Condenser is a device that is used to change the phase of a working medium like converting refrigerant from vapor to liquid.
There are various types of condensers. In this article, we will discuss a specific type of condenser which is an evaporative condenser.
Evaporative Condenser is simple, cheap, and does not require a large quantity of cooling water.
In this process, evaporation of cooling water occurs so it is called an evaporative condenser.
The evaporative Condenser uses both air and water to condense the hot vapor refrigerant and convert it into liquid refrigerant. In short, it is a type of indirect cooling, where the heat of vapor refrigerant is taken by water and thus the water gets cooled.
An evaporative condenser does the combined work of a water-cooled condenser and a cooling tower.
Parts of Evaporative Condenser:
1) Water Pool or Reservoir:
in an evaporative condenser, there is a water pool that contains cool water.
2) Water Pump:
The water pool is connected to a water pump through a pipe.
This header is present on the top and water is supplied to the header from the water pool using a water pump. This header has nozzles that convert water into the spray and then water is sprayed from the header.
4) Steam Inlet:
Steam is supplied through this steam inlet which is to be cooled and converted into water. The steam inlet is connected to the water pool through tubes. These tubes are called finned tubes as there are many fins attached to the tube.
5) Finned Tube:
The tubes which connect the steam inlet and water pool is called finned tube as lots of fins are attached to this tube.
The tubes are in form of coils and their length is more so that they can be used to cool the vapor easily.
The function of fins is to increase the contact time of steam with water sprayed from the header and also increase the contact area of the tube with sprayed water.
These fins will help to coll the steam faster and convert it to water.
Fins will help to cool the tubes faster and tubes will cool the steam faster and convert it into water.
Eliminators are used to eliminate the gas in the vapor and separate the water vapor from the gas in the vapor.
7) Air Extraction Pump:
An air extraction pump is used to take out the air present on the top of the evaporative condenser. Air is also supplied to cool the vapor and this air is taken out by an air extraction pump.
8) Condensate Pump:
Condensate Pump is used to extract the condensed liquid at the end of the finned tube.
Working Of Evaporative Condenser:
1) At first, the water pump starts working and the water from the water pool starts flowing towards the header.
2) When the water reaches the header, water gets sprayed from the nozzles of the header down towards the finned tubes.
3) The sprayed water from the header starts cooling the finned tubes and the fins attached to the tubes increases the contact time and contact area of the tube with water.
4) After that the steam inlet starts supplying the steam to the finned tubes.
5) When the steam travels through the finned tube, the sprayed water will come in contact with the tube and will start cooling the tube.
6) When the sprayed water will come in contact with the hot tube, some water will evaporate also and carry away the heat from the finned tube, so it is called an evaporative condenser.
7) The evaporated water will come out through the air extraction pump and large water particles will be separated by the eliminator and again fall down.
8) The sprayed water will cool the finned tube and also cool the steam flowing through these tubes and the steam will convert into water.
10) At the same time, the air is also supplied in this system which cools the vapor inside the finned tube along with water sprays. Air is supplied from the bottom and moves upwards while cooling the vapor and is taken out by an air extraction pump.
10) In halfway, the vapor inside the finned starts getting converted into liquid.
11) At the end of the finned tube is reached, the vapor gets completely converted to liquid.
12) The condensed Liquid is finally extracted with the help of a Condensate pump.
Advantages Of Evaporative condenser:
1) It requires less energy to operate than other cooling methods such as air-cooled condensers.
2) It does not require a separate cooling tower as the water used for cooling is recycled through the system.
3) It consumes less water than other cooling methods as the water used in an evaporative condenser is recycled and is preferable where an acute shortage of cooling water exists.
4) As t does not require a large quantity of cooling water, so it needs a small capacity cooling water pump.
5) They are compact in size and can be installed in small spaces.
6) Its Operating Cost is less.
Disadvantages Of Evaporative Condenser:
1) It requires regular maintenance to prevent the buildup of mineral deposits on the coil, which can reduce efficiency.
2) Evaporative condensers cannot be used in areas where water is scarce or where the climate is very humid.
3) Evaporative condensers can be the cause of the growth of Legionella bacteria, which causes Legionnaires’ disease.
4) They require protection from freezing temperatures which can be tough in cold climates.
5) These condensers are only suitable for small power plants.
6) The vacuum maintained in this condenser is less.
Applications Of Evaporative Condensers:
1) Evaporative condensers are commonly used in air conditioning systems for commercial and industrial buildings.
2) They are also used in the refrigeration system to cool the refrigerant.
3) These are also used in industrial processes where heat needs to be removed from a fluid eg -They are used in power plants for cooling the water used in the condenser of the steam turbine.
4) They are used in chemical processing plants to cool the water used in various chemical reactions
Types Of Evaporative Condensers:
1) Pad-type evaporative condenser.
2) Spray-type evaporative condenser.
3) Rotating type evaporative condenser.