Compact High Effectiveness Parallel Plate Heat Exchangers

Marquardt, Eric D.; Radebaugh, Ray

doi:10.1007/0-306-47919-2_67

Cited by 10 publications

(8 citation statements)

References 3 publications

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“…(1) and (2), in the boundary conditions (4) and (5), and in the normalization condition (21), rewritten here as F k j(l) = 0, we obtain a hierarchy of problems that can be solved successively at different orders for the unknowns /" and F ki . Thus, to first-order, we have …”

Section: Numerical Solution and Discussion Of Resultsmentioning

confidence: 99%

“…Thus, they are currently used in miniaturized reaction systems involving heterogeneously catalyzed gas-phase reactions [ 1 ], in thermoelectric generators that convert low-grade thermal energy into electrical power [2,3], and in thermoacoustic engines and refrigerators [4]. In addition, they are a key component of many cryogenic systems [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

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Laminar counterflow parallel-plate heat exchangers: Exact and approximate solutions

Vera

Liñán

2010

International Journal of Heat and Mass Transfer

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Multilayered, counterflow, parallel-plate heat exchangers are analyzed numerically and theoretically. The analysis, carried out for constant property fluids, considers a hydrodynamically developed laminar flow and neglects longitudinal conduction both in the fluid and in the plates. The solution for the temperature field involves eigenfunction expansions that can be solved in terms of Whittaker functions using standard symbolic algebra packages, leading to analytical expressions that provide the eigenvalues numerically. It is seen that the approximate solution obtained by retaining the first two modes in the eigenfunction expansion provides an accurate representation for the temperature away from the entrance regions, specially for long heat exchangers, thereby enabling simplified expressions for the wall and bulk temperatures, local heat-transfer rate, overall heat-transfer coefficient, and outlet bulk temperatures. The agreement between the numerical and theoretical results suggests the possibility of using the analytical solutions presented herein as benchmark problems for computational heat-transfer codes.

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Section: Numerical Solution and Discussion Of Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Laminar counterflow parallel-plate heat exchangers: Exact and approximate solutions

Vera

Liñán

2010

International Journal of Heat and Mass Transfer

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“…Baseline calculations assume 97% effectiveness, but ε is also varied to assess its impact. Although this value might seem optimistic, measured effectivenesses as high as 97 − 98 % have been reported for compact counterflow heat exchangers (specially in the context of cryogenic applications), and higher efficiencies can be achieved if a careful design that minimises axial conductivity and flow maldistribution is employed [43,44,45]. A 1% pressure loss is assumed for the working fluid side of all heat exchangers except those rejecting heat to the environment, for which pressure losses are neglected on the grounds that these only require small surface areas.…”

Section: Heat Exchangersmentioning

confidence: 99%

Thermodynamic analysis and optimisation of a combined liquid air and pumped thermal energy storage cycle

Farres-Antunez

Xue

White

2018

Journal of Energy Storage

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Pumped thermal energy storage (PTES) and liquid air energy storage (LAES) are two large-scale electricity storage technologies that store energy in the form of thermal exergy. This is achieved by operating mechanicallydriven thermodynamic cycles between thermally insulated storage tanks. Both technologies are free from geographic restrictions that apply to pumped hydro and most compressed air storage. The present paper describes a novel, combined system in which PTES operates as a topping cycle and LAES as a bottoming cycle. The fundamental advantage is that the cold thermal reservoirs that would be required by the two separate cycles are replaced by a single heat exchanger that acts between them, thereby saving significant amounts of storage media per unit of energy stored. In order to reach cryogenic temperatures, the PTES cycle employs helium as the working fluid, while the LAES cycle uses supercritical air (at around 150 bar) which is cooled sufficiently to be fully liquefied upon expansion, thus avoiding recirculation of leftover vapour. A thermodynamic study of a baseline configuration of the combined cycle is presented and results are compared with those of the separate systems. These indicate that the new cycle has a similar round-trip efficiency to that of the separate systems while providing a significantly larger energy density. Furthermore, three adaptations of the base-case combined cycle are proposed and optimised. The best of these adaptations achieves an increase in thermodynamic efficiency of about 10 percent points (from 60 % to 70 %), therefore significantly exceeding the individual cycles in both energy density and efficiency.

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“…In the finite space, high heat transfer effectiveness can be achieved by enhancing the heat exchanger's compactness, including reducing the hydraulic diameter and increasing the area to volume ratio. 9 With the advance of micro-electro-mechanicalsystems technology, the advantages of the microchannel are highlighted. The microchannel combined with the J-T cooler has been considered because of the microchannel's small diameter, the large ratio of area-to-volume, the high surface heat transfer coefficient and the heat transfer effectiveness up to 99%.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical analysis of the multilayer distributed Joule‐Thomson cooler with pillars

Geng

Cui

She

et al. 2020

Intl J of Energy Research

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The conventional Joule-Thomson cooler is not compact in heat exchanger and insufficient in cooling capacity, which is limited in applying integrated electronics. However, microchannels with pillars are effective in increasing the area to volume ratio and enhancing heat transfer through the presence of vortex. Besides, multilayer microchannels are essential to enlarge the mass-flow rate in the cooler. In this study, a multilayer distributed J-T cooler with pillars is investigated. A new mathematical model of the cooler is developed and validated against the experimental data; the relative errors of the temperature and mass-flow rate are both within 5%. Furthermore, the distribution of temperature and pressure in the microchannel is analyzed by the model calculation. Numerical results show that the temperature of the high-pressure fluid decreased slightly under the influence of the heat exchange and distributed J-T effect. When the inlet pressures are 3.00, 4.00 and 5.40 MPa, the cold-end temperatures are 233.0, 185.8 and 161.2 K, respectively, with the cooling capacity reaching 2.25, 3.40 and 3.87 W, respectively. In addition, the influences of the axial heat conduction and heat leakage on the cooling performance are analyzed by using the models. The temperature rise of the cold end increases by 6.8 and 6.2 K at 5.40 MPa, respectively, considering the above two factors. The simulation model provides a useful tool for the J-T cooler.

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Compact High Effectiveness Parallel Plate Heat Exchangers

Cited by 10 publications

References 3 publications

Laminar counterflow parallel-plate heat exchangers: Exact and approximate solutions

Laminar counterflow parallel-plate heat exchangers: Exact and approximate solutions

Thermodynamic analysis and optimisation of a combined liquid air and pumped thermal energy storage cycle

Experimental and numerical analysis of the multilayer distributed Joule‐Thomson cooler with pillars

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