Shell and tube heat exchanger features a cylindrical shell and an internal tube bundle (comprising multiple tubes) as its core structure, with fluids flowing separately through the tubes and on the shell side.

Plate heat exchanger constructed from a stack of corrugated metal plates, which form flow channels between them. It enables high heat transfer efficiency within a compact space.Plate heat exchangers serve as ideal equipment for liquid-to-liquid and liquid-to-vapor heat exchange applications.

Features fins (ribs) attached to the outer surface of standard smooth tubes; it utilizes this extended surface area (the fins) to enhance heat transfer, and is commonly employed in gas-to-liquid heat exchange applications.

Double pipe (Concentric-Tube) heat exchanger composed of two concentric tubes of differing diameters nested within one another; it is well-suited for applications requiring simplicity, high efficiency, high pressure, or low flow rates.

• Media Combination: High-temperature steam (heating medium) and low-temperature water (cooling medium).
• Working Principle: Utilizes the latent heat released during steam condensation to heat water; offers extremely high heat exchange efficiency and rapid temperature rise.
• Typical Structure: Typically employs floating-head or U-tube shell-and-tube heat exchangers to accommodate the thermal expansion caused by the high temperature of the steam.
• Application Scenarios: Primary stations for urban district heating, industrial process heating, and rapid production of domestic hot water.

• A Water to Air Heat Exchanger (often called a hydronic coil) is a device designed to transfer thermal energy between water flowing inside tubes and air passing over the outside of those tubes. These are staples in HVAC systems, industrial processes, and outdoor wood furnace setups.
• Main types: Finned-tube heat exchangers, plate heat exchangers (specifically designed for gas-liquid exchange), and microchannel heat exchangers.
• Tubes: Usually made of copper, steel, or stainless steel. This is where the liquid medium flows.
• Fins: These are thin metal plates (often aluminum) attached to the tubes. They increase the surface area, allowing more heat to transfer to the air.

• Media Characteristics: Involve thermal oil, crude oil, or lubricating oil. Oil-based media typically possess high viscosity, are flammable, and are prone to coking (carbon deposition) at high temperatures.
• Key Requirements: Must feature anti-fouling designs; construction materials typically consist of high-temperature-resistant alloys or carbon steel; sealing requirements are extremely stringent to prevent leaks that could trigger fires.
• Applications: Petrochemical refining, plastics processing, and temperature control for high-temperature reaction vessels.

• Media Characteristics: Involve air, flue gas, or corrosive gases. Gases generally possess low heat transfer coefficients, necessitating the use of extended heat transfer surfaces (fins) to enhance efficiency.
• Key Requirements: Typically employs a finned-tube structure to increase surface area; if the medium contains corrosive components (such as sulfur), ceramic or fluoroplastic materials must be utilized.
• Applications: Boiler air preheaters, waste heat recovery systems, HVAC fresh air systems.

Function: To heat a fluid to a specific temperature required by the process.
Characteristics: The fluid being heated does *not* undergo a phase change during the process (i.e., it remains in its liquid or gaseous state, neither boiling nor condensing).
Applications: Domestic hot water preparation, heating of feed streams for chemical reactors.

Function: To perform preliminary heating of a fluid prior to its entry into the main process equipment.
Characteristics: Designed to recover waste heat or utilize low-grade heat sources to enhance the overall thermal efficiency of the system, while also establishing standard parameters for subsequent process stages.
Applications: Boiler feedwater preheating, air preheating.

Function: To further heat saturated steam, converting it into superheated steam.
Characteristics: Increases the enthalpy and work potential of the steam, and prevents the steam from condensing into water—which could damage equipment—during transmission.
Applications: Boiler systems in thermal power plants, steam power generation units.

Function: To cool a fluid to a temperature required by the process.
Characteristics: Typically involves *no phase change*; it primarily relies on sensible heat exchange, and the cooling medium used is often water or air.
Applications: Engine lubricant cooling, after-cooling for air compressors, temperature reduction of chemical process streams.

Function: To cool a gas or vapor and condense it into a liquid.
Characteristics: Utilizes latent heat exchange; the fluid undergoes a gas-to-liquid phase transition, releasing a significant amount of heat.
Applications: Refrigeration systems, condensation of overhead vapors in distillation columns, condensation of turbine exhaust steam in power plants.

A Boiler Economizer is a specialized heat exchanger installed in the exhaust (flue gas) path of a boiler. Its primary purpose is to capture “waste heat” from the high-temperature flue gases and use it to preheat the boiler’s feedwater.

By increasing the temperature of the water before it enters the main boiler drum, the system requires significantly less fuel to convert that water into steam.

Function: To heat a liquid, causing it to boil and transform into a gas (vapor).
Characteristics: The fluid undergoes a liquid-to-gas phase transition, absorbing a significant amount of latent heat.
Applications: Seawater desalination, the heat-absorbing side of refrigeration systems, and chemical concentration processes.

Function: To supply heat to the liquid at the bottom of a distillation column, causing a portion of it to vaporize and return to the column.
Characteristics: Essentially a specialized type of evaporator, used to maintain the vapor-liquid equilibrium required for the rectification process.
Applications: Petroleum refining, alcohol distillation, and chemical separation columns.