Characteristics of a Plate Heat Exchanger

Descriptions of Plate Heat Exchanger

• In plate heat exchangers, the two fluid streams are separated by one or more flat plates. These plates are stacked together in a rectangular box. Between each pair of plates there is a space. One fluid stream is pumped through one set of spaces, and the other fluid stream is pumped through the other set of spaces. If there are more than two spaces, then pipes will deliver one fluid stream to every second space, passing through the intervening spaces. This means that the whole heat exchanger will consist of compartments alternating between hot stream and cold stream. Plate heat exchangers are usually made out of metal. The more plates there are, the greater the surface area between the two fluid streams. Plate heat exchangers are further categorized by the way they are connected to the side of the box. They can be welded, brazed, or gasketed. Plates can be stippled or finned so as to increase their surface area hence their heat conductance.

Applications of Plate Heat Exchangers

• Plate heat exchangers are used in modern combination boilers used for domestic central heating systems. Plate heat exchangers also are used in heating, ventilation, and air conditioning (HVAC) systems. They can also be found in domestic refrigerators. They also are used in chemical plants to control reactant temperatures.

Advantages of Plate Heat Exchangers

• Plate heat exchangers are more compact than other types of heat exchangers. This means they can exchange a greater amount of heat per a particular volume of heat exchanger. They are also cheaper to manufacture than other types of heat exchanger because their internal geometry is relatively simple. They are easier to dissemble and hence easier to clean and maintain.

Disadvantages of Plate Heat Exchangers

• Plate heat exchangers tend to leak more than other types of heat exchanger. This is because they tend to be made of cheaper materials and there is a greater length of joins that can potentially break. They also block more easily than other types of heat exchanger, because of the narrow gaps between the plates. This can be a problem if oxidants build up in central heating systems. They also generate a higher pressure drop than comparable heat exchangers, and so the high energy consumption of pumps is also a disadvantage.