chance to work on the wiring and add the baffle I will try it again.

Fortunately I live in a dry climate so the evaporative cooling effect should be usefull. I know the theoretical limit is the dry bulb temperature which appears to be about 75 F during the summer. The temperature on the hot side into the tower should be about 120 F. I am not sure I will get a 55 degree tempearture drop or not. If the approach is 10 F I will be at about 85 F which is about the temperature of the ground water in the summer. I can slow down the wort flow some if necessary to lower the heat load on the tower. I know this is a lot of work for what appears to be no gain but it should save some water which is an issue in Southern California. Also, if this works out as I hope it will I will add an active chiller to get down to pitching temps for lagers, which is the ultimate goal.

I don't expect to need a speed controller for the fan since the heat load will be constant while cooling the wort. Make up water may be required but since knock out is only takes about 10 minutes I am hoping the water level will not drop enough to be an issue.

 

[beermanpete]

I installed the baffle and worked on the wiring for the blower yesterday. I found the motor has two speeds so I wired it for the lower speed which helped some but it is still too fast. Using a Variac to lower the line voltage to the motor I found it runs at a good speed when set to about 60 volts and the line current is still ok.

I put heat into it using boiling water. It works and cools the water ok but not as much as I hoped for. I don't have enough instrumentation to determine the approach but it cooled the "wort" to about 85 F while the ambient temperature was 80 F.

This is the baffle I added to make sure the air flows through the wet deck.

This is the water blowing out the top when the fan is running at full line voltage on the low speed.

 

[Rhaop]

From boiling to 85 is a really good start though