Chiller Build (recently found some time)

[Stewie007]

Pricing Update:

Oh, and the ridiculous prices posted on URI dot com were so inaccurate... I paid like 150 bucks less on the components then stated. The CPR Valve Im pickin up this friday is gonna drop me 80 bucks tax included.... rather than 151... All the other components I got at the local refrigeration store and they were much less than I found on the URI website... The TXV is the only one that was close. So With tax, I spent around 1600 so far. Total costs though in the end will be over 2000 because of the piping, pumps, and additional controls. But if I weren't gonna have all the extra controls and valves, it would be much closer to 1500-1700 total.

[Stewie007]

Hopefully this weekend I'll have time to conduct a water loop test on the condenser. I won't be testing the evaporator side until later.

[runmc]

Is there any way you can label the parts. This looks like a display from a refrigeration school. (compliment )

[Stewie007]

Sure, I've got a series of pics that I'm going to post tonight. I'll see what I can work up. There's a lot of tubing, hehe.

[Stewie007]

Alright, I took some pics today of the mostly finished chiller. Only thing missing is the CPR valve. As you can see the condenser piping has been installed. I tested it to ensure good flow. Well, more so just to fool around with the pump. The pump is pretty quiet, and will be even more so after it has been isolated for vibrations. The block of wood securing the condenser will go away, along with the make shift strap securing it to the cooler. I'm going to put together a stand out of metal that I can then secure to the condenser solidly with metal straps.

[Stewie007]

[Stewie007]

After the chiller is fully assembled, it will be a while before I can begin the next step; which is designing and assembling the pumping rig (station). I've decided on an open reservoir for the condenser loop. The pumps have a good amount of suction so I can fill the system by adding fluid and turning on the pump. After a good while running any air bubbles will be forced out of the system. I tested this pretty extensively. Using a bucket of water I was able to suck the water into the pump and through the system. After about 10 minutes there were no more hissing noises coming from the line and the water through the tubing was clear. The water made no noise as it pumped through the condenser signifying complete saturation of the chamber. It circulated well and I'm assuming with exceptional turbulence inside the HX.

The pumping station will likely spare no expense... Which is why it might be some time before I can build it. Budget constraints apply; going to be moving into my apartment soon. It won't be until the girlfriend moves in that expenses will allow me to resume.

However, I can still use plenty of help on the theory side. I need to know how to implement the pump down, and what kind of controls I'm going to need.

[ultralo1]

The pump down solenoid can be activated 2 different ways
1: A low pressure switch which is connected into the suction side (close on rise)
2: A cold control with its sensing bulb immersed in the liquid (close on rise)

The low pressure control has an adjustable differential. The cold controls are usually a fixed differential.

You will also need a High pressure cutout switch in the discharge line. It will be used to cut power to the comp.

When either one reaches its setpoint the contacts break, stopping electricity from flowing to the coil. The solenoid closes and forces the comp to increas discharge pressure. This will activate the high pressure cutout switch to shut off the comp. The solenoid will stay closed until the differential is exceeded which will activate the low pressure/cold control. Once active the solenoid will open releasing pressure in the discharge line, allowing the comp to come on.

Nice build BTW

[Stewie007]

Could I not do this with a thermostat and an LPS? Where the thermostat signals the valve to open, refrigerant flows through the system activating the compressor when the suction pressure rises above the designated low pressure point. Then, when the temperature is reached, the valve closes, and the compressor remains on until the low side falls below the LPS set point turning the compressor off. Not to be reactivated until the upper temperature limit of the fluid is reached.

A check valve installed on the discharge line before the condenser will prevent back flow of fluid into the compressor.

By the way, I didn't come up with this pump down method... I researched it. The idea is I don't want the system to be controlled by pressure, I want it to be controlled by the temperature of the medium I am cooling.

[ultralo1]

OK 3 ways to do it
Yes that is a good way to do the pump down. Nothing wrong with it.

I like it that you are not relying on the pressure for the temp control. I dont like the pressure method myself. It does not give me the accuracy that I like.

[Stewie007]

The question is, which controls should I get.

Do I have to electrically like all of the equipment, or does the thermostat merely control the solenoid valve alone. Basically, I would connect the thermostat to the solenoid valve, and when the fluid reaches the differential, it would open the valve. Then the Low Pressure switch would turn the compressor on when the pressure rises. So the thermostat could be independent of the system. So, if I wanted to manually turn off the system, all that I would have to do is cut the thermostat power (assuming it has an off switch) and the LPS would handle the compressor power. After that I could close the master switch.

Is this a typical method for controlling a system?

[ultralo1]

It is typical for temp control, the only thing not typical is shutting the system down that way. Usually people just turn off the mains.

Here are some control devices.

The low tech way would be to have a cold control, aka. universal freezer thermostat, controling the solenoid. These are the ones that have 1-10 on the dial and an off position.
Here is one.
http://cgi.ebay.com/Ranco-Freezer-Th...QQcmdZViewItem

You should be able to get on at the local CC dickson.

Here is the more high tech way. It does not have an off position though.

http://cgproducts.johnsoncontrols.co...PDF/125188.PDF

[Stewie007]

I don't want the system to go off at the same time, though. I'm going to run a pump down cycle, so shouldn't the LPS control the compressor power?

[ultralo1]

Yes.
I was not trying to tell you that your way was wrong. I usually see pump down on walkin boxes not on small systems. On walkins they usually use the main disconect as the power switch. There is nothing wrong with the way you are setting the system controls to operate.

[Stewie007]

Oh no, I was just making sure I wasn't doing it some odd way. However, it was suggested to me a while ago that I run a pump down and use a pressure regulating valve to protect the crankcase because my compressor is a bit big for what I am designing. Originally I was just gonna run it like everybody else here. But I figure it couldn't hurt to take precautions. Besides, its more fun this way I think hehe.

[Stewie007]

I wonder if when I were finished with this and it works well anyone would want to buy one from me ^_^ :-D hehehe

[teyber]

You could test things out with r290. if you want some pics of my r290 charging adapter ill get them for you as soon as i charge my cam. i got a can of r507a for $115 or 135 shipped, can't remember but in that ballpark. there are some key's to the ebay searching of refrigerants and ill pm them to you.

cheers!

[Stewie007]

By the way, do you think I should put a check valve on here to protect the compressor for back flow of liquid on the shot down? The refrigerant will be under very high pressure.

[Ozzfest05]

this is looking really good cant wait to see the pump station looks like this will be one hell of a unit

[Stewie007]

Well this is the design for the pumping station. I'm going to build the reservoirs out of quarter inch stainless steel. These pumps exert enough suction that as soon as the cavity is filled, and the pumps activated they will suck the water out of the reservoirs and fill the system, so I can fill the system very easily. Its also self bleeding.

The radiator is a push pull fan configuration. Inside the shroud is the cold radiator. It consists of a dual heat exchanger as seen at the bottom. The air blown over that will cool the condenser water, and the fan on top pulls the air through keeping the air pressure inside the shroud from causing back flow. The air coming out will also be a more acceptable temperature, rather than 100 degrees.

[Fr3akyPete]

Damn!
This is a hell of a setup!
Let me guess....you don't take it to LAN partys?!

[Stewie007]

Whelp, that's a wrap for a little while. I can't spend any money for a couple of months on this. I'm moving into my apartment in a few months and I've gotta keep the cash outflows to a minimum.

Not to worry, I will be resuming work, and in the mean time I'll be getting certified so I'll actually be able to buy refrigerant too .

[Stewie007]

Not exactly progress. Just an update.

The fiancee doesn't have a job and I'm paying for everything, so still no progress. I've run some extended loop tests, but that's it. Right now just updating on my plans.

I've finalized my selection of these electrical controls for my system. Each runs on 115 volts, so there is no need for separate converters or power supplies.

JC A419 Series - Temperature Sensor control (High side Solenoid Control)
A419 Sensor - Temp Sensor for Chilled loop
P70EA-10C - Pressure control for compressor

Question is about radiators. I've decided to use 3 Swiffy MCR320 radiators. I'm creating a polycarbonate enclosure for this and it will be sealed air tight with one inlet. I whipped something up real quick so you could see.

I know....it looks like a barn. The blue coil on the bottom is chilled water. The radiators are obviously on top. The 3 black boxes inside are 115V 120mm fans that push a good amount of cfm. The radiators will be the only outlet.The whole thing will be sealed polycarbonate, and will contain a drain for the water that will collect after the ice on the cold coils melts.

Edit: I'm probably going to box the cold coil in and put the inlet inside there. That way the fans will intake the air through the inlet, and will only be able to blow air through the radiators. I noticed that I didn't show this in the design. I hope that makes sense I typed this up awfully fast.

This is just a basic design. What do you think?

[Stewie007]

I've also decided to use square stainless tubing for the reservoirs. Going to get some 4" Square tubes, and cap them off. Drill a couple of holes here. Make a large fill port there..... presto, reservoirs. This way it'll be much lighter than making my own out of plates.

[Stewie007]

There we go. Created the water piping design. Lost my old renders, but its for the best anyways. Would have been a to rearrange.

So this is the final drawing for the self contained system. It will reside in a chest that is 5' long by 2' wide.

Got some simple renders of the piping. It looks pretty complex. It will be somewhat difficult to build in this routing, but I will endeavor to match the drawing as close as possible. The scale is the same, so for every 1 unit in length in 3DS Max, is 1 inch. The blue piping is the chilled loop. The red is the condenser loop.