My First Chiller

Hello.

A few weeks ago, I built my first water chiller using an R-134a LG LX67LAQG refrigerator/freezer compressor: https://fbcdn-sphotos-a.akamaihd.net...59225277_n.jpg

Something went wrong at first, so I ended up wasting most of the refrigerant, and was left with only 20 psi of pressure in the evaporator.

Despite the low pressure, it froze some of the water anyway (until the coil itself froze into a chunk of ice) and worked, but I didn't think it was working quite as well as it should have. 20 psi is too low, right?

There is a problem: So I bought a second can of HFC-134A today and charged it more until the pressure was 55 psi in the evaporator. When I tested it, this time, the condenser got very hot immediately (within a few seconds), the water warmed noticeably and the evaporator also cooled off much faster than it used to. It become noticeably cold immediately, but now it won't freeze, and it is taking long to cool the water.

Could this be because the condenser is getting so hot? It is much harder to keep it cool now, and during these tests it did get hot. The condenser water reservoir pump is not powerful.

LG said that the power consumption is 177 watts, but my Kill-A Watt meter read 200-300 watts before I added the additional refrigerant, and now that I have added the additional refrigerant, it starts at about 340 watts and climbs quickly up to almost 500 watts. Could this be due to the condenser temperature as well?

Is it that the condenser is just getting too hot? Or am I going to have to let out the refrigerant again?

You probably won't die doing this stuff but it may not be for the want of trying

Kompulsa, we need more information to help you. Suction pressure, cond pressure, subcooling, superheat, condenser water in/out, evap water in/out? And how did you calculate your chiller? Did you add compressor power consumption to cooling capacity to get condenser capacity?

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Originally Posted by AlexG

Kompulsa, we need more information to help you. Suction pressure, cond pressure, subcooling, superheat, condenser water in/out, evap water in/out? And how did you calculate your chiller? Did you add compressor power consumption to cooling capacity to get condenser capacity?

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This guy is completely unqualified and untrained. Any assistance should be given with extreme caution

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Originally Posted by Kompulsa

Or am I going to have to let out the refrigerant again?

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Hi Kompulsa

good to see your still with us and alive !

maybe you could start with some good refrigeration procedures

and reclaim what you want removed from a system, instead of ''let out the refrigerant again''

as for the answers to your questions, you really need to learn the basics first before you start experimenting

when you do, am sure most here will 'then' be only too happy to assist you

R's chillerman

The evaporator pressure is 55 psi. I don't have an access valve on the condenser, the length of the entire tube including the evaporator and condenser is 25 feet, the evaporator tube is a little more than half the length of the condenser.

I wasn't circulating the evaporator water, I just left it in the container. The condenser water pump is rated at 40 GPH.

I don't think I can determine subcooling and superheat. I don't really have proper tools, and I don't have tools to calculate condenser capacity either.

I didn't do much where calculation is concerned, it was

I'm sorry, I need a practical how to book to teach me the necessary procedures from scratch and especially design, but I can't find one. When I can't find these things, I tend to experiment anyway. I've wanted to for many years.

I will reclaim the refrigerant, of course...:)

Not seen this myself as I have many hardback books now

but others seem to like it http://www.refrigeration-engineer.co...G-18th-edition

now what we need to find you is a book on refrigeration principles

R's chillerman

I'm unable to download it, the links are broken. :(

https://rapidshare.com/files/3701695...th_edition.pdf
this should work- it will take a while
it flashes up as error then the rapidshare link opens

Nice one Install

as that other link is now down, its a bit like giving a child an empty sweat rapper

your buddy was not happy !

R's chillerman

the RE thread stopped working a while ago- so i uploaded it on rapidshare but i dont know how long my link will last- dunno if its just 30 days or after 30 days of inactivity

Just a reminder, which I found very helpful: The water becomes cool within seconds, and then the condenser gets hot and it won't cool any more. I really think that it is that the condenser is overheating. It gets hot immediately, and heats much more than it used to, plus, that heat is coming from the evaporator anyway. I think the cooling capacity did increase, a lot...

Based on what I saw, it cools off fast, then overheats and stops working properly.

I put the condenser in cold water today and the evaporator water became cold in half the time that it did before the recharge.

moisture blocking the drier

What drier??

Based on your wattage and pressure readings it sound like the system is seroiusly overcharged, thats why the suction pressure doesn't get lower, theres not enough room in the system for the refrigerant to go to so the evap pressure (and temperature) can drop.

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Originally Posted by install monkey

the RE thread stopped working a while ago- so i uploaded it on rapidshare but i dont know how long my link will last- dunno if its just 30 days or after 30 days of inactivity

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Thank you, it is downloading. :)

I thought the pressure would be in the range of hundreds of psi at least if it was overcharged...It is only 55 psi. The power consumption is definitely excessive, though.

Good on you for having ago on your first chiller, I good way to learn about the refrigeration process. But you are trying to run before you can crawl.
Empty all the refrigerant. add pressure and temperature measuring points to every part of the system. Information is what you need to see what is happening.
When you have done all this, vac the system. add R134a in vapour form only. Charge upto the pressure of the bottle. "close refrigerant charging valve" See what happens! DO NOT predict what will happen at this stage. Make a note of all pressures and temps. I suggest you use a drawing with little data boxes by each point of measurement.
Let us know these figures then we can go onto the next stage.

Kompulsa, it has been said before, if you cannot afford gauges, befriend a fridgie, cry poverty and you will save yourself a lot of time and gas too. It will never work well with moisture or air in there.

Do you have any pawn shops there. You may get a cheap set of gauges for a few bucks.

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Originally Posted by Kompulsa

I thought the pressure would be in the range of hundreds of psi at least if it was overcharged...It is only 55 psi. The power consumption is definitely excessive, though.

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It is overcharged. High power consumption and high pressure on the"cold side". Less than 10 psi only for that reading when it runs. Spun copper drier is meant for another area, and find time to put some feet on the compressor and the terminal cover on the electrics, but not before you run an earth to the compressor.;) Safety first.

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Originally Posted by mikeref

It is overcharged. High power consumption and high pressure on the"cold side". Less than 10 psi only for that reading when it runs. Spun copper drier is meant for another area, and find time to put some feet on the compressor and the terminal cover on the electrics, but not before you run an earth to the compressor.;) Safety first.

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I can't find the terminal over in the local store, nor the feet. I removed some of the refrigerant so the pressure dropped back down to 25 psi like it used to be, and it is working again. It still needs work, though, I think.

I thought the drier was supposed to be on the suction side. :( What should i have done?

Kompulsa, I often read your posts with mixed feelings, some fear mixed with anxiety dashed with a bit of respect, I really worry about you and your experimenting without a clue. It is frustrating to see you put forth the efforts that you do without first taking the time to learn the basics of refrigeration, you would be so much further down the road if you just spent a bit of time reading some refrigeration books. On the other hand I have a lot of respect for your fearlessness you are certainly going to figure it all out if you continue to apply yourself as you do. Is there not any refrigeration companies there that might give you an apprenticeship? or at least offer some knowledge? Be Safe.
Emmett

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Originally Posted by r.bartlett

You probably won't die doing this stuff but it may not be for the want of trying

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R Bartlett that is some funny funny stuff

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Originally Posted by Emmett

Kompulsa, I often read your posts with mixed feelings, some fear mixed with anxiety dashed with a bit of respect, I really worry about you and your experimenting without a clue. It is frustrating to see you put forth the efforts that you do without first taking the time to learn the basics of refrigeration, you would be so much further down the road if you just spent a bit of time reading some refrigeration books. On the other hand I have a lot of respect for your fearlessness you are certainly going to figure it all out if you continue to apply yourself as you do. Is there not any refrigeration companies there that might give you an apprenticeship? or at least offer some knowledge? Be Safe.
Emmett

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I agree. I have my eye open but haven't checked those companies. I don't have certification.

Thanks. :)

I think I realized something. Could the capillary tube be the wrong size? Maybe it is too big? It is a 1/4 hp tube. The compressor was actually rated at 1/5 hp by the store but the manufacturer's specification made me think it is 1/5. Could that be why it freezes and thaws? I noticed that the refrigerant pressure equalizes within only seconds, is this too fast? I suspect this might mean the tube is too big.

Also, the evaporator pressure is 20-25 psi when running, and when I turn the compressor off it quickly spikes back up to 40 psi within seconds and stays there. Could this slim pressure difference indicate that the capillary tube is too big?

drier should be on the liquid line

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Originally Posted by Kompulsa

I can't find the terminal over in the local store, nor the feet. I removed some of the refrigerant so the pressure dropped back down to 25 psi like it used to be, and it is working again. It still needs work, though, I think.

I thought the drier was supposed to be on the suction side. :( What should i have done?

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Originally Posted by install monkey

drier should be on the liquid line

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Ok, so the fact that I put it on the suction line may be affecting performance? I should move the drier to the part just after the capillary tube, right?

So maybe that bubbling noise I hear in the evaporator is liquid which shouldn't be there? (unless it is flooded)

What do I put on the suction line, if anything?

NO NO NO NO NO!!!!!!! Please Kompulsa, if you have the time and money to play with this little project of yours then surely you can afford a book on refrigeration and take the time to read it. It is great fun to help eachother out on this site, but you have not even got a grasp of the basics of refrigeration but your having a go with engineering and building your own chiller:rolleyes: Come on man stop doing the bare minimum and crack open a book for some answers to some of your questions, and stop building things repairing peoles units and installing equipment untill you do.

dont put anything on the suction line-compressor discharge goes into the condenser then into the drier-out the drier to your capillary line,into the evaporator then back to the compressor suction,fit gauge pints on the suction and discharge lines to check performance. ensure you use a vac pump to remove moisture/air from the system otherwise youll kill the compressor and affect performance,good luck

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Originally Posted by Emmett

NO NO NO NO NO!!!!!!! Please Kompulsa, if you have the time and money to play with this little project of yours then surely you can afford a book on refrigeration and take the time to read it. It is great fun to help eachother out on this site, but you have not even got a grasp of the basics of refrigeration but your having a go with engineering and building your own chiller:rolleyes: Come on man stop doing the bare minimum and crack open a book for some answers to some of your questions, and stop building things repairing peoles units and installing equipment untill you do.

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The problem is not that I can't afford a book, but I can't find a book that teaches me the basics of how to actually do these things, I can only find theoretical books so far. I am not working on other people's units, just my own.

I also don't have a professional to teach me how.

I kind of built the chiller already, and it freezes water, so I am making progress and learning. The people in refrigeration forums have been more helpful (where practice is concerned) than the theoretical ebooks I have which don't teach me about design or how to actually do things.

Don't worry, people warned me of the safety risks already, i'm trying to be careful.

Kompulsa, although i know my heating trade quite well, 3 years ago I knew f**k all about the refrigeration process. I spent untold hours asking and reading the theory before I ever touched any component of the system, let alone put one together. Even with this, my first system has gone through many changes (mostly control based).

You must know when and how the liquid boils and condenses and then you will begin to understand where all the components go. If you are like me and really need to do the physical stuff to learn, it is doubly difficult when you have to read everything but that is life and without this basic knowledge we may be forced to assume that Master Bartlett is right and you have a wish for a shorter life (doubtful as it is a small system as you are probably in the brilliant sunshine and not using ammonia).

There are lots of good diagrams on how to put the system together and what each components does. I assume you have downloaded the Alfa Laval heat handbook which is a great resource (someone on here has a downloadable version, search) + all the Sporlan tech sheets which are also searchable. Patience dude.....

Do you have a pawn shop handy........or a scrap yard?

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Originally Posted by Kompulsa

The problem is not that I can't afford a book, but I can't find a book that teaches me the basics of how to actually do these things, I can only find theoretical books so far. I am not working on other people's units, just my own.

I also don't have a professional to teach me how.

I kind of built the chiller already, and it freezes water, so I am making progress and learning. The people in refrigeration forums have been more helpful (where practice is concerned) than the theoretical ebooks I have which don't teach me about design or how to actually do things.

Don't worry, people warned me of the safety risks already, i'm trying to be careful.

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I understand you are an intelligent person who is being mindful of their safety but I think you are missing the point, the books you have most certainly will have told you where in a system a drier should be located, since you did not know the answer you obviously are not using a book, further more there are many books which would have told you that a properly sized metering device would be necessary however you only discovered that fact after building your unit,also there is a weath of information on this site alone which if you chose to use it would have told you how to size a metering device. I am not saying stop doing what you are doing because you obviously wouldn't listen to me anyway, I am just saying take some time to learn the BASICS you will be suprised at how many of the questions you ask on this site would be unnecessary because you would already new the answer, there are a lot of engineers on here who would be glad to assist you in design work if that is your interst but first learn the BASICS.
Mike Holm is right on.
Good luck Kompulsa

http://ebooksfreedownload.org/2010/11/hvac-general-training-air-conditioning-1-2.html

http://www.refrigerationbasics.com/1024x768/readme.htm

Cheers
Stu