How to Select a Plate Heat Exchanger: A Practical Guide

What a plate heat exchanger actually does

A plate heat exchanger transfers heat between two liquids through thin corrugated stainless plates. Because the plates create high turbulence, it achieves a much higher heat transfer coefficient than a shell and tube unit of the same duty — in roughly a quarter of the footprint.

The inputs you need before sizing

To get an accurate proposal, send your engineer:

1. The two fluids and whether either can foul or freeze
2. Flow rates on both sides (m³/h or L/s)
3. Inlet and outlet temperatures — these set your LMTD
4. Allowed pressure drop — usually 0.5–1 bar per side
5. Working pressure and temperature

Key selection trade-offs

• More plates = more area = closer approach temperature, but higher cost and pressure drop.
• Chevron angle controls turbulence: high angle for viscous or dirty fluids.
• Material: 316L for most duties, titanium where chlorides are present.

Common mistakes

• Undersizing to hit a price target, then exceeding allowable pressure drop.
• Ignoring fouling factor, which quietly erodes performance over a season.

FAQ

Q: Can I add plates later to increase capacity? Yes — frame-and-gasket units are designed for it, provided the frame has spare compression length.

Q: How often should gaskets be replaced? Typically 3–5 years depending on duty and temperature cycling.