How Does A Plate Heat Exchanger Work

Plate Heat Exchangers were first produced in the 1920s and have since been widely used in a great number of sectors.A plate heat exchanger (PHE) is a type of heat exchanger that uses metal plates to transfer heat between two fluids. Its design allows for efficient heat transfer and easy maintenance. Here’s a detailed explanation of how it works:

Basic Components

Plates: Thin, corrugated metal plates, usually made of stainless steel, are arranged in a stack. Each plate has gaskets that create separate channels for the two fluids.
Gaskets: These are placed around the edges of the plates to seal and direct the fluids into alternate channels.
Frame: The plates are clamped together in a frame with end covers that provide the necessary pressure and sealing.
Ports: Inlet and outlet ports are located on the frame or plates to allow the fluids to enter and exit the exchanger.

Example Process

Consider a simple example where a plate heat exchanger is used to cool a hot water stream with a cold water stream:
Hot Water Inlet: Hot water enters the heat exchanger through the inlet port.
Flow Through Plates: The hot water flows through alternate channels, transferring its heat to the metal plates.
Cold Water Inlet: Cold water enters through a different inlet port and flows through the channels adjacent to the hot water.
Heat Transfer: Heat from the hot water is transferred through the plates to the cold water.
Outlets: The cooled hot water exits through its outlet port, and the warmed cold water exits through its respective outlet port.
This efficient and compact design makes plate heat exchangers a popular choice for a wide range of heat transfer applications.

The concept of heat transfer

In every system, energy will naturally flow until balance is reached, according to the laws of physics. Heat is released as a result of temperature variations.

A heat exchanger follows the equalisation principle. With a plate heat exchanger, heat cuts through the surface and separates the hot medium from the cold. Thus, heating and cooling fluids and gases use minimal energy levels.

The theory of heat transfer between mediums and fluids happens when: 

1）Heat always moves from a hotter medium to a cooler medium.

2）A temperature contrast between the mediums is necessary at all times.

3）The heat transferred from the warm substance is the same as the heat received by the cool substance.

Working Principle

Plates used in exchangers can vary in size, starting from small dimensions like a few square centimeters (100 mm x 300 mm) and to large sizes reaching 2 to 3 square meters (1000 mm x 2500 mm). The quantity of plates in one exchanger can range from as few as ten to as many as several hundred, resulting in exchange surfaces totaling thousands of square meters.

Fluid Flow: The two fluids (hot and cold) flow through alternate channels formed by the plates. They flow in a counterflow or parallel flow arrangement, depending on the design.

In a counterflow arrangement, the fluids flow in opposite directions, maximizing the temperature difference and heat transfer efficiency.
In a parallel flow arrangement, the fluids flow in the same direction.

Heat Transfer: Heat transfer occurs through the thin metal plates. The hot fluid transfers heat to the metal plate, which then transfers it to the cold fluid on the other side. The corrugated design of the plates increases the surface area for heat transfer and induces turbulence, further enhancing the efficiency.

Separation: The gaskets ensure that the fluids do not mix and flow through their designated channels. This separation allows for effective heat exchange without contamination.

Typically, the plates are shaped with ridges to enhance turbulence, increase the surface area for heat transfer, and add strength to the heat exchanger. The corrugated pattern is formed by cold shaping thin sheet metal ranging from 0.3mm to 1mm in thickness.

Commonly utilized materials for the plates include stainless steel (AISI304, 316), titanium, and aluminium

Advantages

Efficiency: High heat transfer coefficient due to the large surface area and turbulence created by the corrugations.
Compact Design: Smaller footprint compared to shell-and-tube heat exchangers for the same capacity.
Flexibility: Easy to expand or reduce capacity by adding or removing plates.
Easy Maintenance: Plates can be easily removed, cleaned, or replaced if necessary.

Applications
Plate heat exchangers are used in various industries, including:
HVAC: For heating and cooling systems.
Food and Beverage: For pasteurization and other processes.
Chemical Processing: For efficient heat transfer in chemical reactions.
Marine: For engine cooling and other applications.
Power Generation: For cooling and heat recovery.

Ptetank is a professional heat exchanger supplier. In addition to Plate Heat Exchangers ,we also provide shell&tube heat exchanger andfloating head heat exchanger.Learn more!