Will this work or do you have a better idea?

[friesr]

I am trying to come up with an inexpensive way to chill some fluids from about 90 deg F to under 40 in about an hour.

The fluid weighs about 8.5lbs per gallon and I would be chilling about 40 ½ gallon glass containers at one time. The container is about 4.5in in dia and 11in tall.

My idea is to take a 25cuft freezer and seal all the seams with silicone and fill it with about 200 gallons of water. Put the freezer on a external cold control and put a submersible pump in the water to circulate it around the containers.

I figure the freezer’s compressor and the thermal mass of the water will chill the fluid to under 40 within an hour.

What do you think? Any better ideas?


Thx

[Paulajayne]

25cuft freezer and 200 Gallons ????

200 gallons of water weighs 1250 Lbs (just over 1/2 ton) (approx 5 big men) --

Sorry but a standard freezer will not take the weight. - You will have lots of reinforcement to do.

Paula

[US Iceman]

HI friesr,

What you are describing is very similar to the way an old block ice plant was constructed. The old timers would fill large tanks full of water and place them in a very large tank filled with cold brine solution.

A pump circulated the cold brine through the tank and froze the water into three hundred pound blocks of ice.

All of the containers full of "fluids" will displace an equal weight of water, so +/- 200 gallons to fill the "freezer" will probably be too much.

A second point to consider is the refrigeration system on the "freezer". The system is designed to produce a small capacity at low temperatures. What you are suggesting will mean the compressor has to operate at much higher temperatures. This could overload the refrigeration system.

Another aspect of potential problems is; does the refrigeration system have sufficient time and capacity to prevent the water temperature from rising quicker than the refrigeration system will try to pull the load out of the water?

[friesr]

I'm not concerned about the weight, I have had over 2000 lbs in the freezer with no problems.

My question is about the cooling capacity.

I am cooling 20 gallon of fluid from 90 to 40 or a 50deg change. At 8.5lb per gallon I figure this will take 8500 BTU to accomplish this.

Using the thermal mass of the water to do the rapid cooling, 200 gallons of water at 7.5lbs per gallon starting at 32 and raising to 40 would be 12000 BTU's plus the 3000 BTU's of the compressor.

A pump will circulate the water to ensure uniform wather temp and an external cold control will control the compressor with the probe in the water.

Are my calculations correct?
How quickly could I expect the fluid in the glass containers to reach 40 deg?
Can you think of a better way to accomplish this?

[old gas bottle]

the icemans right,you figures probley are too, only thing is a chest type freezer and its machanics are only designed to hold and freeze small quantities of foodstuffs, it kills them on a hotish day to even pull down and hold temperature for there designed purpose,most dont even have a cooling fan and are low back pressure/temp compressors, me thinks you want a good size condensing unit and a plate heat exchanger set up/process chiller. cheers.

[friesr]

I need to cool the fluid in the containers. I need to keep the project under $1000 usd

This is a short term solution untill i can afford something better designed for the task in about a year.

Your thoughts are much appriciated.

[old gas bottle]

well if your happy to try the freezer set up do it , if the compressor fails to cope swap it for a small comecial condensing unit sat outside the case with a med/temp compressor and fan assy and oversize it by approx 25%,the cappilary set up should be o/k with that.

[Dan]

I am trying to come up with an inexpensive way to chill some fluids from about 90 deg F to under 40 in about an hour.

The fluid weighs about 8.5lbs per gallon and I would be chilling about 40 ½ gallon glass containers at one time. The container is about 4.5in in dia and 11in tall.

My idea is to take a 25cuft freezer and seal all the seams with silicone and fill it with about 200 gallons of water. Put the freezer on a external cold control and put a submersible pump in the water to circulate it around the containers.

I figure the freezer’s compressor and the thermal mass of the water will chill the fluid to under 40 within an hour.

What do you think? Any better ideas?

I like the idea of putting the jars in a bath of circulating water. This is a very good way to get fast cooling. How often will you be replacing your product? Is this mass production, where you will be putting another load in as soon as you take one out?

Or, are you just doing one load in a day?

So much for my rhetorical questions. Your idea is a good idea, basically.... depending on how you set things up.

[US Iceman]

Some ideas for your consideration.

If this cooling process is only performed on an intermittent basis, say once a week, this MIGHT work.

Here's what I'm thinking... If the freezer compartment is watertight, start the freezer. Add some water and let the refrigeration system pull the temperature down to about 20F (-6.6C). This would allow the system to operate with a relatively minor load (as compared to the freezer having 200 gallons of tap water in it.

Allow some of the water to freeze on the freezer walls. As the ice starts to build up say 1/8", add a little more water. The ice will melt to cool the added water. This minimizes the shock of the added load to the refrigeration system.

Continue this process until you have the required amount of water. The ice (even though it is a small amount) and the cold water act as a buffer to the refrigeration system.

The heat will be pulled out of the containers only as fast as the water and refrigeration system will allow.

If the calculated load is 8500 Btu, then to accomplish this in one hour, the system would need to have a capacity equal 8500 Btu per hour. If the refrigeration system has a capacity of 4250 Btu per hour, the pull down time will be about 2 hours.

I suspect the freezer system only has a very small system, so you could see the time frame extended out to 4 to 6 hours, if not more.

Now, on the other hand, if this is something you want to accomplish in 2 hours and then cool another batch of containers immediately following this, I don't think this will work.

Just some quick thoughts to consider.

[friesr]

There are two loads a day run thru the system at 12 hr intervials.

Iceman, I know the compressor does not have the capacity to do 8500 btu/hr but trying to figure on the thermal mass of the water to do the rapid chilling. Then, the compressor has 11 hours to lower the the water back to 32. Figure this will take about 1000 btu/hr to accomplis this. I would estimate the freezer to be about 3000but/hr so it should finish this in about 4 hours.

I guess I wont know how well this will work untill i try it. I'll let you know how it turns out in a few days.

[US Iceman]

Sounds like you are going in the right direction.

This is almost the same thing that was used by dairy farmers when they put the fresh milk in cans and set the cans in cold water.

A lonnnng time ago.

[The MG Pony]

and even further back to the old hay, water and nitro method used during the first mining rigs

[friesr]

Got everything setup and running last night. Starting point of the water was 58deg.... 10 hours later 66 degs.

Looks like the experment failed.

Anyone have an idea how I can accomplish this for $$$ not $$$$?

[Larry2]

You could try introducing the water at a slow enough rate that the refrigeration gear can keep up. Perhaps you can get a notion of how fast that would be, working backwards from the nameplate btu rating.

[The MG Pony]

that or hunt down a couple old A/Cs and dump the evaps into the water with a good stronge pumpe to push the watter through, or all out hack an A/C apart and modify it.

http://www.xtremesystems.org/forums/...play.php?f=155 < Here is a forum full of home brew chillers people have built to cool their computer systems, same idea just differant aplication.

Some thing like this would do it >

Source: http://www.xtremesystems.org/forums/...t=22968&page=7

[friesr]

Pony, funney you mention that. I was thinking the exact same thing. There was a 12,000 btu window unit in the paper but it sold already. Going to stop by a used appliance dealer and see what he may have around. I already have a 2200 gph pump to circ the water. Just have to plumb it to flow thru the coils.

[friesr]

BTW, do you think the 12,000 btu area is sufficent?

[The MG Pony]

Aut to be, they go down to -21C, use that guy to pull down the main load then the freezer to finish it.
What I'd do is buy a 1Ton A/C get my self a nice Sporlan 1 Ton TXV and a nice plat exchanger and sit down with some high tensile solder! the most expensive will be the plate exchanger but in the end it will be a very small and loud unit lol, but fierce. If you think it won't be enough you can all ways add more into the loop, thats the beauty of having a modular set up, is you can just plug in more, and with the range of A/Cs you have nearly infinite flexibility; They make a great final solution and a great emergency solution with a bit of modding

[old gas bottle]

another cheap way to possibly achive something like is try and get hold of a flash cooler or python from a pub or bar,ex brewery etc to circulate it round the tank, they have a icebank set up in them,some have plate exchangers and pumps,seen theese adapted for several uses,you can even pull the system out of the bath on some and drop it onto the chest freezer case.