Calculating plate heat exchangers

The calculation of a plate heat exchanger requires the consideration of several parameters to determine the performance and efficiency of the heat exchanger. Here are the basic steps to calculate a plate heat exchanger:

1. gather requirements and data: collect all relevant data, including media (liquid or gas) properties, temperatures, flow rates, pressure drops and specific heat capacities.
2. calculate heat transfer area: The heat transfer area of a plate heat exchanger depends on the specific heat transfer coefficients and temperature differences of the media. Use the formula for the heat transfer rate:

Q = A * U * ΔTlm

Where:

Q: Heat transfer rate (in watts or kilowatts)

A: Heat transfer area (in m²)

U: Total heat transfer coefficient (in W/(m²-K))

ΔTlm: Logarithmic mean temperature difference (in Kelvin)

The logarithmic mean temperature difference (ΔTlm) is calculated using the following formula

ΔTlm = (ΔT1 - ΔT2) / ln(ΔT1 / ΔT2)

Where ΔT1 and ΔT2 are the temperature differences at the inlet and outlet of the media.

3. calculate the overall transfer coefficient: The overall transfer coefficient (U) is made up of the heat transfer coefficients on both sides of the plates and the thermal resistance of the plates. It may require a more complex calculation that takes into account plate spacing, plate geometry and other factors.
4. consider pressure losses: Calculate the pressure drops on both sides of the plate heat exchanger to ensure that flow is not compromised and pump performance is adequate.
5. plate selection and arrangement: Based on the calculated values and the application requirements, select the appropriate plates for the heat exchanger and determine their arrangement.
6. simulation or software tools: Use specialized software tools or simulation software for detailed calculation and modeling of the plate heat exchanger. Such tools often take more complex factors into account and provide more accurate results.

It is important to note that the calculation of a plate heat exchanger can be challenging due to its complex geometry and flow dynamics. In practice, collaboration with experts or the use of specialized software tools may be recommended to achieve accurate results.