How to Size a Plate Heat Exchanger
Plate heat exchanger sizing balances heat duty, temperature approach, pressure drop, fouling factor and plate pattern. Here are the inputs and steps a manufacturer uses.
Step 1 — Define the duty
Heat duty Q (kW) equals mass flow × specific heat × temperature change on either side. Both sides must balance. If only one side's data is known, the other side can usually be calculated from the available temperatures and flow.
Step 2 — Choose the temperature approach
The temperature approach is the difference between the hot outlet and cold inlet (or the cold outlet and hot inlet). Tight approaches (1–3 °C) require more plates and more area; loose approaches (5–10 °C) reduce size and cost. Plate units routinely achieve approaches that are impractical with shell-and-tube.
Step 3 — Set the allowable pressure drop
Pressure drop budget on each side bounds the channel velocity and plate pattern. Higher pressure drop allows higher velocity, more turbulence and a smaller, cheaper unit. Lower pressure drop demands a larger unit with a lower-theta plate.
Step 4 — Apply a realistic fouling factor
Fouling factor adds margin to the heat-transfer surface to keep the unit performing through the maintenance interval. Typical values: 0.00002 m²·K/W for clean water-glycol, up to 0.0001 m²·K/W for fouling services. Over-applying fouling factor is the most common cause of over-sized plate units.
Step 5 — Select plate model, material and gasket
Plate material is usually 316L; switch to titanium or nickel alloys for chlorides and aggressive chemistries. Gasket compound depends on temperature and fluid (NBR, EPDM, Viton). The manufacturer's selection software then computes plate count, channel arrangement and frame size.
What to send the manufacturer
Medium each side, inlet/outlet temperatures, flow rate, allowable pressure drop, design pressure and temperature, material preference and any code requirement. Jiangxing returns a thermal selection and indicative pricing within one to two business days.
Send your working conditions to Evan
Share your medium, temperatures, flow rate and pressure — Evan will return a thermal selection and indicative pricing after reviewing the available data.