Topic
Regenerative heat exchanger
About: Regenerative heat exchanger is a research topic. Over the lifetime, 9395 publications have been published within this topic receiving 82137 citations.
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25 Jul 2003
TL;DR: In this paper, the authors present a classification of Heat Exchanger design according to the number of fluids and their properties, such as surface heat transfer, flow arrangement, and number of transfer units.
Abstract: Preface. Nomenclature. 1 Classification of Heat Exchangers. 1.1 Introduction. 1.2 Classification According to Transfer Processes. 1.3 Classification According to Number of Fluids. 1.4 Classification According to Surface Compactness. 1.5 Classification According to Construction Features. 1.6 Classification According to Flow Arrangements. 1.7 Classification According to Heat Transfer Mechanisms. Summary. References. Review Questions. 2 Overview of Heat Exchanger Design Methodology. 2.1 Heat Exchanger Design Methodology. 2.2 Interactions Among Design Considerations. Summary. References. Review Questions. Problems. 3 Basic Thermal Design Theory for Recuperators. 3.1 Formal Analogy between Thermal and Electrical Entities. 3.2 Heat Exchanger Variables and Thermal Circuit. 3.3 The ?(Epsilon)-NTU Method. 3.4 Effectiveness - Number of Transfer Unit Relationships. 3.5 The P-NTU Method. 3.6 P-N TU R elat ionships. 3.7 The Mean Temperature Difference Method. 3.8 F Factors for Various Flow Arrangements. 3.9 Comparison of the ?(Epsilon)-NTU, P-NTU, and MTD Methods. 3.10 The ?(Psi)-P and P1-P2 Methods. 3.11 Solution Methods for Determining Exchanger Effectiveness. 3.12 Heat Exchanger Design Problems. Summary. References. Review Questions. Problems. 4 Additional Considerations for Thermal Design of Recuperators. 4.1 Longitudinal Wall Heat Conduction Effects. 4.2 Nonuniform Overall Heat Transfer Coefficients. 4.3 Additional Considerations for Extended Surface Exchangers. 4.4 Additional Considerations for Shell-and-Tube Exchangers. Summary. References. Review Questions. Problems. 5 Thermal Design Theory for Regenerators. 5.1 Heat Transfer Analysis. 5.2 The ?(Epsilon)-NTUo Method. 5.3 The ?(Lambda)-?(Pi) Method. 5.4 Influence of Longitudinal Wall Heat Conduction. 5.5 Influence of Transverse Wall Heat Conduction. 5.6 Influence of Pressure and Carryover Leakages. 5.7 Influence of Matrix Material, Size, and Arrangement. Summary. References. Review Questions. Problems. 6 Heat Exchanger Pressure Drop Analysis. 6.1 Introduction. 6.2 Extended Surface Heat Exchanger Pressure Drop. 6.3 Regenerator Pressure Drop. 6.4 Tubular Heat Exchanger Pressure Drop. 6.5 Plate Heat Exchanger Pressure Drop. 6.6 Pressure Drop Associated with Fluid Distribution Elements. 6.7 Pressure Drop Presentation. 6.8 Pressure Drop Dependence on Geometry and Fluid Properties. Summary. References. Review Questions. Problems. 7 Surface Basic Heat Transfer and Flow Friction Characteristics. 7.1 Basic Concepts. 7.2 Dimensionless Groups. 7.3 Experimental Techniques for Determining Surface Characteristics. 7.4 Analytical and Semiempirical Heat Transfer and Friction Factor Correlations for Simple Geometries. 7.5 Experimental Heat Transfer and Friction Factor Correlations for Complex Geometries. 7.6 Influence of Temperature-Dependent Fluid Properties. 7.7 Influence of Superimposed Free Convection. 7.8 Influence of Superimposed Radiation. Summary. References. Review Questions. Problems. 8 Heat Exchanger Surface Geometrical Characteristics. 8.1 Tubular Heat Exchangers. 8.2 Tube-Fin Heat Exchangers. 8.3 Plate-Fin Heat Exchangers. 8.4 Regenerators with Continuous Cylindrical Passages. 8.5 Shell-and-Tube Exchangers with Segmental Baffles. 8.6 Gasketed Plate Heat Exchangers. Summary. References. Review Questions. 9 Heat Exchanger Design Procedures. 9.1 Fluid Mean Temperatures. 9.2 Plate-Fin Heat Exchangers. 9.3 Tube-Fin Heat Exchangers. 9.3.4 Core Mass Velocity Equation. 9.4 Plate Heat Exchangers. 9.5 Shell-and-Tube Heat Exchangers. 9.6 Heat Exchanger Optimization. Summary. References. Review Questions. Problems. 10 Selection of Heat Exchangers and Their Components. 10.1 Selection Criteria Based on Operating Parameters. 10.2 General Selection Guidelines for Major Exchanger Types. 10.3 Some Quantitative Considerations. Summary. References. Review Questions. Problems. 11 Thermodynamic Modeling and Analysis. 11.1 Introduction. 11.2 Modeling a Heat Exchanger Based on the First Law of Thermodynamics. 11.3 Irreversibilities in Heat Exchangers. 11.4 Thermodynamic Irreversibility and Temperature Cross Phenomena. 11.5 A Heuristic Approach to an Assessment of Heat Exchanger Effectiveness. 11.6 Energy, Exergy, and Cost Balances in the Analysis and Optimization of Heat Exchangers. 11.7 Performance Evaluation Criteria Based on the Second Law of Thermodynamics. Summary. References. Review Questions. Problems. 12 Flow Maldistribution and Header Design. 12.1 Geometry-Induced Flow Maldistribution. 12.2 Operating Condition-Induced Flow Maldistribution. 12.3 Mitigation of Flow Maldistribution. 12.4 Header and Manifold Design. Summary. References. Review Questions. Problems. 13 Fouling and Corrosion. 13.1 Fouling and its Effect on Exchanger Heat Transfer and Pressure Drop. 13.2 Phenomenological Considerations of Fouling. 13.3 Fouling Resistance Design Approach. 13.4 Prevention and Mitigation of Fouling. 13.5 Corrosion in Heat Exchangers. Summary. References. Review Questions. Problems. Appendix A: Thermophysical Properties. Appendix B: ?(Epsilon)-NTU Relationships for Liquid-Coupled Exchangers. Appendix C: Two-Phase Heat Transfer and Pressure Drop Correlations. C.1 Two-Phase Pressure Drop Correlations. C.2 Heat Transfer Correlations for Condensation. C.3 Heat Transfer Correlations for Boiling. Appendix D: U and CUA Values for Various Heat Exchangers. General References on or Related to Heat Exchangers. Index.
2,006 citations
TL;DR: In this article, a new process for CO2 removal from flue gas using the reaction CaO + CO2 ↔ CaCO3 was proposed, which consists of two fluidized bed reactors connected by solid transportation lines.
Abstract: A new process is proposed for CO2 removal from flue gas using the reaction CaO + CO2 ↔ CaCO3. This process consists of two fluidized bed reactors connected by solid transportation lines. In one reactor (absorber), CO2 in the flue gas is captured by CaO at 873 K and the produced CaCO3 is transported to another reactor (regenerator), in which CaCO3 is decomposed to CaO at 1223 K. The produced CaO is transported to the absorber again. The heat of decomposition in the regenerator is supplied by feeding coal and pure oxygen, thus the flue gas from the regenerator is high purity CO2 (>95%, dry base). In this work, a conceptual study is conducted for material balance, heat balance, power generation, and power consumption for O2 production and CO2 liquefaction (compression). Also, a kinetic study of CaO+CO2 → CaCO3 was conducted to design the absorber. The required bed height of the absorber was calculated by use of a bubbling fluidized bed model. The bed height was found to be determined not by the chemical reaction rate but by the arrangement of heat transfer tubes for heat recovery.
661 citations
TL;DR: In this article, a reciprocating magnetic refrigerator that uses water as a heat transfer fluid has been demonstrated to achieve cooling powers exceeding 500 watts at coefficients of performance of 6 or more.
Abstract: Magnetic refrigeration has been viewed as primarily a cryogenic technology because the necessary high magnetic fields are most easily provided by superconducting magnets. However, some of the largest magnetocaloric effects are exhibited by gadolinium-based alloys near room temperature. Ames Laboratory and Astronautics Corporation of America have been collaborating to apply such materials to large-scale commercial and industrial cooling near room temperature. Astronautics has designed and operated a reciprocating magnetic refrigerator that uses water as a heat transfer fluid. The device uses the active magnetic regeneration concept of recent cryogenic devices, but in contrast to the cryogenic case, the heat capacity of the fluid in the pores of the regenerator bed is comparable to that of the solid matrix. Using a 5 T field, the refrigerator reliably produces cooling powers exceeding 500 watts at coefficients of performance of 6 or more. This record performance puts magnetic refrigeration in a class with the best of current technology, vapor cycle refrigeration, without having to use volatile, environmentally hazardous fluids.
643 citations
450 citations
TL;DR: In this paper, the ideal gain and maximum energy conversion rates were derived for differentially heated regenerators and the low power gain measurements were made to verify the derived gain equation and practical engines and heat pumps using this principle.
Abstract: The propagation of acoustical waves through a differentially heated regenerator results in gas in the regenerator undergoing a Stirling thermodynamic cycle. One direction of wave propagation results in amplification of the waves and conversion of thermal energy into acoustical energy. The opposite direction results in acoustical energy being used to pump heat. The ideal gain and maximum energy conversion rates are derived in this paper. Low power gain measurements were made which verify the derived gain equation. Practical engines and heat pumps using this principle are discussed.
414 citations