Introduction to Condensers in HVAC - Classification of condensers

Introduction to Condensers in HVAC

 In this article we are going to learn about Condensers and full classification of condensers.

What are Condensers in HVAC?

            Condensers and evaporators are fundamentally heat exchangers in which the refrigerant goes through a state change. Close to Compressors, appropriate design and determination of condensers and evaporators is vital for agreeable execution of any refrigeration framework. Since the two condensers and evaporators are basically heat exchangers, they have a large number of things in common, taking everything into account. But, contrasts exist, taking everything into account, as far as the design is concerned. In condensers the refrigerant fume gathers by dismissing hotness to an outside liquid, which goes about as a hotness sink. Typically, the outside liquid goes through no stage change, besides in some exceptional cases, for example, in cascade condensers, where the outer liquid (another refrigerant) dissipates. In evaporators, the fluid refrigerant dissipates by removing heat from an outer liquid (low temperature heat source). The outside liquid may not go through state change, for instance assuming that the framework is utilized for reasonably cooling water, air or another liquid. There are numerous refrigeration and cooling applications, where the outer liquid moreover goes through state change. For instance, in an average summer cooling framework, the damp air is dehumidified by consolidating water fume and afterward, eliminating the dense fluid water. In many low temperature refrigeration applications freezing or icing of evaporators happens. These angles must be considered while designing condensers as well as evaporators.

            Condenser is a significant part of any refrigeration framework. In a regular refrigerant condenser, the refrigerant enters the condenser in a superheated state. It is first desuperheated and afterward consolidated by dismissing hotness to an outer medium. The refrigerant may leave the condenser as a soaked or a sub-cooled fluid, contingent on the temperature of the outside medium and design of the condenser.

Next we will see how condensers are classified.

What is the classification of condensers ?

            In light of the external liquid, condensers can be categorized as:

* Air cooled condensers

* Water cooled condensers, and

* Evaporative condensers

Air cooled type of Condensers :

            As the name suggests, in air-cooled type of condensers air is the outside liquid, i.e., the refrigerant rejects hotness to air streaming over the condenser. Air-cooled condensers can be further grouped into Natural convection type and Forced convection type.

Natural Convection type of Condensers:

       In Natural convection kind of condensers, heat move from the condenser is by the rule of lightness induced in regular convection and radiation. Since the stream pace of air is little and the radiation heat move is likewise not extremely high, the consolidated hotness move coefficient in these condensers is little. As a result a somewhat huge consolidating surface is expected to dismiss a given measure of hotness. Subsequently these condensers are utilized for little limit refrigeration frameworks like family fridge and freezers. The regular convection type condensers are either plate surface sort or finned tube type. In plate surface sort of condensers, which is utilized in little fridges and coolers, the refrigerant conveying tubes are appended to the external dividers of the fridge. The entire body of the cooler (with the exception of the entryway) behaves like a balance. Protection is given between the external cover that behaves like balance and the internal plastic front of the cooler. It is thus that external body of the fridge is warm 100% of the time. Since the surface is warm, the issue of dampness buildup on the dividers of the cooler doesn't emerge in these frameworks. These condensers are at times gotten back to as flat back condensers. 

        The finned type condensers are mounted either beneath the fridge at a point or on the rear of the fridge. On the off chance that, it is mounted beneath, then, at that point, the warm air ascends and to help it an air envelope is framed by giving a coat on rear of the cooler. The balance dispersing is kept huge to limit the impact of fouling by dust and to permit air to stream unreservedly with little opposition. In the more seasoned plans, the condenser tube (in serpentine structure) was joined to a plate and the plate was mounted on the rear of the fridge. The plate behaved like a blade and warm air ascended along it. In one more typical plan, thin wires are welded to the serpentine cylinder loop. The wires behave like balances for expanded heat move region.

Forced Convection type of Condensers:

            In forced convection type of condensers, the flow of air over the condenser surface is kept up with by utilizing a fan or a blower. These condensers typically use balances on air-side for great hotness move. The balances can be either plate type or annular sort. Constrained convection kind of condensers are typically used in window sort of forced air systems, water coolers and bundled AC. These are either case mounted or remote mounted. In Chassis mounted type, the compressor, Induction motor, condenser with condenser fan,accumulator, HP/LP cut-out switch and pressure measures are mounted on a solitary case. It is called consolidating unit of evaluated limit. The parts are matched to gather the expected mass flow rate of refrigerant to meet the appraised cooling limit. The remote mounted type, is either vertical or then again rooftop mounted level sort.

The next type of condensers we are going to explore is :

Water Cooled Type of Condensers :

            In water cooled type of condensers, water is the outer liquid. Contingent on the development, water cooled condensers can be additionally grouped into:

* Double pipe or tube-in-tube type

* Shell and coil type

* Shell and tube type

Double pipe of tube in tube type of condensers:

            Double pipe type of condensers are ordinarily utilized up to  10 TR limit. In these type of condensers the cold water courses through the inward cylinder, while the refrigerant moves through the annulus in counter stream. Headers are utilized at both the finishes to make the length of the condenser little and diminish pressure drop. The refrigerant in the annulus dismisses a piece of its hotness to the environmental factors by free convection and radiation. The hotness move coefficient is typically low as a result of unfortunate fluid refrigerant waste in the event that the tubes are long.

Shell and coil type of condensers :

            These condensers are utilized in frameworks up to 50 TR limit. The water moves through various curls, which might have fins to build the heat transfer coefficient. The refrigerant courses through the shell. In more modest limit condensers, refrigerant courses through coils while water courses through the shell. At the point when water courses through the coils, cleaning is finished by circling reasonable synthetic chemicals through the loops.

Shell and tube type of condensers :

        This is the most widely recognized sort of condenser, utilized in frameworks from 2 TR upto huge number(thousands) of TR limit. In these condensers the refrigerant courses through the shell while water moves through the tubes in single to four passes. The consolidated refrigerant gathers at the lower part of the shell. The coldest water contacts the fluid refrigerant with the goal that some subcooling can likewise be acquired. The fluid refrigerant is depleted from the base to the collector. There may be a vent associating the beneficiary to the condenser for smooth seepage of fluid refrigerant. The shell additionally goes about as a recipient. Further the refrigerant too rejects hotness to the environmental elements from the shell. The most widely recognized type is flat shell type. Vertical shell-and-tube type of condensers are normally utilized with ammonia in huge limit frameworks so that cleaning of the cylinders is conceivable from top while the plant is running.

Next, we will see the third type in the classification of condensers.

Evaporative type of condensers:

            In Evaporative type of condensers, both air and water are utilized to extricate heat from the gathering refrigerant. Evaporative type of condensers join the highlights of a cooling tower and water- cooled condenser in a solitary unit. In these condensers, the water is showered from top part on a bank of tubes conveying the refrigerant and air is incited upwards. There is a slim water film around the condenser tubes from which evaporative cooling happens. The heat transfer coefficient for evaporative cooling is extremely enormous. Subsequently, the refrigeration framework can be worked at low consolidating temperatures (around 11 to 13 K over the wet bulb temperature of air). The water splash counter momentum to the wind current goes about as cooling tower. The job of air is fundamentally to build the pace of vanishing of water. Evaporative type of condensers are utilized in medium to huge limit frameworks. These are regularly less expensive contrasted with water cooled condensers, which require a different cooling tower. Evaporative condensers are utilized where water is scant. Since water is utilized in a shut circle, just a little piece of the water vanishes. Make-up water is provided to take care of the evaporative losses. The water utilization is regularly exceptionally low, around 5% of a comparable water cooled condenser with a cooling tower. Be that as it may, since condenser has to be kept outside, this sort of condenser requires a more drawn out length of refrigerant tubing, which calls for bigger refrigerant stock and higher pressure drops. Since the condenser is kept outside, to keep the water from freezing, when outside temperatures are extremely low, a radiator is set in the water tank. When outside temperatures are exceptionally low it is conceivable to turn off the water siphon and run just the blowers, with the goal that the condenser goes about as an air cooled condenser.

One more straightforward type of condenser utilized regularly in more established type cold stockpiles is called as Atmospheric condenser. The guideline of the barometrical condenser is like evaporative condenser, with a distinction that the wind current over the condenser happens by normal means as no fans or blowers are utilized. A shower framework splashes water over condenser tubes. Heat move outside the cylinders takes by both reasonable cooling and vanishing, as a result the outside heat move coefficient is somewhat huge. The condenser pipes are ordinarily enormous, and they can be either level or vertical. However these condensers are powerful and practical they are being supplanted with different sorts of condensers due to the issues, for example, green growth development on condenser tubes, uncertainity because of outside air dissemination and so forth.

Well, this is everything about the classification of condensers, hope this article was helpful in giving you some insights on condensers and different types of condensers in HVAC.

Access Full Free HVAC Course by clicking on the link below 👇👇👇

Full Free HVAC Course - Click Here!!!!