How do I calculate heat exchanger size?

How do I calculate heat exchanger size?

ΔTm =

  1. ΔTm =
  2. = 94.9 °F. 0.10536.
  3. The preliminary area estimate of the heat exchanger can now be calculated as: A = Q / (U x ΔTm) =
  4. A = 2, 035, 000 Btu/hr.
  5. = 178.7 ft² (120 Btu/h.ft².°F).(94.9°F)
  6. The required mass flow rate of water can be calculated from Q = m.Cp. ΔTm: Rearranging:
  7. m = Q…… = Cp x ΔTm.
  8. m = (2,035,000 Btu/hr)

How is heat exchanger design calculated?

Preliminary heat exchanger design to estimate the required heat exchanger surface area can be done using the basic heat exchanger equation, Q = U A ΔTlm, if values are known or can be estimated for Q, U and ΔTlm. Heat exchanger theory tells us that ΔTlm is the right average temperature difference to use.

How do you calculate the heat load of a heat exchanger?

The heat load of a heat exchanger can be derived from the following two formulas:

  1. Heat load, Theta and LMTD calculation. Where: P = heat load (btu/h)
  2. Heat transfer coefficient and design margin. The total overall heat transfer coefficient k is defined as:

How is exchanger duty calculated?

U = Q / (A x LMTD) Where Q is the heat duty, A is the heat transfer area of the exchanger and LMTD is tem- perature driving force.

What is the pitch of a tube?

The distance between the centers of the tube hole is called the tube pitch; normally the tube pitch is 1.25 times the outside diameter of the tubes. Other tube pitches are frequently used to reduce the shell side pressure drop and to control the velocity of the shell side fluid as it flows across the tube bundle.

How is heat exchanger efficiency calculated?

There are generally two ways to evaluate the performance of heat exchangers. One is Log Mean Temperature Difference, abbreviated as LMTD, and the other is the Effectiveness NTU-method, denoted by ε-NTU.

How to design shell and tube heat exchangers?

Different types of shell and tube exchangers can be easily configured by changing the shell and tube arrangement. Shell and tube heat exchanger design is an iterative process, which goes through the following steps. Define design parameters such as – number of tube passes, tube size, shell ID etc.

How to calculate overall heat transfer in a heat exchanger?

Overall heat transfer in any exchanger is governed by the following equation – Equation-1 where, Q = overall heat transfer rate U = Overall heat transfer coefficient

What are the mechanical design calculations for a heat exchanger design?

With the heat exchanger geometry defined, the mechanical design calculations must be performed to ensure that the heat exchanger design is valid for the design pressure and conditions. The typical calculations are: Calculation of shell wall thickness. Calculation of nozzle wall thickness.

How do you calculate LMTD in a heat exchanger?

It is calculated with the following equation. ΔT 2 → the temperature difference between hot and cold fluids at the other end of the heat exchanger. However the LMTD is valid only for heat exchanger with one shell pass and one tube pass.

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