Exergoeconomic optimization of a shell-and-tube heat exchanger

The paper presents an economic optimization of a STHX with two commonly adopted (i.e., Kern and Bell-Delaware) and one rarely explored (i.e., Wills-Johnston) methods. A detailed numerical code concerning thermal, hydraulic, exergy, and economic analysis of STHX is developed for all three methods. Normalized sensitivity analysis, parametric study, and Genetic Algorithm are used to ascertain the most influential parameters and optimize the total cost. It is observed that the calculations made using the Wills-Johnston method were reasonably close to the Bell-Delaware method. While the Kern method showed a significant deviation in the shell side calculations because of the several assumptions in this method. The parametric analysis showed that increasing the mass flow rate and the number of baffles increased the operating cost because of an exponential increase in the pressure drops. Finally, the optimization reduced the heat transfer area by ~26.4%, capital cost by ~20%, operational cost by ~50%, total cost by ~22%, and the stream cost by ~21%

Optimizing the Energy Recovery Section in Thermal Desalination Systems for Improved Thermodynamic, Economic, and Environmental Performance

Integration of energy recovery section with thermal desalination systems improves their performance from thermodynamics, economics, and environmental viewpoints. This is because it significantly reduces input energy, heat transfer area, and capital cost requirements. Above all, the system outlet streams can achieve thermal equilibrium with the environment by supplying heat for useful preheating purposes thus reducing the environmental impacts. The plate heat exchangers are generally employed for this purpose as preheaters. The current paper presents a comprehensive investigation and optimization of these heat exchangers for thermal desalination systems applications. An experimentally validated numerical model employing Normalized Sensitivity Analysis and Genetic Algorithm based cost optimization is developed to investigate their performance at assorted operating conditions. The analysis showed that the heat transfer coefficient, pressure drop, and outlet water cost were improved by an increase in feed flow rate. However, with an increased flow rate, the comprehensive output parameter (h/ΔP) decreased due to the high degree increase in pressure drop. Moreover, an increase in the chevron angle reduced the heat transfer coefficient, pressure drop, and water cost. Finally, the optimization lowered the heat transfer area by ~79.5%, capital investment by ~62%, and the outlet cost of the cold stream by ~15.7%. The operational cost is increased due to the increased pressure drop but the overall impact is beneficial as Ctotal of equipment is reduced by ~52.7%

Exergoeconomic and Normalized Sensitivity Analysis of Plate Heat Exchangers: A Theoretical Framework with Application

Heat exchangers are the mainstay of thermal systems and have been extensively used in desalination systems, heating, cooling units, power plants, and energy recovery systems. This chapter demonstrates a robust theoretical framework for heat exchangers investigation based on two advanced tools, i.e., exergoeconomic analysis and Normalized Sensitivity Analysis. The former is applied as a mutual application of economic and thermodynamic analyses, which is much more impactful than the conventional thermodynamic and economic analyses. This is because it allows the investigation of combinatory effects of thermodynamic and fiscal parameters which are not achieved with the conventional methods. Similarly, the Normalized Sensitivity Analysis allows a one-on-one comparison of the sensitivity of output parameters to the input parameters with entirely different magnitudes on a common platform. This rationale comparison is obtained by normalizing the sensitivity coefficients by their nominal values, which is not possible with the conventional sensitivity analyses. An experimentally validated example of a plate heat exchanger is used to demonstrate the application of the proposed framework from a desalination system

A comprehensive design and optimization of an offset strip-fin compact heat exchanger for energy recovery systems

Energy recovery in conventional thermal systems like power plants, refrigeration systems, and air conditioning systems has enhanced their thermodynamic and economic performance. In this regard, compact heat exchangers are the most employed for gas to gas energy recovery because of their better thermal performance. This paper presents an economic optimization of a crossflow plate-fin heat exchanger with offset strip fins. A detailed software-based numerical code for thermal, hydraulic, economic, and exergy analysis is developed for three fin geometries. Genetic Algorithm, parametric, and normalized sensitivity analyses are used to discover the most influential parameters to optimize the total cost. The parametric study showed that with the increase of mass flow rates and plate spacing, outlet stream cost and operating cost increased due to the rise in pressure drops. Finally, the optimization reduced the operational cost by ∼78.5%, stream cost by ∼64.5%, and total cost by ∼76.8%

Exergoeconomic Analysis of Energy Conversion Systems: From Fundamentals to Applications

Exergoeconomic analysis, a simultaneous investigation of exergetic and monetary performance has attained significant attention to analyze and improve the performance of energy conversion systems. This combined analysis allows an individual audit of all the components in the system. The research is particularly useful for multi-component systems to get a better understanding of how effectively each component consumes energy and economic capital. This chapter aims to present a comprehensive theoretical framework for exergoeconomic study of thermal systems. For this purpose, the framework is initially developed for standalone heat exchangers and then extended to commercial-scale thermal desalination systems consisting of preheaters, pumps, evaporators, and compressors, etc. The exergetic and economic values of each stream in the system were evaluated using the developed framework. The sensitivity and parametric analysis of different thermodynamic and economic parameters on the system performance was conducted to study the performance variations. The presented model can be generalized for performance analysis of other systems

Experimental and Numerical Analysis of a Plate Heat Exchanger Using Variable Heat Transfer Coefficient

Thermal design and analysis of heat exchangers are predominantly conducted considering constant heat transfer coefficients. However, these vary along the length and affect the calculations of heat transfer rates and area allocations. The current paper investigates the variations in the heat transfer coefficients in plate heat exchangers (PHX), using different numerical approaches. The heat transfer coefficient is calculated at the inlet, outlet, and systematically selected intermediate points for each method. The analysis is conducted for two different systems, i.e., a laboratory-scale and an industrial scale PHX at different chevron angles. It is concluded that the effect of the variable heat transfer coefficient is more significant for the large-scale heat exchanger due to high flow rates, geometrical specifications, Reynolds number, and thermophysical properties. The deviation of the local heat transfer coefficient along the heat exchanger length is approximately 9–14% and 3–6% for industrial and laboratory scale PHX, while an area deviation of around 15% is observed