Calculation of the Heat Transfer Surface Area of Heat Exchangers for Waste Heat Recovery with the Kaline Cycle

The purpose is to calculate the heat transfer surface area of the shell and tube heat exchanger aiming recovery to waste heat with Kalina cycles. The procedure for calculating the area was implemented in software Engineering Equation Solver (EES), where the calculation of the LMTD was held with the existing functions in EES for the correction factor calculation, and additional correlations were implemented in the EES to calculate the thermodynamic properties of NH3-H2O mixture and to determine the transport properties of the phase change regions. As input data for the calculations were employed geometry (internal and external diameters of the tubes, the exchanger arrangement, geometrical arrangement of the tubes) and the heat balance of the heat exchanger (temperature, concentration of NH3-H2O mixture, etc.) obtained by simulation of the Kalina cycle. As an example of the results that were obtained for the evaporator, the overall heat transfer coefficient was found to be 108,5 W/m2K and the heat transfer surface area of 1170 m2. This value of the overall heat transfer coefficient is within the ranges reported in the literature by other researchers.