LMTD

Excel Usage

=LMTD(Thi, Tho, Tci, Tco, counterflow)

• Thi (float, required): Inlet temperature of hot fluid (K)
• Tho (float, required): Outlet temperature of hot fluid (K)
• Tci (float, required): Inlet temperature of cold fluid (K)
• Tco (float, required): Outlet temperature of cold fluid (K)
• counterflow (bool, optional, default: true): True for counterflow, False for co-current. Default True.

Returns (float): LMTD (K)

Examples

Example 1: Counterflow LMTD

Inputs:

Thi	Tho	Tci	Tco
100	60	30	40.2

Excel formula:

=LMTD(100, 60, 30, 40.2)

Expected output:

43.20041

Example 2: Parallel flow LMTD

Inputs:

Thi	Tho	Tci	Tco	counterflow
100	60	30	40.2	false

Excel formula:

=LMTD(100, 60, 30, 40.2, FALSE)

Expected output:

39.75251

Example 3: Equal temperature differences

Inputs:

Thi	Tho	Tci	Tco
100	60	60	20

Excel formula:

=LMTD(100, 60, 60, 20)

Expected output:

80

Example 4: Crossflow LMTD case

Inputs:

Thi	Tho	Tci	Tco
150	100	80	120

Excel formula:

=LMTD(150, 100, 80, 120)

Expected output:

24.66303

Python Code

from ht.core import LMTD

def lmtd(Thi, Tho, Tci, Tco, counterflow=True):
    """
    Log-mean temperature difference.

    See: https://ht.readthedocs.io/en/latest/ht.core.html#ht.core.LMTD

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

    Args:
        Thi (float): Inlet temperature of hot fluid (K)
        Tho (float): Outlet temperature of hot fluid (K)
        Tci (float): Inlet temperature of cold fluid (K)
        Tco (float): Outlet temperature of cold fluid (K)
        counterflow (bool, optional): True for counterflow, False for co-current. Default True. Default is True.

    Returns:
        float: LMTD (K)
    """
    try:
        return float(LMTD(Thi=float(Thi), Tho=float(Tho), Tci=float(Tci), Tco=float(Tco), counterflow=counterflow))
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator