The Influence of Availability Costs on Optimal Heat Exchanger Design

1988 ◽  
Vol 110 (4a) ◽  
pp. 830-835 ◽  
Author(s):  
L. C. Witte
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Operating Costs ◽  
Second Law ◽  
Optimal Point ◽  
Optimal Heat ◽  
Available Energy ◽  
Heat Exchanger Design ◽  
A New Technique ◽  
Made In

Optimizing heat exchangers based on second-law rather than first-law considerations ensures that the most efficient use of available energy is being made. In this paper, second-law efficiency is used to develop a new technique for optimizing the design of heat exchangers. The method relates the operating costs of the exchanger to the destruction of availability caused by the exchanger operation. The destruction of availability is directly related to the second-law efficiency of the exchanger. This allows one to find the NTU at which the benefits of reduced availability losses are offset by the costs of added area; this is the optimal point. It can be difficult to determine the proper cost of irreversibility to be used in the optimization process. This issue can be handled by including the irreversibility cost in a dimensionless parameter that represents the ratio of annual ownership costs to annual operating costs that include irreversibility costs. In this way, each heat exchanger designer can estimate the costs of irreversibilities for his particular system, and then use the generalized method that is developed herein for determining the optimal heat exchanger size. The method is applicable to any heat exchanger for which the ε-NTU-R relationships are known.

Two Principles of Differential Second Law Heat Exchanger Design

1991 ◽  
Vol 113 (2) ◽  
pp. 329-336 ◽  
Author(s):  
R. B. Evans ◽  
M. R. von Spakovsky
Keyword(s):  
Heat Exchanger ◽  
Temperature Difference ◽  
Heat Exchangers ◽  
Second Law ◽  
First Principle ◽  
Heat Exchanger Design ◽  
Geometric Average ◽  
Mean Temperature ◽  
Second Law Analysis ◽  
Basic Treatment

In this paper, two fundamental principles of differential Second Law analysis are set forth for heat exchanger design. The first principle defines a Second Law temperature, while the second principle defines a Second Law temperature difference. The square of the ratio of the Second Law temperature difference to the Second Law temperature is shown always to be equal to the negative of the partial derivative of the rate of entropy generation (for heat transfer) with respect to the overall conductance of the heat exchanger. For the basic design of elementary heat exchangers, each of these two Second Law quantities is shown to take the form of a simple geometric average. Nonelementary considerations result in corrected geometric averages, which relate directly to the corrected log-mean temperature difference. Both the corrected log-mean temperature difference (nonelementary considerations) and the uncorrected or just log-mean temperature difference (elementary considerations) are widely used in heat exchanger analysis. The importance of these two principles in both exergy and essergy analysis is illustrated by a unified basic treatment of the optimum design of elementary heat exchangers. This results in a single optimization expression for all flow arrangements (i.e., counterflow, parallel flow, and certain crossflow cases).

On Application of the Second Law to Heat Exchangers

2008 ◽  
Author(s):  
Ahmad Fakheri
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Performance Measure ◽  
Second Law ◽  
Design Information ◽  
Entropy Minimization ◽  
Heat Exchanger Design ◽  
Entropy Flux ◽  
Measure Entropy

The application of entropy minimization to heat exchangers leads to inconsistent results and does not yield much useful design information. In this paper it is shown that in applying the second law to heat exchangers, three assumptions are typically made that are incorrect and that once they are removed, useful and consistent results are obtained from the second law. In addition, a new performance measure, entropy flux is introduced and it is shown that the objective in heat exchanger design should be the maximization of the entropy flux.

Basis of the Tubesheet Heat Exchanger Design Rules Used in the French Pressure Vessel Code

1992 ◽  
Vol 114 (1) ◽  
pp. 124-131 ◽  
Author(s):  
F. Osweiller
Keyword(s):  
Heat Exchanger ◽  
Pressure Vessel ◽  
Heat Exchangers ◽  
Tube Bundle ◽  
Outer Edge ◽  
Design Rules ◽  
Effective Elastic Constants ◽  
Heat Exchanger Design ◽  
Solid Plate ◽  
Main Basis

For about 40 years most tubesheet exchangers have been designed according to the standards of TEMA. Partly due to their simplicity, these rules do not assure a safe heat-exchanger design in all cases. This is the main reason why new tubesheet design rules were developed in 1981 in France for the French pressure vessel code CODAP. For fixed tubesheet heat exchangers, the new rules account for the “elastic rotational restraint” of the shell and channel at the outer edge of the tubesheet, as proposed in 1959 by Galletly. For floating-head and U-tube heat exchangers, the approach developed by Gardner in 1969 was selected with some modifications. In both cases, the tubesheet is replaced by an equivalent solid plate with adequate effective elastic constants, and the tube bundle is simulated by an elastic foundation. The elastic restraint at the edge of the tubesheet due the shell and channel is accounted for in different ways in the two types of heat exchangers. The purpose of the paper is to present the main basis of these rules and to compare them to TEMA rules.

A Heuristic for Designing Hybrid Compact Heat Exchangers for Nuclear Applications

2021 ◽  
Author(s):  
Venkata Rajesh Saranam ◽  
Peter Carter ◽  
Kyle Rozman ◽  
Ömer Dogan ◽  
Brian K. Paul
Keyword(s):  
Heat Exchanger ◽  
Diffusion Bonding ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
Nuclear Industry ◽  
Compact Heat Exchangers ◽  
Bonding Parameters ◽  
Heat Exchanger Design ◽  
Creep Fatigue ◽  
Gen Iv

Abstract Hybrid compact heat exchangers (HCHEs) are a potential source of innovation for intermediate heat exchangers in nuclear industry, with HCHEs being designed for Gen-IV nuclear power applications. Compact heat exchangers are commonly fabricated using diffusion bonding, which can provide challenges for HCHEs due to resultant non-uniform stress distributions across hybrid structures during bonding, leading to variations in joint properties that can compromise performance and safety. In this paper, we introduce and evaluate a heuristic for determining whether a feasible set of diffusion bonding conditions exist for producing HCHE designs capable of meeting regulatory requirements under nuclear boiler and pressure vessel codes. A diffusion bonding model for predicting pore elimination and structural analyses are used to inform the heuristic and a heat exchanger design for 316 stainless steel is used to evaluate the efficacy of the heuristic to develop acceptable diffusion bonding parameters. A set of diffusion bonding conditions were identified and validated experimentally by producing various test coupons for evaluating bond strength, ductility, porosity, grain size, creep rupture, creep fatigue and channel deviation. A five-layer hybrid compact heat exchanger structure was fabricated and tensile tested demonstrating that the bonding parameters satisfy all criteria in this paper for diffusion bonding HCHEs with application to the nuclear industry.

Optimal Configuration Selection Through Experimental Tests on Branched Heat Exchanger With R134 Organic Fluid

2019 ◽  
Author(s):  
Roberto Capata ◽  
Alfonso Calabria
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Test Bench ◽  
Experimental Tests ◽  
Constructal Theory ◽  
Detailed Knowledge ◽  
Nusselt Numbers ◽  
Configuration Selection ◽  
Efflux Velocity ◽  
Made In

Abstract The aim of this work the analysis of compact branched heat exchangers, by measuring thermal efficiency and the pressure drop in several experimental tests. Three different heat exchanger configuration have been considered. In the first device, the constant efflux velocity, in the internal channels, was imposed. The second exchanger was realized by imposing constant the value of the Reynolds number. The last device was created according to the instructions of the constructal theory. All three exchangers are aluminum made. In addition, in order to have a more detailed knowledge of the phenomenon and to identify what are the parameters that govern heat transfer, an organic fluid has been used and tested. In our case R1234 organic fluid. It was therefore necessary to realize an appropriate test bench for the use of the organic fluid. Once realized, several tests were conducted. Finally in order to be able to indicate which configuration results the optimal one, the Prandtl and Nusselt numbers were obtained and compared.

Earth-Air and Earth-Water Heat Exchanger Design for Ventilation Systems in Buildings

2010 ◽  
Author(s):  
Michel De Paepe ◽  
Christophe T’Joen ◽  
Arnold Janssens ◽  
Marijke Steeman
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Design Methodology ◽  
Energy Use ◽  
Polyethylene Tube ◽  
Dynamic Simulations ◽  
Tube Heat Exchanger ◽  
Heat Exchanger Design ◽  
The Earth ◽  
Software Codes

Earth-air heat exchangers are often used for (pre)heating or (pre)cooling of ventilation air in low energy or passive house standard buildings. Several studies have been published in the passed about the performance of these earth-air heat exchangers [1–8]. Often this is done in relation to the building energy use. Several software codes are available with which the behaviour of the earth-air heat exchanger can be simulated. De Paepe and Janssens published a simplified design methodology for earth-air heat exchangers, based on thermal to hydraulic performance optimisation [7]. Through dynamic simulations and measurements it was shown that the methodology is quite conservative [9–10]. Hollmu¨ller added an earth-air heat exchanger model to TRNSYS [11]. In stead of using earth-air heat exchangers, earth-water heat exchangers are now getting more attention. In this system the ventilation air is indirectly cooled/heated with the water flow in a fin-tube heat exchanger in the inlet of the ventilation channel. The water-glycol mixture transfers heat with the earth by flowing through e.g. a polyethylene tube. In the second part of this paper a design methodology is first derived and then applied to this type of system.

Analysis and Design of the “Solar One” Thermal Storage Subsystem Heat Exchangers

1984 ◽  
Vol 106 (3) ◽  
pp. 279-285
Author(s):  
F. R. Weiner
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Thermal Storage ◽  
Design Solution ◽  
Process Conditions ◽  
Analysis And Design ◽  
Heat Exchanger Design ◽  
Central Receiver ◽  
Final Design ◽  
Design Requirements

This paper describes the analysis and design of the five kinds of heat exchangers used in the thermal storage subsystem of the 10 MWe Solar Central Receiver Pilot Plant, now becoming more known as “Solar One.” The paper discusses the practices and standards used in the designs of the heat exchangers, lists the heat exchanger design requirements, and discusses the process conditions. The design assumptions and constraints, the geometrical considerations, and the tradeoff studies that were conducted to optimize the designs are also discussed. A description of each heat exchanger reveals the final design solution. Novel and unique features of a power plant that must operate on a daily sun-cycle are identified.

A Numerical Algorithm and a Graphical Method to Size a Heat Exchanger

2011 ◽  
Author(s):  
Torsten Berning
Keyword(s):  
Heat Exchanger ◽  
Numerical Algorithm ◽  
Heat Exchangers ◽  
Graphical Method ◽  
Application Software ◽  
Microsoft Excel ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient ◽  
Heat Exchanger Design ◽  
Shell And Tube

This paper describes the development of a numerical algorithm and a graphical method that can be employed in order to determine the overall heat transfer coefficient inside heat exchangers. The method is based on an energy balance and utilizes the spreadsheet application software Microsoft Excel™. The application is demonstrated in an example for designing a single pass shell and tube heat exchanger that was developed in the Department of Materials Technology of the Norwegian University of Science and Technology (NTNU) where water vapor is superheated by a secondary oil cycle. This approach can be used to reduce the number of hardware iterations in heat exchanger design.

scholarly journals HAZARDS OF STANDARD HEAT-EXCHANGE EQUIPMENT IMPLEMENTATION IN CHEMICAL TECHNOLOGY WITHOUT CONSIDERING THE PROCESS SPECIFIC CHARACTER

2016 ◽  
Vol 11 (5) ◽  
pp. 57-64
Author(s):  
K. O. Goncharuk ◽  
D. S. Kornilova ◽  
D. S. Yakovlev ◽  
N. N. Prokhorenko
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Heat Transfer Process ◽  
Chemical Plants ◽  
Standard Equipment ◽  
Tube Heat Exchanger ◽  
Standard Heat ◽  
Conditions Of Work ◽  
Made In

Standard equipment is a considerable part of modern equipment of chemical plants. In particular, standard heat exchangers are widespread. Possible deviations in the operation of heat exchangers at plants from the preset parameters of their operation can lead to deterioration of the operation of the whole technological system. For this reason an attempt is made in the article to suggest a hypothesis explaining what can lead to disfunction in the operation of heat exchangers. The authors use a method of calculating technological reliability to study the operability of a vertical shell-and-tube heat exchanger. First, the size of the heat transfer surface of the vertical heat exchanger is calculated for specific conditions of work, and a standard device is chosen. Then a method of calculating the technological reliability of the calculated and standard heat exchangers is applied. An operating problem is solved on the assumption that external impacts on the heat transfer process are not fixed, but varied and are within their acceptable intervals. After comparing the probability of the workability of the calculated heat exchanger and of the chosen standard apparatus, a conclusion is made about the expediency of using the standard heat exchanger.

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