Correct pump selection for water cooling?

[TheMechwarrior]

All,

I've finally gotten round to setting up my VM still but the 7500L/h 5M head (mag) pond pump I purchased is only capable of running either the cooling coil...slowly or the Leibig brilliantly.

The back pressure of my coils is really testing the pump.

I'm interested to hear from others what they are using.

I have a 2" double helix coil of 1/4" and it's around 300mm long.

I would like to be able to use a single pump solution.

Regards,

Mech.

[FreeMountainHermit]

Sounds like you are using a tee inline or you have them connected in series to take care of both. If money isn't an issue I would run two pumps or maybe install a valved bypass to relieve the back pressure providing it doesn't affect cooling efficiency. Only one way to find out.

I'm running a 1/3 hp 2500 gph submersible to feed my deflag & shotgun but then they are 1/2 inch and aren't choked down as much as your 1/4 inch.

FMH.

[meatheadinc]

I had similar problems with back pressure.
I modified my coil with a 1/2 inch cold finger and both 1/4 coils running parrall off the cold finger.( doubling my water flow through the coil )
I now run both reflux and PC plus a bypass. Bypass helps with turbulence and further cooling.

[TheMechwarrior]

Hi guys,

Thanks for the prompt feedback

Since it's a magnetic pump it will only pump what the system resistance will allow, the rated 7500Lph is under ideal conditions.
I have a 3m head to get to the still and the return line has the same 3m head to overcome, a total of 6m head not counting line resistances.

I've tested it one cooling loop at a time and the leibig performs beautifully thanks to the lack of resistance/back pressure.
The cooling coil will proivide a minimial flow at the still but the pump cannot overcome the 3m head on the return loop to return the water back to my tank.

I had hoped for a single pump solution as I have a lot of control valve options available to me as well as flow meters if I so desire.

Cheers,

Mech.

[meatheadinc]

return line should offer some syphon effect
The return line will not add to head height.
I have a similar pump and was experiencing similar problems.
After removing g the restrictive coil and replacing it with a cold finger unit and replacing all hoses from 1/4 to 1/2. I have ample flow.
I run 2 in lines and 2 out. One for reflux ( 1 Litre/min) and one for pc.(1.5L/M) plus 2litres/min bypass
The return lines ounces primed will aid the pump with a syphon effect.
I was amazed at the difference after the changes.

[TheMechwarrior]

Thanks meatheadinc,

I'll consider a change to the primary condenser coil after I try this:

Going to drop my supply and return lines from the ceiling (aesthetics) to the ground level (practicality) to see if the drop in head helps.

I'm unable to benefit from the siphoning effect on the return as I just cant get the return flow high enough to begin the siphon.

I did find a few decent pumps on Ebay capable of 20m head +, since these are not mag pumps I'll need to add a bypass loop but that's fine once I've got the flows I need the surplus can go to the bypass.

Will post pics of the completed setup later this week.

Cheers,

Mech.

[TheMechwarrior]

All,

I've dropped my supply and return lines to ground level and I now have flow!
Clearly the rated 7,500L/h of my magnetic pond pump is a far cry from the reality I've experienced below.

Here are the flows I've been able to achieve through various independent circuits:
Out of interest I tested a couple of different sized condenser coils, very interesting. Even though the larger coil has a greater surface are for cooling the dropped rate in flow doesn't support an argument to go to the larger coil. Correct me if I'm wrong here?


Any thoughts about those flows guys and gals?

Cheers,

Mech.

[meatheadinc]

Flow look good on. PC
RC Still restricted by 1/4 coil. Depending on power input it maybe OK (low power(
Just check for escaping vapors

[TheMechwarrior]

The condensing coil needs to be able to handle all the vapour from the 2.4kW heating element in my 50L keg.

I'm interested to here what flow rates others are achieving?

Cheers,

Mech.

[meatheadinc]

My double 1/4 with 1/2 cold finger is currently running at 1.1 liters per min on 2000w
Both 1/4 coils run parralel to reduce back pressure

[meatheadinc]

Water temps currently 33 deg c

[TheMechwarrior]

Thanks mate!

The shitty pump I got from China may be great for a fish tank but its just not doing the job for me here.

I've just ordered 3 x 750GPH (3.3LPM)bilge pumps: http://www.ebay.com.au/itm/Hot-12V-Subm ... ac0&_uhb=1

And a transformer to manage the job for me: http://www.ebay.com.au/itm/150w-12v-Out ... cff&_uhb=1

Lets see how they go.

Cheers,

Mech.

[friendly1uk]

Forget the capacity of your pump, they are all up to capacity. You need to look at the head. That is how well it can shove water through things.

I will pop back later... I shouldn't be here

[FreeMountainHermit]

I can fight a fire with mine. Don't know what your voltage is across the pond though.
2400 GPH. 25 foot head.

http://www.amazon.com/Superior-Pump-913 ... B000X07GQS" onclick="window.open(this.href);return false;" rel="nofollow

FMH.

[friendly1uk]

You need to make sure the return pipe makes a constant fall. If you have a dip with fluid in then that would explain why you can't get a syphon going. Your pump don't have the guts to push that dribble out, because the air it needs to push it through with is too elastic.

Good call on going 12v. I'm afraid the pump you have ordered won't cut it though. It's just more of the same.
Have a look at these. The bore is about 8mm and a 3 meter lift only reduces it from 15L to 12L. I don't think falling back down through some 6mm will slow it below 5L. Leaving a few spare for the liebig. Or you could use one of the new 3 for the liebig.
http://www.whalepumps.com/rv/siteFiles/ ... pGuide.pdf" onclick="window.open(this.href);return false;" rel="nofollow
Just 50w so no heat problem.

It is a pity car fuel pumps rust so quickly. They would get through a night in the woods though. Some dangerous pressure from one of them.

Made in Bangor. Although you could get an unknown chinese one for peanuts.

[TheMechwarrior]

Awesome thanks! Those Whale pumps look good, now for a price check.
At $15 for the bilge pumps I have an alternative use for them if they don't cut the mustard.

BTW, this is the pond pump I started with:
(It stated 5m of head and 5,000LPH...I can assure you all that those stated numbers are VERY optimistic from the supplier)
http://www.aquariumproducts.com.au/cata ... 7&catID=13" onclick="window.open(this.href);return false;" rel="nofollow

Cheers,

Mech.

[FreeMountainHermit]

No exp. with the bilge type pumps but I'm wondering if they will withstand the rigors of continuous duty during hours of run time as well as the aforementioned constriction of the small coil diameter.

Your thoughts ?


FMH.

[googe]

I use a $70 submersible 550w from Bunnings, have had it almost two years and never had a problem, have run it dry, very rarely clean it and keeps going, more than enough power for my needs.

[FreeMountainHermit]

I use a $70 submersible 550w from Bunnings, have had it almost two years and never had a problem, have run it dry, very rarely clean it and keeps going, more than enough power for my needs.

Darn nice pump. The OP should take a good hard look at it .Almost 3/4 hp.
http://113.20.129.186/commercial-electr ... p_p4813554" onclick="window.open(this.href);return false;" rel="nofollow

FMH.

[TheMechwarrior]

Yeah, might pick that pump up from Bunnings tomorrow.

I've had reports from others using the 750GPH bilge pumps and they've used them successfully for over 3years now on this duty.
I only needed 2 for my needs but got the 3rd as a hot swap spare just in case, they were only $15 after all.

That Bunnings pump sure kicks arse, not sure it will fit into the 150mm opening of my 1,000L IBC.

[googe]

Thats the one freemountiam!, I paid $50 for it 2 years ago, been a great pump and know many people using them, nice and quiet too!. You might have to do some cutting themechworriar lol. You could maybe have a small tank beside it with the pump in it connected to the ibc if you don't want to cut it, I'm sure you'll work it out. I put a copper tee on the output line inside the tank just as a realise cause they do have good pressure.

[TheMechwarrior]

While waiting for my bilge pumps to arrive I went out and purchased the 550W pump from Bunnings for $79.
http://113.20.129.186/commercial-electr ... p_p4813554

When I have all the pumps on site I'll individually test every loop option I have available to me and post the flow-rate data for you all so you can see for yourselves the difference each pump can make.
This will all be in a single/simple table for you with results in L/min and G/min.

Cheers for now,

Mech.

[rager]

I can fight a fire with mine. Don't know what your voltage is across the pond though.
2400 GPH. 25 foot head.

http://www.amazon.com/Superior-Pump-913 ... B000X07GQS" onclick="window.open(this.href);return false;" rel="nofollow

FMH.

I bought the same pump just 1/4 hp. very solid built pump. I haven't run it yet though. paid 49 bucks off amazon

[TheMechwarrior]

Folks I've listened!

I went out and bought the $79 Bunnings 550W pump today and I'm bloody impressed with it!

Still waiting on the bilge pumps to arrive so I don’t have any data on them yet, but at least with this new pump I have the option of running both the Liebig and the cooling coil in counter-current series:
(More flow rate data to come once the bilge pumps arrive - I'll update my build pics as well at the time as I have not updated the pics since........2010 )



Cheers all,

Mech.

[meatheadinc]

Now your talking !!!!!
Just remember to hook a bypass as to no over heat the pump

[noobsauce]

having made a solar heater for my kids swimming pool....STAY away from pond pumps. i went through 3 different ones (more and more gph) and not one of them achieved the head they claimed or anywhere near it. they are also more expensive than other pumps as i found out. i eventually went and bought a "portable" submersible sump pump that has a 50 foot head and pumps about 1200 gph. got it on sale for 40$ which was quite cheaper than small pumps. this info should help i hope


*i hope u dont end up with head issues with bilge pumps as they arent intended for much raise in pumping hieght but hopefully u dont

[apdb]

..at a box store? I'm looking for a "better" deal up here but everything is around the $70-$100 area. Lots of stuff at Princess Auto worth checking.

[FreeMountainHermit]

Folks I've listened!I went out and bought the $79 Bunnings 550W pump today and I'm bloody impressed with it!

but at least with this new pump I have the option of running both the Liebig and the cooling coil in counter-current series:
Cheers all,

TheMechwarrior, I'd seriously reconsider running your liebig and coil in series instead opting to run each individually by installing a Y or Tee in your feed line from the pump to them with a bypass line for each condenser and a valve at the outlet of each so that each is controlled in separately.This way you will be able to monitor your output temps at each outlet and your pump won't work as hard pushing coolant though the small coil or overloading your liebig.

Thanks for posting the chart. Was your still operating at the time or did you have the pumps hooked up to each condenser just for testing purposes ?

When running your rig at flow rates it likes it would be interesting to see them posted in another chart.You have gone to a lot of effort for us. Thank you.

FMH.

[TheMechwarrior]

Thanks mate, I'll post up a pick tonight to show you my supply and return options as I have a great deal of flexibility at my disposal. I intend on running in series, my initial pump was not capable of doing this though. That’s how all this testing got started.

You'll see a supply port 1 to 4 with each of the 4 ports having a flow meter and a ball valve for coarse control.
You'll see the return port 4 to 1, again with each of the 4 ports containing a ball valve for coarse control.

Depending on how I connect my hoses I can run individual supply and return loops to each cooler or I can run in series.

I also have a collection of gate valves for finer control if needed.

The tests I did were all "offline" for testing purposes only.
I'm gathering data I felt was missing from our centralised collective knowledge base.

Now that I have a function cooling supply and return I'm hoping to fire the beast up this weekend and do a vinegar run and a sacrificial goon bag run. If that all goes well I'll put a couple of fermenters on...finally. It's only been 4 years, 2 jobs, 2 houses and 2 kids in the making!

Cheers,

Mech.

[FreeMountainHermit]

I also have a collection of gate valves for finer control if needed.

Speaking of gate valves. I couldn't pass this deal up. Going to change out my 1/2 inch full flow ball valves for finer control. They arrived the other day and I'm just tickled shitless. Nice valves.

http://www.ebay.com/itm/261361660415?ss ... 1439.l2649" onclick="window.open(this.href);return false;" rel="nofollow


FMH.