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Plate Heat Exchanger Surface Area & NTU Calculator mechanical
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Plate Heat Exchanger Surface Area & NTU Calculator

Size gasketed and brazed plate heat exchangers (PHE) to determine thermal length (NTU), required plate count, port velocities, and chevron angle selection.

Thermal Duty & Temperatures

Plate Geometry & Hydraulics

Typical 750-1,100 for water-water PHE

Plate Pack & Thermal Performance

Required Thermal Plates
-- Plates
-- sq ft total surface area
Thermal Length (NTU)
--
-- chevron pattern
Port Fluid Velocity
-- FPS
Ideal 10 - 18 FPS
True Counterflow LMTD: -- °F
PHE Frame Pack Tightening Dimension: -- inches
Area Density Advantage vs Shell & Tube: 3x to 5x higher U-value
Plate heat exchangers operate with pure countercurrent flow, easily handling close temperature approaches down to 2°F to 3°F (1°C to 2°C).

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Frequently Asked Questions

What is the Number of Transfer Units (NTU) in a Plate Heat Exchanger?

NTU (often called thermal length or Theta, θ) measures the temperature change of a fluid stream relative to the log mean temperature difference: NTU = ΔT / LMTD. A high-NTU heat exchanger achieves large temperature changes across small temperature differences, requiring chevron plates with obtuse corrugation angles (e.g. 60°).

Why do Plate Heat Exchangers achieve 3x to 5x higher U-values than Shell and Tube?

The pressed chevron corrugation pattern forces fluid into a continuous three-dimensional swirling vortex. This triggers turbulence at extremely low Reynolds numbers (Re < 50), dramatically thinning the stagnant thermal boundary layer and achieving overall heat transfer coefficients exceeding 800 to 1,200 BTU/hr·ft²·°F.

What is the significance of the plate pack tightening dimension (A-dimension)?

The tightening dimension (A-dimension) is the exact distance between the fixed head and movable pressure plate measured with calipers. Gaskets must be compressed to their precise manufacturer-specified sealing thickness; under-tightening causes fluid leaks, while over-tightening permanently deforms plate corrugations and crushes elastomeric gaskets.