A plate heat exchanger is a new type of highly efficient heat exchanger formed by stacking metal plates with specific corrugated shapes. Its structure includes gaskets, pressing plates (movable end plate, fixed end plate), and a frame (upper and lower guide rods, front pillar). The plates are sealed and guided by gaskets, separating the cold and hot fluid channels. The cold and hot heat exchange media flow through their respective channels, exchanging heat with the adjacent plates to achieve the user's desired temperature.

Each plate has openings at its four corners. After assembly into a plate bundle, these form the fluid distribution and collection pipes. After heat exchange, the cold and hot media return through their respective collection pipes for recycling.

The relationship between parameters such as the flow rate, temperature, and heat transfer coefficient of the two phases in a plate heat exchanger can be calculated using relevant formulas. Referring to the "Chemical Process Design Handbook" (Fourth Edition, Volume 1), the calculation logic and formulas summarized in the text, combined with reference charts for fluid and heat transfer, an Excel-based "Plate Heat Exchanger Design Calculation Sheet" was compiled.

4.1 Input parameters such as the cold-side material name, inlet and outlet temperatures, and flow rate; input parameters such as the hot-side material name, inlet and outlet temperatures. Then, based on the qualitative temperature of the cold and hot-side materials (t=(t₁+t₂)/2), query the physical property table and fill in parameters such as density, viscosity, specific heat, and thermal conductivity. The calculation sheet will automatically compute key data such as the logarithmic mean temperature difference Δtlm, heat transfer rate, hot-side flow rate, and heat exchanger power.