Valeriy Maisotsenko - Academia.edu (original) (raw)

Papers by Valeriy Maisotsenko

Research paper thumbnail of Maisotsenko power cycle technologies: Research, development and future needs

Applied Thermal Engineering, Mar 1, 2023

Research paper thumbnail of Thermodynamic performance assessment of a novel air cooling cycle: Maisotsenko cycle

International Journal of Refrigeration-revue Internationale Du Froid, Jun 1, 2011

This study presents energy and exergy analyses and sustainability assessment of the novel evapora... more This study presents energy and exergy analyses and sustainability assessment of the novel evaporative air cooling system based on Maisotsenko cycle which allows the product fluid to be cooled in to a dew point temperature of the incoming air. In the energy analysis, Maisotsenko cycle's wet-bulb and dew point effectiveness, COP and primary energy ratio rates are calculated. Exergy analysis of the system is then carried out for six reference temperatures ranging from 0 C to 23.88 C as the incoming air (surrounding) temperature. The specific flow exergy, exergy input, exergy output, exergy destruction, exergy loss, exergy efficiency, exergetic COP, primary exergy ratio and entropy generation rates are determined for various cases. Furthermore, sustainability assessment is obtained using sustainability index method. As a result, maximum exergy efficiency is found to be 19.14% for a reference temperature of 23.88 C where the optimum operation takes place.

Research paper thumbnail of Brayton’s subatmospheric inverse cycle with regeneration of output heat by Maisotsenko’s cicle

Reports of the National Academy of Sciences of Ukraine, 2015

Research paper thumbnail of Capillary Nylon 6 polymer material produced by femtosecond laser processing

Optics Express, 2019

A wicking Nylon 6 polymer material was produced through surface structuring by a direct femtoseco... more A wicking Nylon 6 polymer material was produced through surface structuring by a direct femtosecond laser nano/microstructuring approach. The produced wicking structure is an array of parallel microgrooves, the surface of which is textured with irregular nanostructures and fine microstructures. High-speed imaging of water spreading vertically uphill against the gravity discloses a series of capillary flow regimes with h ∝ t, h ∝ t1/2, and h ∝ t1/3 scaling laws, where h is the height of capillary rise and t is the time. In the initial stage, the capillary flow occurs with a single front, from which at a certain time a precursor front forms and advances ahead of the main one. Our study shows that the onset of the precursor front occurs in h ∝ t flow regime. The created material exhibits excellent wicking properties and may find applications in various technologically important areas.

Research paper thumbnail of Solar Ejector System for Heating and Air-Conditioning

Proceeding of 5-6th Thermal and Fluids Engineering Conference (TFEC), 2021

Research paper thumbnail of Experimental study on combined low temperature regeneration of liquid desiccant and evaporative cooling by ultrasonic atomization

International Journal of Refrigeration, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Research paper thumbnail of Water spreading on laser - treated silicon sample at three different temperatures

The three videos were recorded at speed 1000 frames per second. Each video consists of two parts.... more The three videos were recorded at speed 1000 frames per second. Each video consists of two parts. In the first part, the video is played at 1000 frames per second. In second part, the video is played in slow motion mode at 100 frames per second.

Research paper thumbnail of Evaporative Duplex Counterheat Exchanger

Research paper thumbnail of Overview of the Maisotsenko cycle – A way towards dew point evaporative cooling

Renewable and Sustainable Energy Reviews, 2016

The Maisotsenko Cycle (M-Cycle) is a thermodynamic conception which captures energy from the air ... more The Maisotsenko Cycle (M-Cycle) is a thermodynamic conception which captures energy from the air by utilizing the psychrometric renewable energy available from the latent heat of water evaporating into the air. The cycle is well-known in the air-conditioning (AC) field due to its potential of dew-point evaporative cooling. However, its applicability has been recently expanded in several energy recovery applications. Therefore, the present study provides the overview of M-Cycle and its application in various heating, ventilation, and air-conditioning (HVAC) systems; cooling systems; and gas turbine power cycles. Principle and features of the M-Cycle are discussed in comparison with conventional evaporative cooling, and consequently the thermodynamic limitation of the cycle is highlighted. It is reported that the standalone M-Cycle AC (MAC) system can achieve the AC load efficiently when the ambient air humidity is not so high regardless of ambient air temperature. Various modifications in MAC system design have been reviewed in order to investigate the M-Cycle applicability in humid regions. It is found that the hybrid, ejector, and desiccant based MAC systems enable a huge energy saving potential to achieve the sensible and latent load of AC in humid regions. Similarly, the overall system performance is significantly improved when the M-Cycle is utilized in cooling towers and evaporative condensers. Furthermore, the M-Cycle conception in gas turbine cycles has been realized recently in which the M-Cycle recuperator provides not only hot and humidified air for combustion but also recovers the heat from the turbine exhaust gases. The M-Cycle nature helps to provide the cooled air for turbine inlet air cooling and to control the pollution by reducing NOx formation during combustion. The study reviews three distinguished Maisotsenko gas turbine power cycles and their comparison with the conventional cycles, which shows the M-Cycle significance in power industry.

Research paper thumbnail of Method and disk device for dew point evaporative cooler

Research paper thumbnail of Systeme et procede d'alimentation

L'invention concerne un systeme d'alimentation (90). Ledit systeme d'alimentation com... more L'invention concerne un systeme d'alimentation (90). Ledit systeme d'alimentation comprend un dispositif (3, 43, 300) d'extraction d'energie d'un flux gazeux chaud afin d'alimenter un arbre de transmission (4a). Un echangeur de contre-chaleur duplex evaporatif (5, 9, 24, 59, 60, 130, 202) est place en communication fluidique avec le dispositif d'extraction d'energie. L'echangeur duplex comprend un premier echangeur de chaleur (72) presentant un premier canal d'ecoulement principal (80a) et un canal de contre-chaleur (82a, b) en communication fluidique avec ce dernier. Un second echangeur de chaleur (74) comprend un second canal d'ecoulement principal (80b) adjacent au canal de contre-chaleur (82a, b). Un fluide evaporatif est injecte dans le canal de contre-chaleur afin de refroidir par evaporation l'ecoulement dans les canaux d'ecoulement principaux.

Research paper thumbnail of Method and apparatus for evaporative cooler plate dew point

Una placa (6) para intercambio de calor y enfriamiento evaporativo indirecto de al menos una corr... more Una placa (6) para intercambio de calor y enfriamiento evaporativo indirecto de al menos una corriente de fluido, consistiendo la placa en: a) un costado seco (9) que tiene baja permeabilidad a un liquido evaporativo; yb) un costado humedo (10) disenado para que tenga humeda dicha superficie del costado humedo por la accion de un liquido evaporativo; donde el costado seco de la placa forma al menos un primer canal (4) para guiar la corriente de gas activo (2) y segundos canales (3), generalmente en paralelo con respecto al primer canal, para guiar una corriente fluida del producto (1); y caracterizado por el hecho de que la placa ademas forma al menos una perforacion (11) a traves de la placa en el primer canal para permitir que la corriente activa sea transfiera al costado humedo de la placa.

Research paper thumbnail of A method and apparatus for plate-dewpoint fordampningsköler

Research paper thumbnail of Ejector based climate control systems with heat and mass recuperation through the Maisotsenko cycle

Electricity remains the main source of energy for conventional air-conditioning systems, while na... more Electricity remains the main source of energy for conventional air-conditioning systems, while natural gas is traditionally utilized for space heating. In both cases the thermodynamic processes are inefficient, as high-grade energy wastes its potential for the processes close to ambient temperatures. The paper describes the methods of multiplication of high, middle and low-grade heat to maximize the effect of space cooling and heating by combining thermally-driven ejector system with the heat recuperation process in the Maisotsenko cycle Heat and Mass Exchanger (HMX). Such a comprehensive and cost-efficient solution for space heating and cooling will help to lower the environmental loads at least twofold, save fossil fuels by 25-30%, displace 100% of the inhaled air at no extra cost and reduce by at least 10 times the energy consumption in the most intensive sector at the expense of the increased efficiency of the proposed technology over the existing systems.

Research paper thumbnail of Simulation analysis of heat recovery humidifier

Research paper thumbnail of Dispositif sous forme de plaque pour refroidisseur evaporatif au point de rosee et technique correspondante

Cette invention a trait a des ameliorations apportees a une technique, ainsi qu'au dispositif... more Cette invention a trait a des ameliorations apportees a une technique, ainsi qu'au dispositif correspondant, relatifs a un refroidissement evaporatif indirect d'une veine fluidique permettant d'amener celle-ci quasiment a sa temperature de point de rosee. Cet echangeur de chaleur en plaque est pourvu de perforations (11) et de canaux (3, 4 et 5) pour gaz ou pour liquides situes sur ses deux cotes, sec et humide. Les veines fluidiques (1) traversent le cote sec (9), transferant la chaleur vers la plaque. La veine gazeuse (2), qui traverse le cote sec et s'ecoule par les perforation dans les canaux (5) situes sur le cote humide (10), est ensuite refroidie par refroidissement evaporatif ainsi que par un transfert de chaleur par conduction et rayonnement depuis la plaque. Un materiau de drainage sert a l'humidification du cote humide. Dans d'autres modes de realisation, on utilise une roue hydroscopique pour deshumidifier les veines de gaz, l'air pouvant etre...

Research paper thumbnail of Solar low-pressure turbo-ejector Maisotsenko cycle-based power system for electricity, heating, cooling and distillation

International Journal of Low-Carbon Technologies, 2015

The article describes the innovative solutions of power, heating and cooling generation utilizing... more The article describes the innovative solutions of power, heating and cooling generation utilizing low-or medium-grade heat sources. The proposed technology based on the well-known irreversible Brayton cycle and the revolutionary Maisotsenko cycle (M-cycle) operates at atmospheric or sub-atmospheric pressures. Such energetic systems are simple and reliable and utilize moisture-saturated air as a working fluid. The ejector replacing the mechanical compressor in the Brayton cycle system allows increasing the cycle work by three to five times at the constant airflow. At the same time, the utilized heat serves for simultaneous heating and cooling production that makes the system economically viable and environmentally friendly with the increased integral performance. For system's performance improvement, the schematic and the cycle were upgraded allowing the off-the-shelf components to be employed and replace the electrically driven fan with fluidic jet-fan that served for energy saving of the innovative turbo-ejector system operation.

Research paper thumbnail of Exergetic Analysis of a Maisotsenko-Process-Enhanced Cooling Tower

Volume 6: Energy, Parts A and B, 2012

The Maisotsenko-process (M-process or M-cycle) is a complex process associated with humid air. He... more The Maisotsenko-process (M-process or M-cycle) is a complex process associated with humid air. Heat transfer and evaporative cooling occur in a unique indirect evaporative cooler resulting in product temperatures that approach the dew point temperature. This process utilizes the enthalpy difference between air at its dew point temperature, and air saturated at a higher temperature. This enthalpy difference is used to reject heat from the air stream with the high temperature. The different applications of the M-process contribute to effective energy savings. The M-process technology was realized initially in the year 1984. By enhancing cooling towers with the M‐process it is possible to (a) cool water to dew point temperature; (b) reduce pressure drop and required fan power, and (c) modify existing cooling towers to substantially decrease cooled water temperature. An exergetic analysis identifies the real thermodynamic inefficiencies and the potential of improvement for the M-process. This paper demonstrates the detailed exergetic analysis of the M-process with separate consideration of the thermal and mechanical exergies (as two parts of the physical exergy) and the chemical exergy.

Research paper thumbnail of Spreading and Drying Dynamics of Water Drop on Hot Surface of Superwicking Ti-6Al-4V Alloy Material Fabricated by Femtosecond Laser

Nanomaterials

A superwicking Ti-6Al-4V alloy material with a hierarchical capillary surface structure was fabri... more A superwicking Ti-6Al-4V alloy material with a hierarchical capillary surface structure was fabricated using femtosecond laser. The basic capillary surface structure is an array of micropillars/microholes. For enhancing its capillary action, the surface of the micropillars/microholes is additionally structured by regular fine microgrooves using a technique of laser-induced periodic surface structures (LIPSS), providing an extremely strong capillary action in a temperature range between 23 °C and 80 °C. Due to strong capillary action, a water drop quickly spreads in the wicking surface structure and forms a thin film over a large surface area, resulting in fast evaporation. The maximum water flow velocity after the acceleration stage is found to be 225–250 mm/s. In contrast to other metallic materials with surface capillarity produced by laser processing, the wicking performance of which quickly degrades with time, the wicking functionality of the material created here is long-lastin...

Research paper thumbnail of Superwicking Functionality of Femtosecond Laser Textured Aluminum at High Temperatures

Nanomaterials

An advanced superwicking aluminum material based on a microgroove surface structure textured with... more An advanced superwicking aluminum material based on a microgroove surface structure textured with both laser-induced periodic surface structures and fine microholes was produced by direct femtosecond laser nano/microstructuring technology. The created material demonstrates excellent wicking performance in a temperature range of 23 to 120 °C. The experiments on wicking dynamics show a record-high velocity of water spreading that achieves about 450 mm/s at 23 °C and 320 mm/s at 120 °C when the spreading water undergoes intensive boiling. The lifetime of classic Washburn capillary flow dynamics shortens as the temperature increases up to 80 °C. The effects of evaporation and boiling on water spreading become significant above 80 °C, resulting in vanishing of Washburn’s dynamics. Both the inertial and visco-inertial flow regimes are insignificantly affected by evaporation at temperatures below the boiling point of water. The boiling effect on the inertial regime is small at 120 °C; howe...

Research paper thumbnail of Maisotsenko power cycle technologies: Research, development and future needs

Applied Thermal Engineering, Mar 1, 2023

Research paper thumbnail of Thermodynamic performance assessment of a novel air cooling cycle: Maisotsenko cycle

International Journal of Refrigeration-revue Internationale Du Froid, Jun 1, 2011

This study presents energy and exergy analyses and sustainability assessment of the novel evapora... more This study presents energy and exergy analyses and sustainability assessment of the novel evaporative air cooling system based on Maisotsenko cycle which allows the product fluid to be cooled in to a dew point temperature of the incoming air. In the energy analysis, Maisotsenko cycle's wet-bulb and dew point effectiveness, COP and primary energy ratio rates are calculated. Exergy analysis of the system is then carried out for six reference temperatures ranging from 0 C to 23.88 C as the incoming air (surrounding) temperature. The specific flow exergy, exergy input, exergy output, exergy destruction, exergy loss, exergy efficiency, exergetic COP, primary exergy ratio and entropy generation rates are determined for various cases. Furthermore, sustainability assessment is obtained using sustainability index method. As a result, maximum exergy efficiency is found to be 19.14% for a reference temperature of 23.88 C where the optimum operation takes place.

Research paper thumbnail of Brayton’s subatmospheric inverse cycle with regeneration of output heat by Maisotsenko’s cicle

Reports of the National Academy of Sciences of Ukraine, 2015

Research paper thumbnail of Capillary Nylon 6 polymer material produced by femtosecond laser processing

Optics Express, 2019

A wicking Nylon 6 polymer material was produced through surface structuring by a direct femtoseco... more A wicking Nylon 6 polymer material was produced through surface structuring by a direct femtosecond laser nano/microstructuring approach. The produced wicking structure is an array of parallel microgrooves, the surface of which is textured with irregular nanostructures and fine microstructures. High-speed imaging of water spreading vertically uphill against the gravity discloses a series of capillary flow regimes with h ∝ t, h ∝ t1/2, and h ∝ t1/3 scaling laws, where h is the height of capillary rise and t is the time. In the initial stage, the capillary flow occurs with a single front, from which at a certain time a precursor front forms and advances ahead of the main one. Our study shows that the onset of the precursor front occurs in h ∝ t flow regime. The created material exhibits excellent wicking properties and may find applications in various technologically important areas.

Research paper thumbnail of Solar Ejector System for Heating and Air-Conditioning

Proceeding of 5-6th Thermal and Fluids Engineering Conference (TFEC), 2021

Research paper thumbnail of Experimental study on combined low temperature regeneration of liquid desiccant and evaporative cooling by ultrasonic atomization

International Journal of Refrigeration, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Research paper thumbnail of Water spreading on laser - treated silicon sample at three different temperatures

The three videos were recorded at speed 1000 frames per second. Each video consists of two parts.... more The three videos were recorded at speed 1000 frames per second. Each video consists of two parts. In the first part, the video is played at 1000 frames per second. In second part, the video is played in slow motion mode at 100 frames per second.

Research paper thumbnail of Evaporative Duplex Counterheat Exchanger

Research paper thumbnail of Overview of the Maisotsenko cycle – A way towards dew point evaporative cooling

Renewable and Sustainable Energy Reviews, 2016

The Maisotsenko Cycle (M-Cycle) is a thermodynamic conception which captures energy from the air ... more The Maisotsenko Cycle (M-Cycle) is a thermodynamic conception which captures energy from the air by utilizing the psychrometric renewable energy available from the latent heat of water evaporating into the air. The cycle is well-known in the air-conditioning (AC) field due to its potential of dew-point evaporative cooling. However, its applicability has been recently expanded in several energy recovery applications. Therefore, the present study provides the overview of M-Cycle and its application in various heating, ventilation, and air-conditioning (HVAC) systems; cooling systems; and gas turbine power cycles. Principle and features of the M-Cycle are discussed in comparison with conventional evaporative cooling, and consequently the thermodynamic limitation of the cycle is highlighted. It is reported that the standalone M-Cycle AC (MAC) system can achieve the AC load efficiently when the ambient air humidity is not so high regardless of ambient air temperature. Various modifications in MAC system design have been reviewed in order to investigate the M-Cycle applicability in humid regions. It is found that the hybrid, ejector, and desiccant based MAC systems enable a huge energy saving potential to achieve the sensible and latent load of AC in humid regions. Similarly, the overall system performance is significantly improved when the M-Cycle is utilized in cooling towers and evaporative condensers. Furthermore, the M-Cycle conception in gas turbine cycles has been realized recently in which the M-Cycle recuperator provides not only hot and humidified air for combustion but also recovers the heat from the turbine exhaust gases. The M-Cycle nature helps to provide the cooled air for turbine inlet air cooling and to control the pollution by reducing NOx formation during combustion. The study reviews three distinguished Maisotsenko gas turbine power cycles and their comparison with the conventional cycles, which shows the M-Cycle significance in power industry.

Research paper thumbnail of Method and disk device for dew point evaporative cooler

Research paper thumbnail of Systeme et procede d'alimentation

L'invention concerne un systeme d'alimentation (90). Ledit systeme d'alimentation com... more L'invention concerne un systeme d'alimentation (90). Ledit systeme d'alimentation comprend un dispositif (3, 43, 300) d'extraction d'energie d'un flux gazeux chaud afin d'alimenter un arbre de transmission (4a). Un echangeur de contre-chaleur duplex evaporatif (5, 9, 24, 59, 60, 130, 202) est place en communication fluidique avec le dispositif d'extraction d'energie. L'echangeur duplex comprend un premier echangeur de chaleur (72) presentant un premier canal d'ecoulement principal (80a) et un canal de contre-chaleur (82a, b) en communication fluidique avec ce dernier. Un second echangeur de chaleur (74) comprend un second canal d'ecoulement principal (80b) adjacent au canal de contre-chaleur (82a, b). Un fluide evaporatif est injecte dans le canal de contre-chaleur afin de refroidir par evaporation l'ecoulement dans les canaux d'ecoulement principaux.

Research paper thumbnail of Method and apparatus for evaporative cooler plate dew point

Una placa (6) para intercambio de calor y enfriamiento evaporativo indirecto de al menos una corr... more Una placa (6) para intercambio de calor y enfriamiento evaporativo indirecto de al menos una corriente de fluido, consistiendo la placa en: a) un costado seco (9) que tiene baja permeabilidad a un liquido evaporativo; yb) un costado humedo (10) disenado para que tenga humeda dicha superficie del costado humedo por la accion de un liquido evaporativo; donde el costado seco de la placa forma al menos un primer canal (4) para guiar la corriente de gas activo (2) y segundos canales (3), generalmente en paralelo con respecto al primer canal, para guiar una corriente fluida del producto (1); y caracterizado por el hecho de que la placa ademas forma al menos una perforacion (11) a traves de la placa en el primer canal para permitir que la corriente activa sea transfiera al costado humedo de la placa.

Research paper thumbnail of A method and apparatus for plate-dewpoint fordampningsköler

Research paper thumbnail of Ejector based climate control systems with heat and mass recuperation through the Maisotsenko cycle

Electricity remains the main source of energy for conventional air-conditioning systems, while na... more Electricity remains the main source of energy for conventional air-conditioning systems, while natural gas is traditionally utilized for space heating. In both cases the thermodynamic processes are inefficient, as high-grade energy wastes its potential for the processes close to ambient temperatures. The paper describes the methods of multiplication of high, middle and low-grade heat to maximize the effect of space cooling and heating by combining thermally-driven ejector system with the heat recuperation process in the Maisotsenko cycle Heat and Mass Exchanger (HMX). Such a comprehensive and cost-efficient solution for space heating and cooling will help to lower the environmental loads at least twofold, save fossil fuels by 25-30%, displace 100% of the inhaled air at no extra cost and reduce by at least 10 times the energy consumption in the most intensive sector at the expense of the increased efficiency of the proposed technology over the existing systems.

Research paper thumbnail of Simulation analysis of heat recovery humidifier

Research paper thumbnail of Dispositif sous forme de plaque pour refroidisseur evaporatif au point de rosee et technique correspondante

Cette invention a trait a des ameliorations apportees a une technique, ainsi qu'au dispositif... more Cette invention a trait a des ameliorations apportees a une technique, ainsi qu'au dispositif correspondant, relatifs a un refroidissement evaporatif indirect d'une veine fluidique permettant d'amener celle-ci quasiment a sa temperature de point de rosee. Cet echangeur de chaleur en plaque est pourvu de perforations (11) et de canaux (3, 4 et 5) pour gaz ou pour liquides situes sur ses deux cotes, sec et humide. Les veines fluidiques (1) traversent le cote sec (9), transferant la chaleur vers la plaque. La veine gazeuse (2), qui traverse le cote sec et s'ecoule par les perforation dans les canaux (5) situes sur le cote humide (10), est ensuite refroidie par refroidissement evaporatif ainsi que par un transfert de chaleur par conduction et rayonnement depuis la plaque. Un materiau de drainage sert a l'humidification du cote humide. Dans d'autres modes de realisation, on utilise une roue hydroscopique pour deshumidifier les veines de gaz, l'air pouvant etre...

Research paper thumbnail of Solar low-pressure turbo-ejector Maisotsenko cycle-based power system for electricity, heating, cooling and distillation

International Journal of Low-Carbon Technologies, 2015

The article describes the innovative solutions of power, heating and cooling generation utilizing... more The article describes the innovative solutions of power, heating and cooling generation utilizing low-or medium-grade heat sources. The proposed technology based on the well-known irreversible Brayton cycle and the revolutionary Maisotsenko cycle (M-cycle) operates at atmospheric or sub-atmospheric pressures. Such energetic systems are simple and reliable and utilize moisture-saturated air as a working fluid. The ejector replacing the mechanical compressor in the Brayton cycle system allows increasing the cycle work by three to five times at the constant airflow. At the same time, the utilized heat serves for simultaneous heating and cooling production that makes the system economically viable and environmentally friendly with the increased integral performance. For system's performance improvement, the schematic and the cycle were upgraded allowing the off-the-shelf components to be employed and replace the electrically driven fan with fluidic jet-fan that served for energy saving of the innovative turbo-ejector system operation.

Research paper thumbnail of Exergetic Analysis of a Maisotsenko-Process-Enhanced Cooling Tower

Volume 6: Energy, Parts A and B, 2012

The Maisotsenko-process (M-process or M-cycle) is a complex process associated with humid air. He... more The Maisotsenko-process (M-process or M-cycle) is a complex process associated with humid air. Heat transfer and evaporative cooling occur in a unique indirect evaporative cooler resulting in product temperatures that approach the dew point temperature. This process utilizes the enthalpy difference between air at its dew point temperature, and air saturated at a higher temperature. This enthalpy difference is used to reject heat from the air stream with the high temperature. The different applications of the M-process contribute to effective energy savings. The M-process technology was realized initially in the year 1984. By enhancing cooling towers with the M‐process it is possible to (a) cool water to dew point temperature; (b) reduce pressure drop and required fan power, and (c) modify existing cooling towers to substantially decrease cooled water temperature. An exergetic analysis identifies the real thermodynamic inefficiencies and the potential of improvement for the M-process. This paper demonstrates the detailed exergetic analysis of the M-process with separate consideration of the thermal and mechanical exergies (as two parts of the physical exergy) and the chemical exergy.

Research paper thumbnail of Spreading and Drying Dynamics of Water Drop on Hot Surface of Superwicking Ti-6Al-4V Alloy Material Fabricated by Femtosecond Laser

Nanomaterials

A superwicking Ti-6Al-4V alloy material with a hierarchical capillary surface structure was fabri... more A superwicking Ti-6Al-4V alloy material with a hierarchical capillary surface structure was fabricated using femtosecond laser. The basic capillary surface structure is an array of micropillars/microholes. For enhancing its capillary action, the surface of the micropillars/microholes is additionally structured by regular fine microgrooves using a technique of laser-induced periodic surface structures (LIPSS), providing an extremely strong capillary action in a temperature range between 23 °C and 80 °C. Due to strong capillary action, a water drop quickly spreads in the wicking surface structure and forms a thin film over a large surface area, resulting in fast evaporation. The maximum water flow velocity after the acceleration stage is found to be 225–250 mm/s. In contrast to other metallic materials with surface capillarity produced by laser processing, the wicking performance of which quickly degrades with time, the wicking functionality of the material created here is long-lastin...

Research paper thumbnail of Superwicking Functionality of Femtosecond Laser Textured Aluminum at High Temperatures

Nanomaterials

An advanced superwicking aluminum material based on a microgroove surface structure textured with... more An advanced superwicking aluminum material based on a microgroove surface structure textured with both laser-induced periodic surface structures and fine microholes was produced by direct femtosecond laser nano/microstructuring technology. The created material demonstrates excellent wicking performance in a temperature range of 23 to 120 °C. The experiments on wicking dynamics show a record-high velocity of water spreading that achieves about 450 mm/s at 23 °C and 320 mm/s at 120 °C when the spreading water undergoes intensive boiling. The lifetime of classic Washburn capillary flow dynamics shortens as the temperature increases up to 80 °C. The effects of evaporation and boiling on water spreading become significant above 80 °C, resulting in vanishing of Washburn’s dynamics. Both the inertial and visco-inertial flow regimes are insignificantly affected by evaporation at temperatures below the boiling point of water. The boiling effect on the inertial regime is small at 120 °C; howe...