Cooling Effect Of Evaporation Research Articles

Effect of Evaporative Cooling of Condenser on the Performance of Air Conditioner

Effect of Evaporative Cooling of Condenser on the Performance of Air Conditioner

“Phase Diagram” of Surface Temperature Distribution of Sessile Droplets and the Effects of Evaporative Cooling

“Phase Diagram” of Surface Temperature Distribution of Sessile Droplets and the Effects of Evaporative Cooling

Combined Effects of Radiative and Evaporative Cooling on Fruit Preservation under Solar Radiation: Sunburn Resistance and Temperature Stabilization.

Excessive solar radiation and high temperature often cause considerable loss and waste of fruits during transportation, retail, and storage. In the current study, a natural deep eutectic solvent-based polyacrylamide/poly(vinyl alcohol) hydrogel with nanoparticles (NPs/NADES@PAAm/PVA) is developed for fruit quality protection from solar radiation and high-temperature stress by achieving the combined effect of radiative and evaporative cooling. NPs/NADES@PAAm/PVA presents an average solar reflectance of ∼0.89 and an average emittance at the atmospheric window of ∼0.90. Besides, NPs/NADES@PAAm/PVA possesses excellent flexibility, robust mechanical strength, and good swelling behavior. The fruit preservation experiments under sunlight demonstrate that the pear (Pyrus sinkiangensis) treated with NPs/NADES@PAAm/PVA can achieve an average temperature decrease of ∼15.3 °C after sun exposure compared with the blank, and its quality-related attributes, including color, total soluble solid, relative conductivity, and respiration rate, are similar to the fresh one. Multivariate data analyses, including principal component analysis and cluster analysis, further verify that the pear treated with NPs/NADES@PAAm/PVA possesses similar quality to the fresh one after sun exposure. Thus, NPs/NADES@PAAm/PVA has promising prospects for fruit transportation, retail, and storage under solar radiation in a low-operation-cost and sustainable manner.

Nanocomposite Hydrogel Reinforced by Natural Deep Eutectic Solvent (Nades) for Combined Effects of Radiative and Evaporative Cooling

Nanocomposite Hydrogel Reinforced by Natural Deep Eutectic Solvent (Nades) for Combined Effects of Radiative and Evaporative Cooling

Preparation of Passive Daytime Cooling Fabric with the Synergistic Effect of Radiative Cooling and Evaporative Cooling

AbstractPassive daytime radiative cooling (PDRC) has attracted intensive attention due to its great potential in reduced energy consumption. However, the practical application for PDRC is greatly affected by geographical location and the intrinsic cooling power. Herein, a composite flexible fabric with the synergistic effect of evaporative cooling and radiative cooling is reported. A porous polymer coating with both a high solar reflectivity (90%) and a high infrared thermal emissivity (83%) is fabricated on the top side of the fabric, which can achieve effective PDRC performance. Meanwhile, hygroscopic salts are loaded on the bottom side of the fabric, which can capture water vapor at night and realize evaporative cooling during the daytime. The temperature reduction of 10.8 °C can be achieved under the direct sunlight irradiation (465 W m−2) for the prepared fabric in the outdoor experiment. The combination of radiative cooling and evaporative cooling breaks through the traditional single passive cooling mode and has great potential in further improving the performance of passive cooling.

Effect of Evaporative Cooling Combined with Heat Sink on PV Module Performance

A pin fins array as a heat sink along with a moist wood wool pad to serve as novel cooling system to cool PV panel has been used. The present cooling system was based on the evaporative cooling concept and extended area of heat transfer. The results gave enhancements in output power and panel’s efficiency about 32.7% and 31.5% respectively. This improvement in the module performance was attributed to the reduction in the operation temperature of the solar cell. The reduction in module temperature was about 26.05%.

Effect of Trans-Nasal Evaporative Intra-arrest Cooling on Functional Neurologic Outcome in Out-of-Hospital Cardiac Arrest

Therapeutic hypothermia may increase survival with good neurologic outcome after cardiac arrest. Trans-nasal evaporative cooling is a method used to induce cooling, primarily of the brain, during cardiopulmonary resuscitation (ie, intra-arrest). To determine whether prehospital trans-nasal evaporative intra-arrest cooling improves survival with good neurologic outcome compared with cooling initiated after hospital arrival. The PRINCESS trial was an investigator-initiated, randomized, clinical, international multicenter study with blinded assessment of the outcome, performed by emergency medical services in 7 European countries from July 2010 to January 2018, with final follow-up on April 29, 2018. In total, 677 patients with bystander-witnessed out-of-hospital cardiac arrest were enrolled. Patients were randomly assigned to receive trans-nasal evaporative intra-arrest cooling (n = 343) or standard care (n = 334). Patients admitted to the hospital in both groups received systemic therapeutic hypothermia at 32°C to 34°C for 24 hours. The primary outcome was survival with good neurologic outcome, defined as Cerebral Performance Category (CPC) 1-2, at 90 days. Secondary outcomes were survival at 90 days and time to reach core body temperature less than 34°C. Among the 677 randomized patients (median age, 65 years; 172 [25%] women), 671 completed the trial. Median time to core temperature less than 34°C was 105 minutes in the intervention group vs 182 minutes in the control group (P < .001). The number of patients with CPC 1-2 at 90 days was 56 of 337 (16.6%) in the intervention cooling group vs 45 of 334 (13.5%) in the control group (difference, 3.1% [95% CI, -2.3% to 8.5%]; relative risk [RR], 1.23 [95% CI, 0.86-1.72]; P = .25). In the intervention group, 60 of 337 patients (17.8%) were alive at 90 days vs 52 of 334 (15.6%) in the control group (difference, 2.2% [95% CI, -3.4% to 7.9%]; RR, 1.14 [95% CI, 0.81-1.57]; P = .44). Minor nosebleed was the most common device-related adverse event, reported in 45 of 337 patients (13%) in the intervention group. The adverse event rate within 7 days was similar between groups. Among patients with out-of-hospital cardiac arrest, trans-nasal evaporative intra-arrest cooling compared with usual care did not result in a statistically significant improvement in survival with good neurologic outcome at 90 days. ClinicalTrials.gov Identifier: NCT01400373.

An experimental investigation on solar powered solid desiccant air conditioning (SPSDAC) based on regenerative evaporative cooling system with PCM unit

ABSTRACT A solar powered solid desiccant air conditioning (SPSDAC) with PCM unit was explored for cooling purposes for the duration of sunlight and sunset hours. Two unique modes of the indirect evaporative cooler (IEC) was adopted during the operation of the SPSDAC. During mode-1, the water circulated through the copper coil and annular space of the hollow circular pipe was vacant. Whereas in mode-2, the water circulates through copper coil and annular space. It was concluded that COP of the system is more than the exergy efficiency and exergy efficiency varied from 1.83% to 1.99%. The desiccant wheel thermal effectiveness (28.81% and 46.06%) is lower than the indirect and direct evaporative cooler effectiveness. The setup under mode-2 is advantageous as compared to mode-1. The pay back time of the setup is 23.2 months. The mean overall thermal storage capacity of the system in mode-1 is 1796.1 W whereas in mode-2 is 1817.7 W.

Three Stages of Indirect Evaporative Cooling: Experimental and Theoretical Evaluation Study

Economical energy, reduction of cost and utilization of clean energy are required to meet the human needs. Evaporative cooling units are considered as a solution for these requirements by transforming such systems into technologies that meet these needs. The equipment’s cost, installation and operating costs are simple and low compared with refrigeration systems. An effective design is obtained by employing three stages settlement that equipped with a cross flow heat exchanger, direct and indirect evaporative coolers. In order to assess the design performance, a program code is developed. Flow and design parameters namely, air flow rate, piping length and diameter are studied. In addition to that the inlet air-dry bulb temperature at several different time duration over day is studied. The study was conducted in Tikrit University, Iraq (34. 35N; 43.37 E). Readings are recorded in June, July and end of August for two days (24 hours a day). The results show that, saturation of direct evaporative cooler effectiveness varies in the range, 67% - 96% and overall effectiveness of the unit varies in the range, 80% - 120%. It is provided that the system is efficient in dry and hot areas, and an improvement in the performance of the current design is achieved successfully.&#x0D; © Copyright 2018 JASET, International Scholars and Researchers Association

The Effects of Evaporative Cooling on Folliculogenesis and Ovarian Hormones during the Estrous Cycle of Dairy Holstein Cows during the Summer Months in Saudi Arabia

Heat stress is identified as a major cause of lower productive and reproductive performance in animal farming. This situation is more common in Saudi Arabia than in other countries because of extremely high ambient temperatures experienced during the summers. The evaporative cooling cow group had significantly increased serum E2 concentrations on days 7 and 14 - 19 of their estrous cycles, and significantly decreased serum P4 concentrations on days 7 - 18 of their estrous cycles. Evaporative cooling plus shade lowered ambient temperatures (41.80 ± 0.74 versus 47.40˚C ± 0.84˚C) have increased the relative humidity (0.33 ± 0.01 versus 0.24 ± 0.01) and decreased the temperature humidity index (80.24 ± 0.60 versus 84.77 ± 0.68) when compared with shade alone. However, cows under shade alone, compared to cows under evaporative cooling with shade, had a larger number of small (10.04 ± 0.54 versus 4.72 ± 0.58), medium (2.80 ± 0.21 versus 1.79 ± 0.17), and large follicles (6.82 ± 0.28 versus 5.66 ± 0.22). These results demonstrated that while evaporative cooling had positive effects on dairy cows in this experiment, changes could have been more profound, if installations of curtains and fans were implemented, which might need further investigation.

The Effects of Evaporative Cooling on Heat Stressed Dairy Holstein Cows Under a Semi-Arid Environment in Riyadh Area, Saudi Arabia

Heat stress has been identified as a major cause of lower productive and reproductive performance in animal farming. Methods for protecting livestock from heat stress were investigated during the summer months, where one six Holstein cows kept under shade only (group 1), and another six cows kept under shade with evaporative cooling (group 2). The results show that shade and water sprayers (evaporative cooling) significantly lowered ambient temperature and thus reduced the heat stress experienced by dairy cows in Saudi Arabia. Evaporative cooling plus shade, lowered ambient temperature (41.80 ± 0.74 vs. 47.40 ± 0.84°C), increased relative humidity (0.33 ± 0.01 vs. 0.24 ± 0.01) and decreased the temperature humidity index (80.24 ± 0.60 vs. 84.77 ± 0.68) when compared to shade alone. In addition, cows kept under evaporative cooling (38.4 ± 0.32°C) experienced lower rectal temperatures compared to cows under shade alone (39.53 ± 0.44°C). Cows under evaporative cooling had higher serum concentrations of triidothyronine (2.50 ± 0.90 vs. 0.75 ± 0.20 ng/ml) and thyroxine (11.94 ± 1.60 vs. 7.22 ± 1.88) than cows under shade alone. Thus, evaporative cooling can decrease the heat stress experienced by dairy cows in Saudi Arabia and limit its associated detrimental effects.

The Effects of Evaporative Cooling in Tropical Climate

The performance of thermal power plants, achievement of human comfort, preservation of groceries etc. are generally adversely affected by poor environmental conditions. In order to provide solutions to these challenges, an evaporative cooling system was developed and studied. The study was aimed at providing lower temperatures for the efficient performance of machineries and human comfort as well as lower temperature and higher relative humidity necessary for overcoming the above adverse condition. The performance of the cooler was evaluated in terms of temperature drop, cooler capacity, saturation efficiency and feasibility index. The results showed that evaporative cooling is achievable with feasibility index of F*≤ 10, when the difference between inlet dry bulb temperatures and wet bulb temperature are greater, T1-Tw = 11.5°C and T1-T2= 25.22°C with F*=9; T1-Tw= 12°C and T1-T2= 7.109°C with F*=10 respectively. The results also affirmed that cooler capacity and the saturation index are higher where the feasibility indexes are comparatively low.

Exergy Analysis of Combined Effect of Evaporative Cooling and Steam Injection on Gas Turbines Performance Enhancement in Hot and Humid Climates

In this paper, an exergy analysis has been used to examine for a combination of cooling the compressor intake air and inject steam in the combustion chamber the performance enhancement of gas turbine power plants using by a combination of intake air cooling the compressor intake air and injecting steam in the combustion chamber is studied. The limits of the cooling capability of an evaporative cooler are analyzed and formulated in terms of the characteristic dimensionless groups: the temperature ratio (ξ T ), the power gain ratio (PGR), Thermal efficiency change (TEC) and humidity ratio (RH). Similarly the effect of steam injected is presented as a ratio (y) of total volumetric flow rate. The effect of different pressure ratio (PR) is examined for Saudi Arabia summer weather when the turbine inlet temperature, T 3 , is a predetermined of 1373.15 K. The results for a specific example where the air evaporative cooler drops the temperature to the wet bulb temperature is presented and show the power gain ratio enhancement depends on the ambient temperature, relative humidity, evaporative cooler effectiveness and slightly on the pressure ratio. The results indicate for PR =10, the PGR is enhanced by 9% at 20% relative humidity and drops to 3.37% at 60% relative humidity. The daily performance of the cooling method is examined for the hot humid conditions of Jeddah, Saudi Arabia. The results show that the evaporative cooler increased both the daily power output and the thermal efficiency by 2.52% and 0.112% respectively. In addition, the result shows that the combustion irreversibility is the dominant in the governing the system PGR and TEC with various steam injection ratios for PR=10.

Effect of Over-Tree Evaporative Cooling in Orchards on Microclimate and Accuracy of Insect Model Predictions.

Orchard design and management practices can alter microclimate and, thus, potentially affect insect development. If sufficiently large, these deviations in microclimate can compromise the accuracy of phenology model predictions used in integrated pest management (IPM) programs. Sunburn causes considerable damage in the Pacific Northwest, United States, apple-producing region. Common prevention strategies include the use of fruit surface protectants, evaporative cooling (EC), or both. This study focused on the effect of EC on ambient temperatures and model predictions for four insects (codling moth, Cydia pomonella L.; Lacanobia fruitworm, Lacanobia subjuncta Grote and Robinson; oblique-banded leafroller, Choristoneura rosaceana Harris; and Pandemis leafroller, Pandemis pyrusana Kearfott). Over-tree EC was applied in July and August when daily maximum temperatures were predicted to be ≥30°C between 1200-1700 hours (15/15 min on/off interval) in 2011 and between 1200-1800 hours (15/10 min on/off interval, or continuous on) in 2012. Control plots were sprayed once with kaolin clay in early July. During interval and continuous cooling, over-tree cooling reduced average afternoon temperatures compared with the kaolin treatment by 2.1-3.2°C. Compared with kaolin-treated controls, codling moth and Lacanobia fruitworm egg hatch in EC plots was predicted to occur up to 2 d and 1 d late, respectively. The presence of fourth-instar oblique-banded leafroller and Pandemis leafroller was predicted to occur up to 2 d and 1 d earlier in EC plots, respectively. These differences in model predictions were negligible, suggesting that no adjustments in pest management timing are needed when using EC in high-density apple orchards.

Limitations of Inlet Air Evaporative Cooling System for Enhancing Gas Turbine Performance in Hot and Humid Climates

This paper aims to investigate the evaporative cooling limitations of compressor intake-air for improving the performance of gas turbine power plants. The limitations of the evaporative cooling capability are analyzed and formulated in terms of the characteristic dimensions involving the temperature ratio, the power gain ratio (PGR), thermal efficiency change, and humidity ratio. The effects of different pressure ratios (PRs) are examined for Saudi Arabia summer weather when the turbine inlet temperature is predetermined at1373.15 K. The results of a specific example where the air evaporative cooler drops the temperature to the wet bulb temperature are presented. These indicate that the power gain ratio enhancement depends on the ambient temperature, relative humidity, evaporative cooler effectiveness, and slightly the PR. Especially for PR =10, the PGR is enhanced by 9% at 20% of relative humidity and dropped to 3.37% at 60% of relative humidity. The daily performance of the evaporative cooling method is examined for the hot humid conditions of Jeddah, Saudi Arabia. The results show that the evaporative cooler increased both the daily power output and the thermal efficiency by 2.52% and 0.112%, respectively.

Thermal Analysis of a Novel Integrated Air Conditioning System with Geothermal Energy

AbstractThermal analysis of a novel integrated system of a desiccant wheel, a solar collector, a heat exchanger, a ground heat exchanger, and a water spray evaporative cooler is performed for air conditioning cooling systems. The effects of the following parameters were studied: inlet air temperature Tin,air, the inlet air humidity ratio ωin,air, regeneration temperature TReg, heat exchanger effectiveness eHE, solar radiation Gt, cooling coil unit effectiveness eECCU, and evaporative cooler effectiveness eEC on the behavior of supplied air temperature Tsup,air, supplied air humidity ratio ωsup,air, cooling water flow rate m˙w, area of solar air collector ASol, efficiency of solar air collector ηSol, and desiccant wheel effectiveness eDW. The system with geothermal energy was found to be more efficient and to provide more human thermal comfort than the system without geothermal energy. This novel hybrid system significantly decreased the supplied air temperature from 10 to 19.5°C. The simulation results re...

Comparative Effects of Evaporative Cooling, Kaolin Particle Film, and Shade Net on Sunburn and Fruit Quality in Apples

We investigated the effects of evaporative cooling (EC), kaolin particle film (KP) and 20% shade net (SN) on the control of sunburn, fruit temperature amelioration and fruit quality of `Cripps' Pink' and `Royal Gala' apples [Malus domestica Borkh.] under orchard conditions during the 2003–04 season in Stellenbosch, South Africa. On days with maximum air temperatures of 34 to 37 °C, SN fruit were 5.4 to 9.7 °C cooler, EC fruit were 3.1 to 5.8 °C cooler and KP fruit were 1.5 to 6.4 °C cooler compared to the control (nontreated, CO) fruit. SN was effective in reducing fruit temperature from mid-morning until midafternoon; KP was most effective during late morning and early afternoon but not at midday; EC was effective from late morning on days when EC was activated. SN, followed by KP, was the most effective technique for controlling sunburn in fruit of both cultivars, with EC being less effective. The different technologies reduced fruit blush color compared to the CO treatment, with SN showing the most reduction and EC the least. EC increased fruit mass compared to all other treatments in `Royal Gala', and also increased fruit diameter and mass compared to CO in `Cripps' Pink'. We conclude that under the high radiation levels experienced in South African apple production areas, technologies which reduce irradiance as well as fruit temperature (KP, SN) are more effective in reducing sunburn than those which only reduce fruit temperature (EC). However, radiation-reducing technologies are potentially detrimental to color development on blushed apples.

Effect of Water Spray Evaporative Cooling at the Inlet of Regeneration Air Stream on the Performance of an Adsorption Desiccant Cooling Process

Effect of Water Spray Evaporative Cooling at the Inlet of Regeneration Air Stream on the Performance of an Adsorption Desiccant Cooling Process

Application of solar assisted heating and desiccant cooling systems for a domestic building

The performance of solar assisted heating and desiccant cooling systems for a domestic two story residence located in Baghdad was evaluated. A computer simulation was developed to assess the effects of various designs and operating conditions on the performance of the system and its components. The solar air heating system included a V corrugated solar air heater array, a rock bed storage unit and an auxiliary heat source. A rotary silica gel desiccant dehumidifier, a sensible cooler and an evaporative cooler were added to the above system to form an open cycle solar assisted desiccant cooling system. The variable base degree-day method was employed in order to incorporate the hourly variations of solar heat gain and internal heat gains of the space in the estimation of the heating load. The transfer function method was used to evaluate the hourly variation of the cooling load. Only two collector rows in series were employed to provide the required supply air temperature for the heating system and the required regeneration temperature for the desiccant cooling system. This array gave an air outlet temperature of approximately 62°C at an air mass flux of 0.06 kg/s m 2 at midday in July, while a 36°C outlet air temperature was achieved for the same array and mass flux in January. The results of simulation of the solar air heating system indicated that the major design parameter is the collector area. The effect of air mass flux through the collector array was not significant. Also, increasing the rock bed storage volume produces only slight improvements in the solar fraction. Simulation of the open cycle solar assisted desiccant cooling system showed that the ambient temperature, regeneration temperature, heat exchanger effectiveness and evaporative cooler effectiveness have major influences on the system performance, whereas the dehumidifier has a minor effect. Also, the simulated system was capable of providing a cool supply of air at acceptable comfort conditions for various summer days in Baghdad.

Turning with Environment-Friendly Cooling Method Using Water Evaporation : 1st Report, Cooling Effect of Water Evaporation and Its Applicability to Tool Tip Cooling

In the 21st century, as it is important to produce a product with care for protecting the earth, a producer must be careful on conservation of energy, saving of resources and reducing waste which break environment down. However, in machining such as cutting, cutting fluids are used for improving of tool life and surface roughness, and this gives the earth and a worker large harm. Though cutting with oil mist or cold air cooling were used for the countermeasure, these aren't sufficient yet. Therefore, in this paper, turning with environment-friendly cooling method using water evaporation was investigated for the earth. At first, cooling effect of water evaporation was evaluated by easy experiment and FEM analysis. Then, its applicability to tool tip cooling was experimented and evaluated. Method of supplying water are two kinds ; one method is supply using an intravenous drip on the cloth which was bonded on the tool tip and another one is supply using an oil mist device only at the tool tip. It is concluded from the results that ; (1)Turning with environment-friendly cooling method using water evaporation was very effective. (2)In case of the turning using an intravenous drip, the tool life was 1.5 times of the dry cutting, and this method is a low cost and low environmental pollution. (3)In case of the turning using an oil mist device, the tool life was 2 times of the dry cutting.