Thermal Design and Modeling of Shell and Tube Heat Exchangers Combining PTSC and ORC Systems

A design problem for a shell and tube heat exchanger that combines a parabolic trough solar collector and an organic Rankine cycle was formed to find the desired output parameters for certain fluid types and operating conditions. The design problem was modeled mathematically and the equations originating from this model were solved using Engineering Equation Solver. A parametric study was then performed to study the effect of some of the important parameters (e.g., pipe diameter, pipe length, and baffle spacing and configuration) on the output parameters (e.g., overall heat transfer coefficient and pressure drop). Furthermore, an exergy assessment was conducted to study the effect of solar radiation and different working fluids on the exergetic efficiency of the shell and tube heat exchanger. The results showed that noncontinuous baffle type yielded a higher shell-side heat transfer coefficient and thus increased the overall heat transfer coefficient. On the other hand, when the solar radiation changed from 800 to 2700W/m², the overall heat transfer coefficient decreased from 1579 to 1491W/m²K, the heat transfer surface area increased from 7 to 25.25m², and the pumping power increased from 0.8723 to 0.9227kW.