Air Conditioning Compressor

it would be a bit of overkill, but the theory's are exactly the same. Air conditioning came first then the technology was applied to refrigeration.

Thanks!! Actually to be more specific..... I have a business on a tropical island. I sell BBQ and cold beer. I have a bottle cooler that can hold approx 20 cases of beer. only problem is that the cooler blows the hot air into the business. And I thought, maybe if I put a split unit air conditioning compressor outside it would solve two problems.... The beer gets cold faster... and the hot air stays outside... it`s hot enough inside...

anyway thanks.

It might be better to duct the waste hot air from the beer cooler to a point outside the building in the first instance, perhaps?

Why not try to duct the hot air up and out of the building. Plywood, or perhaps larger beer company signs could be fitted to the sides of the cooler with duct tape, joined behind the cooler and then closed on top. Cut a 15 inch hole in the top panel and attach a circulator fan to it. Slide a section of prefab duct over the fan and seal to the roof or 90* it to the exterior wall. That would bring the hot air outside. Lower the temperature in the building. And because the cooler is now sucking in cooler air, should cool Faster. This would be real low tech = low cost. Good luck.

It's a question of design. I guess your beer temp would ideally be about 5 deg C so the part of the fridge that cools it would run at about 12 degrees lower than this - say minus 7 deg C. Your cooling part of the AC unit would run at about 15 deg C, to give you an air temp of about 24 deg C? The exact temps are not really important, but you can see that the fridge unit is expected to produce a much lower temperature. Your AC compressor unit may not produce air cool enough to give you drinkable beer. Without becoming too technical, the AC compressor may have internal thermostats or other control instruments that prevent it running down to such a low temperature. In order not to disappoint your customers, just try cooling one case of beer with your AC unit set at it's lowest temperature setting. If it works, then you can transfer over your stock, but to be honest, I don't think it will. Since your fridge unit will have an air condenser, you could reduce the heat output by directing the cold air from the AC unit into the fresh air inlet for this, which will reduce the temp of the air out. It would make a grown man cry (and me!) to see 200 cases of undrinkable luke warm beer!

Here we serve our beer at approx -3°C, just above freezing point of the beer itself. Due to the ambient temp. it will slowly warm up to drinkable temp. I think it`s a Caribbean thing to serve beer this cold. Anyway,serving beer above -3°C is considered not cold enough. What i really want is something like a supercharged bottle cooler. And by using the air conditioner`s compressor which has a greater capacity than my bottle cooler`s. My guess was that it may work faster and with the added benefit that all the hot air is blown outside of the building. And as I understood from your comment "Your AC compressor unit may not produce air cool enough to give you drinkable beer" I`m not planning to build in the evaporator, just replace the compressor. The air remains the same temp it is already producing.

Anyway thanks.

The real answer is almost emphatically NO. The fridge and the freezer are two different animals. Small appliances have critically design matched components. The condenser coil, evaporator coil, metering orifice and compressor are critically matched. Even the electric motor direct coupled to the compressor within the hermetic can is JUST barely strong enough to run that compressor under it's maximum designed load with the SAME refrigerant it was designed for.

A 1 HP low temp compressor will NOT substitute for a 1 HP medium temp compressor which will not substitute for a high temp compressor. ( High temp is air conditioning, medium temp is food storage ( 34° F ) and low temp is frozen food ( - 20° F )

Now if you were "hell-bent" on building this thing yourself, just for the fun of it, then strip all of the matching components off of a KNOWN working fridges and re-install them.

IF a fridge were 18 cu.feet, you would only be able to do about 9 cu.feet on your beer dispenser, because the fridge was never designed for the "load" you'd be putting on it nor the number of door openings per hour.

You'd also be better off NOT to cut then try to re-splice the capillary tube, cut the condenser coil.

well, That is not strictly true. the motor and capacitor and compressor are matched, but the fridge has a far lower average load than the air conditioner. On the fridge the load varies with the ambient temperature and the number of times you open and close it, thus admitting heat. Air conditioners usually run flat out.

You can try to use some ducting to get the hot side outside. If you have a fridge shop there, he can open your system, save the freon, add a loop so the expanded gas goes outside to be compressed and lose heat and cooled compressed gas comes back to your expansion coils.

Can you do this? I doubt it, as soo as you cut into the line your compressed freon heads to the moon. You need a special pumpdown system you attach to your system and it sucks out the freon and stores it in a container at high pressure for later use.

Then the line needs to be lengthened and new water traps installed and air sucked out and the freon re-installed, plus some extra for the longer lines.

Most large places have central compressors, roof mounted heat radiators and expansion coils in the cool box.

The condensing unit should be able to be moved outdoors. Like previously mentioned, this should be done by a professional w/proper certification and tools. There might be a limit of how far you might be able to run the lines. Get a quote; if you get beer there, you should be able to get a refrigeration tech there.

You are right , I have seen certain malls , theaters , ice creame parlours using ducting for there refrigerator

Oh Mr. Aurizon, I beg to differ with you. I work with AC for a living as well as being an EPA certified section 608 instructor and test administrator ( refrigerant handling certification) I think you'll find my post is accurate.

There are thousands of different compressor models and they are custom designed for specific refrigerants and specific operating temperatures. On small appliances, altering the capillary tube 1" in length will change its performance (worse). Check this site for example

http://www.emersonclimate.com/images/pdf/Commercial_Scroll_Brochure_2006CC-218R1.pdf

Your statement "Air conditioners usually run flat out." proves your lack of understanding of refrigeration theory. The only time a (for example ) 6,000 btu window AC actually moves 6000 btu's is when the outdoor temp is at its design temp ( typically 90°F) and the indoor temp is typically 74°F with approx. 50% RH ) It can and will move more or less than 6000 btu's, depending on operating conditions. These can be documented by visiting the ARI website http://www.aridirectory.org/ari/

Check page 13 and 15 then page 26 of this pdf

http://www.yorkupg.com/PDFFiles/251933-YTG-C-0507.pdf

where you'll see an example of integrated heating capacity. Note how the btu's capacity varies on the 3-ton rtu heat pump. The COP also varies. The actual full integrated capacity chart shows btu output and kw input in 10 degree intervals from York shows them from -10 to +60 degrees F.Also note how airflow and temperatures affect performance.

To summarize, just hacking up a refrigeration system and re-installing it in another application will NOT yield the results you are looking for.

By flat out, I mean it is not throttled. It is turned on and off. It is never run at 60%, 50%.

Then for optimum efficiency you do indeed match the components of the system, however you can, and I have made, cooling machines from disparate components.

The advantage is you get to use scrap components = almost free. The problems are that power on islands is costly and over time to lower efficiency of a make shift machine will eat up in electrical costs what you save in fabrication.

A firiend of mine had an old beer fridge that ran 24/7 that used 1100 watts of power. I told him to throw it away. he paid 12 cents per KWH =~$3/day for that thing, and he did not realize this and 1.5 years saving would buy a new fridge that would only use 300 watts and have a far lower duty cycle than 24/7 = $$ in the bank.

So even on these islands in the sun, the master hand of efficiency interferes with our plans.

You have good point there....even if it is lots less efficient, there's a lot of personal value in building something yourself....hooray for all the experimenters in this world !

I would add that he's lucky that it ran at all. In one of my night classes I taught, we changed components on window A/C's we butchered. We then tested them for operating efficiency. Just putting a different refrigerant in a factory matched system makes a huge performance loss. And sticking R-22 into an older R-12 window shaker makes it stop on excessive amp draw.

I only "jumped" on you about the "flat out" remark because that is a very common misconception that an AC system always gives nameplate performance just like an electric heater....not so. My apology sir....Brad.

Three cheers for Monsieur Carrier, the pioneering mind behind the company named after him.

My first playing around was with ammonia refrigerators, ouch my nose, then I went into electronics.

I have worked on air conditioners, and seen that when the indoor fan fails the standard compressor is capable of turning the evaporator coil into a sheet of ice. An air conditioning duty compressor has suction and discharge valve openings sized to handle the operating pressures of an air conditioning system. A refrigeration duty compressor typically has larger suciion valve openings sized to handle the lower pressures of a refrigeration system. Your proposed compressor changout MAY work, but the capacity--and probably the reliability--of the compressor will be decreased.