CALC_CMAX

This function computes the larger of the two stream heat-capacity rates in a heat exchanger using mass flow and specific heat for each stream. It is used in effectiveness-NTU and P-NTU analysis to normalize heat transfer performance.

The calculation is C_{max} = \max(m_h C_{p,h},\; m_c C_{p,c}).

Excel Usage

=CALC_CMAX(mh, mc, Cph, Cpc)

mh (float, required): Mass flow rate of hot stream (kg/s).
mc (float, required): Mass flow rate of cold stream (kg/s).
Cph (float, required): Heat capacity of hot stream (J/kg/K).
Cpc (float, required): Heat capacity of cold stream (J/kg/K).

Returns (float): Maximum heat capacity rate (W/K).

Example 1: Cmax for example flows

Inputs:

mh	mc	Cph	Cpc
22	5.5	2200	4400

Excel formula:

=CALC_CMAX(22, 5.5, 2200, 4400)

Expected output:

48400

Example 2: Cmax for equal flow rates

Inputs:

mh	mc	Cph	Cpc
3	3	2000	1800

Excel formula:

=CALC_CMAX(3, 3, 2000, 1800)

Expected output:

6000

Example 3: Cmax with larger hot stream

Inputs:

mh	mc	Cph	Cpc
10	2	4200	3000

Excel formula:

=CALC_CMAX(10, 2, 4200, 3000)

Expected output:

42000

Example 4: Cmax with larger cold stream

Inputs:

mh	mc	Cph	Cpc
2	8	3500	4200

Excel formula:

=CALC_CMAX(2, 8, 3500, 4200)

Expected output:

33600

Python Code

Show Code

from ht.hx import calc_Cmax as hx_calc_Cmax

def calc_Cmax(mh, mc, Cph, Cpc):
    """
    Calculate the maximum heat capacity rate of two streams.

    See: https://ht.readthedocs.io/en/latest/ht.hx.html

    This example function is provided as-is without any representation of accuracy.

    Args:
        mh (float): Mass flow rate of hot stream (kg/s).
        mc (float): Mass flow rate of cold stream (kg/s).
        Cph (float): Heat capacity of hot stream (J/kg/K).
        Cpc (float): Heat capacity of cold stream (J/kg/K).

    Returns:
        float: Maximum heat capacity rate (W/K).
    """
    try:
        result = hx_calc_Cmax(mh=mh, mc=mc, Cph=Cph, Cpc=Cpc)
        return result
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

mh *

Mass flow rate of hot stream (kg/s).

mc *

Mass flow rate of cold stream (kg/s).

Cph *

Heat capacity of hot stream (J/kg/K).

Cpc *

Heat capacity of cold stream (J/kg/K).