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4 Types of Condensers and Their Uses

A condenser is a mechanical device that uses heat transfer and/or compression to turn hot vapour or steam into liquid. Condensers are widely utilized in the automobile, construction, industrial plants, cooling systems, and steam power turbine sectors. ASME, HEI, AHRI, ASHRAE, and other international standards control the design, performance, environmental compliance, and safety of condensers. Copper, brass, aluminium, carbon steel, and stainless steel are commonly used materials in condensers. In this post, we will look at the fundamentals of condensers, including their specifications, types, uses, and selection.



The condenser is the ‘hot’ end of a refrigeration system and may be utilized as a heat source when low-temperature heat is required, such as for washing water. On the other hand, the effects of increasing the condenser temperature to increase the usefulness of available heat should be carefully considered. Another possible heat source is the oil cooler—higher temperature heat recovery is obtained by desuperheating the compressor output gas. When big compressors are utilized, energy recovery from oil coolers can be beneficial (ICAEN, 1998). A thorough examination is needed before specifying heat recovery from a refrigeration facility.

Functions of Condenser

There are three different stages in every condenser. The first stage is the desuperheating phase. The vapour that enters the condenser has previously been superheated and compressed in the evaporator and compressor. Desuperheating is the process of eliminating heat from vapour and turning it into a liquid. The next phase is the changing or condensation state, which occurs when we lose more heat and reach a position where 10% of the refrigerant is vapour and 90% is liquid. The final stage is a sub-cooling state. Even if the temperature rises, the sub-cooling condition assures that the liquid refrigerant does not revert to vapour.

Condenser Specification

The customer often specifies condenser specifications in the form of a condenser datasheet. All of the condenser’s standards or specifications are listed on the manufacturer’s design and selection sheet. In general, the specification of a standard condenser includes the following details:

  1. Condensing Capacity
  2. Allowable pressure drop
  3. Coolant or Refrigerant Capacity
  4. Condenser Material
  5. Design and Operating Temperature
  6. Design and Operating Pressure
  7. Flow rate

Types of Condensers

Condensers are categorized based on many factors, such as condensing medium, heat transfer technique, applications, and so on. Condensers are categorized into two types based on heat transfer systems:

  1. Direct Contact Condensers: Heat transfer occurs when the gas and liquid come into direct contact.
  2. Indirect Contact Condensers: Heat exchange occurs through a thermally conductive boundary medium such as a plate, shell, or tube
  3. Surface Condensers: They are shell and tube heat exchangers that are utilized in big thermal power stations and refrigeration systems. They are further subdivided into tube-side condensation and shell-side condensation.

Condensers are grouped into three types based on their application:

  • Refrigeration and HVAC condensers
  • Car or Automotive condensers
  • Process Condensers like distillation column condensers.
  • Marine Condensers

The primary classification of condensers, however, is based on the condensing medium. Condensers are classified into three categories based on the condensing medium used to collect heat from the system.  Depending on the scenario, each should be handled carefully.

Air-cooled Condenser:

This type of condenser uses a finned constant tube coil. The vapour from the compressor discharge enters the coil at the top and leaves the bottom, where it flows into receivers underneath the base. A fan installed on the compressor motor pulleys blows across the condenser coil. The device should be stored in a well-ventilated and cool area. The less electricity is used for a particular capacity, the lower the ambient air temperature.

The major advantage of this type of condenser is that it is easy to install and inexpensive. Self-contained units, such as household refrigerators, freezer cabinets, display cases, water coolers, and air conditioners, are the most prevalent applications. This condenser removes heat from the system by using air as the external fluid. In air-cooled condensers, the refrigerant passes via copper coils. However, this is not the entire picture; natural convection and forced convection are two subgroups of this type.

The air-cooled condenser has two categories:

  • Natural Convection Type:

In the natural convection type, heat is transported from the condenser by buoyancy-induced natural convection and radiation. Because the airflow speed is moderate, the total heat transfer coefficient in these condensers is limited, as is the radiation heat transfer. As a result, to reject a given quantity, a relatively large condensing surface is required. As a result, these condensers are used in low-capacity refrigeration systems such as residential refrigerators and freezers.

Natural convection condensers are of the plate surface or finned tube type. The refrigerant-carrying tubes of plate surface condensers, which are used in small refrigerators and freezers, are connected to the external wall of the refrigerator. Except for the door, the whole body of the refrigerator works as a fin. Insulation is provided between the outer cover, which serves as a fin, and the interior plastic cover of the refrigerator. As a result, the outside body of the refrigerator is always heated. Moisture condensation on the refrigerator walls is not a concern with these systems since the surface is heated. These condensers are also known as flat-back condensers.

  • Forced Convection Type:

In forced convection condensers, a fan or blower keeps air circulating over the condenser surface. These condensers often include fins on the airside for effective heat transfer. Fins can be plate-shaped or annular in form. In the chassis-mounted type, the compressor, induction motor, condenser, condenser fan, accumulator, HP/LP cut-out switch, and pressure gauges are all placed on a single chassis. It is referred to as a condensing unit because its components are rated capacity and are matched to condense the requisite refrigerant mass flow rate to rate cooling capacity.

Forced convection condensers are used in window air conditioners, water coolers, and packaged air conditioning plants. These can be installed on the chassis or can be installed remotely. The remote-mounted type can be installed vertically or horizontally on the roof. Air velocity is normally between 2 and 3.5 m/s for economical design, with airflow rates ranging from 12 to 20 cm per tonne of refrigeration (TR). The density of the air is 1.2 kg/m3, and the specific heat is 1.005 kJ/kg-K. The temperature rises ta = 3.5167/(1.21.005 x 16/60) = 10.9°C for 1 TR with an average airflow rate of 16 cm. As a result, the air temperature rises by 10 to 15 degrees Celsius, whereas the water in water-cooled condensers rises by 3 to 6 degrees Celsius.

Water-cooled Condenser:

Water-cooled condensers are used with compressors of one horsepower or above. When there is an appropriate supply of clean water with minimum corrosion and an acceptable and cost-effective means of water disposal, they are often the most affordable solution for condensers. In this type of condenser, water is utilized to cool the heated refrigerant and transform it into a liquid. The components are matched to calculate cooling capacity by condensing the needed refrigerant mass flow rate. The less water is used in a water-cooled condenser, the higher the condensing temperature and the higher the power expenditure.

There are three types of water-cooled condensers:

  1. Double Tube Condenser: Coldwater flows through the inner tube of the condenser while the refrigerant flows in the opposite direction via the annulus. Headers are used at both ends of the condenser to shorten its length and reduce pressure loss. The refrigerant in the annulus loses part of its heat to the environment via free convection and radiation. Because of poor liquid refrigerant drainage, the heat transfer coefficient is usually low when the tubes are longer. Double pipe condensers with capacities of up to 10 TR are widely used.
  2. Shell and Coil Condenser: A welded shell holds a coil of finned water tubing in a shell-and-coil condenser. In this type of water-cooled condenser, the heated refrigerant flows in the shell while cooling water circulates inside the coils and condenses the refrigerant.
  3. Shell and Tube Condenser: With capacities ranging from 2 TR to thousands of TR, this is the most common type of condenser. The refrigerant flows through the shell of these condensers while water flows through the tubes in one to four passes. The condensed refrigerant accumulates at the bottom of the shell. The coldest water comes into contact with the liquid refrigerant, which allows for some sub-cooling. The liquid refrigerant is released from the bottom into the receiver. There may be a vent connecting the receiver to the condenser for smooth liquid refrigerant drainage. The shell, in addition to being a transmitter, also works as a receiver.

In addition, the refrigerant releases heat from the shell into the environment. The horizontal shell is the most common. Vertical shell-and-tube condensers are often used in large-capacity ammonia systems because the tubes may be cleaned from the top while the plant is working.

In addition, the refrigerant releases heat from the shell into the environment. The horizontal shell is the most common. Vertical shell-and-tube condensers are often used in large-capacity ammonia systems because the tubes may be cleaned from the top while the plant is working.

Evaporative Condenser:

Lastly, the evaporative condenser is the condenser’s final type. It’s an air-cooled and water-cooled condenser. In evaporative condensers, the condensing medium is either air or water. A sump in the condenser sprays water over the coils. A fan blows air into the condenser. The sprayed water evaporates across the coils, and the heat necessary for the vaporizing water is obtained from the heat of the refrigerant. Although some water is circulated by descending into the sump, extra water is supplied to the sump’s water supply to compensate for the proportion evaporated.

The following is a comparison of three types of condensers:

Air-cooled condensers are less difficult to create than water-cooled condensers. There is also continuous exposure to air. Air-cooled systems require less maintenance than water-cooled ones. Evaporators are usually less costly than water-cooled systems that necessitate the use of a cooling tower. In areas where water is scarce, evaporators are used. Because the evaporator is located outside, the water pump is turned off in cold weather to keep the water from freezing.

Selection of Condensers

Condenser selection is governed by application and various parameters like:

  • Condensing Capacity, Full or Partial condensing, Heat rejection calculation
  • Type of Industry
  • Temperature (Design, operating, Dry bulb, wet bulb)
  • Condenser material
  • Pressure drop criteria
  • Space availability
  • Types of condensing medium
  • Corrosion
  • Fouling factor, etc



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