Air cooler sizing and rating (ht.air_cooler)¶

ht.air_cooler.
Ft_aircooler
(Thi, Tho, Tci, Tco, Ntp=1, rows=1)[source]¶ Calculates logmean temperature difference correction factor for a crossflow heat exchanger, as in an Air Cooler. Method presented in [1], fit to other’s nonexplicit work. Error is < 0.1%. Requires number of rows and tube passes as well as stream temperatures.
\[ \begin{align}\begin{aligned}F_T = 1  \sum_{i=1}^m \sum_{k=1}^n a_{i,k}(1r_{1,m})^k\sin(2i\arctan R)\\R = \frac{T_{hi}  T_{ho}}{T_{co}T_{ci}}\\r_{1,m} = \frac{\Delta T_{lm}}{T_{hi}  T_{ci}}\end{aligned}\end{align} \]Parameters:  Thi : float
Temperature of hot fluid in [K]
 Tho : float
Temperature of hot fluid out [K]
 Tci : float
Temperature of cold fluid in [K]
 Tco : float
Temperature of cold fluid out [K]
 Ntp : int
Number of passes the tubeside fluid will flow through []
 rows : int
Number of rows of tubes []
Returns:  Ft : float
Logmean temperature difference correction factor []
Notes
This equation assumes that the hot fluid is tubeside, as in the case of air coolers. The model is not symmetric, so ensure to switch around the inputs if using this function for other purposes.
This equation appears in [1]. It has been verified. For some cases, approximations are made to match coefficients with the number of tube passes and rows provided. 16 coefficients are used for each case; 8 cases are considered:
 1 row 1 pass
 2 rows 1 pass
 2 rows 2 passes
 3 rows 1 pass
 3 rows 3 passes
 4 rows 1 pass
 4 rows 2 passes
 4 rows 4 passes
References
[1] (1, 2, 3) Roetzel, W., and F. J. L. Nicole. “Mean Temperature Difference for Heat Exchanger DesignA General Approximate Explicit Equation.” Journal of Heat Transfer 97, no. 1 (February 1, 1975): 58. doi:10.1115/1.3450288 Examples
>>> Ft_aircooler(Thi=125., Tho=45., Tci=25., Tco=95., Ntp=1, rows=4) 0.5505093604092708