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This paper presents the design and implementation of automatic cooling and cleaning system (ACCS) for PV modules to optimize the performance of the PV module based on electrical efficiency drop resulting from increased cell temperature at loading and dust accumulation on PV module s surfaces. An increase in PV module temperature causes a linear reduction in its performance, affecting electrical power generation. Pressurized water jets by nozzles are used to cool and clean the front surface of the PV module. The theoretical model of the PV module is verified by MATLAB/Simulink software. The operational performance of ACCS was recorded and analyzed. The experimental results showed before cooling, the maximum power produced by the PV module was 65.31W, while after cooling increased by 73.24W. Also, electrical efficiency yield of before cooling the rate of decreasing efficiency 0.052% per 1℃ while after cooling the efficiency increased by 0.13% for each decrease 1℃. [ABSTRACT FROM AUTHOR]

This research was based on the development of a 3D numerical model to investigate the efficiency of solar energy harvesting using photovoltaic panels combined with thermoelectric generator modules (PV-TEG). The effects of different numbers and distributions of thermoelectric modules when using a passive cooling unit on the performance of PV-TEG system were thus investigated. Seven models of a hybrid system (M1-M7) with different numbers and distributions of TEG items were tested and simulated numerically, and the optimum model performance of the PV-TEG was compared with that of both photovoltaic only and photovoltaic/thermal (PV/T) systems. Based on the results obtained, the optimum model for the hybrid system was determined to be M1. The electrical power of the PV-TE system was also found to be higher than that of the PV only and PV/T systems, by 16.3% and 1.79%, respectively, when exposed to solar radiation of 1,000 W/m2 at an ambient temperature of 25 °C. The average temperature of the PV upper surface for the M1 model PV-TEG was about 47.95 °C, whereas, the average temperature of the PV upper surface for the PV and PV/T systems were 73.3 °C and 46.76 °C, respectively. The theoretical results indicated thus suggest that the effect of passive cooling on the PV-TEG system causes performance to decrease. [ABSTRACT FROM AUTHOR]

Elastomeric materials are broadly used for damping augmentation in variety of applications due to their simple design, low weight density and high reliability and low tensile strength. Generally, the components of elastomers are manufactured in large quantity through injection moulding process. However, when required in small numbers for the specific applications such as aerospace, ship building, biomedical engineering etc and also 000when required in complex shapes and higher accuracy manufacturing elastomeric components through injection moulding process turns out to be an expensive process due to higher initial cost. Under those circumstances machining appears to be a promising process due to its versatility and accuracy. On the other hand machining Elastomers in normal circumstances is not so easy due to high elastic deformation that occurs in the entire workpiece during machining which results in poor product quality. Cryo-cooling assisted machining provide solution to this problem which is nothing but an extended quenching process in the conventional heat treatment cycle in which high elastic property disappears temporarily. The present paper aims at brief literature survey on recent developments in cryogenic machining of elastomers. [ABSTRACT FROM AUTHOR]

The use of a water spray system as the glass cover cooling of single slope solar still was experimentally investigated as an attempt to enhance the daily productivity of solar still. The cooling water was sprayed in a pulse form for 30 sec while the time between any two successive pulses was altered as 5 minutes, 10 minutes, 20 minutes, and 30 minutes, respectively. the present work also considered the form of continuous cooling water spray. The collected result highlighted that the daily productivity of conventional single slope solar still enhanced by 10%, 14%, 27%, 17.5%, as single slope solar integrated with a cooling system of (30 sec/ 30 min), (30 sec/ 20 min), (30 sec/ 10 min), and (30 sec/ 5 min), respectively. Where the best pulse timing was (30 sec/ 10 min) since any farther increment induces a negative influence on the daily output of the conventional single slope solar still. [ABSTRACT FROM AUTHOR]

Based on the study, it can be concluded that the use of porous cooling in the form of separate inserts into the finned ventilation apparatus will be an additional source of heat removal from heated surfaces. The use of porous inserts reduces the thermal boundary layer of the air flow of the brake disc ventilation ducts. This is ensured by an additional change of air masses in the boundary layer rather than using a solid impermeable rib of the ventilation apparatus. After theoretical studies of the parameters of porous cooling, mathematical modeling of the parameters of influence on the efficiency of porous cooling and air flow rate when passing through the porous inserts was carried out. With an increase in the length of the porous insert, the efficiency of porous cooling and the flow rate of the air flow through the porous insert decreased. The intensity of the decrease was determined by the flow regime of the air flow in the thermal boundary layer and the order of the value of the air flow rate. [ABSTRACT FROM AUTHOR]

Solar Heat for Industrial Processes (SHIP) is a growing-interest concept in the context of the reduction of both energy consumption and greenhouse gases emissions. As industry often needs cooling power at negative temperatures, solar-fuelled NH3/H2O absorption systems can be employed for this task. In the context of the FriendSHIP European project, different innovative solutions are investigated for cooling production at -20°C and -40°C from 100-250°C solar heat. The first proposition concerns a GAX (Generator-Absorber heat eXchange) cycle based on Plate Heat Exchangers (PHE). This innovative design improves heat and mass transfers, thus performance. In addition, manufacturing costs decrease, as the needed components are standardized and available in the market. Two variants are simulated on EES (Engineer Equation Solver) for -20°C and -40°C cooling production. Other absorption cycles are modified to fit PHEs, in particular the pressure-staged cycle, the vapour-exchange cycle and the Semi-GAX cycle. They all are two-stage cycles and are simulated for -40°C cooling production only. The numerical comparison allows identifying the best solutions for the SHIP integration, giving an overview on the operating temperature ranges for each cycle. In particular, the following results are obtained. At ambient temperature TAMB = 20°C and below, the GAX cycle is the most performing one. It shows a maximum Coefficient of Performance (COP) of 0.53 for a cold production TE,OUT = -20°C (+27% compared to the single-stage cycle), and a COP of 0.36 at TE,OUT = -40°C (+60% than the single-stage cycle). For TAMB > 30°C, the pressure-staged cycle with GAX is the preferable one, as it can be operated with COP>0.15 at TAMB up to 50°C. The Semi-GAX cycle seems the most adapted to operation at low heat source temperature, being able to operate down to 80°C with COP>0.20. [ABSTRACT FROM AUTHOR]

This work evaluates the impact of using supercritical carbon dioxide mixtures (s-CO2/COS, s CO2/H2S, s-CO2/NH3, and s-CO2/SO2) as a working fluid carried out Brayton s-CO2 power cycles. Some complex configurations were studied: partial cooling with recompression without reheating (PCRC), partial cooling with recompression and reheating (PCRC RH), partial cooling with recompression and two reheatings (PCRC 2RH), and partial cooling with recompression and three reheatings (PCRC 3RH). The design parameters evaluated are the solar plant performance at the design point, the pinch point in the heat recuperators, and total conductance (UAtotal) with values between 5 – 20 [MW/K]. This analysis is complemented by studying the effects of the compressor inlet temperature (CIT) variation in each configuration. Interesting results are obtained from this work; the mixtures containing COS and H2S provide better efficiency from a CIT = 55 °C compared to the pure s-CO2 fluid in PCRC configuration. While in the PCRC-RH and PCRC-2RH configurations, this occurs at a compressor inlet temperature higher than 57 °C. Finally, in the PCRC-3RH configuration, the efficiency is only slightly better when the CIT is 60 °C. [ABSTRACT FROM AUTHOR]

The present study deals with numerical investigation of mixed convection of Al2O3-water nanofluid with consideration of variable properties inside a rectangular inclined multi-vented cavity heated from one side. Effects of variations of volume fraction of nanoparticles and the positions of outlet port of the cavity on flow and temperature field and rate of heat transfer are studied. The obtained results show that the existence of nanoparticles in the base fluid leads to a significant heat transfer increase. Moreover, a better cooling inside the cavity was found by a displacement of the outlet port from the left to the right of wall. [ABSTRACT FROM AUTHOR]

The problem of plane strain pure bending of a plate made of a linearly elastic–perfectly plastic material with a through-the-thickness gradient of strength properties and tension-compression asymmetry is considered. The gradient of strength properties was produced by accelerated one-sided cooling of the plates made of A32 ship steel from the austenitic temperatures. The purpose of the present work was to analyze the effect of various approximations of the strength gradient on the accuracy of determining the critical bending moment corresponding to the complete yielding of the sheets. [ABSTRACT FROM AUTHOR]

In this paper, the study of titanium high-pressure spherical tank billets produced by wire-based electron beam additive manufacturing was carried out. The billets were produced with no active cooling. The macro- and microstructure of the billet material in the "as-built" state was investigated, and static tensile tests were performed to determine the mechanical properties. The studies showed that the thermal conditions of the 3D-printing process of such products lead to a significant decrease in the material strength compared to the target values for the Ti-6Al-4V alloy. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries has promising future in electric vehicles and storage of electricity. The two main issues with these batteries are the charging time and the heating problems. When we vary the discharging and charging rate of the battery, the temperature also increases/decreases respectively. Battery thermal management has a crucial role of maintaining life-cycle and performance of.battery. A battery thermal management system ensures thermal repeatability and prevents thermal runaway of battery. The paper presents the results derived from the experimentation undertaken with this purpose. An experiment was performed on Lithium-ion 18650 battery cells, which are charged with 2 C charging rate which are cooled with immersion cooling via dielectric fluid. The use of this BTMS ensures the thermal runaway is minimized and all the cells are cooled uniformly, which make sure that all the cells are working under desirable conditions. The simulation was verified with experimentally. [ABSTRACT FROM AUTHOR]

In the article under consideration, the state of hydrothermal grain processing in industrial conditions is analyzed, certain requirements are imposed on the selection of the method and design of instrumentation for grain moisture control, as well as their high measurement accuracy. The importance of choosing the optimal humidity parameter of the object of study is shown, based on the analysis and evaluation of the accuracy of the dielkometric method of measuring humidity, the basic requirements for the design of humidity control devices, devices of increased accuracy and reliability, allowing to synthesize an electric capacitive model of the primary measuring transducer, are formulated. Recommendations for the synthesis of a measuring device for grain and products of their processing in industrial conditions are given. [ABSTRACT FROM AUTHOR]

Earth-to-air heat exchangers (EAHE) are passive technologies used to cool and heat buildings. This paper aims to review published research on this topic. The review has structured into several sections that focused on the use of numerical evaluation of the performance of the earth tube heat exchanger in the ventilation of the buildings. The review also dealt with the results of studies that concentrated on the heat exchanger performance within different burial depths, the impact of soil, climate characteristics on the heat exchanger performance, and the effect of the merging mechanism adopted with the building (direct or with the cooling and heating systems attached to it). Finally, the paper reviewed the final conclusions reached by the researchers. [ABSTRACT FROM AUTHOR]

Solar energy is utilized by converting it to electrical energy using solar photovoltaic (PV). Solar energy is absorbed and converted by PV up to 30%. The remaining energy is wasted in the form of heat which raises the surface temperature and causes damage to the solar photovoltaic. So that it can affect the performance produced by solar photovoltaic. Lowering the temperature of solar photovoltaic using a heatsink as a heat transfer medium. The effectiveness of the heatsink is influenced by the air flow so as to facilitate heat transfer. Therefore, the study conducted experiments with the addition of an air concentrator to be installed as a support for heatsink performance in the solar photovoltaic cooling process. The addition of a concentrator at the peak intensity of the solar panel can reduce the working temperature by 4.8°C. Solar panels with concentrators can increase the maximum power value by 1.45 W and efficiency by 0.38% higher than panels without concentrators. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) are an environmentally friendly energy source. One EV application uses Lithium-ion (Li-ion) battery cells. In practice, li-ion operation generates heat which will burden battery performance. Therefore, this review paper will discuss the battery thermal management system (BTMS). There are several methods of BTMS, but this paper review will only focus on air-cooled and liquid-cooled BTMS, where it is still rare to find a comparison of these two cooling methods. The goal is to know about the best cooling method. The results show that liquid-cooled BTMS is superior in uniform temperature distribution but is more complex, and fluid leakage can occur. In comparison, air-cooled BTMS has the advantage of a more accessible system, but the temperature distribution between batteries is less even. [ABSTRACT FROM AUTHOR]

Nowadays, split air conditioners used by the public use refrigerants that are not yet environmentally friendly, one of which is refrigerant R32. The original R32 split air conditioner with a 1 PK cooling capacity was replaced with an refrigerant R290. This study aims to test the performance of refrigerant R290 compared to refrigerant R32. The mass of R290 that is charged to the split AC is 60% with an ambient temperature of 30°C at room temperatures of 23 C, 25 C, and 27 C. With another ambient temperature of 35°C at room temperatures of 25 C and 27 C. The power consumption of R290 is 35% decrease from that of R32. The cooling capacity of R290 has decreased by 33.15% from that of R32. For the COP value, R290 was a decrease 20.01% from R32. The results obtained show that the performance of the refrigerant R290 has not been maximized to replace refrigerant R32. [ABSTRACT FROM AUTHOR]

The heat exchanger network system is an important part of the process industry. Closed-loop fresh cooling water heat exchanger network in ammonia manufacturing plant is used for the cooling of process fluids. From commission stage to the present operation stage, the heat loads in various heat exchangers of fresh cooling water network system got varied in the ammonia manufacturing plant. Some heat exchangers were overloaded and some running at sub cooled below the process requirements. An optimization study was carried out on fresh cooling water network system to fix the heat load distribution across the network system. The process-side heat duty was calculated by using the heat of formation for each component at the inlet and outlet of individual heat exchanger. The calculated heat duty values were compared with the values obtained from Aspen HYSYS simulation modeling techniques. The total flow required through the whole network can be reduced by 3000 m3/h without affecting the production of the plant and approximately $ 65000-130000 can be saved per year. [ABSTRACT FROM AUTHOR]

This article focuses on methods of cooling and dissipating thermal energy from electrical components installed in electric vehicles, control centers, information technology, space projects and others. The aim is to research the heat dissipation and the formation of temperature fields of a semiconductor power component installed in closed or tight spaces. The method of cooling the components is based on the method of heat transfer and the cooling technology used. For the design of cooling, it is necessary to know the location and position of the examined component, as well as the possibility of heat dissipation. This introductory part of the heat transfer theory defines the already known methods of heat transfer, on the basis of which the design of the cooling capacity is defined. [ABSTRACT FROM AUTHOR]

The aim of this study is to determine the effect of dissolved coffee concentration on the cooling process and to calculate the value of the cooling constant for each coffee solution. During the cooling process, dissolved coffee temperatures are monitored using a temperature sensor that has been linked to the computer through Arduino Uno R3. The dissolved coffee temperature scor e at a 1 minute range will be read on IDE Arduino software and monitored through PLX-DAQ software. Based on the data of the cooling process in the dissolved coffee, the concentration of the dissolved does not affect the cooling process, but it does affect the value of cooling constant. The values of Newton's cooling constant of the dissolved coffee at concentration 6%, 7.67% and 10% are 22.24 x 10−3 s−1, 22.22 x 10−3 s−1, 20.11 x 10−3 s−1, respectively. These results indicate that Newton's cooling constant decreases as the concentration of the solution increases. [ABSTRACT FROM AUTHOR]

This research is made to investigate the effectiveness of Minimum Quantity Lubrication (MQL) over flood-cooling lubrication in lathe turning operation on a 1-inch-thick mild steel rod. The cutting tool used for this operation was a tungsten carbide Chemical Vapor Deposition (CVD) coating. Two results needed to be determined; surface roughness value and chip formations. These were carried out using an orthogonal array (OA), and the analysis of variance (ANOVA). The experiment was carried out using cutting speeds of 460, 750 and 1250 rpm and feed rates of 0.2, 0.4 and 0.8 mm/rev. The depth of cut was maintained at 0.125 mm throughout the whole experiment. It was observed that cutting speed and feed rate have significant effect on surface roughness. In terms of chips produced from the turning operation, there were more discontinuous chips being obtained in flood-cooling conditions than in MQL conditions. In comparison, more segmented chips were produced in MQL conditions. The optimum process parameter setting of the experimental design was obtained, with high cutting speed and low feed rate in both MQL and flood-cooling lubrication. [ABSTRACT FROM AUTHOR]

The advancement in electronic fields make devices smaller but has high heat flux. Therefore, heat dissipation for electronic devices plays a significant role to ensure their safe and good performance. The heat dissipation components including the heat sink, fans eliminate the heat of electronic devices as soon as possible, or else chips will be damaged, malfunction, sort lifetime by overheating. However, it is difficult to predict its operating temperature. Therefore, the CFD based method has been popularly applied in this field to optimise the design, save time and display the temperature distribution of the electronic device. In this paper, a real cross-cut heat sink's dimension was obtained, and then its model was developed by Inventor software. After that, a CFD based investigation was conducted to evaluate its thermal performance. The simulation was carried out with different powers and air velocity as well as at two rotation angles such as:0o and 90o clockwise around X-axis to evaluate the operation parameters. The results show that this heat sink could be applied for electronic devices with a power lower than 6 W without the fan. The heat sink's thermal resistance can be reduced with the increase of air velocity. Even, the temperature of the 10W chip can go down from 87.5oC to 65oC when the velocity increases from 0 m/s to 0.25 m/s. Furthermore, at a 90o clockwise angle, chip temperature under natural convection is somewhat lower than that at a 0o angle. [ABSTRACT FROM AUTHOR]

In recent years around Europe several investigations, measurements were carried out in order to reduce the buildings energy need, but the energy need for cooling, still shows a growing curve. In relation to residential buildings different standards has distinct requirements for internal/operative temperature. To assure the required air temperature and comfort different types of air conditioning systems are installed in buildings. Therefore, in many countries especially in summer period the power networks are strongly overloaded. The internal air temperature in a residential building through two different summer periods was measured. In the first period the internal air temperature was measured without residential ventilation and air conditioning system. In the next summer period measurements were accomplished with residential ventilation and air conditioning system. The indoor air temperature variation was calculated using the EN ISO 13790 standard's methodology, values obtained from the measurements were compared with the analytical values. The theoretical values were used in the case of summer, hot and torrid days for heavy construction buildings. Certainly, the indoor air temperature variation and the energy need for cooling was analysed for one residential building. [ABSTRACT FROM AUTHOR]

Spot cooling is the process of directing a stream of cool air into a designated equipment or a group of people. Using Air as a natural refrigerant in the Spot cooling application brings in fresh air into the building and cools the area. The method of cooling are many, but sustainability is the biggest concern of this industry. The available refrigerants in the market are either effecting ODP (Ozone Depletion Potential) or GWP (Global Warming Potential). The only way out is to introduce sustainable and natural refrigerants. The Hypothesis which is brought into this research is to study the different types of spot cooling techniques available in the industry and challenge it with natural Air as a refrigerant. Sustainability is a paramount importance of our existence. This paper brings in the aspect of using natural refrigerants in comparison with currently used Freon's. This paper tries to introduce spot cooling comparison for basic industrial application and warehouse. Usually in the industry machinist and some times even the machine is not cooled for different reasons. If the cooling is provided both the machinist and machine will have better productivity and performance output. The paper puts light on different ways of spot cooling and the parameters important of the application. Best Worst Method has been applied using industrial expert opinion was taken into consideration. The results were a well-defined application for industrial use for cooling machine is established. Which can act as reference for other researchers to follow. All industrial facilities, warehouses and areas where production work takes place can apply the result of this research paper. [ABSTRACT FROM AUTHOR]

This work aims at designing two Earth to Air Heat Exchangers (EAHX) for air cooling and heating of a primary school in Arfoud city Morocco, which is located in the South-East of Morocco and characterized by a desert climate. The school is constituted of two independent buildings. The Earth to Air Heat Exchangers should supply cool or warm air at a temperature of around 26°C and 20°C respectively. A total airflow rate of around 2000 m3/h is required for each building. The objective here is to identify the best EAHX parameters combination based on these requirements. For this purpose, a parametric study is performed using the well-validated TYPE 460 of TRNSYS software. Intermittent operation mode from 7 am to 6 pm during the school days (Monday to Saturday) is considered. The identification of the best combinations of the EAHX parameters is based on maximum and minimum EAHX exit temperature for cooling and heating purpose respectively, total cooling and heating capacity and the total pressure drop of the air inside the pipes. It was found that the best EAHX parameters combination is constituted of 4 pipes of 100 m length and 0.195 m internal diameter each buried at 5.7 m depth and operated at 4.63 m/s air velocity. [ABSTRACT FROM AUTHOR]

This work is focused on the numerical modeling of steady laminar mixed convection flow in a Ventilated inclined enclosure filled with water-Al2O3 nanofluid and heated from one side. A parametric study is conducted and a set of graphical results is presented and discussed to illustrate the effects of volume fraction of the nanoparticles (0 ≤ ϕ ≤ 0.05), aspect ratio of the cavity (0.5 ≤ A ≤ 4) and mode of imposed external flow (injection or suction) on the flow and heat transfer characteristics. The obtained results showed that the presence of nanoparticles increases the heat transfer and the mean temperature within the cavity. In addition, a better cooling inside the cavity was found for a rectangular enclosure (A = 2). [ABSTRACT FROM AUTHOR]

Now a days everyone has a refrigerator in their home for the purpose to store foods, medicines and eatables etc. Some foods based on its property we can directly use after we taken out from the refrigerator. But under some conditions we can't use the products directly from the refrigerator so we need to bring the product into room temperature for better usage. If not done so some medical issues are being raised so to avoid this, we have a solution smart container in refrigerator which does the de-cooling in the refrigerator itself no need to keep it in temperature and this is a remotely operable from anywhere using IOT. This must be done in an efficient manner and the approach to solve this aspect is discussed further. The following we made cad design for the smart container. Before manufacturing we need the visual proof whether it is suitable are not to our daily household use the factor considered is the refrigerator temperature and the environmental temperature. Under this condition we are going to calculate the time. How long it will take to cool the container. The whole analysis is made in computational manner using the ANSYS software. The final verified result shows the time taken to cool the container is 14 seconds. The analysis result for time taken to de cool the container is 19.5 sec. According to the ANSYS report 20 iterations are need to make the calculation of the time. This will give the better and expected results. [ABSTRACT FROM AUTHOR]

The WASCOP (Water Saving for Concentrated Solar Power) project is an EU project dedicated to water saving in CSP power plants. Among the different technologies and aspects considered in the project, the concept of cold thermal energy storage (cTES) has been developed. cTES is considered in addition to the cooling system and used when ambient temperature is too high and may lead to turbine efficiency and electricity production reductions. In these conditions, heat from the condenser is partially stored in the cTES and evacuated trough the available cooler when ambient temperature is lower, typically during the night. A prototype of cTES has been built in the CEA site of Cadarache. Experimental results are presented and shows the relevancy of the test loop and of the cTES concept. [ABSTRACT FROM AUTHOR]

Laser Ceilometers make use of the elastic LIDAR by emitting signals vertically in the atmosphere and analyzing the profile of the backscattered signal to detect clouds and calculate cloud-base height [1]. Due to the high temporal and vertical resolution, the data provided by the ceilometer is rather useful for solar radiation forecasting or assessing the potential of night radiative cooling of a fluid. To characterize cloudiness, we calculated the cloud occurrence and frequency distribution of cloud-base height in Seville, in a similar way to [2]. Furthermore, we analyze the backscatter signal to obtain a time series, with hourly resolution, of estimated cloud depth and cloud optical thickness that would be useful to determine the effects of clouds on solar radiation and night radiative cooling. [ABSTRACT FROM AUTHOR]

Several last superconducting wigglers fabricated at BINP have indirect cooling. They all have a small aperture of cryogenic temperature. This feature makes measurement quite a complicated task. A magnetic measurement system designed especially for one of such wigglers is described in this article. Results of magnetic measurements both with a Hall probe and by the stretched wire method are also presented. [ABSTRACT FROM AUTHOR]

Correspond with population growth, Indonesia's energy consumption has been increasing for the past decade. In the last few years, the demand for energy increases by 7.1% every year. The highest energy consumption for a building is in the cooling sector. Much research has been conducted to increase the performance of cooling equipment to reduce their energy consumption. Past research found that hydrocarbon (R290), a natural refrigerant, has higher performance than the most commonly used refrigerant in Indonesia. Furthermore, the hydrocarbon is environmentally friendly, unlike HCFC and HCF. This research is designed to analyze the effects of sub-cooler on the performance of R290 chiller used in an auditorium air conditioning system, and the results show that there is an increase on COP by 6.9% when using sub-cooler on medium part cooling load operation. [ABSTRACT FROM AUTHOR]

To accurately predict the cooling performance of internal cooling channels, it is critical to properly model the heat transfer mechanism near the solid-liquid interfaces. In this study, a single straight cooling pipe is used to study the modelling of the heat transfer at the solid-liquid interface. Two turbulence models and two inlet flow conditions have been applied and compared. A mesh independence study has also been conducted. Results show that the inlet flow condition does not have a significant impact on the prediction of the overall cooling performance. It has been shown that both the Realizable k-ε and Shear Stress Transport k-ω turbulence models have the capability to accurately simulate both the turbulent flow and the convective heat transfer. Numerical results have been compared with experiments to ensure the validity of the numerical model. This study addresses fundamental modelling issues of importance for a subsequent numerical investigation of the cooling performance of conformal cooling channels in injection molds. [ABSTRACT FROM AUTHOR]

The temperatures of the condensers' cooling media (water and air) can vary in a wide range depending on the ship's route. For example, on the route from Odessa to Hopen (Norway), the water temperature changes in the range from 18 ° C to -2 ° C, and air does from 20 ° C to -13 ° C (according to the data for April 13, 2018). Therefore, the well-known recommendations for determining the condensation temperature in the existing calculation methods cannot be applied to a refrigeration unit with composite cooling condensers because they provide different condensation temperature values. To determine the condensation temperature and study the operation of the marine refrigeration unit with composite cooling, a technical-and-economic calculation methodology has been developed. This methodology includes the calculation peculiarities of the composite condenser cooling, the cost of the main refrigeration equipment, the electricity cost and climate data for the ship's route. This method solves the problem of determining the condensation temperature to calculate the condensers and compressors of a marine refrigeration unit. The paper shows the results of the parametric analysis performed for a marine refrigerating unit for the route Odessa – Hopen. The recommended design value for the condensation temperature was 27°C (which corresponds to a pressure of 1066 kPa). It has been proven that the condensation temperature can be precisely determined for a composite condenser cooling at constantly changing cooling medium temperatures, while the technical-and-economic parameters of the refrigerating unit will be optimal. New design values of condensing pressures (temperatures) are obtained to calculate and select heat-exchange surfaces of refrigerating unit's condensers. [ABSTRACT FROM AUTHOR]

Evaluation of energy efficiency of a combined cooling system that uses night radiative cooling together with refrigerating machine, with accumulation of cold without a phase transition and the supply of liquid coolant (propylene glycol) to the air cooler was performed based on the results of computer simulation. In the cooling system located in Kostanay (Kazakhstan), there are radiators (12 m2) that cool the coolant at night, as well as a conventional vapor compression refrigerating machine with a reciprocating compressor. The cooling system is used to maintain air temperature at the level of 0 ± 1 °C in a small refrigeration chamber (36 m3) with a low value of heat emission from stored products and the absence of other operational heat influx. It was found that 78.8 days a year, the cooling system can maintain the required temperature due to the operation of radiators without turning on the refrigerating machine. This saves 242 kWh of electricity. Thus, the combined refrigeration system provides 7.6% reduced energy consumption, and also reduces physical deterioration of the refrigerating machine compressor for the annual cycle, which should reduce the financial costs for operating the refrigeration warehouse. [ABSTRACT FROM AUTHOR]

This study explores the possible performance enhancement of a biomass-fuelled GT based integrated power and cooling plant by employing inlet air cooling for the compressor. The waste heat of the power plant is used to run a cooling plant operating on NH3-H2O based VAR cycle. A portion of the cooling effect is used to reduce the air temperature to 10 °C at the compressor inlet. Results suggest that the GT system efficiency improves by 2-3% with consequent nominal reduction of cooling effect by about 1-2%. The overall exergetic performance of the plant improves by 1-2% compared to a similar plant without inlet air cooling. The improvement in performances are marginal for lower value of pressure ratio but shows better result for higher value of pressure ratio. The price of electricity is found to be 0.083 USD/kWh. The estimated payback period of the plant is obtained as 12.66 years. This plant is found to be economically beneficial when compared to a similar plant without inlet air cooling. [ABSTRACT FROM AUTHOR]

The cooling of electronic gadgets is the biggest challenge in recent years. The selection of innovative cooling techniques leads to the improvement in reliability and performance of electronic systems. Hence, the present study deals with the 3-D numerical modeling and simulation of seven high power protruding heat sources mounted on an SMPS (Switch Mode Power Supply) board using ANSYS FLUENT (R-16) under transient heat transfer mode. The heat sources are cooled under air medium using a velocity of 15 m/s and the heat dissipation rate is 10 W/cm². The objective is to study the surface radiation effect on the cooling of these heat sources under forced convection and to analyze the heating and cooling cycle of the heat sources. Four different surface conditions (Ꜫ = 0.90, Non-metallic paint), (Ꜫ = 0.86, Gray surface, Ꜫ = 0.8, Steel oxidised paint) and (Ꜫ = 0.65, Fe-Cast surface) are considered to analyze the radiation effect and the values are compared with respect to the polished surface (Ꜫ = 0.1). It has been concluded that the surface radiation reduces the temperature of the heat sources by 18 to 25% and helps in better cooling. The time taken for both charging (heating) and discharging (cooling) of the heat sources are also reported for the above emissivity values, and it has been found that charging (heating) takes more time as compare to discharging (cooling) of the heat sources. To generalize the problem, a correlation is put forward for the non-dimensional temperature excess (θ) of the heat sources in terms of their surface emissivity (Ꜫ) and cooling rate (time). [ABSTRACT FROM AUTHOR]

In the present paper, a three-dimensional hydrogen absorption model is applied to a cylindrical LaNi5 hydride bed embedded with multiple U-shaped cooling channels having fins fitted in different orientations. Four number of cooling channels are placed radially at equal distances to achieve uniform heat removal from the bed. The fins are fixed to the coolant channel in transverse and radial directions. The fins volumetrically collect heat from the bed and deliver to the coolant channels. Three metal hydride bed cases are numerically studied, they are with: only coolant channels - case 1, coolant channels fitted with transverse fins - case 2 and coolant channels with transverse and radial fins - case 3. From the simulation results, it is revealed that the presence of fins in the coolant channels significantly improves the heat transfer and hydrogen absorption rate in the bed. The hydrogen absorption in the bed approaches 90% of saturation in 998 s, 867 s and 656 s for case 1, 2 and 3, respectively. Detailed multi-dimensional contours of temperature and hydrogen to metal ratio distributions in the bed are presented for different cases. This study provides a better understanding of heat and mass transfer during the hydrogen absorption in a metal hydride bed. [ABSTRACT FROM AUTHOR]

A non-commercial power reactor with the thermal power of 10 MW is being designed based on a hightemperature gas-cooled (HTGR) reactor called the Experimental Power Reactor (RDE). RDE is designed to generate electricity and to supply thermal energy for experimental purposes. The energy conversion system in the RDE design is designed in cogeneration configuration with a Rankine cycle. The outlet temperature at the reactor design is 700 °C and the outlet temperature in the design of the steam generator outlet is 530 °C. Performance parameters for the design of RDE energy conversion systems are expressed with thermal efficiency parameters and energy utilization factors. To support and complement the RDE design especially the design of energy conversion systems, research is needed relating to the performance parameters of energy conversion systems. This research aims to calculate and analyze the optimal parameters of thermal efficiency and energy utilization factors in the design of the RDE energy conversion system. The calculation and analysis of cooling thermodynamic parameters and coolant system performance parameters of RDE are performed by simulation using ChemCad. The results showed that at 90 bar vapor pressure and cooling mass flow rate of 3.3 kg/s, the highest thermal efficiency is 29.21%. [ABSTRACT FROM AUTHOR]

Microthrottle heat-exchange devices as part of microcryogenic technology systems are used to solve the problems of thermostatic control and cooling of sensors, devices, as well as in medicine. Today, design of such heatexchange devices in a small-size housing with a diameter of about 1.5 mm was developed. The present work using experimental data and calculation considers issues of cooling dynamics and capacity when using such devices in pairs. Results of this study could be used in designing the arrangement of groups of microthrottle heat exchange devices close to heat sources. [ABSTRACT FROM AUTHOR]

The defects forming during the manufacturing of polymetallic samples of the "copper-titanium" system are investigated. The samples were obtained by simultaneous wire feeding into the molten bath. A number of factors causing the formation of various macrostructural defects related to the heterogeneity of the sample cooling and its components, insufficient temperature for the filament melting or excessive temperature of the substrate heating have been revealed. The formation of cracks, pores, unmelted particles of copper filament and inhomogeneities in the distribution of polymetallic components was found. [ABSTRACT FROM AUTHOR]

Mapping equation for the bunched beam stochastic cooling is formulated. For the NICA project parameters, the obtained result is compared with analytical description. According to the results the preferable stochastic cooling method for the NICA collider is clarified. [ABSTRACT FROM AUTHOR]

Photovoltaic panels exhibits lower conversion efficiency due to increased surface temperature. Hence the thermal management of panel is important which can be active or passive in nature. However, passive methods are gaining importance due to its inherent advantages. In the present CFD study, the degree of panel cooling is analyzed by optimizing various geometrical parameters of the solar thermal combi system. The optimized geometry yielded air flow rate of 0.034 kg/s which can cool the PV panel by 5°C when exposed to solar radiation level of 800 W/m2. This cooling rate is further validated through experiment. As the solar thermal combi system does air heating and panel cooling processes simultaneously, the overall system efficiency is better and is cost effective compared to two individual units. [ABSTRACT FROM AUTHOR]

Buildings and activities in buildings contribute to a major share of global environmental degradation. Hence the incorporation of sustainable technologies in domestic building cooling is the urgent need of the hour. Passive and energy efficient active building cooling methods are closely linked to human comfort of the residents by reducing the heat gains, maintaining the thermal balance and removing the internal heat from buildings. A comprehensive study focussing on sustainable building cooling technologies for building sector is presented in this paper. [ABSTRACT FROM AUTHOR]

We study thermal integrity problem and design solutions for heat sinks used in electronic devices. We discuss modelling challenges using finite-element, finite-volume, and algebraic topological methods. We demonstrate the suitability of algebraic topological method for modelling multiphysics (electro-thermal) problems using the case of radiative and convective cooling in heat sinks. [ABSTRACT FROM AUTHOR]

The WASCOP (Water Saving for Concentrated Solar Power) project is an EU project dedicated to water saving in CSP power plants. Among the different technologies and aspects considered in the project, the concept of cold thermal energy storage (cTES) has been developed. cTES is considered in addition to the cooling system and used when ambient temperature is too high and may lead to turbine efficiency and electricity production reductions. In these conditions, heat from the condenser is partially stored in the cTES and evacuated trough the available cooler when ambient temperature is lower, typically during the night. A prototype of cTES has been built in the CEA site of Cadarache. Preliminary commissioning has been performed. Final commissioning is expected to be done before Spring 2019 and experimental tests will be made during Summer 2019. [ABSTRACT FROM AUTHOR]

Crystallization is an essential solid-liquid separation technique which is widely used in the industry such as in pharmaceuticals, pigments, food, plastics, semi-conductors and others due to its capability to produce high quality of crystals. The final specification of the crystal product usually is given in terms of crystal size distribution (CSD), shape and purity. However achieving the target CSD for the case of batch seeded cooling crystallization is always a challenge due to the limited control on the production of fine crystals. Generally crystallization process is controlled to be operated in the metastable zone where the crystal particles will grow until the end of the operation. If the crystallization process is operated beyond the metastable concentration, excessive nucleation is expected due to the high supersaturation. As a consequence the target crystal product is able to achieve but there is unnecessary amount of fine crystals by the end of the operation. This unnecessary nucleation can be reduced by incorporating the crystallization process with dissolution phenomena where the temperature of the solution is controlled so that the solution is operated in the undersaturated condition. This condition is enabling the grown crystal particles to dissolve back into solution. Thus reducing the amount of fine crystals in the overall CSD. Therefore the objective of this study is to develop and evaluate controlled cooling for batch seeded crystallization of potassium nitrate incorporating dissolution phenomena. The mathematical model for potassium nitrate crystallization is developed and simulated in MATLAB software where it is validated against experimental data. The optimization algorithm is then developed in order to determine the set-point trajectory for closed­ loop control. Based on this optimal trajectory a closed-loop control is proposed to maintain the crystallization operation at its set-point using two types of controller which consists of Proportional (P) and Proportional-Integral (PI) controllers. Two important criteria are measured in the closed-loop simulation which are the performance of PI controller to follow the given set-point trajectory and the achievement of target CSD. Based on the closed-loop control it is shown that the PI control is more superior than P control by maintaining the operation at its set-point and successfully achieved the desired CSD. In addition the production of fines particle is greatly reduced indicating this new optimal trajectory is capable of producing the target CSD and minimizes the effects of nucleation. [ABSTRACT FROM AUTHOR]

Natural convection in an attic space with top cooling is investigated by three dimensional numerical simulation for a wide range of Rayleigh numbers. The numerical results show the development of natural convection flow in attic space. Three stages: an initial stage, a transitional stage and a fully developed stage are involved. At higher Rayleigh numbers, the flow in the attic space is three dimensional and asymmetry with respect to geometric symmetry plane. The critical Rayleigh number for asymmetric flow is found. [ABSTRACT FROM AUTHOR]

This paper describes a numerical study of internal pin-fin cooling performance of a trailing-edge cutback configuration for gas turbine blade. The study was performed at two steps: first, to validate simulation results from an existing TE cutback cooling with staggered pin-fin arrays inside the cooling passage against experimental measurements. Three structured meshes were used for grid convergence and to evaluate film-cooling effectiveness and discharge coefficient; second, to investigate the pin-fin cooling performance with various blowing ratios. Simulations were performed by keeping the same initial and boundary conditions as the corresponding experiment. The results show that validation can be considered acceptable by keeping quality grid and its resolution in near wall regions. Both computational data of the adiabatic film-cooling effectiveness and the discharge coefficient are in fairly good agreement with the test data. The pin-fin array has important roles to promote flow turbulence activity inside the cooling passage, in addition to increase surface areas for heat transfer. Hence the turbulence intensity is more pronounced due to the existence of the pin-fin and it is concomitant with the coolant flow inside the wedge-shaped duct. [ABSTRACT FROM AUTHOR]

The effect of a distance between a nozzle and hot plate on flow and heat transfer characteristics was investigated numerically for an array of submerged air microjets. The considered numerical model consisted of 16 microjets, arranged in the regular array of 4×4. The compressible steady state air flow, including turbulent effects, was model applying the SST k-ω turbulence model. The numerical simulator was developed in the ANSYS Workbench environment. During analyses the jet diameter-based Reynolds number and the jet pitch to the jet diameter ratio were equal to Red = 1100 and s/d = 31.25, respectively, while the ratio of the distance between the nozzle and hot plate to the jet diameter was set to H/d = 3.125, 25 and 50. In terms of heat transfer, the best distance-to-jet diameter ratio was found to be H/d = 25. Decrease of this ratio below and increase above 25 resulted in more non-uniform and uniform, respectively, distributions of temperature and heat transfer coefficient on the hot surface as well as in drop in the cooling performance. The obtained average temperatures and heat transfer coefficients on hot plate were equal to 332.4, 315.5 and 318.7 K as well as 160, 274 and 239 W/m²/K for H/d = 3.125, 25 and 50, respectively. The effect of lateral flow on adjacent jets and heat transfer rate was also observed and increased with rise in the H/d ratio. [ABSTRACT FROM AUTHOR]

The article presents the numerical optimization of an innovative and original design that allows to supply the cutting fluid (CF) through the cutting tool directly into the cutting zone during the gear hobbing. The main task of this solution is to increase the efficiency of CF reaching into the contact zone of the active cutting edge of the hob cutter with the workpiece, and consequently extending the tool life. This is extremely important from the viewpoint of machining efficiency, which translates into a reduction in manufacturing costs. In order to reduce costly workshop tests, a preliminary CAD design was made in the Autodesk Inventor program, followed by numerical simulations of the flow of cutting fluid in the ANSYS CFX program. Geometric values that were changing during the numerical optimization of the new construction’s working conditions were: diameters of the CF supply openings to the cutting zone (d = 1 mm and 2 mm), the inclination angle of CF supply openings (α = 0° and 15°), number of supply rows (n = 2 and 3). The result of numerical analysis of the flow was the pressure loss in the entire system of the optimized structure. [ABSTRACT FROM AUTHOR]

In this paper we will present the design of a laboratory assembled portable EDXRF spectrometer that uses the secondary target excitation mode and its analytical performance. In secondary target configuration, the sample is excited mainly with the target material characteristic emission radiation, which allows to reduce the detected continuum background and to improve the detection limits. The instrument is based on a low power, air cooled, Ag anode X-ray tube (Eclipse III) and thermoelectrically cooled Si-PIN detector arranged in a specially built geometrical setup that allows the use of secondary targets. In our design, all spectrometer elements (x-ray tube, secondary target, sample and detector) are arranged in such a way that distances are minimal while keeping the excitation and detection angles optimal as well (φ = φ = 45°). The possibility to use different secondary targets enables the optimization of detection limits for different groups of elements in various types of samples. Examples of the application of the spectrometer for the analysis of different kind of samples will be presented. [ABSTRACT FROM AUTHOR]