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This study presents a review of advances made in evaporative cooling technologies, emphasizing their application in indoor thermal comfort. It highlights that the rising demand for cooling has primarily been met by conventional mechanical vapor compression systems. However, these systems face two significant issues: high electrical energy requirements and the use of refrigerants like chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs), which contribute to ozone layer depletion and global warming. The findings indicate that evaporative cooling technology is a promising alternative due to its low energy demand and potential to integrate renewable energy, therefore enhancing its environmental benefits. The study also details various evaporative cooling technologies, recent improvements in their performance, practical applications, challenges, and opportunities for providing indoor thermal comfort. [ABSTRACT FROM AUTHOR]

Outdoor atriums have recently been applied with increasing frequency for natural illumination, but they produce a harsh thermal environment easily in summer. Moreover, overheating of the outdoor atrium necessitates air-conditioning to moderate indoor thermal comfort. Simultaneously, the substantial heat emissions from air-conditioning outdoor units worsen the outdoor thermal environment, creating a vicious cycle. Traditional passive evaporative methods involving water and greenery, while capable of regulating the thermal environment, suffer from low evaporative efficiency and pose significant challenges. To improve thermal environment in outdoor atriums, the spray system was employed due to its high cooling efficiency, especially in open or semi-open spaces. In this study, a comparative experiment was conducted to evaluate the effectiveness of using a spray system for evaporative cooling in open outdoor spaces. Furthermore, employing high-efficiency evaporative cooling through spraying to disrupt the vicious cycle of indoor and outdoor thermal environments. The dual goals include regulating indoor and outdoor thermal conditions while also mitigating the local heat island effect. Temperature and humidity distribution within the atrium and adjacent hallways were monitored, along with the impact on air-conditioning operation consumption in neighboring offices. Results showed that the spray system significantly improved the thermal environment in the outdoor atrium, reducing the average and peak air temperatures by 0.94–2.83 °C and 2.92–5.21 °C, respectively. It also resulted in a drop in the average temperature by 0.56–1.62 °C and the peak temperature by 2.31–3.25 °C in adjacent hallways. This effectively eased the issue of overheating in these areas while raising the comfort level in adjacent office spaces. The predicted mean vote decreased from 1.46 to 0.87, indicating a significant improvement in thermal environment in neighboring offices. Furthermore, the daily energy consumption was reduced by 10.6–12.4% in neighboring offices. This study provided the valuable guidance for improving thermal environments within outdoor atrium. [ABSTRACT FROM AUTHOR]

Energy demand for the air conditioning sector is increasing due to increasing population, increasing living standards, and global warming. This increase in demand must be accompanied by efforts to increase energy efficiency. Evaporative cooling is one effort that can be chosen to increase the energy efficiency of the air conditioning system. The use of evaporative cooling by utilizing condensate water from the evaporator has been experimentally investigated. This research was conducted directly on an air conditioner unit that had already been installed in a room. Specifically, experiments were carried out by flowing and dripping condensate water into the compressor body of an air conditioner and examining its effect on the performance of the air conditioner. The research results show that the use of condensate water can reduce suction temperature, discharge temperature and condensation temperature by 0.7°C, 3.2°C, and 1.2°C, respectively. As a result, cooling capacity increases by 2.8%, energy consumption decreases by 3.5%, and energy efficiency ratio increases by 7.6%. Overall, the use of condensate water for compressor cooling can improve air conditioner performance. [ABSTRACT FROM AUTHOR]

Earth's temperature has risen by ≈0.18 °C per decade since 1981 and year 2022 is the sixth‐warmest year on record. The exploration of cooling strategies that operate with less energy consumption is thus highly desirable. Through this project, a camel‐fur‐inspired passive membrane encapsulated sorbent cooler that can periodically absorb moisture from the atmosphere and release it for daytime evaporative cooling, leading to effective regulation of building temperature without additional energy input is demonstrated. This sorbent cooler with high sorption capacity is made of anhydrous salt and modified expanded graphite and further encapsulated by a breathable porous membrane. This novel material is shape‐stabilized, and it has excellent cycling performance, and remarkable water adhesion ability. In this evaporative‐cooling demonstration, the average cooling power of the camel‐fur‐inspired sorbent can reach up to 630 W m−2, which is much higher than the radiative cooling approach. This theoretical model implies that the proposed sorbent cooler has the potential to cut down cooling energy carbon emission by 61% to 87.83% when compared to emissions released from cooling energy usage in reference buildings. This nature‐inspired approach paves a new way for efficient space cooling without extra water supply and with minimized energy consumption. [ABSTRACT FROM AUTHOR]

Decoupling cooling and ventilation tasks with an existing air conditioning methodology are a promising performance-enhancement technology. In this direction, different configurations of a desiccant-integrated independent ventilation element attached to a conventional cooling system are proposed in this study. This work establishes a quantitative comparative performance analysis among the different process air cooling (obtained through desiccant dehumidification) techniques for three different climates, namely, hot-dry, tropical, and Mediterranean. EnergyPlus simulations have been executed on a small-scale office building of 400-m2 area. The building constructional details and other required simulation input parameters follow benchmark standards. As the chemical dehumidification increases, the process air, i.e., supply air temperature that cannot be sent directly to the room, needs to be cooled. Three approaches for process air cooling have been considered: direct expansion (DX) cooling coil, indirect evaporative cooling (IEC), and sensible heat recovery wheel (SHRW). A solar collector assembly with a supporting heating arrangement is coupled with desiccant unit for regeneration. Outdoor air is used for regeneration in the case of the DX cooling coil and IEC, whereas return air is used in the heat recovery wheel case. Annual simulation results reveal that the SHRW-aided case performs superior than DX coil case for the pertinent climatic conditions, with 9.6 to 45.01% of annual energy savings. For the IEC, energy consumption was 1.8 to 18.38% less than that of DX coil. Also, using return air in this best-suited case reduces the net thermal energy requirement for regeneration by 14.63 to 71.65% with respect to DX coil. [ABSTRACT FROM AUTHOR]

Separate sensible and latent cooling (SSLC) is a promising technology for enhancing the energy efficiency of space cooling systems. In this paper, we propose an SSLC configuration consisting of an indirect evaporative cooling (IEC) device and vapor compression cycle (VCC) for handling space sensible load, and a desiccant wheel for handling space latent load. The performance of the proposed configuration is investigated using physics-based or empirical models for each component. A year-round simulation study of the proposed SSLC system is performed for 12 different cities with diverse climatic conditions. This study considers electrical, thermal, or solar energy for desiccant wheel regeneration. Parameters governing the system performance such as the air flowrate ratio in the IEC and the DW, DW regeneration air temperature, and supply temperature are studied. The proposed SSLC configuration is superior to the conventional system in all cities. The enhancement of seasonal coefficient of performance (sCOP) ranges between 50 and 261 %, 67 and 387 %, and 60 and 2072 % with yearly electrical energy savings of 33 and 72 %, 40 and 79 %, and 38 and 95 % for electrical, thermal, and solar energy for regeneration of DW, respectively. [ABSTRACT FROM AUTHOR]

• A direct evaporative cooler (DEC) integrates with split air conditioner (SAC). • DECSAC significantly improves C O P by 10.54 %−70.14 %. • Total cost rate (T C R) of DECSAC reduces by 5.07 %−25.36 %. • Water consumption for 1 kWh energy saving varies between 5.5 – 9.8 L. • Simple payback period lies between 1.21 to 2.99 years with maximum I R R being 59 %. As concerns regarding energy consumption and environmental impact continue to grow, the need for efficient and sustainable cooling technologies becomes increasingly significant. Among various alternatives, direct evaporative cooling (DEC) has emerged as a promising solution due to its energy-efficient operation and low environmental footprint. This paper aims to provide a comprehensive thermo-economic assessment of a 5.25 kW capacity split air conditioner (SAC) integrated with direct evaporative cooling, focusing on evaluating its performance, energy consumption, coefficient of performance (C O P) , and economic viability. A numerical model is developed to determine the reduction in the condenser inlet air temperature due to direct evaporative cooling. The ambient temperature (30–45 ⁰C), relative humidity (20–80 %), and evaporator temperature (3–12 ⁰C) are taken as the design variables. Box–Behnken design (BBD) technique of response surface methodology is applied for multi-objective optimization. The C O P , total cost rate (T C R) , and total exergy destruction ( E ˙ D , t ) are set as the objective functions. Cooling capacity, life period, operation time, interest rate, maintenance factor, and electricity cost are taken as constants. The thermoeconomic optimization evolved maximized C O P enhancement of 68.94 %, and reduction in TCR and E D , t by 26.12 % and 57.23 %, respectively. The water consumption to energy saving ratio varies from 5.5 to 9.8 L/kWh for different months of the cooling season. The thermoeconomic performance and sustainability of DECSAC is observed to significantly improve compared to conventional SAC specifically in hot-dry climates. The simple payback of the proposed system ranges between 1.21 to 2.99 years depending upon the operating conditions. [ABSTRACT FROM AUTHOR]

Economy and productivity are the two most important elements of modern manufacturing systems. Economy is associated with energy-efficient operations, which results in an overall high input-to-output ratio, while productivity is related to quality and quantity. This specific work presents experimental investigations of the use of cooling conditions (dry, MQL and wet) as input variables alongside other input parameters, including depth of cut, feed and cutting speed. This research aimed to investigate the variation in output responses including tool wear, specific cutting energy, and surface roughness while machining Inconel 718, a nickel-based super alloy. For experimentation, three levels of depth of cut, feed, and cutting speed were chosen. The Taguchi method was used for the experimental design. The contribution ratio of each input parameter was ascertained through analysis of variance (ANOVA). Use of coolant showed a positive effect on process parameters, particularly MQL. By adapting the optimum machining conditions, specific cutting energy was improved by 27%, whereas surface roughness and tool wear were improved by 15% and 30%, respectively. [ABSTRACT FROM AUTHOR]

The so-called indirect evaporative cooling technology is widely used in air conditioning applications. The thermal characterization of tube-type indirect evaporative coolers, however, still presents challenges which need to be addressed to make this technology more reliable and easy to implement. This experimental study deals with the performances of a tube-type indirect evaporative cooler based on an aluminum tube with a 10 mm diameter. In particular, the required tests were carried out considering a range of dry-bulb temperatures between 16°C and 18°C and a temperature difference between the wet-bulb and dry-bulb temperature of 2°C~4°C. The integrated convective heat transfer coefficient inside the tube in the drenching condition has been found to lie in the range between 36.10 and 437.4 (W/(m²•K)). [ABSTRACT FROM AUTHOR]

Data center is one of the indispensable infrastructures in the modern information society, however, its high energy consumption and carbon emission have become an urgent problem. In order to reduce the large energy consumption of data centers in hot and humid areas due to mechanical cooling and air-conditioning systems, the operation of an indirect evaporative cooling (IEC) air-conditioning system was simulated in a hot and humid area data center based on Matlab and the Energy Plus platform, its annual energy consumption was evaluted. The impact of solar assisted dehumidification (LDD) system on the three operation modes and the performance of IEC air-conditioning system were also investigated. The results show that the IEC air-conditioning system can achieve 16.5% annual energy saving intensity compared to a conventional mechanical cooling system, and that the addition of an LDD unit can increase the wet mode operating time of the IEC air-conditioning system by 35.9% and reduce the system energy consumption by 20.1%. Therefore, IEC air-conditioning systems have significant energy-saving advantages in hot and humid data centers and can significantly improve the operational efficiency and sustainability of data center air-conditioning systems. [ABSTRACT FROM AUTHOR]

Aiming at the difficulty of accurately reflecting the actual effect of the engineering application of the data center’s energy consumption evaluation results. In this paper, on the basis of the existing data center energy efficiency evaluation index, from the data center, data center air conditioning system, indirect evaporative cooling air conditioning equipment in three dimensions, respectively, put forward the data center indirect evaporative cooling air conditioning PUE coefficient, data center air conditioning energy utilization efficiency, indirect evaporative cooling air conditioning equipment refrigeration density and other evaluation indicators. Using the new evaluation indexes as well as the assignment analysis method, case studies were conducted on data centers with different cooling systems. The results show that the indirect evaporative cooling air-conditioning system has obvious advantages of power and water saving compared with the traditional chilled water system, but its refrigeration density index still has much room for improvement. The proposal of the new index improves the energy efficiency evaluation system of data centers and can lead to further improvement of the performance quality of related air conditioning products. [ABSTRACT FROM AUTHOR]

In this study, an evaporative cooling device (ED) was developed using the evaporative cooling pad (EP) made of cellulose-based materials with related accessories to actually install on a condenser of the automotive air conditioner (MAC) to improve the operating performance of HR-12 MAC. The ED was used to pre-cool the air entering the condenser by evaporative cooling instead of directly spraying water to cool the condenser. This approach can effectively reduce the risk of condenser corrosion and contamination. The HR-12 MAC performance was assessed at three different outdoor ambient temperatures (T oa : 30 °C, 35 °C, and 40 °C) and EP thicknesses (3 cm, 5 cm, and 7 cm). The configuration of the optimum EP thickness was identified through the results of HR-12 MAC performance experiments. The operating performance of HR-12 MAC with ED improved with the increase in T oa and EP thickness. However, according to most test results, ED could not effectively improve the performance of HR-12 MAC at the T oa of 30 °C. Under optimal conditions, the coefficient of performance (COP) of the refrigeration system and the energy efficiency ratio (EER) of the air conditioning system of HR-12 MAC with ED were respectively 7.76% and 13.09% higher than the original HR-12 MAC at the T oa of 40 °C, and the EP thickness of 7 cm. [ABSTRACT FROM AUTHOR]

Evaporative cooling is widely recognized as an energy efficient and environmentally-friendly air conditioning solution, and it has drawn a lot of market interest in recent years. However, this technology is accompanied by several challenges. For instance, insufficient evaporation due to poor and non-homogenous water distribution of the pre-cooling pad significantly reduces the cooling performance. The aim of the study is to develop a technique for numerical simulation of the distribution of a droplet liquid (water) on the mesh surface of an adiabatic cooler to improve the performance of air conditioning equipment. Modern computer-aided design (CAD)/computational fluid dynamics (CFD) programs were used to solve the issue. For the mathematical modelling of the medium motion, non-stationary Navier–Stokes equations were used. Parameters such as heat, mass transfer, and the efficiency of liquid droplet spraying were determined. The current study presents CAD modelling, conducted in SolidWorks platform, of water distribution on the adiabatic cooling pad’s mesh surface for improving air conditioning equipment performance. This study provides the methodology for computer modeling and numerical calculation of the parameters of adiabatic cooling, such as modelling of water atomization process. The results show that the use of additional metal mesh intended as cooling pads increases the mass transfer coefficient by Sh ≈ 15–40%; heat transfer coefficient Nu increases by ≈20–40%; and the atomization efficiency increases by ≈30–40%. The installation of metal pad mesh allows for equalized uniformity of the water distribution. The results imply that there are more opportunities to optimize the parameters of adiabatic cooling, which should be evaluated in further research on the subject.

Global warming and increased living standards have rapidly increased the demand for cooling systems. Meeting this demand in less economically developed areas is highly challenging due to a lack of electricity. In this paper, we have demonstrated a high‐performance and wide relative humidity (RH) solar‐driven evaporative cooling strategy that uses only atmospheric water. Developed here for the first time, we designed a metal–organic framework (MOF‐801) based composite with a high‐performance atmospheric water absorption across a wide range of RH. The as‐synthesized composite can adsorb atmospheric water up to ~22% (~80%) of its weight at an RH@28% (~70%). Our demonstration has shown that the corresponding cooling powers range from 136 to 344 W/m2 in a wide range of RH and solar intensities, and the passive cooling temperature is up to 14°C lower than the device's reference counterpart. Our study thus proposes a solar‐driven cooling coating with high cooling powers across a wide range of RH based on an as‐synthesized composite, which pinpoints a pathway to replace traditional compression‐based cooling systems (e.g., air conditioners) and which will also have a significant impact in future global energy consumption. [ABSTRACT FROM AUTHOR]

Waste heat capture from systems such as photovoltaics (PV) and refrigerators can lower their energy efficiency by increasing their operating temperature. In this study, we evaluate the potential of final-effect evaporative cooling and internal heat recovery in a multi-effect diffusion distillation (MEDD) to produce pure water without negatively impacting the energy efficiency of the waste-heat source. Lab-scale experimental results from a multi-effect membrane distillation module validate the concept, showing that water production can be enhanced by >20 % while simultaneously pulling down the module's operating temperature. A detailed numerical model of a solar-MEDD is implemented and validated. The incorporation of sensible heat recovery and evaporative cooling increase pure water production by approximately 10 % each. Although the pure water production of a standalone MEDD increases with increasing effects N , when coupled to a solar PV module, increasing N also decreases PV electricity production. Therefore, a PV-MEDD with fewer effects (≤ 4) is preferable and such a system can produce sufficient water for electrolysis (green H 2 production) while maintaining or improving PV electrical energy production throughout the year under varying climatic conditions. [Display omitted] • Waste heat capture reduces energy efficiency by increasing process temperature. • Evaporative cooling enables pure water production without reducing efficiency. • Distillate sensible energy recovery can result in 20 % higher pure water production. • Large number of effects improves water production, but reduces overall energy efficiency. • PV with 4-effect distillation with EC produces enough distilled water for green H 2. [ABSTRACT FROM AUTHOR]

The water harvesting potential of atmospheric water generators (AWGs) in high-altitude semiarid regions can be diminutive relative to the water generation capacity. Operational parameters for the dehumidification process can be augmented to increase atmospheric water in the defined zone available for harvesting. In this paper, the feasibility of augmenting the microclimates of AWGs at the point of air extraction through an evaporative cooling system (ECS) was investigated. Water yield and capacity utilisation were measured from two AWGs piloted on a plant in Ga-Rankuwa, South Africa. This was implemented between December 2019 and May 2021. The study revealed that although the ECS did impact the operating parameters through decreasing temperature and increasing relative humidity (p < 0.05), variance in water yield was not significant (p > 0.05). Capacity utilisation of the AWGs remained below 50% after augmentation. Cooling efficiency of the ECS ranged between 1.4–74.5%. Energy expenditures of 0.926 kWh/L and 0.576 kWh/L for AWGs 1 and 2 were required under pristine conditions, respectively. Under the modified conditions, energy expenditure decreased to 0.855 kWh/L for AWG 1, but increased/L to 0.676 kWh for AWG 2. ECS is deduced to not be a feasible intervention for augmenting water harvesting potential for AWGs in this semiarid zone. [ABSTRACT FROM AUTHOR]

Evaporative cooling is widely recognized as an energy efficient and environmentally-friendly air conditioning solution, and it has drawn a lot of market interest in recent years. However, this technology is accompanied by several challenges. For instance, insufficient evaporation due to poor and non-homogenous water distribution of the pre-cooling pad significantly reduces the cooling performance. The aim of the study is to develop a technique for numerical simulation of the distribution of a droplet liquid (water) on the mesh surface of an adiabatic cooler to improve the performance of air conditioning equipment. Modern computer-aided design (CAD)/computational fluid dynamics (CFD) programs were used to solve the issue. For the mathematical modelling of the medium motion, non-stationary Navier–Stokes equations were used. Parameters such as heat, mass transfer, and the efficiency of liquid droplet spraying were determined. The current study presents CAD modelling, conducted in SolidWorks platform, of water distribution on the adiabatic cooling pad's mesh surface for improving air conditioning equipment performance. This study provides the methodology for computer modeling and numerical calculation of the parameters of adiabatic cooling, such as modelling of water atomization process. The results show that the use of additional metal mesh intended as cooling pads increases the mass transfer coefficient by Sh ≈ 15–40%; heat transfer coefficient Nu increases by ≈20–40%; and the atomization efficiency increases by ≈30–40%. The installation of metal pad mesh allows for equalized uniformity of the water distribution. The results imply that there are more opportunities to optimize the parameters of adiabatic cooling, which should be evaluated in further research on the subject. [ABSTRACT FROM AUTHOR]

In order to solve the problem of high energy consumption of air conditioning in data cen-ter refrigeration system, the energy consumption of existing indirect evaporative cooling air conditioning was analyzed based on energy saving. The enthalpy difference laboratory was used to simulate different operation modes of air conditioning, and the influence law of outdoor dry and wet bulb temperature on total power and coefficient of performance(COP) of air conditioning unit was tested. Urumqi (dry area), Beijing (medium humidity area) and Guangzhou (high humidity area) were selected to simulate and analyze the annual operating time of "dry mode+ wet mode" of the air conditioning unit, accounting for 95%, 74% and 36% respectively. At the same time, the annual accumulative power consumption is 296 662, 357 108, 490 169 kW • h respectively, and the annual accumulative power saving is 345,738, 285,292, 152 231 kW • h respectively, which has good applicability and power saving. [ABSTRACT FROM AUTHOR]

The rapid development of the internet era has driven the construction of numerous data centers worldwide. In hot climate, data centers consume significant energy for cooling. Cold-mist direct evaporative cooling offers a natural cooling solution that can help reduce this energy consumption. This study investigates the temperature and relative humidity changes of natural high-temperature air after being cooled using a cold-mist direct evaporative cooling test bench. The effects of several control factors such as spray angle, spray flow rate, and air speed on the cold-mist direct evaporative cooling performance was systematically examined. The findings revealed that: (1) the optimal spray angle for cold-mist direct evaporative cooling treatment air is 65°; (2) high-temperature air between 27 °C and 37 °C can be cooled to 23.57 °C – 25.58 °C after cold-mist direct evaporative cooling treatment, with relative humidity levels of 67.0 % – 78.8 %, meeting the air supply requirements for data centers; (3) the proposed approach could reduce the data center energy consumption by 14 % – 41 %, while extending the annual natural cooling period by 3.16 % – 20.45 %. [ABSTRACT FROM AUTHOR]

Evaporative cooling has a major role to play in fighting climate change and in achieving a low‐carbon economy. As it helps to reduce energy demand for air conditioning, it is gaining attention in terms of improving energy efficiency in buildings. Evaporative cooling from wetted media can enhance water–air contact, thereby improving heat and mass transfer further and avoiding aerosols. Wetted media are commonly called evaporative cooling pads and are widely used in greenhouses, intensive livestock farming, and industrial facilities. However, a deep understanding of evaporative cooling pad performance can enhance their application to indoor occupied spaces such as residential or commercial cooling, or in hybrid air conditioning systems. Most studies analyze pad performance mainly in terms of pressure drop and saturation effectiveness. However, some studies propose alternative cooling efficiency parameters and others provide insights into key aspects such as power requirements and the coefficient of performance, water consumption, risk of water entrainment, material decay, and air quality, as well as the effect of water temperature and salinity, solar radiation, or wind speed. Existing results on these less studied performance issues are reviewed, and we identify the gaps in the literature in addition to highlighting the main challenges encountered, in an effort to guide future researchers in the field and enhance the application of direct evaporative cooling. This article is categorized under:Energy Efficiency > Systems and InfrastructureEnergy Systems Analysis > Systems and Infrastructure [ABSTRACT FROM AUTHOR]

In this study, a microchannel flat-tube condenser was introduced to a domestic freezer, and experiments were conducted to investigate the dynamic characteristics of the system at different ambient temperatures. Based on the dynamic variations of temperature in the main components, the refrigerant migration during the compressor-off stage and cooling output performance during the compressor-on stage were analyzed. The results show that the time proportion of the no-cooling output stage increased from 4.9% to 7.3%, while that of the refrigerant migration decreased from 25.6% to 21.2%, and energy consumption for no-cooling output stage increases from 0.0016 kW·h to 0.0023 kW·h as the ambient temperature increased from 16 °C to 32 °C. In addition, the freezer was compared to a system with a traditional circular tube condenser. The results show that the microchannel heat exchangers could contain more refrigerant charge due to the multi-channel structure during the compressor-off stage, weakening the "evaporative cooling" effect and reducing the migration loss. Therefore, the microchannel flat-tube condenser exhibited better stability at different ambient temperatures. The results of this study elucidate dynamic characteristics and advantages of applying a microchannel flat-tube condenser to a freezer, and provide a direction for reducing the energy consumption of a domestic freezer. [ABSTRACT FROM AUTHOR]

In order to solve the problem of high energy consumption of air conditioning system in data center, a new type of indirect evaporative cooling air conditioning unit was designed, which combines evaporative cooling, evaporative condensation and mechanical refrigeration. Through the enthalpy difference laboratory, the performance of the prototype was tested by simulating different secondary and primary air volume ratios and different dry and wet working conditions. The results show that the optimal air volume ratio range of the unit is 2.2～2.4,the efficiency of the indirect evaporative cooling section is 72%,61% and 53.45% in dry region, medium humidity region and high humidity region respectively, and the air supply temperature of the unit is about 24 ℃,which meets the air supply requirements of the data center room. The applicability analysis of the unit in three typical cities of lanzhou, Beijing and Shanghai in different climate zones shows that the cooling time of the unit in the three cities using natural cooling source accounts for 98%,78% and 62% of the total operating hours of the year respectively, showing good applicability. [ABSTRACT FROM AUTHOR]

Air conditioning plays a significant role to maintain a cool atmosphere in warm conditions, However, the power consumed by the machine is higher. The commercial prevailing cooling systems are required to operate ventilation and cooling systems in buildings and in turn consumes more power. These systems apart from consuming electricity it also adds to the CO2 emissions to our environment. These energy consumption and CO2 emissions can be decreased by the assistance of energy effective frameworks to the prevailing air conditioning system. The study was conducted on a package unit of 414.2kW by measuring the relative humidity, dry bulb, and wet bulb temperature to investigate the effect of indirect evaporative cooling on the systems COP. Also, the modelling of the package unit was done using Creo software and the analysis was carried out using ANSYS considering the flow and thermal analysis for different components of the package units. From this analysis it can be observed that by implementing the adiabatic cooling in package unit it is possible to save energy consumption. From the results it can be concluded that energy efficiency was more and the return on investment is high. Also, coefficient of performance of this machine is high and consumes less electricity and the expected energy savings is 20%. [ABSTRACT FROM AUTHOR]

A significant portion of global energy consumption is due to energy consumption in the buildings. Heating, cooling, and air conditioning systems have the largest share in this energy consumption. Evaporative cooling systems, which have the advantage of being economical, zero pollution, and easy maintenance are preferred to reduce energy consumption in buildings. These systems are used in many areas such as greenhouses, broiler houses, and warehouses. In this study, analyzes of exergy, sustainability, and cooling efficiency in four different situations of a ground source direct evaporative cooling system were made. The system was studied in four different cases. While the highest exergy efficiency was obtained in case 3 with 20.83%, the exergy efficiencies in other cases were obtained as 16.83%, 17.49%, and 18.36%, respectively. In addition, the highest specific exergy loss was determined as 100.51 J/kg in case 2, while it was calculated as 73.08 J/kg, 80.23 J/kg, and 73.05 J/kg for the other cases, respectively. It is seen that the sustainability values are in parallel with the exergy efficiency when the evaporative cooling system is examined for four different cases. The sustainability values were determined as 1.20 for case 1, 1.21 for case 2, 1.26 for case 3, and 1.22 for case 4. It is determined that the exergy efficiency gives precise information about the usability and sustainability of the system when these situations are evaluated. The exergetic improvement potential (EIP) was determined as 0.061 for case 1, 0.082 for case 2, 0.063 for case 3, and 0.059 for case 4, respectively. Although the highest exergy efficiency is obtained in case 3, it has a higher recovery potential than case 1 and case 4. In addition, cooling efficiencies for four different cases were obtained as 33.70%, 34.81%, 41.69%, and 36.95%, respectively. The temperature differences between the room and ambient temperatures were determined as 1.45 °C, 1.21 °C, 1.6 °C, and 1.48 °C for each case, respectively.

Agriculture and agro-based industries consume more energy, mainly derived from fossil fuels. The postharvest storage of agricultural products is crucial for the minimization of postharvest losses, which, throughout the supply chain, are controlled through the provision of optimum temperature and relative humidity conditions. A technoeconomic assessment of nonconventional energy resources (solar, wind and hybrid) in Sudan revealed that solar PV was more suitable in most studied sites for irrigation water pumping, as compared to wind and wind-solar hybrid energy systems [[4]]. [Extracted from the article]

Membrane-based absorption cycle is a novel technology to provide excellent heat and mass transfer performance in the main components for the convenience of small-scale applications. An overview is provided to summarize its progress and gives insights and possibilities for future development. A development trends analysis shows that the membrane-based absorption cycle is an emerging technology and attracts increasing attention in recent decades. Plate-and-frame module and hollow-fiber module are two common membrane-based modules that can improve the heat and mass transfer of absorber, desorber, and solution heat/mass exchanger. Besides, integrated components, including integrated evaporator-absorber and integrated condenser-desorber, have been proposed for further system size reduction. A thorough review of the cycle configurations indicates that the closed-type membrane-based absorption cycles could provide stationary cooling or heating capacity with better cycle performance, while the open cycles are more suitable for waste heat recovery and gas dehumidification. Apart from the conventional H 2 O–LiBr and NH 3 –H 2 O working fluids, ionic-liquid-based mixtures are promising candidates to overcome the existing constraints. But they also face some shortcomings, including high cost and possible high viscosity. This work is expected to facilitate the development and application of the membrane-based absorption cycle towards compact and efficient renewable/waste energy utilization. • A critical review illustrates the development of membrane-based absorption cycles. •Plate-and-frame and hollow fiber are key modules in membrane-based absorption cycle. •Membrane-based modules double the efficiency and compactness to traditional ones. •Closed cycle is reliable with high COP, but open cycle is good at dehumidification. •Ionic liquids are promising absorbents for widely applicable absorption cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • A high-performance HSEC coating is fabricated for large-scale building cooling. • The HSEC coating has high average solar reflectance (95.1%) and MIR-infrared emissivity (92.5%). • The HSEC coating realizes ambient cooling up to 4.2 °C during the daytime. • The HSEC coating shows excellent anti-contamination property and radiative stability. The building cooling has aroused widespread attention due to its significant contribution to both global warming and energy usage. To combat global warming and reduce energy consumption, an environmentally friendly beneficial alternative to electric cooling for buildings is passive daytime radiative cooling (PDRC). However, many of the reported radiative coolers still suffer from the challenge of complex preparation processes and high costs, making it difficult to scale up for building applications. Herein, the utilization of abundant and low-cost natural resources (i.e., cellulosic biomass and minerals) is strategized to produce radiative cooling material and incorporate this material into building cooling systems to boost global carbon neutrality. Guided by this concept, a hydrophobic SiO 2 /EC composite (HSEC) coating is designed by embedding nano-sized wollastonite-based SiO 2 particles into porous ethyl cellulose (EC) polymer, and subsequently through polydimethylsiloxane (PDMS) dispersion spray treatment. Benefiting from the sufficient scattering by the nano-SiO 2 particles and randomly dispersed light-scattering air voids, the resulting cooling coating shows a high solar reflectivity of 95.1 %. More importantly, the molecular vibration of the chemical in HSEC coating results in a high atmospheric window emissivity of 92.5 %. In the field test, the HSEC coating remained approximately 4.2 °C below the ambient temperature under intense solar irradiation of 412.5 W⋅m−2. This work not only offers a promising strategy for realizing the high-value utilization of wollastonite resources in building materials, but also provides a controllable approach for large-scale preparation of highly efficient radiative cooling materials to alleviate building cooling demands. [ABSTRACT FROM AUTHOR]

We propose the high-performance evaporative spray cooling strategy by combining the hierarchical flake formation and the intermittent spraying. A simple, scalable, and cost-effective method was introduced to fabricate hierarchical flakes with multi-scale wicks where the size of the pores varies along the direction normal to the wick plane, which provides substantially improved wicking capability for capillary pumping. In addition, the intermittent spray methods allowed for more efficient evaporative cooling by enabling the reduction in spraying volume. Through the thermal management experiments, the hierarchical flake heat exchanger could provide up to ∼32.1% reduced amount of sprayed water and ∼ 1.8 times higher energy efficiency compared to the untreated aluminum heat exchanger during intermittent spraying. Using the quantitative analysis on the single-droplet evaporation and water retention ability, we systematically demonstrate the effects of the combination of hierarchical flake and intermittent spray scheme on the efficient thermal management. We believe that our outcomes of this work show the potential of the spray cooling method for the heat exchangers and present the scalable evaporative surfaces applicable to various evaporative cooling applications. • Hierarchical flake fin is fabricated via a scalable dipping method. • Wicking capability is quantified by a single-drop evaporation test. • Water retention ability is systematically evaluated during intermittent spraying. • Water savings and energy efficiency are demonstrated by a heat exchanger test. • Hierarchical flake with intermittent spray facilitates efficient thermal management. [ABSTRACT FROM AUTHOR]

Summary: In freshwater‐scarce coastal regions, increasing water demand has always been met via coupling thermal desalination systems with combined heat and power plants for many decades. These mature hybrid plants are known as cogeneration power and desalination plants (CPDP). Gas turbine (GT) driven CPDPs to suffer a performance drop in the summer months due to the high‐temperature ambient air intake which coincides with the season when power demand is highest. As a result, fuel consumption increases significantly to maintain these plants at full load conditions. At the expense of purified water, evaporative cooling (EC) has been proven to be a cost‐effective solution to combat the degradation in the plants' performance in the summer months. Several studies in the past propose the more complex waste heat or solar energy‐fired absorption refrigeration (AR) systems to combat this performance degradation. By performing an energy/exergy analysis and an hour‐by‐hour simulation on a conceptual plant representing an existing utility‐scale GT‐driven CPDP, this study analyzes the thermodynamic performance with and without EC and AR systems. Based on the simulation results, the power generated per GT unit decreases 0.65% for every 1°C rise in ambient air temperature. As a result, the plant's total fuel consumption increases by up to 12.4% relative to the design conditions to maintain the 100% power and water load. At the average summer conditions, integrating EC and AR systems increases the energy utilization factor of the plant by 5.89% and 9.11%, respectively. The plant's overall exergetic efficiency also increases by 5.96% and 6.73%, respectively. While EC systems increase the plant's annual in‐house water consumption by 32.4%, the annual total freshwater exports reduce by 0.151% only. Payback periods were calculated to be 1.84 and 5.70 years when integrating EC and AR systems, respectively and emissions savings ranged from 139 to 187 million kg of CO2 annually. [ABSTRACT FROM AUTHOR]

The paper presents actual data regarding the indirect evaporative cooling (IEC). This cooling technology is promising to develop within the close to future because of its terribly low energy consumption and high potency in it vary of applications. The review is presenting in details: theory, operating principles, flow and construction. The IEC instrumentality and technology is appropriate in several air-con applications: industrial, industrial, residential or knowledge centers. The IEC technology is totally environmentally friendly and has terribly low heating impact. The only disadvantage of IEC is that the water consumption. [ABSTRACT FROM AUTHOR]

The most commonly used conventional drying techniques causes several nutritional, physical and chemical changes which makes food unacceptable to the consumer. The increase in demand of higher retention of nutrients and physico-chemical characteristics of food products requires the development of novel drying technique. Refractance Window™ (RW™) drying has huge potential to cause minimal changes in the quality properties of food. RW™ drying uses circulating hot water to bring thermal energy to the material to be dried. To understand the potential opportunities of RW™ drying in food applications, it is very essential to examine it's effect on different quality characteristics. The present review article summarizes the working principle and the effect of RW™ drying on the retention of bioactive compounds and physicochemical properties of food products. In RW™ drying, the evaporative cooling at the surface of the drying material restricts the temperature of 70 and 85 °C. At this reduced temperature material quality and heat sensitive nutritional compounds can be highly retained in the final dried product. This characteristic of RW™ drying extends its applications for high value food products. Comparison of RW™ drying with other drying process confirms that it provides more advantageous in terms of retention of heat labile compounds, retention of quality parameters and energy efficiency with reduced operating cost. • Refractance Window™ is newer and moderate temperature drying technique. • Summarizes effect of RW™ drying on bioactive compounds and physicochemical properties. • Machinery requires less energy consumption compared to conventional drying processes. • Product quality and heat sensitive compounds retained in the final dried product. • Higher energy efficiency, safety and environmental impact. [ABSTRACT FROM AUTHOR]

In this study, performance, energy efficiencies of widely used conventional roof type packaged air conditioners and condenser side evaporative cooling roof type packaged air conditioners are compared. Evaporative cooling is provided by high efficient direct evaporative cooling pad. The main purpose of this application is to increase energy efficiency. The study was carried out for 50 kW cooling capacity unit considering working conditions of EUROVENT and tropical region. Pad usage, the same cooling capacity is achieved while the condenser air inlet temperature decreased and the compressor size reduced. COP, EER values increased by approximately 30%. In tropic region, the increment in COP, EER is much larger (50%). As a result, it is revealed that compressors and condensers can be downsized and energy efficient roof type air conditioners can be built by using pads. [ABSTRACT FROM AUTHOR]

Different designs of air conditioning systems for railway transport with the use of only environmentally safe natural working substances (air and water) are investigated relative to energy efficiency in the case of not only arid but also humid climates. A compound design of an air conditioning system consisting of an expander in front of which a humidifier is additionally mounded, with the water in the humidifier being fed from the supply tank of the railway coach, is proposed. Calculations demonstrate that the maximally allowable pressure behind the expander as well as the temperature difference in the heat exchanger may be increased through humidification of the auxiliary flow in front of the expander. In turn, this makes it possible to reduce the power consumption and overall dimensions of the air conditioning system by decreasing the required surface area of the regenerative heat exchanger. [ABSTRACT FROM AUTHOR]

A flyback topology has advantages like simplicity, better reliability and low cost, but comes with voltage stresses on semiconductor switches caused by the transformer leakage inductance. An improved regenerative snubber has been proposed to meet ever growing demand for higher efficiency. The proposed snubber topology is a modified LCD flying capacitor snubber and has advantages over conventional prototypes promising high efficiency of leakage energy recovery in high power applications. The beneficial features include: reduced circulating currents in snubber circuits; reduced current RMS on the secondary side; the possibility of recovering part of the leakage energy directly to the secondary output. The operation of the proposed snubber is analyzed to reveal benefits and simulation results are presented to verify performance. The stage by stage analysis with governing formulas has been provided. Design considerations are discussed. [ABSTRACT FROM AUTHOR]

CO2 is one of the rediscovered, ecologically safe refrigerants with very low global warming potential which has favorable thermo-physical properties. The CO2 booster refrigeration system has already been identified as a suitable choice for the supermarket application to replace the conventional R404A (high GWP) system. However, the performance of the CO2 booster system is still comparatively lower than the conventional R404A system, especially when operated at high ambient temperature, which compels to improve the performance of the CO2 system with suitable modification. In the present work, an attempt has been made to examine the year-round performance of the basic booster system and basic booster system with the integrated modified evaporative cooling system for Ahmedabad city weather conditions (Hot and Dry climate region). The experimentally investigated and validated data are used for the modified evaporative cooling system with real-time weather data taken from the weather station installed in the institute. Subsequently, the performance of the BBS, BBS-MEC, and R404A systems have been compared in terms of COP, power consumption, and seasonal energy efficiency ratio. The results show that for BBSMEC, SEER enhances by 28.66% and annual power consumption decreases by 22.89% as compared with BBS. In addition to that, the total environment warming impact is also found significantly lower in the case of the BBS-MEC system. [ABSTRACT FROM AUTHOR]

In order to improve energy efficiency and overcome the shortcomings of single refrigeration technology, a new type of composite refrigeration air-conditioning system driven by low grade energy is proposed:solar energy refrigeration and dew point evaporative cooling coupling air-conditioning system. Take a project in Nanjing as an example. The cooling capacity, power consumption and coefficient of performance of dew-point evaporative cooling subsystem and solar ejector refrigeration subsystem are calculated and analyzed respectively. By comparing the Pcop with indirect evaporative cooling-ejector refrigeration air conditioning system, it is concluded that the system performance of the proposed system increases by 6.38%, and the energy saving is about 6%. Compared with the traditional mechanical compression refrigeration system, the Pcop of the proposed system is increases by more than 70% and the power consumption is reduced by 44%. In the last part of this paper, the initial investment and operating cost of the composite system was analyzed, showing that the system can save 476.5 RMB annually, with a payback period of 6 years. It is economical and environmentally friendly. [ABSTRACT FROM AUTHOR]

An experimental investigation of the performance of a direct-indirect evaporative cooling fresh air handling unit with different modes of operation is presented. Linear regression analysis is used to fit the experimental results, and the correlation coefficient is evaluated. It is found that the highest temperature reduction of 18.8°C is achieved across the heat exchanger for the tested unit when the water shower mode is implemented at an ambient dry-bulb temperature of 44°C in conditions of relative humidity less than 20%. In the water shower and the combined mist injection and water shower modes of operation, the temperature reduction across the heat exchanger generally reduces, with increasing relative humidity. Furthermore, the results showed that water consumption increased with increasing ambient dry-bulb temperature and decreased with increasing ambient relative humidity. Finally, the lowest energy consumption of 1.64 kWh occurred with the water shower mode operated at peak dry-bulb temperature design condition. The energy consumptions for the mist injection mode of operation were 1.89 kWh and 2.15 kWh for the peak dry-bulb temperature and peak wet-bulb temperature design conditions, respectively. At these design conditions, the energy consumptions of the combined mist injection and water shower mode of operation are 2.7 kWh and 2.83 kWh, respectively. [ABSTRACT FROM AUTHOR]

In this work, a numerical and experimental study is performed to evaluate the affecting variables on energy efficiency of a novel regenerative evaporative cooler utilizing dew-point indirect evaporative cooling. For first time, an investigation is experimentally and numerically carried out to study the effects of the channel number on important parameters such as product temperature and humidity ratio. Investigations are carried out for five configurations with various channel numbers. The comparison of the numerical and experimental results is obtained and well accuracy observed. For the five studied configurations, the results show that with an increase in the number of channels, the outlet temperature decreases. For an inlet air flow rate of 100–600 m3/h, the cooled outlet flow temperature changes to the range of 23.4–30.7°C, 19.7–28.3°C, 18–26.4°C, 17.2–25°C and 16.6–23.8°C. For the configurations with finned channels, the percentage of increase in produced air temperature reaches 11.5% for HMX B, 18.6% for HMX C, 23.4% for HMX D and 26.9% for HMX E, as compared with HMX A. [ABSTRACT FROM AUTHOR]

Energy consumption of air conditioning accounts for a large proportion of energy consumption of buildings, and it is indispensable to reduce the operational cost of air conditioning. Indirect evaporative cooling (IEC), especially dew point evaporative cooling (DPEC) technology, which takes away heat through water evaporation for cooling, becomes an effective technology to improve energy efficiency. In this review, the indirect DPEC technology is introduced and the current research states are summarized in detail. The improvements of performance and model analysis of DPEC are investigated by numerical simulations, experimental works and machine learnings, which are elaborately described respectively. DPEC can reduce the air temperature to the dew point to achieve higher cooling effectiveness than the conventional IEC. The impacts of the design, intake conditions, geometry and water distribution, membrane materials on the performances of DPEC heat exchanger are also explored, including the wet and dry-bulb efficiencies, cooling capacity, coefficient of performance and other parameters to evaluate the performances. Based on the experimental researches, the mathematical models with different theories such as finite volume method, enthalpy method, and other methods are built, which are based on Energyplus, Matlab, Fluent and other tools. DPEC is suitable for hot and dry regions. The applications of DPEC in hot and humid region are extended by integrated with dehumidifier to meet requirements of moisture removal. The optimal analyses of machine learning for the combination mode of DPEC and hybrid system are described subsequently. Finally, the future research directions and application occasions of DPEC are proposed. [Display omitted] • Classifications and optimizations of DPEC technology are comprehensively described. • Impacts of design, intake conditions, geometry, membrane materials on the performances of DPEC are summarized. • The expansions of applications for DPEC by integrating with other systems are described. • Future research directions and application occasions of DPEC, such as machine learning with AI model, are proposed. [ABSTRACT FROM AUTHOR]

Passive daytime radiative cooling (PDRC) is a cooling technology with no energy consumption and no pollution generation. It emits self-generated heat to outer space using thermal radiation, thus reducing its temperature. Radiative cooling technology aims to the energy consumption problem of buildings and environmental pollution caused by the use of Freon in compressor air conditioners. Many kinds of radiative cooling coatings have been attempted, but the cost and large-scale practical application have been challenging. This work prepared a composite coating with a radiative cooling function using calcined kaolin (CK) powder and waterborne fluorocarbon (WF). The inexpensive CK has a wide particle size distribution and exhibits high solar reflectivity (RS) and infrared emissivity (EIR). The excellent adhesion and chemical stability of waterborne fluorocarbon (WF) provides a good guarantee for the practical use of the coating. As a result, the CK/WF coating achieves an RS of 91% and an EIR of 95% in the transparent atmospheric window (ATW) of 8–13 µm. The coating demonstrated a temperature decline of 3.8 °C under direct sunlight in the field. The coating meets the conditions for large-scale applications. When used as a roofing material for simulation, it can save up to 30% of energy consumption throughout the year. Overall, the CK/WF coating has outstanding energy saving and pollution reduction performance, which will further advance the radiant cooling material into real-world applications. [Display omitted] • The RS and EIR of Calcined kaolin/ water-based fluoro olefin vinyl ether copolymer (CK/WF) coating reached 91% and 95%. • The low powder content of the CK/WF coating provides high adhesion force. • Cheap CK powder provides a new idea to reduce the cost of radiation-cooling coating. • Under direct sunlight, the CK/WF coating can achieve a cooling effect of − 3.8 °C. • EnergyPlus simulations show that the coating could save 10% of energy consumption in most areas of China. [ABSTRACT FROM AUTHOR]

In this study, researchers investigated the efficacy of natural cooling in a residential building employing a horizontal windcatcher alongside a direct evaporative cooling system featuring a cross-flow pattern. ANSYS Fluent was used to model the three-dimensional airflow, while MATLAB measured the system's thermal performance. The study assessed thermal comfort and natural ventilation in accordance with the Adaptive Thermal Comfort Standard (ATCS) and ISO/EN7730 Standard. The impact of environmental conditions and window aperture on the hybrid system's functionality was scrutinized, culminating in design guidelines dictating the acceptable range of window openings to ensure compliance with thermal comfort conditions. The passive system demonstrated the capability to maintain thermal comfort within the test building under a maximum cooling load of 12,000 W (ATCS) and 6000 W (ISO/EN7730). Moreover, the natural cooling system decreased hourly electricity consumption during hot seasons in Tehran, Iran, by 0.0155 (k W / m 2) compared to split air conditioners and 0.00087 (k W / m 2) compared to evaporative coolers. The study also investigated the influence of neighboring buildings positioned at specific distances relative to the test building on the system's performance. Furthermore, adopting the suggested horizontal windcatcher instead of conventional vertical windcatchers resulted in a 50 % reduction in energy consumption. [Display omitted] • A novel system for natural ventilation and cooling of residential buildings is presented. • A design guideline determining the allowable windows opening range is proposed. • Thermal comfort is obtained for a maximum of 12,000 W cooling load in the test building. • The system can decrease hourly electric energy consumption by about 0.0155 kW h/m2. [ABSTRACT FROM AUTHOR]