We start at the compressor, go through the condenser, then through the restriction, then through the evaporator and finally back to the compressor where the cycle starts all over again.
Luckily, their names are quite self explanatory. The Compressor can be thought of as the heart of the process. It acts like a pump to create the circulation by compressing the refrigerant gas, creating a pressure difference that drives the refrigerant around the circuit in a continuous cycle.
The Condenser cools and condenses the refrigerant gas coming from the compressor in to a vapour and finally in to a liquid. The restriction restricts the liquid refrigerant flow and creates a pressure difference between itself and the evaporator. The Evaporator evaporates the liquid refrigerant in to a vapour and then in to a gas before it gets back to the compressor. It is this changing of state within the refrigerant that produces the refrigeration effect, and is the main principle of the refrigeration cycle — more on this a bit later.
In other words, refrigeration is artificial human-made cooling. The important part of this definition is the removal of heat. One very important aspect to grasp when understanding the refrigeration cycle is that heat is relative. We tend to think of heat in terms relative to our everyday experiences and situations. But when we look at those temperatures in relation to other temperatures, the reality is very different.
But it is important to understand that this only happens with water at sea level where the atmospheric pressure is at 1 bar. If we were at the top of mount Everest, where the pressure is only 0. The effect of reducing the pressure to reduce the boiling temperature of water is brilliantly demonstrated by boiling water at room temperature by placing the water in a vacuum:.
The changing of state within the refrigerant, from a liquid to a gas, is achieved by manipulating its pressure. If we return to the refrigeration cycle with the aid of some diagrams, we can see how these pressure changes causing changes of state within the refrigerant actually happen.
This is a requirement of many building codes. Rubatex is the most common form of refrigerant line insulation. Liquid lines generally are insulated. If liquid lines pass through a space that is warmer than the refrigerant i. Discharge lines are generally uninsulated. Hot gas bypass lines should be insulated, especially if the runs are long or if the piping is exposed to cold temperatures. Watch out : condensation on the suction line and at the bottom of the compressor could be an indication of excess liquid refrigerant returning to the compressor via the suction line.
This liquid slugging of the compressor can damage or destroy the motor. We discuss refrigerant flooding and six common causes of liquid refrigerant slugging the compressor. Our photographs illustrate that the importance of not compressing refrigeration line insulation is no joke. In our photo below, notice those drip stains below the condensate lines at each location where the insulation was compressed by a too-tight plastic tie?
It leaves me worried about condensation and water accumulation inside the wall cavity as well. Since I know this installer is not stupid we're left thinking he has a bit of contempt for his customers, or a limited concept of workmanship. Imagine that same dripping and accumulation of water where the installer made the same mistake in a fiberglass-batt insulated wall or a wall or ceiling inside which the dew point may be reached on the refrigeration lines? The accumulation of water in a building cavity is asking for a costly mold, insect, or rot damage problem later on.
We removed the leaky, incomplete, and ugly squashed insulation on the refrigeration lines for this system above left , replacing the squashed foam insulating tubing with new insulation shown below. Below you can see the new refrigerant tubing insulation being installed: we're peeling out the edge tape so that the split foam insulation sides can adhere to one another. Incidentally, just clipping off the old plastic wire ties to "release" the squashed refrigerant line foam insulation won't work: after a few months the insulating foam remains permanently squashed, as you can see in our photo at left.
We paid particular attention to sealing and insulating the refrigeration line at the exit point from the building wall, reducing the chances of leaks into the wall at that point. To keep the refrigeration line insulation in place you can still use a plastic tie if you like - just don't tighten it so far as to squash the insulation.
The manufaturer Sanyo recommends covering the foam insulation on the refrigeration line with weatherproof tape which we did at the end of this job. I admit that we "over-designed" the final insulation job shown in our last photo with that extra layer of foam that surrounds both lines, as we used more thickness of insulation than necessary.
We did so to end with a neat, weather-protected job that, combined with the application of black weatherproof tape, should last for a long time. Notice that the aluminum or plastic ties used to hold components in place were left loose - we did not squash the new refrigerant line insulation, and we made sure it was continuous, neat, and protected from the weather.
A neat installation takes what, maybe five minutes longer than a sloppy one, but it took about an hour to buy the replacement refrigerant line insulation, remove the original sloppy installation, and do the job right the second time. Manufacturers also recommend wrapping the insulated refrigerant lines exposed to outdoor weather, using an appropriate weatherproof tape. During the first season of use of the newly-installed Sanyo split system air conditioner the building occupants noticed water stains and rippled wall paint extending down the wall below the indoor air handler cooling unit.
Our photo left shows where the refrigerant lines rise in the wall to enter the wall-mounted half of the split system air conditioner that larger white area below the left end of the unit and the blue tape marks where we first saw condensate water dripping from the unit.
On inspection we ran the air conditioner for an hour or so on a hot humid day, then inspected the wall surface for moisture. Simply touching or pressing on the plastic bottom of the wall-mounted cooling unit sent a cascade of water droplets down the building wall interior surface. To his credit, the tech came immediately to the job site. Disassembling and inspecting the indoor cooling unit by removing its plastic cover and then lifting it carefully away from the wall mounting bracket watch out to avoid bending refrigerant lines and causing a refrigerant leak , he found that there was no insulation whatsoever on the refrigeration lines that ran horizontally along the rear bottom of the unit.
The result was condensation on the refrigeration lines that did not drip into the unit's condensate tray but rather fell into the plastic bottom where water leaked out onto and into the building wall. The condensate tray in a wall-mounted split system air conditioner or heat pump unit is designed to catch water condensing on the cooling coils, directing it to a drip pan and then to the condensate drain line.
But depending on routing of the refrigerant lines, these may provide another source of condensation that does not fall into the tray. The "fix" for this condensate leak was the installation of foam insulation along the refrigerant lines inside the unit, from their point of exit from the building interior wall surface to their point of connection to the cooling coil. The leak was stopped.
Is making the switch a good idea? This product provides pre-insulated copper refrigerant tubing. The insulation is polyethylene closed-cell foam on copper tubing.
Detailed technical specifications and the ASTM Standards with which this product complies are provided by the manufacturer at the web page we cite below. Fair question, M. Insulation on what. As long as the insulating properties and weather and damage resistance of the alternative insulation meet the original Mitsubishi specifications I doubt that there is a concern with the change you cite.
PDM Gelcopper is a polyethylene closed-cell foam refrigeration tubing insulation. I'm doubtful that changing the insulation choice affects system operation. Of course depending on where the insulation is installed its life may vary. For example insulation products vary in durability where exposed to sunlight and weather. Here is what the manufacturer says:. Ra approved: Gelcopper can be used in applications where high-pressure gases are used as refrigeration source.
UV resistant: Gelcopper is UV resistant Paintable: the insulation can be painted to match the surroundings. Watch out : improper swaging can damage copper tubing leading to future failures and leaks. This article describes three different temperature ranges for soldering copper piping or tubing along with some general copper pipe or tubing soldering advice. The copper tubing ends to be connected are cleaned, sanded, treated with soldering or brazing flux, and soldered or brazed.
When a capillary tube is to be soldered take are not to place soldering flux too far into the joint or the solder may flow over and close the end of the capillary tube. Soldered connections are much less likely to leak under the harsh conditions to which refrigerant piping is subjected: vibration, high pressures, high temperature swings, and outdoors, weather exposure.
For example, measuring the refrigerant gas line pressure drop or temperature change on the suction line return to the compressor will show typically that a 4 degree temperature loss through the refrigerant line will result in an 8 percent loss in cooling capacity of the system.
Or on the discharge line output from the compressor will show typically that a 4 degree temperature loss through the refrigerant line will result in a 2 percent percent loss in cooling capacity of the system. ASHRAE[7] and some air conditioner manufacturers such as McQuay[6 ] provide a refrigeration piping guide that gives complete, detailed guidance and charts on refrigerant line sizing diameter as a function of length of run. The company points out that the entire liquid refrigerant line is composed of more than just piping, and includes.
Each of these devices or components contributes volume to the refrigerant piping system and must be considered in designing the "equivalent length" of the entire refrigerant piping system in order to determine the proper refrigerant charge. For example,. In some refrigeration system designs, a low-temperature heat laden vapor line suction line is soldered alongside the high-temperature, high-pressure liquid refrigerant line. The purpose of this line-to-line soldering is to act as a heat exchanger, to reduce the temperature of the liquid refrigerant that is going to enter the metering device TEV or cap tube , gaining some benefit to system operation - we want a lower refrigerant temperature at the point where the liquid refrigerant is about to be metered or released into the cooling coil evaporator coil in the air handler.
A second benefit of this heat exchange is that in the larger suction line entering the compressor, the refrigerant enters at a higher temperature, easing the compressor's job of compressing and raising the refrigerant temperature on the condenser side, so that the refrigerant is by being hotter better able to transfer heat to ambient air in the environment around the condensing coil.
Other forms of air conditioner and heat pump economizers and economizer tricks of the trade are discussed. On by mod - routing refrigerant piping under the roof decking. John, Thank you that's a helpful question. I don't think you will find an explicit statement in the model building codes about the distance below roof deck that's acceptable for routing air conditioning or heat pump refrigerant lines.
However the lines do need to be routed in a way that they're not exposed to damage. Because it's common for roofing nails to penetrate the roof deck it would make sense that the refrigerant lines would be several inches away from the deck. That's the same reasoning as applies to routing electrical wires that might be sent through rafters.
Is there a code that states a minimum distance below a roof deck for refrigerant lines to be installed? The refrigeration valve on my Trane condenser keeps releasing and a large amount of liquid is discharged. Is this normal? A friend of mine is having some problems with a room sized split air conditioner in his home.
The unit is about three years old. A few months ago the unit stopped cooling and an air conditioning technician confirmed that the gas had leaked out. To inspect the lines some drywall had to be removed form a lowered ceiling, and upon inspection a cracked flare nut was found.
The technician said that this is a not uncommon occurrence. Have you ever come across cracked flare fittings in small air conditioners? It seems to me that it's just a case of poor quality fittings. What do you think? Anyway, the damaged fitting was replaced and the unit again functioned properly. This is also a new on one me. The tubing was professionally installed and there are few bends. Unfortunately the tubing is in the wall, and partly behind a tiled bathroom wall, so revealing all of it to find the point of failure will be serious undertaking.
My friend is thinking of rerouting for convenience though the result will not be as aesthetic and the rerouted tubing will inconveniently routed on the roof of his home, where the compressor is located.
Do you have any experience with leaks in copper tubing except at bends or points of "trauma? Thanks for any insights. JD Yes, you can buy a suitable copper tubing reducer, but depending on the difference in piping diameter the technician may simply use a swaging tool to join the copper tubing.
If the connection on New ac is bigger and and the lines coming out house is smaller can you get a converter and join both together? Tux Yes it's possible to relocate a refrigeration compressor - commonly done with commercial systems and walk-in coolers.
Not below a floor - it needs to be able to cool. BTW - the compressors fine Its a great Hoshizaki residential under counter machine that gravity drains to the basement utility room below and never has issues. Alternatively, is it a feasible idea to extend the compressor lines below the floor into the utility room? Moving the compressor to a room where the noise is isolated?
I may want to use a flexible line so the machine can still be pulled out when needing to be serviced. Never needed to in 7 years but planning for the worst if possible. Just checking if its feasible if I find a good AC or fridge guy to do it. Deb If in the course of removing a freezer compressor motor or coils you break open the refrigerant piping, if there is refrigerant in the system you'll discharge it into the environment - a step that's illegal in many countries as it's a contaminant.
If you keep them intact then you avoid that issue, but you may still need to contact your local environmental authority to ask how to dispose of that equipment. The greater hazard is leaving doors on old refrigerators and freezers - a child hazard.
I have an old small deep freeze no longer any good I went to take the coils off back and the motor or whatever it is is it safe to unhook Arquette the copper tubing. On - by mod - increase in electric bill with new Rheem central air unit. Renee I really do not know but that won't stop a guess: a wiring error including a short or current leak could be at fault here. You might get better diagnosis with an experienced electrician on site. The ac stopped cooling within the first 2 wks, said the breaker was tripped but took them 2 trips to figure it out.
My heating stopped working 2 days ago, they said the breaker was tripped but there was also a hole in the cooper line. Why does it keep tripping the breaker? Is it suppose to be insulated? Thickness, hardness, intended use. I hsve not seen "type R" copper piping per se, but type "ACR" is specifically intended for use in refrigeration, air conditioning, heat pump systems.
What's the difference between L and R tubing? Barbara Well I hate to get in the middle of dispute like this because I know someone's going to be mad. But I have to say that people installing refrigerant piping should be perfectly aware of where it's vulnerable and should take steps to protect it. Claiming that an older house doesn't have ro comply with code is a poor excuse in my opinion.
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