Condensers can be found in any kind of mechanisms that imply heat transfer. They are used for condensing substances from a gaseous state to a liquid state through a cooling process. When the change happens, the substance gives up its latent heat, which is transferred to the condenser coolant. Condensers come in a wide range of designs, varying in size. Small condenser units are usually used in residential areas, while large units are needed in the pharmaceutical or agricultural processes. Even your home refrigerator has a condenser that helps it evacuate the heat that has been extracted from within the unit. Condenser units are also used in the industrial chemical field (for example in steam power plants or distillation), in air conditioners and in various heat exchange devices. The great majority of conditioner condensers will use the surrounding air or the cooling water as a coolant agent.
Types of condensers
Condenser units have various uses and can be implemented in a number of devices, carrying out different processes.
- Surface condensers are made out of a tube heat exchanger and a shell, which are connected to the outlet of steam turbines. Most of the times, this device will use cooling water, which will flow through the tube side, allowing the steam to enter the shell side. This is the place where condensation takes place on the outside of the heat transfer tools. The condensate water will drip down, collecting at the bottom, in what is called a hotwell, a built-in pan. Generally, the shell side will operate at a partial or complete vacuum, which is produced, most of the times, by air ejectors.
- Industrial distillation processes will use large condensers to cool down distilled vapor, transforming it into liquid distillate. As a rule, the coolant will flow through the tube side, while the distilled vapor will pass through the shell side and the distillate will collect or will flow out the bottom side.
- Condenser units are employed in central air conditioner units. These have heat exchanger sections, which are in charge with cooling down and condensing the incoming refrigerant vapor, transforming it into liquid. An air conditioning condensing unit also has a compressor, which raises the pressure within the refrigerant and passes it along. A fan is used for blowing air via the heat exchanger, in order to cool down the refrigerant inside. Here is how the configuration of an AC condenser looks like: the heat exchanger will wrap around the unit’s sides. The refrigerant will go through several tube passes, all of which are surrounded by hear transfer fins, which allow cooled air to move inside the unit from outside. The motorized fan within the condenser will blow the outside cooling air in with the help of the heat exchange section that can be found at the sides and on the top side. A home condenser unit is usually placed on the outside of the building, and tubes are used to connect the building to the unit. One tube is used for the vapor refrigerant, which enters the device, and another one for the liquid refrigerant that leaves the device. The fan and the compressor need an electric power to function.
- Direct contact condensers use vapors that are directly poured into the liquid. The vapors will lose their latent heat, and, as a consequence, the vapors will transfer the heat into the hot liquid. The liquid and the vapor are the same kind of substance in this particular type of condensation.
Other examples of condensers
HVAC (heating, ventilation, and air conditioning) use condensers to a large extent. There are three types of condensers employed in HVAC systems.
- Evaporative condensers are not among the most popular choices out there. These can be installed outside or inside a building, operating at a low condensing temperature. This type of condenser is most of the times installed in large commercial air-conditioning units. While they get the job done, they are not the most efficient ones on the market.
- Water cooled condensers are on the pricey side in the condensers’ market, however, they are the most efficient ones out there. They call for regular maintenance and they are usually installed for swimming pools. Water cooled condensers need a cooling tower in order to conserve water. Water treatment and makeup water are a must if you want to keep corrosion and algae at bay. You can choose from three types of water cooled condensers: shell and coil, tube in tube and shell and tube.
- Air cooled condensers are generally installed on the outside of the unit, ejecting heat to the outdoors. Easy to install, air cooled condensers are commonly found in upright freezers, refrigerator and in air conditioning units. What makes this type of condensers easy to manage is that it doesn’t take a lot of time or effort to clean them. A clean air cooled condenser is essential for optimum performance.
A C condenser
Air cooled condensers are generally used for residential AC systems. This type of devices include earth cooled condensers and combinations of water cooled and air condensers. Using outdoor air to reject the heat absorbed by the unit from the indoor air, air condenser units comprise a fan blade, a motor, coils and a compressor. The job of the condenser fan is to increase the capacity of the unit to reject heat.
Acting as heat exchanger devices, air conditioner condensers are similar to evaporators. The condenser unit will take in the high temperature and high pressure refrigerant gas from the compressor, turning it into high temperature, high pressure liquid refrigerant. The entire process behind air conditioner condenser units is transforming vapor refrigerant into liquid refrigerant. The refrigerant will undergo three essential changes:
- The compressor will produce a hot vapor that needs to be de-superheated and brought to vapor saturation point. The de-superheated process involves getting rid of the sensible heat within the refrigerant that is under the temperature of the refrigerant.
- A blend of liquid or gas refrigerant can be found in the middle of the condenser, the place where the refrigerant vapor has to transform into liquid refrigerant.
- The refrigerant has to reach a temperature under liquid saturation point.
Air conditioner condenser unit maintenance
As with any other HVAC device, cleaning, maintenance and regular repairs are key to preserving the longevity of the device. Condenser units are no exception. Regular maintenance is not rocket science, it doesn’t have to be done too often and can save you a lot of money in the long run. The task can be completed in less than an hour and it is bound to increase the efficiency of your AC condenser unit.
Neglecting to clean your condensing units for a year translates into clogged cooling fins, a lot of debris and dirt. As a consequence, your AC isn’t doing a proper job at cooling down your entire home, like it used to do last summer. What is there to do? Before you schedule a pricey maintenance appointment, there are some steps you can perform to de-clog, clean up and increase the performance of you air conditioning unit. Of course, you won’t be able to check the coolant level, but you can save a hundred dollars by clearing out some dry leaves. These procedures apply to most air conditioning devices out there and you need only the instructions manual to figure out the trickier parts. However, don’t neglect calling in a technician every couple of years for a thorough investigation.
- The first step is turning off the power. This is usually done by turning its switch to the OFF position or pulling out a block. If you’re not sure how to turn off the power, you can completely shut down the AC from the electrical panel.
- Use a vacuum and a soft brush attachment to get rid of any dry leaves, debris or grass clippings from the fins. You should also get rid of the grass and weeds surrounding the condenser.
- It’s not uncommon to notice bent fins on close inspection. These could hinder your air conditioning from working properly. Use a knife to realign the fins, but be careful not to insert it more than half an inch inside the unit.
- Unscrewing the grille, gently take out the fan and clean it and the interior with a cloth.
- The fins can now be cleaned with a hose nozzle, from the inside out.
- Reinstall the fan and get ready to restart the unit. Head to the thermostat and switch it to off. Next up, turn the power back on, but allow the unit to sit for a day, giving the heating element of the compressor enough time to warm up the internal lubricant. After 24 hours pass, you can turn the thermostat on to the cool setting again.
- For cleaning the indoor unit, you’ll want to turn off the power or shut it down completely from the main electrical panel. Only then you can pull out the filter and change it if it’s the case.
- Vacuum inside the unit and lubricate the ports with four or five electric motor drops.
- The drain tube can be cleaned with a water and bleach mixture poured into the tube.
- Clean out the drain port to get rid of debris using a pipe cleaner.
- After reattaching the drain tube, you can turn the power back on.
Image sources: 1, 2, 3.