Water Chiller Help

[Aschillaci]

I'm setting up a home darkroom in TX, and as you can imagine, the regular water temperature over summer is pretty high.
I'm looking into getting a Elkay remote water chiller and I found a very cheep one , but only does 8 GPH (gallons per hour).
I read on other threads that they got a 32GPH so that make me wonder what is the best GPH for a darkroom. I only need it to go with my Jobo processor and water regulator.
Any advice?

Thanks!

[ic-racer]

I'm setting up a home darkroom in TX, and as you can imagine, the regular water temperature over summer is pretty high.
I'm looking into getting a Elkay remote water chiller and I found a very cheep one , but only does 8 GPH (gallons per hour).
I read on other threads that they got a 32GPH so that make me wonder what is the best GPH for a darkroom. I only need it to go with my Jobo processor and water regulator.
Any advice?

Thanks!

Are you going to be running the output of the chiller to the cold water solenoid of a CPP2? At a rate of 8 gallons per hour it may work fine but it depends on how hot your darkroom is and how cold the chiller makes the water. If you are running a standard process at 24C and your darkroom is 30C and the chiller is 10C my experienced guess is that 8 gph will be fine.

I don't have a chiller but I have run an 18C process at a room and water temp of 22C by placing ice water/slush (4C) in 4 of the six one liter bottles in the CPP2. I'd have to replace the 4 bottles with fresh crushed ice water about each 20 minutes. I eventually ran out of ice from the kitchen ice maker.

[Aschillaci]

Yes, its going to be for a CPP2. Until now, I have been doing the same with the frozen bottles to cool it down.
My new darkroom has a split unit AC and my hope is to connect the water chiller to the temp controller to the CPP2.
I got the Elkay water chiller for $100 box, so I'm going to install it and running as a test, worst case scenario, the installation will be done and I only will need to replace the water chiller for a bigger one.
I will keep you guys updated.

[Harold_4074]

I've given the question considerable thought for my own darkroom---the water comes in at a minimum of 71F, but much warmer in the summer. The 8 GPH number doesn't sound like much, unless you figure out that it is almost 200 gallons per day. I need about three gallons to do a batch of film, so it would take a few minutes to accumulate enough cold water.

The answer, to me, seems to be an insulated holding tank (electric hot water heater with the elements removed?) and a circulating pump of the kind that drives the hot water loop in commercial buildings. Well water would to into the top of the holding tank, cold water to the temperature control valve would come out of the bottom, and the circulating pump would allow the chiller to bring the stored water back down between cycles. The chiller will take out a certain amount of heat per pass, so I could keep the holding tank at about 50F (slightly above the usual dew point in my neighborhood) and expect a rise to only about 54F after replacing three gallons of cold water with warm incoming water. Of course, it wouldn't take three gallons of 50F water to process a batch of film at 68F, so this is pretty conservative. Assuming that I haven't muffed the arithmetic...

For economy, the holding tank would have extra insulation and the "cold" temperature would be just low enough to meet the temperature differential specification for the control valve, using well water instead of heated water any time the incoming water was already warm enough. A water heater holding at 85F or so would be nice for hand washing and the like, and would certainly keep the control valve happy :)

Any practical experience out there with this approach?

[Daniel Stone]

What about this:
Buy some spare(say 6-10) Jobo 1L bottles, fill them 3/4 of the way up with water, and FREEZE THEM(so they become giant ice blocks themself). Cheaper and easier than filling bottles w/ ice from your fridge/freezer(or buying ice), and you won't have to plumb your darkroom with a chiller unit(not to mention not needing something else to maintain down the line).
http://www.catlabs.info/product/jobo-3381-six-pack-of-1000ml-bottles-4-transparent-2-black

You can add a couple of mils (say 1:100 ratio, 1% solution) of isopropyl alcohol to the frozen bottles, to inhibit any bacterial growth, but it won't be a large enough alcohol volume to inhibit freezing.

P.S. If your kitchen freezer is limited in terms of storage space, get your darkroom a small chest freezer and you can store them in there, along with your film/paper :)
I purchased two of these last year, and they've only run me ~$4/mo in terms of cost, each. Nice, small little units:
http://www.homedepot.com/p/GE-5-0-cu-ft-Chest-Freezer-in-White-FCM5SUWW/203547584?keyword=ge+5.0+freezer

-Dan

[gleaf]

Water takes 1 BTU per pound (= 1 pint) to change temperature by 1 Degree F.
So flow in gallons * 8 * (water temp-desired temp) = needed BTU at your chosen flow rate.
Every chiller should have a BTU capacity rating hiding in the specifications some where.

[Lenny Eiger]

I think it would be easier to move your times to match the temperature. When I lived elsewhere I was able to use 68 F. Now I use 72F as a basis. I just develop a little shorter.... I see no reason not to go to 72-75 degrees... as long as the times are adjusted.

Lenny

[Aschillaci]

Thank you guys for all the suggestions!!

[robertrose]

So what worked? Same question in California.

[Luis-F-S]

I think it would be easier to move your times to match the temperature. When I lived elsewhere I was able to use 68 F. Now I use 72F as a basis. I just develop a little shorter.... I see no reason not to go to 72-75 degrees... as long as the times are adjusted.
Lenny

When the temperature hits 80 Deg & above, there is no "shortening" the development time. The film reticulates and slides off the base. It's pretty impressive.

You'll get more " chilled" water if you hook the cold tap to the "hot" side of the control valve and the the chilled line to the "cold" side of the control valve. I've never run out of 68 Deg water with my set up & a 32 gpm chiller even when washing film for over an hour. I had an entire thread devoted to the installation of a Hass control valve & chiller:

http://www.largeformatphotography.info/forum/showthread.php?109688-Hass-Intellifaucet-Installation

L

[Jim Andrada]

I've seen the "cold" water temp reach almost 90 in the Summer. I use the frozen bottles in the Jobo but it's not really satisfactory if I want to run several cycles on the same evening as the ice gets used up too quickly.

[largeformat apt]

A temprite for beer maybe an option, we use them here for kegs you get from the hotel, buy the beer get the temprite. It has an inlet and outlet and is fitted into an insulated box. Fill the box with ice and start pouring beer. have a look on line for a design. Not hard to make, I have the same problem here with hot tap water, not hot beer!!!

[robertrose]

Thanks to everyone who has a suggestion. I think I got this figured out. I am going to order a wort chiller coil on eBay. Around $50. That hooks up to a hose, and I will put the coil in a plastic bucket and add ice. Water flowing through the coil will then be chilled before it goes to the Jobo CPP. As an added advantage I will add some beer to the ice. Then I can drink the beer.

[robertrose]

I went to school in Tucson. It is too hot in the summer to do anything. See my beer/ice solution below.

[gleaf]

Not sure what is practice in The Great South West. Indiana/Kentucky grade indoor food operation etc, the beverage cooler has a removable top and is filled with ice. ice feeds the ice dispenser as well as cooling the room temperature beverage between the feed side and the dispensers.
My understanding is the lines are just fairly lengthy food grade plastic tubing of an appropriate size. Cola folks could probably tell you the recipe for how much tubing and how much flow with your source water temperature. Also ice consumption for your ground water temperature. A ton of ice cooling rating is about 12,000 BTU 8 lbs a gallon * degrees difference needed etc...

[jdaivpmed]

Aschillaci,

I ran into a similar issue a few years ago with our water supply here in San Antonio. The cold water, just isn't really cold at all!

In my case, I was running a Jobo ATL2 so my solution was a little easier than yours. I picked up an old recirculating chiller (basically the same thing you have with a built in pump to circulate the water through a closed loop). I then took about 3-4 feet of 3/8" copper tubing and rolled it into a coil that would fit in the bottom of the Jobo (I think I used a broom handle to form the coil). I connected this coil (now acting as a water to water heat exchanger) to the inlet and outlet of the recirculating chiller and submerged it in the bottom of the Jobo. I set the temperature for the chiller to a few degrees below the target temperature for whatever process I was running that day, in this way, the electric heater in the Jobo worked against the chiller and maintained the temperature on its own (with no need for external tempered cooling water).

In the case of the ATL, the rinse water is tempered internally using the main reservoir below the processing tray, but I don't see any reason you couldn't use this same (or similar) arrangement with your CPP. You would have no need for any external water connections since you have to manually pour all of your chemicals and rinses. You could keep your rinse water in the extra containers (the ones you currently fill with ice water) submerged in the water bath, which would temper them to your process temperature, the same as it does with your chemicals.

This arrangement worked fine for me here in San Antonio. In fact, my ATL2 was set up on the screened in back porch of our former house, so it was essentially running outdoors in San Antonio summer temperatures. The Jobo heater working against the chiller did a great job of keeping the temps to within a tenth of a degree or so. I had more issues with water quality (we have some seriously hard water here in San Antonio) than I did with temperature after building this setup.

Good luck,

John IV

[mcherry]

Even in New England it can get warm. I have developed at 75 degrees but prefer 68. I'm plumbing an aquarium chiller into my Jobo. Based on how I *believe* the cold water solenoid works, I don't think it makes sense to use it. Instead, I'll plumb it like an aquarium with a constant flow of water in and out of the Jobo using an aquarium pump. This way, 68 degree water will constantly be flowing through the unit, maintaining temp. When developing color, I just turn off the cooling system.

That's today's plan at least.