This is one more in a collection of columns addressing advanced basics in the knowledge of the refrigeration cycle. In this column and also the next (on July 4), we look at components.

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This column will resolve the compressor, discharge line, and also condenser. The July 4 column will focus on the receiver, liquid line, metering device, evaporator, and suction line. Details will be provided around each component"s function.

Mastering the attribute of each individual component deserve to aid the technician with analytical troubleshooting skills. In the lengthy run, this will save time and money for both technician and also customer.


Pumps refrigerant:One of the primary features of the compressor is to circulate refrigerant. Without the compressor as a refrigerant pump, refrigerant could not reach other mechanism components to perform its warm carry attributes.

Separates pressures: Anvarious other function of the compressor is to separate the high-press side from the low-press side of the refrigeration system. Due to the fact that a distinction in pressure is the driving potential for liquid (gas or liquid) flow, there wouldn"t be any refrigerant circulation without a push separation.

Elevates temperature: Another feature of the compressor is to raise the temperature of the refrigerant vapor over the ambient (surrounding) temperature. This is accomplished by adding occupational - or warm of compression - to the refrigerant vapor during the compression cycle. The temperature and also the press of the refrigerant is being elevated.

By elevating the refrigerant temperature above the ambient temperature, warmth soaked up in the evaporator and suction line - and any kind of warmth of compression created in the compression stroke - deserve to be rejected to this lower-temperature ambient. Most of the warmth is rejected in the discharge line and condenser.

Remember, warm flows from hot to cold, and also tbelow must be a temperature difference for any kind of heat deliver to take area. The temperature climb of the refrigerant throughout the compression stroke is a measure of the raised interior kinetic energy included by the compressor.

Increases density: The increase in the refrigerant vapor"s push brings with it an increase in the thickness of the vapors. This helps load the refrigerant gas molecules exceptionally tightly together and aid in the condensation or liquefaction of the refrigerant gas molecules in the condenser as soon as the right amount of warmth is rejected to the ambient. The compression of vapors in the time of the compression stroke actually gets the vapors ready for condensation or liquefactivity.

Discharge Line

Transports vapor:One function of the discharge line is to carry the high-push, superheated vapor from the compressor"s discharge valve to the entrance of the condenser.

Desuperheats: The discharge line also cools the superheated vapors (desuperheating) that the compressor has compressed. This warm is given up to the ambient (surrounding) air.

The compressed vapors contain every one of the heat that the evaporator and also suction line have actually soaked up, together with the compression stroke"s warm of compression. Any created motor winding warmth might likewise be included in the discharge line"s refrigerant. This is why the beginning of the discharge line is the hottest component of the refrigeration mechanism.

On warm days, when the mechanism is under a high load and may have a dirty condenser, the discharge line deserve to reach over 400 degrees F or more. By desuperheating the refrigerant, the vapors will certainly be cooresulted in the saturation temperature of the condenser. Once the vapors reach the condensing saturation temperature for that pressure, condensation of vapor to liquid will certainly take place, as even more warm is shed.



Desuperheats:The first passes of the condenser desuperwarm the discharge line"s gases even farther. This, consequently, gets the high pressure and also superheated vapors coming from the discharge line also more all set for condensation, or the phase change from gregarding liquid, to occur.

Remember, these superheated gases have to lose all of their superwarmth prior to reaching the condensing temperature for a specific condensing pressure. Once the initial passes of the condenser have actually rejected sufficient superwarm, and the condensing temperature or saturation temperature has actually been reached, these gases are referred to as 100-percent saturated vapor. The refrigerant is shelp to have actually reached the 100-percent saturated vapor suggest. (See Figure 1.)

Condenses: One of the main functions of the condenser is to conthick the refrigerant vapor to liquid, hence the name condenser. Condensing typically takes location in the lower two-thirds of the condenser but is system-dependent. Once the saturation or condensing temperature has actually been got to in the condenser and also the refrigerant gas has actually got to 100-percent saturated vapor, condensation deserve to take location if any more warmth is rerelocated.

As even more warm is taken ameans from the 100-percent saturated vapor, it will certainly pressure the vapor to become a liquid or condense.

When condensing, the vapor will slowly phase readjust to liquid till 100-percent liquid is all that stays. This phase adjust, or gas liquid state change, is an instance of a latent warm rejection process. The phase adjust will certainly happen at one temperature also though heat is being removed.

An exception to this is a near-azeotropic blfinish of refrigerants where tright here is a temperature glide or range of temperatures as soon as phase changing.

The heat rerelocated is latent warmth, not sensible warm. This one temperature is the saturation temperature corresponding to the saturation push in the condenser. This push have the right to be measured all over on the high side of the refrigeration device as lengthy as line and valve push drops and also losses are negligible.

Subcools: The last function of the condenser is to subcool the liquid refrigerant. Subcooling is defined as any warm taken away from 100-percent saturated liquid. Once the saturated vapor in the condenser has phase adjusted to saturated liquid, the 100-percent saturated liquid allude has been got to. If any kind of more heat is removed, the liquid will certainly go via a cautious heat-rejection procedure and also lose temperature as it loses heat.

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That liquid, which is cooler than the saturated liquid in the condenser, is subcooled liquid. Subcooling is an important procedure because it starts to lower the liquid temperature closer to the evaporator temperature. This will certainly reduce flash loss in the evaporator, so more of the vaporization of the liquid in the evaporator have the right to be used for helpful cooling of the fill.

John Tomczyk is a professor of HVACR at Ferris State College, Big Rapids, Mich., and the writer of Troubleshooting and Servicing Modern Air Conditioning & Refrigeration Equipment, published by ESCO Press. To order, contact 800-726-9696. Tomczyk have the right to be got to by e-mail at tomczykj