does anyone have a pic of the inside of a compressor ?? They are sealed in oil correct ?? So how does the "refrigerant" travel through the compressor itself or is it in a gas state while inside the compressor? I do understand from a more simple standpoint that as the liquid (what I remember as and what used to be called freon) would take the "heat" out of the air and become a gas, the compressor would then "compress" and make the gas hotter ?? right ?? and then be dissipated through another set of coils/fins, what have you and be cooled to a "liquid" state again, by having the heat removed, so is it the actual compression of the gas and heating it up hotter that MAKES IT TURN BACK to a liquid ?? in other words, does it have to be heated to have the ability to get "cold" again, am I making sense ?? hahahaha, And I guess without getting to technical, I have heard of older AC's with two compressors, how on earth does that work. I was working on my early 60's Gibson AC (noisier compressor) and my '56 Philco AC earlier tonight and both compressors are pretty big, the Philco being perfectly round and SUPER quiet, I mean you cannot hear this thing run at all. However, the Gibson, (oval shaped compressor) runs "louder" for sure. Carrier AC's seemed to always have noisier compressors too.
compressors and dual compressors on an old AC ??
- Thread starter gregm
- Start date
Help Support :
Refrigeration compresser
I don't have a pix of one to put up-wished I did for this.Most of the AC compressers(esp the old ones) are of the reciprocating piston type.If you looked at a cutaway of one would be very similar to an air compresser.Its just that it is working a refrigerant gas instead of air.The "hermetic" compresser you have is NOT in oil.It is in a refrigerant atmosphere.There is a lubricant in the refirgerant to lube the compresser as it runs.Both the motor and compresser of the hermetic unit are sealed in the compresser enclosure.An AC induction motor is ideal for this.The start and run caps are on the outside.The compresser does act as a "pump" to circulate the refrigeant thru the system.It is above atmospereic pressure.The refrigerant "gas enters the compresser after it has been "evaporated" in the evaporator coil(placed in the part you want to cool)The heat evaporates the refrigerant.The gas goes into the "suction" side(intake) of the compresser where the refrigerant gas is compressed.The "heating" comes from the act of compression-squeezing the gas molecules closere together.That does make it hot-same thing with air-If you felt the cyclinder head on an air compresser-it would indeed be very hot from the compression of the air molecules.After the refrigerant is compressed-it comes out of the compresser(high pressure side of the system) and goes to the condenser where the heat is disappated-the refrigerant turns back to a liquid-and flows back to the evaporater coil to repeat the cycle.The pressure in the system keeps the refrigerant flowing.The idea of compressing the refrigeant does raise its temp and pressure-making it easier to remove the heat from it in the condenser.As far as sound and vibration of the compresser-depends on its design-some have counterweights(like the air compresser or an engine)to compensate for the weight of the piston(s).The counterweigths are mounted on the crankshaft-and its driven directly by the motor.Hope this helpted-Thermodynamics can be quite involved--
I don't have a pix of one to put up-wished I did for this.Most of the AC compressers(esp the old ones) are of the reciprocating piston type.If you looked at a cutaway of one would be very similar to an air compresser.Its just that it is working a refrigerant gas instead of air.The "hermetic" compresser you have is NOT in oil.It is in a refrigerant atmosphere.There is a lubricant in the refirgerant to lube the compresser as it runs.Both the motor and compresser of the hermetic unit are sealed in the compresser enclosure.An AC induction motor is ideal for this.The start and run caps are on the outside.The compresser does act as a "pump" to circulate the refrigeant thru the system.It is above atmospereic pressure.The refrigerant "gas enters the compresser after it has been "evaporated" in the evaporator coil(placed in the part you want to cool)The heat evaporates the refrigerant.The gas goes into the "suction" side(intake) of the compresser where the refrigerant gas is compressed.The "heating" comes from the act of compression-squeezing the gas molecules closere together.That does make it hot-same thing with air-If you felt the cyclinder head on an air compresser-it would indeed be very hot from the compression of the air molecules.After the refrigerant is compressed-it comes out of the compresser(high pressure side of the system) and goes to the condenser where the heat is disappated-the refrigerant turns back to a liquid-and flows back to the evaporater coil to repeat the cycle.The pressure in the system keeps the refrigerant flowing.The idea of compressing the refrigeant does raise its temp and pressure-making it easier to remove the heat from it in the condenser.As far as sound and vibration of the compresser-depends on its design-some have counterweights(like the air compresser or an engine)to compensate for the weight of the piston(s).The counterweigths are mounted on the crankshaft-and its driven directly by the motor.Hope this helpted-Thermodynamics can be quite involved--
Oil
I wouldn't say "sealed in oil", but the old compressors sat in oil and even had a little oil pump to lubricate them. The idea of the "sealed system" (General Electric had this first) is that the compressor and it's motor are both inside the system so there is no pump shaft seal to leak refrigerant like there was on an old fan-belt driven compressor.
Many older a/c compressors also used a start relay, like a refrigerator does.
Ken D.
I wouldn't say "sealed in oil", but the old compressors sat in oil and even had a little oil pump to lubricate them. The idea of the "sealed system" (General Electric had this first) is that the compressor and it's motor are both inside the system so there is no pump shaft seal to leak refrigerant like there was on an old fan-belt driven compressor.
Many older a/c compressors also used a start relay, like a refrigerator does.
Ken D.
Did the GE hermetic compresser have a separate lube system-The compressers that use freon and other flurocarbon refrigerants used a special type of oil that circulated in the refrigerant.A small heating element in the compresser when it wasn't in use helped keep the lubricant in vapor form so it could be used by the compresser.Compresser starting relays used Current sense,potential(voltage sense) and thermal to cycle the start winding on a split phase motored compresser.Since the arcing centrifical switch cannot be used in the refrigerant atmosphere-the relay is used instead.The relay has to be matched to the current and start characteristics of the motor.Current relays work by using the high current draw of the motor upon start-the current keeps its coil enrgized and the contacts closed.As the motor picks up speed-the current drops and its contacts open-disconnecting the start winding.With voltage start-the relay senses the voltage increase as the motor gets up to speed-diconnecting the start winding at that point.The thermal start relay uses the thermal wire to heat a bimetal contact-the current of the motor heats it to where it opens after the motor has reached its speed.The potentail relay is now most used.I did see a very large hermetic centrifical compresser that used a separate oil pump for the motor and compresser bearings.The oil system used a refrigerant cooled cooler to cool the oil.It is in a Trane 1200 Ton capacity water chiller used for building air conditioning.The system had 5 of these units to cool two buildings. learned how it worked-was pretty neat.With three phase motors the start relays aren't required-a contactor is used instead.A current overload system is used to protect the motor-if it draws too much current-the OL system opens the contactor.Oh yes the GE Monitor top system was pretty durable-some are still in use today-even with no recharging the system.Thought these used sulphur Dioxide as the refrigerant.Some AC tech say hermetic compressers "wear in" rather than wearing out.
sulphur dioxide
I think they got rid of sulphur dioxide in the very early 20's, I think even the "monitor" tops made in the 30's do NOT have sulphur dioxide, but I am not 100% certain. When I lived in VA, we had central AC and the outside unit was heated by natural gas and the "refrigerant" was ammonia. Can anyone elaborate how that worked??
I think they got rid of sulphur dioxide in the very early 20's, I think even the "monitor" tops made in the 30's do NOT have sulphur dioxide, but I am not 100% certain. When I lived in VA, we had central AC and the outside unit was heated by natural gas and the "refrigerant" was ammonia. Can anyone elaborate how that worked??
Moving heat (energy)
Good afternoon,
I have extensive experience with automotive A/C and can at least explain the basic theory of operation:
The system is based on energy transfer during state change, from a gas to a liquid and from a liquid to a gas. Compessors only pump gas as it is impossible to compress a liquid (or solid).
The compressor pressurizes the refrigerant and discharges a high temperature gas which then cools to a high temperature liquid in the condenser. This processes removes heat from the refrigerant as it condenses from a high pressure gas to a high pressure liquid.
The gas then travels to a control device, in a car, it is called an expansion valve. This valve controls the flow of refrigerant into the evaporator. This valve also divides the system into the high pressure side and the low pressure side. As the liquid passes through a small orifice inside the expansion valve, it expands into the evaporator and the pressure lowers. As the gas expands it aborbs heat energy from the surrounding air.
As the air in the car (or in the house/room) is pushed across the evaporator by the blower (fan), the liquid refrigerant evaporates into a gas again. This change of state from a liquid to a gas absorbs an enormous amount of heat energy. The result is cool air blows out of the evaporator. (search Latent Heat of Evaporation on the internet for more info)
The refrigerant is then sucked back into the compressor as a low pressure gas and discharged as a high pressure gas to repeat the cycle. Note that the process is continous so we are constantly moving the heat energy from inside the car/room/house at the evaporator and discharging the heat at the condenser outside.
Actual systems are more complex and have temperature and pressure sensors, and possibly other valves to control referigerant flow. For more info with graphics click the link below.
home.howstuffworks.com
Good afternoon,
I have extensive experience with automotive A/C and can at least explain the basic theory of operation:
The system is based on energy transfer during state change, from a gas to a liquid and from a liquid to a gas. Compessors only pump gas as it is impossible to compress a liquid (or solid).
The compressor pressurizes the refrigerant and discharges a high temperature gas which then cools to a high temperature liquid in the condenser. This processes removes heat from the refrigerant as it condenses from a high pressure gas to a high pressure liquid.
The gas then travels to a control device, in a car, it is called an expansion valve. This valve controls the flow of refrigerant into the evaporator. This valve also divides the system into the high pressure side and the low pressure side. As the liquid passes through a small orifice inside the expansion valve, it expands into the evaporator and the pressure lowers. As the gas expands it aborbs heat energy from the surrounding air.
As the air in the car (or in the house/room) is pushed across the evaporator by the blower (fan), the liquid refrigerant evaporates into a gas again. This change of state from a liquid to a gas absorbs an enormous amount of heat energy. The result is cool air blows out of the evaporator. (search Latent Heat of Evaporation on the internet for more info)
The refrigerant is then sucked back into the compressor as a low pressure gas and discharged as a high pressure gas to repeat the cycle. Note that the process is continous so we are constantly moving the heat energy from inside the car/room/house at the evaporator and discharging the heat at the condenser outside.
Actual systems are more complex and have temperature and pressure sensors, and possibly other valves to control referigerant flow. For more info with graphics click the link below.
How Air Conditioners Work
Air conditioning has fundamentally changed how people experience the world. When it's hot outside, walking into an air-conditioned house is like walking into another season. How do air conditioners keep us cool?
home.howstuffworks.com
fascinating
gheeez, thanks for your time and input, I really love reading about this stuff ........... obviously the idea of AC came about after the invention of refrigeration. Whereas when cooling an obvious larger space like a room vs the space in refrig, you need a fan. In a refrig just the exposed evaporator coils will cool that space. The condensor coils are usually on the back to dissipate the heat. I am correct ?? evaporator coils inside change liquid to gas and condns. outside the opposite ......
gheeez, thanks for your time and input, I really love reading about this stuff ........... obviously the idea of AC came about after the invention of refrigeration. Whereas when cooling an obvious larger space like a room vs the space in refrig, you need a fan. In a refrig just the exposed evaporator coils will cool that space. The condensor coils are usually on the back to dissipate the heat. I am correct ?? evaporator coils inside change liquid to gas and condns. outside the opposite ......
Yes-the condenser disapates the heat removed from the space to be cooled by the evaporator.In thinking about the GE Monitor fridge versus ones made today--In some fridges built today the condenser is on the back.In most built now its under the cabinet-on thebottom-and the compresser is there as well.Why do they put two heat producing components under the cabinet you are trying to cool??sort of like putting a hole in your boat.the GE Monitor top was a clever peice of engineering-the condenser and compresser were on TOP of the space being cooled-the heat produced from the compresser and condenser won't try to get into the box.Alsoi the bottom mounted condensers may need a fan to cool them-and collects all kin ds of dust in the process-sort of a built in bagless vacuum!And that dust reduces the efficiency of the condenser unless you vacuum and clean it out.Anyway-the evaporator is in the space you want to cool-remove the heat-the condenser is placed outside that space to disapate the heat that was removed.The space could be your fridge or your AC for your home or car.Ibcarguy's explanation was very excellent as well-I should have put in the expansion valve-but left it out for simplicity.As he mentionmed-its a very crucial component in the system-All refrigeration systems have the expansion valve.I had to learn some of this for fixing radio station studio systems.One jock was pestering me so much-it was a hot summer day-I let him COOK in his studio for his shift and fixed the unit after it.Had to climb on the buildings HOT roof to fix the stations unit.Usually a fan belt breaking or wearing out.The fan and motor in the unit was OK-tensions were good-it just wore out belts.Glad I don't have to deal with it anymore.
heat expansion
My folks have a forced hot water heating system that has an "expansion tank" to "absorb" the buildup of pressure as the heated water expands ......... I guess there is some detailed physics going on here. I never did well in math, physics, chemistry, etc. Now that I am older and understand my "learning disabilities", I can overcome them and understand these principals and concepts especially under application. AGAIN, fascinating info to me to listen to you folks about this.
My folks have a forced hot water heating system that has an "expansion tank" to "absorb" the buildup of pressure as the heated water expands ......... I guess there is some detailed physics going on here. I never did well in math, physics, chemistry, etc. Now that I am older and understand my "learning disabilities", I can overcome them and understand these principals and concepts especially under application. AGAIN, fascinating info to me to listen to you folks about this.
Yeah, it's a VERY common misconception that refrigerators and air conditioners make cold, when in fact what they do is MOVE heat from one place to another. I get a kick out of explaining that when opportunity arises.
Yes Dadoes: thats what its about-Cold is Absence of heat.I find the devices interesting-transfering energy to another place.That energy being heat.
Not only with water heat systems-expansion tanks are on some of the VERY large oil cooled transformers in some of the transmitters I use-gives some place for the liquid to go as the transformer heats up.Boilers may use them as well.In one of the transfoers here-had to top up its oil level by putting ithe oil into the tank and allowing it to go into the transformer case.Other very large transformers use expansion tanks-Look in a substation and you will see the tank above the transformer case-behind the insulators.-mounted on the back of the case.
Not only with water heat systems-expansion tanks are on some of the VERY large oil cooled transformers in some of the transmitters I use-gives some place for the liquid to go as the transformer heats up.Boilers may use them as well.In one of the transfoers here-had to top up its oil level by putting ithe oil into the tank and allowing it to go into the transformer case.Other very large transformers use expansion tanks-Look in a substation and you will see the tank above the transformer case-behind the insulators.-mounted on the back of the case.
GE used sulphur dioxide after the monitor tops. I remember cutting open a GE that was late 30's early 40's,and being greeted with the gawdawfullest smell you can imagine. Nasty stuff!
kennyGF
kennyGF
Rex, I know what you mean when you say the DJ was cooking,those transmitters are HOT! A friend I worked with`s dad owned a few radio stations in our aera and he would buy us breakfast on sunday morning to help him set up pragraming for the week.(and I could tape all the music I wanted while there!) I couldnt believe the amount of heat those things put out! The am station was in an old old Tv station and the transmitters were huge and tube powered.I had hoped to get one of the old tubes for my collection.
Sulphur Dioxide
Sulphur Dioxide was used untill the late 30s, even by GE. Check out this link.
Sulphur Dioxide was used untill the late 30s, even by GE. Check out this link.
I just read that article again and it has lots of mistakes in it. All you have to do to tell if a refrigerator uses freon is read the tag!
Ken D.
Ken D.
Transmitters
Yes Drmitch-transmitters get hot.At he station where the DJ was -that was the studio location.the transmitter site was on the other side of town.However Studio equipment puts out a lot of heat as well.-Even in winter and its solid state studio gear.On solid state console I dealt with put out as much heat as an old Gates tube board.The Op-amp Ic's got so hot there was a warning on the PC boards that they could BURN you if touched.They had ceramic cases.That DJ nagged me too much that day.Yes-transmitters get HOT-used them to heat a transmitter building I worked in.TV transmitters get HOTTER(analog) because the visual RF stages are biased Class A.The tube is conducting wehter there is signal on it or not.At the SW site I am at now they generate lots of heat-direct roof vents above each one.These transmitters generate 250Kw each!Some have what is called Vapor cooling.the tube anode is in a water filled container and generates steam-the steam goes to a blower cooled condenser outside and returns to liquid-then goes back into the tube boiler.No high horsepower pumps needed.Just a 1/3hp one to "level" the water in the boilers. Its in GE transmitters built in 1963.Love the vintage gear.I have some transmitter tubes in my collection-harder to get though-the duds can be sent in to tube companies and rebuilt.One transmitter out here uses tubes built in Switzerland-they cost $150,000Each!and they weigh 300Lbs each.Need a crane to lift them in or out of the Tx.I also have a few vintage parts from Tx's like a nameplate from a 50Kw one.Stations do get cash for dud tubes from some tube rebuilders.
Yes Drmitch-transmitters get hot.At he station where the DJ was -that was the studio location.the transmitter site was on the other side of town.However Studio equipment puts out a lot of heat as well.-Even in winter and its solid state studio gear.On solid state console I dealt with put out as much heat as an old Gates tube board.The Op-amp Ic's got so hot there was a warning on the PC boards that they could BURN you if touched.They had ceramic cases.That DJ nagged me too much that day.Yes-transmitters get HOT-used them to heat a transmitter building I worked in.TV transmitters get HOTTER(analog) because the visual RF stages are biased Class A.The tube is conducting wehter there is signal on it or not.At the SW site I am at now they generate lots of heat-direct roof vents above each one.These transmitters generate 250Kw each!Some have what is called Vapor cooling.the tube anode is in a water filled container and generates steam-the steam goes to a blower cooled condenser outside and returns to liquid-then goes back into the tube boiler.No high horsepower pumps needed.Just a 1/3hp one to "level" the water in the boilers. Its in GE transmitters built in 1963.Love the vintage gear.I have some transmitter tubes in my collection-harder to get though-the duds can be sent in to tube companies and rebuilt.One transmitter out here uses tubes built in Switzerland-they cost $150,000Each!and they weigh 300Lbs each.Need a crane to lift them in or out of the Tx.I also have a few vintage parts from Tx's like a nameplate from a 50Kw one.Stations do get cash for dud tubes from some tube rebuilders.
Refrigerant spill
Kenwashesmonday: Interesting link.Kinda sad for that fridge though.Probably some appliance hound would love to have it.Sadly it will go to the krusher.Yes-the appliance nameplate should have the type and quantity of the refrigerant used.At one aircraft test facility I visited-We stood under a tank that had 150tons of Methyl chloride in it-another nasty one.
Kenwashesmonday: Interesting link.Kinda sad for that fridge though.Probably some appliance hound would love to have it.Sadly it will go to the krusher.Yes-the appliance nameplate should have the type and quantity of the refrigerant used.At one aircraft test facility I visited-We stood under a tank that had 150tons of Methyl chloride in it-another nasty one.
Similar threads
