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Pre-cooling of inlet air using evaporative cooling is an effective approach to enhance the performance of air-cooled condensers in air conditioning applications. Ultrasonic mist generators have emerged as a promising alternative to conventional evaporative cooling systems based on cooling pads or spray cooling. This paper presents the developed numerical model of an ultrasonic mist generator for the evaporative pre-cooling of the inlet air of the condenser in air conditioning applications. The model was validated against the experimental data obtained in a wind tunnel experimental facility. A parametric analysis including some physical variables involved in the cooling process was carried out, including the main axial air velocity, the injection air velocity and the water mass flow rate of atomized water. The dimensionless groups water-to-air mass flow and air-to-air mass flow ratios were found to most affect the average evaporative cooling efficiency. A maximum value of 0.654 was found for the studied conditions. The optimization analysis carried out shows that the operational ranges leading to the best overall performance are 5 × 10 − 4 ≤ m ˙ w / m ˙ a T ≤ 0.002 and 0.035 ≤ m ˙ a i / m ˙ a T ≤ 0.05 . Under these conditions, there is a better distribution of the water mist throughout the control section and a more homogeneous and effective evaporative cooling process.
Javier Ruiz; Pedro Martínez Martínez; Iñigo Martin M.; Manuel Lucas; Javier Ruiz Ramírez; Íñigo Martín Melero; Lucas Miralles Manuel. Numerical Characterization of an Ultrasonic Mist Generator as an Evaporative Cooler. Energies 2020, 13, 1 .
AMA StyleJavier Ruiz, Pedro Martínez Martínez, Iñigo Martin M., Manuel Lucas, Javier Ruiz Ramírez, Íñigo Martín Melero, Lucas Miralles Manuel. Numerical Characterization of an Ultrasonic Mist Generator as an Evaporative Cooler. Energies. 2020; 13 (11):1.
Chicago/Turabian StyleJavier Ruiz; Pedro Martínez Martínez; Iñigo Martin M.; Manuel Lucas; Javier Ruiz Ramírez; Íñigo Martín Melero; Lucas Miralles Manuel. 2020. "Numerical Characterization of an Ultrasonic Mist Generator as an Evaporative Cooler." Energies 13, no. 11: 1.
Solar cooling provides an ideal coupling between solar energy and the need for cooling, since both reach their maximum during the summer. However, solar refrigeration technologies either have not been competitive or are in a preliminary stage of development. Photovoltaic (PV) driven compression chillers are the most promising and close to market solar solutions today in the case of small to medium units (¡50 kW cooling) due to the tremendous decrease in the cost of PV modules. The main objective of this work is to improve the efficiency of a PV panel by cooling it on its upper face by water sliding and on its back side using a solar chimney. In addition, the system is used as heat sink of a water chiller working as a low scale cooling tower. The work developed consisted of adapting and testing a prototype, changing its mode of operation to overcome the limitations encountered in the first campaign of measures. Several tests were performed by modifying the water mass flow rate circulated to the nozzles (spray) and onto the PV upper surface (water film). For the test with a water flow rate in nozzles of 500 l/h and sliding 250 l/h the results show an average cooling of the panel of 15°C and an improvement in the electrical efficiency of the panel of about 10%. The modified system is still able to dissipate a thermal power of about 1500 W with a thermal efficiency exceeding 30% in summer conditions.
M. Lucas; J. Ruiz; F.J. Aguilar; C.G. Cutillas; A.S. Kaiser; Pedro Vicente-Quiles. Experimental study of a modified evaporative photovoltaic chimney including water sliding. Renewable Energy 2018, 134, 161 -168.
AMA StyleM. Lucas, J. Ruiz, F.J. Aguilar, C.G. Cutillas, A.S. Kaiser, Pedro Vicente-Quiles. Experimental study of a modified evaporative photovoltaic chimney including water sliding. Renewable Energy. 2018; 134 ():161-168.
Chicago/Turabian StyleM. Lucas; J. Ruiz; F.J. Aguilar; C.G. Cutillas; A.S. Kaiser; Pedro Vicente-Quiles. 2018. "Experimental study of a modified evaporative photovoltaic chimney including water sliding." Renewable Energy 134, no. : 161-168.
M. Lucas; F.J. Aguilar; J. Ruiz; C.G. Cutillas; A.S. Kaiser; Pedro Vicente-Quiles. Photovoltaic Evaporative Chimney as a new alternative to enhance solar cooling. Renewable Energy 2017, 111, 26 -37.
AMA StyleM. Lucas, F.J. Aguilar, J. Ruiz, C.G. Cutillas, A.S. Kaiser, Pedro Vicente-Quiles. Photovoltaic Evaporative Chimney as a new alternative to enhance solar cooling. Renewable Energy. 2017; 111 ():26-37.
Chicago/Turabian StyleM. Lucas; F.J. Aguilar; J. Ruiz; C.G. Cutillas; A.S. Kaiser; Pedro Vicente-Quiles. 2017. "Photovoltaic Evaporative Chimney as a new alternative to enhance solar cooling." Renewable Energy 111, no. : 26-37.
The energy consumption increase in the last few years has contributed to developing energy efficiency policies in many countries, the main goal of which is decreasing CO2 emissions. One of the reasons for this increment has been caused by the use of air conditioning systems due to new comfort standards. In that regard, cooling towers and evaporative condensers are presented as efficient devices that operate with low-level water temperature. Moreover, the energy consumption and the cost of the equipment are lower than other systems like air condensers at the same operation conditions. This work models an air conditioning system in TRNSYS software, the main elements if which are a cooling tower, a water-water chiller and a reference building. The cooling tower model is validated using experimental data in a pilot plant. The main objective is to implement an optimizing control strategy in order to reduce both energy and water consumption. Furthermore a comparison between three typical methods of capacity control is carried out. Additionally, different cooling tower configurations are assessed, involving six drift eliminators and two water distribution systems. Results show the influence of optimizing the control strategy and cooling tower configuration, with a maximum energy savings of 10.8% per story and a reduction of 4.8% in water consumption.
Clemente García Cutillas; Javier Ruiz Ramírez; Manuel Lucas Miralles. Optimum Design and Operation of an HVAC Cooling Tower for Energy and Water Conservation. Energies 2017, 10, 299 .
AMA StyleClemente García Cutillas, Javier Ruiz Ramírez, Manuel Lucas Miralles. Optimum Design and Operation of an HVAC Cooling Tower for Energy and Water Conservation. Energies. 2017; 10 (3):299.
Chicago/Turabian StyleClemente García Cutillas; Javier Ruiz Ramírez; Manuel Lucas Miralles. 2017. "Optimum Design and Operation of an HVAC Cooling Tower for Energy and Water Conservation." Energies 10, no. 3: 299.
The existence of cooling towers arises from the need to evacuate power to the environment from engines, refrigeration equipment and industrial processes. Water drift emitted from cooling towers is objectionable for several reasons, mainly due to human health hazards. It is common practice to fit drift eliminators to cooling towers in order to minimise water loss from the system. The presence of the drift eliminator mainly affects two aspects of cooling towers: their thermal performance and the amount of water drift loss. This paper experimentally studies the drift loss emissions from a cooling tower without drift eliminator and fitted with six different drift eliminators. Chemical Balance is the selected method and Australian Standard methodology is taken as a reference. Some modifications are proposed to reduce uncertainty by increasing the duration of the test and the number of water samples. Installation of a drift eliminator, even in the worst case, reduces the water drift level to less than half of the situation without the eliminator. The water drift losses obtained with the different drift eliminators installed at the pilot plant, from 0.0118% to 0.161%, are within the range generally reflected in the literature. Finally, a criterion for designing drift eliminators in order to optimise both the collection efficiency and the cooling tower’s thermal performance is proposed.
M. Lucas; P.J. Martínez; A. Viedma. Experimental determination of drift loss from a cooling tower with different drift eliminators using the chemical balance method. International Journal of Refrigeration 2012, 35, 1779 -1788.
AMA StyleM. Lucas, P.J. Martínez, A. Viedma. Experimental determination of drift loss from a cooling tower with different drift eliminators using the chemical balance method. International Journal of Refrigeration. 2012; 35 (6):1779-1788.
Chicago/Turabian StyleM. Lucas; P.J. Martínez; A. Viedma. 2012. "Experimental determination of drift loss from a cooling tower with different drift eliminators using the chemical balance method." International Journal of Refrigeration 35, no. 6: 1779-1788.
Water drift emitted from cooling towers is objectionable for several reasons, mainly due to human health hazards. A numerical model to study the influence of psychrometric ambient conditions on cooling tower drift deposition was developed as a tool to evaluate liquid droplet dispersion and risk area. Both experimental plume performance and drift deposition were employed to validate the numerical results. This study shows the influence of variables like ambient dry bulb temperature, ambient absolute humidity and droplet exit temperature from cooling tower on the drift evaporation (and therefore deposition) and on the zone affected by the cooling tower. The strongest effect detected corresponds to the ambient dry bulb temperature. When a higher ambient temperature was present, deposition was lower (evaporation was therefore higher) and the zone affected by the cooling tower was smaller. The influence of the other two variables included in the study was weaker than the dry bulb ambient temperature. A high level of ambient absolute humidity increased drift deposition and also the size of the zone affected by the cooling tower. Finally, a high level of droplet exit temperature decreased deposition and increased the zone affected by the cooling tower.
M. Lucas; Pedro J. Martinez; J. Ruiz; A.S. Kaiser; Antonio Viedma. On the influence of psychrometric ambient conditions on cooling tower drift deposition. International Journal of Heat and Mass Transfer 2010, 53, 594 -604.
AMA StyleM. Lucas, Pedro J. Martinez, J. Ruiz, A.S. Kaiser, Antonio Viedma. On the influence of psychrometric ambient conditions on cooling tower drift deposition. International Journal of Heat and Mass Transfer. 2010; 53 (4):594-604.
Chicago/Turabian StyleM. Lucas; Pedro J. Martinez; J. Ruiz; A.S. Kaiser; Antonio Viedma. 2010. "On the influence of psychrometric ambient conditions on cooling tower drift deposition." International Journal of Heat and Mass Transfer 53, no. 4: 594-604.
Cooling towers are equipment devices commonly used to dissipate heat from power generation units, water-cooled refrigeration, air conditioning and industrial processes. Water drift emitted from cooling towers is objectionable for several reasons, mainly due to human health hazards. It is common practice to fit drift eliminators to cooling towers in order to minimize water loss from the system. It is foreseeable that the characteristics of the installed drift eliminators, like their pressure drop, affect the thermal performance of the cooling tower. However, no references regarding this fact have been found in the reviewed bibliography. This paper studies the thermal performance of a forced draft counter-flow wet cooling tower fitted with different drift eliminators for a wide range of air and water mass flow rates. The data registered in the experimental set-up were employed to obtain correlations of the tower characteristic, which defines the cooling tower’s thermal performance. The outlet water temperature predicted by these correlations was compared with the experimentally registered values obtaining a maximum difference of ±3%.
M. Lucas; P.J. Martínez; A. Viedma. Experimental study on the thermal performance of a mechanical cooling tower with different drift eliminators. Energy Conversion and Management 2009, 50, 490 -497.
AMA StyleM. Lucas, P.J. Martínez, A. Viedma. Experimental study on the thermal performance of a mechanical cooling tower with different drift eliminators. Energy Conversion and Management. 2009; 50 (3):490-497.
Chicago/Turabian StyleM. Lucas; P.J. Martínez; A. Viedma. 2009. "Experimental study on the thermal performance of a mechanical cooling tower with different drift eliminators." Energy Conversion and Management 50, no. 3: 490-497.
Water drift emitted from cooling towers is objectionable for several reasons, mainly due to human health reasons. These objections make the installation of the cooling towers difficult and penalize the COP of the cooling plants. The dry and adiabatic fluid cooler works as a standard fluid dry cooler enhancing the dry cooler's capacity with adiabatic pre-cooling of the air intake. The objectives of this work were twofold: the first one was to review the available drift test methods usually used on cooling towers, and the second one was to carry out drift measurements on a dry and adiabatic fluid cooler and on a cooling tower of similar capacity working in real facilities. No drift was registered on the dry and adiabatic fluid cooler when using the sensitive paper drift test method, while a drift of 0.0023% was measured in the cooling tower.
M. Lucas; Pedro J. Martinez; Antonio Viedma. Comparative experimental drift study between a dry and adiabatic fluid cooler and a cooling tower. International Journal of Refrigeration 2008, 31, 1169 -1175.
AMA StyleM. Lucas, Pedro J. Martinez, Antonio Viedma. Comparative experimental drift study between a dry and adiabatic fluid cooler and a cooling tower. International Journal of Refrigeration. 2008; 31 (7):1169-1175.
Chicago/Turabian StyleM. Lucas; Pedro J. Martinez; Antonio Viedma. 2008. "Comparative experimental drift study between a dry and adiabatic fluid cooler and a cooling tower." International Journal of Refrigeration 31, no. 7: 1169-1175.