Performance of finned tubes used in low-pressure capillary-assisted evaporator of adsorption cooling system

Thimmaiah, Poovanna Cheppudira; Sharafian, Amir; Huttema, Wendell; Osterman, Chantal; Ismail, Ameer; Dhillon, Aashkaran; Bahrami, Majid

doi:10.1016/j.applthermaleng.2016.06.038

Cited by 23 publications

(5 citation statements)

References 24 publications

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“…As was underlined above, the highest total heat transfer rate is equal to Q max = 1140.01 kW and can be obtained for all kinds of tubes, but only for bottom-to-top tube pass arrangement (PA = 3) and the selected optimal operational conditions n and m (Figure 8). However, to minimize operational costs and the negative effect of the hydrostatic pressure of the refrigerant, the n and m should be reduced [30][31][32]. The developed AGENN model allows selecting the optimal mass flow rate of the refrigerant, corresponding to the minimum value n = 0.8 of flooded tubes for each kind of tubes KT, allowing to obtain Q max .…”

Section: The Best Strategy For Heat Transfer Efficiency Of the Evapormentioning

confidence: 99%

“…Falling film evaporators are heat exchangers commonly used in adsorption chillers, as this kind of evaporator provides the most efficient heat transfer conditions [29][30][31][32][33]. Because of the complexity of two-phase flow in the falling film, different factors affect their heat transfer performance, including designing factors (e.g., configuration of enhanced surfaces, tube pass arrangements) and operating factors (e.g., falling film flow rate) [34].…”

Section: Introductionmentioning

confidence: 99%

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A General Approach in Optimization of Heat Exchangers by Bio-Inspired Artificial Intelligence Methods

Krzywański

2019

Energies

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The paper introduces the artificial intelligence (AI) approach as a general method for the design and optimization study of heat exchangers. Genetic Algorithms (GA) and Artificial Neural Networks (ANN) are applied in the paper. An AGENN model, combining Genetic Algorithms with Artificial Neural Networks, was developed and validated against the desired data on a large falling film evaporator. A broad range of operating conditions and geometric configurations are considered in the study. Four kinds of tubes are deliberated, including plain and enhanced tubes. Different tube pass arrangements, i.e., top-to-bottom, bottom-to-top, and side-by-side, are discussed. Finally, the effects of liquid refrigerant mass flow rate, as well as the number of flooded tubes on the performance of the evaporator, are analyzed. The total heat transfer rate of the evaporator, predicted by the model, is in good agreement with the desired data; the maximum error is lower than ±3%. The highest heat transfer rate of the evaporator is 1140.01 kW and corresponds to Turbo EHP tubes, and bottom-to-top tubes pass arrangements, which guarantee the best thermal energy conversion. The presented approach can be referred to as a complementary technique in heat exchanger design procedures, besides the common rating and sizing tasks. It is an effective and alternative method for the existing approaches, considering the complexity of analytical and numerical techniques as well as the high costs of experiments.Construction features of the direct-transfer-type heat exchangers are the base of their classification, according to the geometry of construction criterion. Considerable flexibility in heat exchangers design can be observed for tubular ones where tube diameter, the number of tubes, the tube length, the pitch of the tubes, and the tube arrangement can be easily modified. Tubular heat exchangers can be classified into double-pipe, shell-and-tube and spiral-tube-type heat exchangers as heat transfer coefficients in a spiral tube are higher than those in a straight one. Plate heat exchangers are built of thin plates (plain, wavy, or corrugated) forming flow channels and can be categorized into: gasketed plate (consists of a series of thin plates with corrugation or wavy surfaces that separate the fluids), spiral plate (formed by rolling two long, parallel plates into a spiral), and lamella (Ramen) type of heat exchanger (a set of parallel, thin plate channels or lamellae (flat tubes or rectangular channels) placed longitudinally in a shell) [2].Extended surface heat exchangers contain fins or appendages on primary heat transfer surfaces to increase the heat transfer area (usually on the gas side).According to the heat transfer mechanisms criterion, there can be distinguished: 1. single-phase convection on both sides, 2. single-phase convection on one side and two-phase convection on other side, 3. two-phase convection on both sides.Finally, according to the flow arrangements criterion, the following fluid-flow path through the heat exchanger can exist:...

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Section: The Best Strategy For Heat Transfer Efficiency Of the Evapormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A General Approach in Optimization of Heat Exchangers by Bio-Inspired Artificial Intelligence Methods

Krzywański

2019

Energies

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“…Due to the low operating pressures in the 760-2340 Pa range, the evaporator of the adsorption chillers is essential to the adsorption cooling-desalination (ACD) facility. [18][19][20] The condensation phase occurs under certain physical circumstances as it proceeds in the entire volume of saturated vapor and starts due to the vapor subcooling below the saturation temperature at a given pressure. As the vapor condenses, a rapid volume reduction occurs in the pipe wall's direct vicinity, resulting in unidirectional adsorbate flow toward the wall.…”

Section: Introduction 1| Adsorption Cooling and Desalination Systemsmentioning

confidence: 99%

“…The harnessing of heat from the water flowing through the heat exchanger enables the production of so‐called chilled water. Due to the low operating pressures in the 760–2340 Pa range, the evaporator of the adsorption chillers is essential to the adsorption cooling‐desalination (ACD) facility 18–20 …”

Section: Introductionmentioning

confidence: 99%

AutoML‐based predictive framework for predictive analysis in adsorption cooling and desalination systems

Krzywanski,

Sztekler,

Skrobek

et al. 2024

Energy Science & Engineering

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Adsorption cooling and desalination systems have a distinct advantage over other systems that use low‐grade waste heat near ambient temperature. Since improving their performance, including reliability and failure prediction, is challenging, developing an efficient diagnostic system is of great practical significance. The paper introduces artificial intelligence (AI) and an automated machine learning approach (AutoML) in a real‐life application for a computational diagnostic system of existing adsorption cooling and desalination facilities. A total of 1769 simulated data points containing data indicating a failure status are applied to develop a comprehensive AI‐based Diagnostic (AID) system covering a wide range of 42 input parameters. The paper introduces a conditional monitoring system for adsorption cooling and desalination systems. The novelty of the presented study mainly consists of two aspects. First, the intelligent system predicts the health or failure states of various components in a complex three‐bed adsorption chiller installation using the extensive input data sets of 42 different operating parameters. The developed AID expert tool, based on selecting the best from 42 models generated by the DataRobot platform, was validated on the complex, existing three‐bed adsorption chiller. The AID system correctly identified healthy and failure states in various installation components. The developed expert system is very efficient (AUC = 0.988, RMSE = 0.20, LogLoss = 0.14) in predicting emergency states. The proposed method constitutes a quick and easy technique for failure prediction and represents a complementary tool compared to the other condition monitoring methods.

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“…This can be particularly useful to understand the impact of design improvements of various components on the second law efficiency. Capillary evaporators are one of such relatively recent developments in ACS, which are seen to eliminate the need for a circulation pump in the evaporator chamber and save auxiliary electric power consumption [37][38][39][40][41]. The present study attempts to explore the impact of a capillary-assisted evaporator design on the second law efficiency, over that of a falling film design.…”

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confidence: 99%

Entropy generation minimization of an advanced two-bed adsorption refrigeration system

Yagnamurthy

Chauhan

Saha

et al. 2022

International Communications in Heat and Mass Transfer

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Performance of finned tubes used in low-pressure capillary-assisted evaporator of adsorption cooling system

Cited by 23 publications

References 24 publications

A General Approach in Optimization of Heat Exchangers by Bio-Inspired Artificial Intelligence Methods

A General Approach in Optimization of Heat Exchangers by Bio-Inspired Artificial Intelligence Methods

AutoML‐based predictive framework for predictive analysis in adsorption cooling and desalination systems

Entropy generation minimization of an advanced two-bed adsorption refrigeration system

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