Cooling Technology Research Articles

A cascade electrocaloric cooling device for large temperature lift

Cooling technology that is both compact and flexible is increasingly vital for the thermal management of wearable electronics and personal comfort. Electrocaloric (EC) cooling provides a potential solution, but the low adiabatic temperature change of EC materials has been the bottleneck in its progress. We demonstrate a cascade EC cooling device that increases the temperature change, with enhanced cooling power and cooling efficiency at the same time. The device integrates multiple units of EC polymer elements and an electrostatic actuation mechanism, all operating in synergy. Every two adjacent EC elements function in antiphase (in terms of both actuation and EC effect) to allow heat flow to be continuously relayed from the heat source to the heat sink. The antiphase operation also enables internal charge recycling, which enhances the energy efficiency. Operating at the EC electric field at which the adiabatic temperature change of the material is 3.0 K, a four-layer cascade device achieves a maximum temperature lift of 8.7 K under no-load conditions. The coefficient of performance is estimated to be 9.0 at the temperature lift of 2.7 K and 10.4 at zero temperature lift. Solid-state caloric cooling is a promising alternative to vapour-compression refrigeration yet practical devices are not sufficiently efficient for applications. Meng et al. combine cascade device design with charge recovery and improve the cooling efficiency and temperature lift of an electrocaloric device.

Heat Transfer Performance of Gas Cooling Technology utilizing a Passing Flow between Lotus-fins

Heat Transfer Performance of Gas Cooling Technology utilizing a Passing Flow between Lotus-fins

Analysis of Resilience of Ventilative Cooling Technologies in a Case Study Building

Buildings globally are subjected to climate change and heatwaves, causing a risk of overheating and increasing energy use for cooling. Low- energy cooling solutions such as night cooling are promising to realize energy reduction and climate goals. Apart from energy performances, resilience is gaining importance in assessing the performance of the building and its systems. Resilience is defined as “an ability to withstand disruptions caused by extreme weather events, man-made disasters, power failure, change in use and atypical conditions; and to maintain capacity to adapt, learn and transform.” However, there is a clear lack of Resilience indicators specific for low energy cooling technologies. In this paper, the resilience of the night cooling in a residential building in Belgium is assessed for two external events: heat wave and shading failure. This paper shows the first attempt of a resilience indicator for night cooling as the effect on the shock of solar shading failure, heat wave or combination of both. It take 3.4 days to bring down the temperature below 25?, in case of shading failure and heatwaves compared to 9 hours in the reference case. Further research is needed to determine resilience indicators as a performance criteria of low-energy cooling systems.

A Review on Recent Development of Cooling Technologies for Photovoltaic Modules

When converting solar energy to electricity, a big proportion of energy is not converted for electricity but for heating PV cells, resulting in increased cell temperature and reduced electrical efficiency. Many cooling technologies have been developed and used for PV modules to lower cell temperature and boost electric energy yield. However, little crucial review work was proposed to comment cooling technologies for PV modules. Therefore, this paper has provided a thorough review of the up-to-date development of existing cooling technologies for PV modules, and given appropriate comments, comparisons and discussions. According to the ways or principles of cooling, existing cooling technologies have been classified as fluid medium cooling (air cooling, water cooling and nanofluids cooling), optimizing structural configuration cooling and phase change materials cooling. Potential influential factors and sub-methods were collected from the review work, and their contributions and impact have been discussed to guide future studies. Although most cooling technologies reviewed in this paper are matured, there are still problems need to be solved, such as the choice of cooling fluid and its usability for specific regions, the fouling accumulation and cleaning of enhanced heat exchangers with complex structures, the balance between cooling cost and net efficiency of PV modules, the cooling of circulating water in tropical areas and the freezing of circulating water in cold areas. To be advocated, due to efficient heat transfer and spectral filter characters, nanofluids can promote the effective matching of solar energy at both spectral and spatial scales to achieve orderly energy utilization.

Flue Gas Water Recovery by Indirect Cooling Technology for Large-Scale Applications: A Review

With social development and economic enhancement, energy is facing significant worldwide demand, and fossil fuels are the prime energy sources for various energy systems over past decades. Furthermore, among fuel-consumed applications, power plants are the primary source of energy consumption. There is a lot of waste heat and steam accompanied by the latent heat produced in the exhaust flue gas. Therefore, the latent heat recovery from the flue gas plays an important role in increasing the efficiency of the system and saving water. To recover the heat and mass in power plants, three primary methods are proposed to condense the vapor based on previous studies: (1) flue gas condensation technology, (2) liquid desiccant-based dehydration (LDD) technology and (3) membrane technology. This paper mainly reviews and summaries the indirect cooling technology in flue gas condensation technology. The numerical simulation and theory of flue gas condensation are introduced. Different heat exchanger types and conducted experiments are also summarized. The performance of the indirect cooling technology is affected not only by its own configuration and design but also by the flue gas inlet temperature, velocity, water vapor mass fraction, etc. The major concerns and outlook of practical applications for further study are attributed to the heat exchanger size and cost, acid corrosion, ash accumulation in flue gas, etc.

A review on thermoelectric cooling technology and its applications

Controlling devices thermally is an important issue to increase the span of any equipment that converts energy and nowadays available latest automation like LED, computer processers and electric battery. Thermoelectric Cooling Technology (TCT) is best option because it has high reliability and also its usage of energy is low for the cooling of devices, which are working on the basis of Peltier effect. TCT have features such as it is not big in size, very light in weight. Also it has no mechanical moving part which results in no or less noise, eco friendly and it does not has any working fluid. This paper presents a comprehensive review of TCT to understand the state of art in the cooling techniques and its applications on heat pipe cooling, sensible air cool warm fan and solar still productivity enhancements. The challenges and opportunities for future research are also highlighted.

Substantiation for the Implementation of Controlled Coil Cooling Technology after Hot Rolling of Strip Steel

The analysis of technology for the production of hot-rolled strip steel in coils has shown that the technological instructions for this metallurgical processing stage finishes at the stage of winding a finished hot strip into a coil. The development and implementation for technology to control the cooling of hot-rolled strip coils in accordance with the grade-and-size assortment, as well as with customer’s requirements, are necessary.

Advances of Solar PV System Output Improvement through Cooling Technologies in Malaysia

Solar photovoltaic (PV) panel is the most widely used renewable energy technology in Malaysia due to constant irradiation throughout the year as the country is located near the equator. According to the current state of the Malaysian weather, the ambient temperature is around 25°C and can go up to 30°C. The electrical efficiency of a PV panel is sensitive towards temperature where it is known that the power and efficiency decrease at the rate of ±0.5%/°C and ±0.05%/°C respectively as the ambient temperature increases [1]. This paper discusses the cooling of solar PV technologies, the methodologies of the cooling system and its effectiveness. Generally, the effectiveness of the studies conducted were derived from the solar PV panel temperature reduction and solar PV electricity power output increment. This paper elaborates the trend of methodologies for cooling of solar PV in Malaysian climate. The methodologies that were used by the researchers vary according to the specific objectives which can be categorized as active cooling and/or passive cooling. The gaps of the studies were also identified alongside with the possible solutions to mitigate the problems.

Mounting and Cooling Technology for System Integration on Power Electronics

Mounting and Cooling Technology for System Integration on Power Electronics

Evaluation of the Hot Air Recirculation Effect and Relevant Empirical Formulae Applicability for Mechanical Draft Wet Cooling Towers

Due to the hot air recirculation, the inlet air enthalpy h1 of mechanical draft wet cooling towers (MCTs) was usually greater than the ambient air enthalpy ha. To realize the cooling performance and accurate design of MCTs, this paper clarified the feasibility of the inlet air enthalpy empirical formula presented by the Cooling Technology Institute (CTI) of the USA. A three-dimensional (3D) numerical model was established for a representative power plant, with full consideration of MCTs and adjacent main workshops, which were validated by design data and published test results. By numerical simulation, the influence of different wind directions and wind speeds on hot air recirculation (HAR) and the influence of HAR on the cooling performance of the MCTs were qualitatively studied based on the concept of hot air recirculation rate (HRR), and the correction value of HRR was compared with the calculated value of the CTI standard. The evaluation coefficient ηh, representing the ratio of the corrected value to the calculated value was introduced to evaluate the applicability of the CTI formula. It was found that HAR was more sensitive to ambient crosswind, and an increase in HRR would deteriorate the tower cooling performance. When the crosswind speed increased from 0 to 15 m/s, ηh, changed from 2.42 to 80.18, and the calculation error increased accordingly. It can be concluded that the CTI empirical HRR formula should be corrected when there are large buildings around the MCTs, especially under high-speed ambient crosswind conditions.

Dynamics model for the thermal performance from a lyophilization process, based on a complete transfer functions matrix

During the beginning of the XX century lyophilization was developed as an alternative technology to extend the storage time for fruit and vegetables or other kind of food; however, the energetic consumption of this technology makes it not an option for common food producers, less over for those one that work by the open field cultivation technique. The main energy consumption in a lyophilization systems are the motors from the vacuum pump and from the refrigerant compressors; due to the temperature range needs the lyophilization systems use to have more than one cooling thermodynamic system based on vapor compression. This paper describes an experimental methodology to get a complete state transfer functions matrix, based on the graphical analysis of the concerned transfer functions magnitude spectra. This experimental data came from a set of test performed at the National Laboratory for Cooling Technology Research (LaNITeF) at the Engineering Center for Industrial Development (CIDESI). The intention of this transfer functions matrix is to be applied in a control strategy to then optimize the energetic performance of the concerned lyophilization system. This function transfer matrix is considered complete because there is not a dynamic order reduction considering its degrees of freedom. The transfer functions matrix describes the dynamic relationship between both the inputs variables that describe the energetic consumption of the lyophilization system, and the ambient conditions, as well as the output variables that represent the dynamical states vector with the variables of interest from the concerned process. The simulation from an experimental scenario worked as the graphical validation of the transfer functions matrix characterized experimentally, so the main conclusion of this scientific work is that this transfer functions matrix can be used as dynamic model to implement control and optimization algorithms.

Development of an Innovative Digital Cooling Technology (Differential Heat Treatment) for EVRAZ NTMK Rails

TEC-DT differential heat hardening technology is developed based on the process of digital control of air humidity by high-efficiency mixing of air flows and the water ejected by it. The wide-range cooling rate control (2–14°C/s) makes it possible to heat hardened rails made of different steels, such as carbon steels, with a wide range of carbon content, and microalloyed and alloyed steels, while achieving the level of properties required for rails of both general and special purposes (low-temperature reliability and increased wear resistance). The rails, differentially hardened by reheating, have a highly dispersed pearlite structure, and a high level of ductility, impact strength, fatigue strength, and survivability.

Paints as a Scalable and Effective Radiative Cooling Technology for Buildings

Jyotirmoy Mandal completed his PhD in Applied Physics at Columbia University in the City of New York and is currently a Schmidt Science Fellow and a postdoctoral researcher at University of California, Los Angeles. His research interests include low-cost optical designs for radiative cooling and solar heating, with a focus on applications in developing countries. Yuan Yang is an associate professor in the Department of Applied Physics and Applied Mathematics at Columbia University in the City of New York. His research interests include electrochemical energy storage and thermal energy management. Dr. Yang has published over 70 peer-reviewed journal articles, including in leading journals such as Science, Proceedings of the National Academy of Sciences, Advanced Materials, and Joule. Nanfang Yu is an associate professor in the Department of Applied Physics and Applied Mathematics at Columbia University in the City of New York. His research interests include mid-infrared and far-infrared optics, metamaterials, biophotonics, and biologically inspired flat optics. Dr. Yu’s research has been published in leading journals like Science, Nature Materials, Nature Nanotechnology, and Joule. Aaswath P. Raman is an assistant professor of Materials Science and Engineering at the University of California, Los Angeles (UCLA). He is also co-founder and chief scientific officer of SkyCool Systems, a startup commercializing radiative cooling technologies. Dr. Raman’s research interests include nanophotonics, metamaterials, radiative heat transfer, and energy applications, including radiative cooling. His works have been published in leading journals such as Nature, Nature Energy, Physical Review Letters, and Joule.

Defect and Stress Reduction in High-Pressure and High-Temperature Synthetic Diamonds Using Gradient Cooling Technology

In order to eliminate filiform defects in high-pressure and high-temperature synthetic diamonds, we have developed a gradient cooling technology and applied it during the synthesis assembly cooling...

The effect of mean pressure on the performance of a single-stage heat-driven thermoacoustic cooler

Abstract Waste heat is an environmental issue in the world. There are some technologies that can be used to recovery the waste heat, one of which is thermoacoustic cooler technology. Thermoacoustic technology can be divided into two parts: one is thermoacoustic engine and cooler. To design the cooler system having high efficiency and lower onset heating temperature, the effect of mean pressure is investigated. By increasing mean pressure from 0.5 to 3 MPa, the heating temperature generating acoustic power can be decreased from 831 to 580 K. Moreover, 15% of Thermodynamic upper limit value of the whole cooler system is achieved.

Application of Passive Cooling Technologies in Commercial Buildings

World over building sector is largest consumer of electrical energy. Energy requirement for air cooling and refrigeration is found to be 40 % of total consumption of electrical energy used in building sector. Passive cooling technologies used in building have good potential of indoor air cooling many building built on these principles are showing reduction in energy requirements. In present work, passive cooling technologies such as planform, shading devices, garden trap bond, fenestration, air ducts, earth berming, and indoor gypsum wall finishes, false ceiling etc. had been integrated into building design of a commercial building at Tuljapur in the hot and dry climatic zone of India. Field experimentation work of measurement of temperatures in indoor and outdoor locations of the building had been conducted to assess the cooling potential of these technologies. It was found that average temperature reduction in indoor atmosphere was archived as 3°C except the temperature difference between indoor and outdoor atmosphere. This was a cumulative effect of above mentioned passive cooling technologies integrated in building design.

Decomposition of endothermic fuel using washcoated HZSM-5 on metal foam

Cooling technology exploiting the endothermic reaction of fuel has been developed to prevent structural deformation in engines due to air friction and overheating during supersonic flight. Endothermic fuels are liquid hydrocarbon fuels that can absorb heat through endothermic reactions. The initial heat sink capacity of conventional pellet type catalysts for the endothermic reaction cannot be maintained, leading to more rapid deactivation due to coke formation. To maintain the heat sink performance of decomposition catalysts, HZSM-5 catalyst washcoated on metal foam(HZSM-5/metal foam) was used herein. The reactions were carried out in a batch reactor at 673 K at a pressure of 50 bar using methylcyclohexane (MCH) and n-dodecane as reactants. The total MCH conversion achieved with the pellets and HZSM-5/metal foam was same at 93 %. In the case of n-dodecane, the total conversion achieved with the HZSM-5/metal foam (91 %) was superior to that achieved with the pellets (69 %).

Development and Implementation of Solar Assisted Desiccant Cooling Technology in Developing Countries: A Case of Saudi Arabia

This paper presents a comprehensive overview of the potential and feasibility of using solar thermal cooling systems in the Kingdom of Saudi Arabia (KSA). The performance of a desiccant cooling system has been determined based on climatic data of 32 cities spread all over the territory of the country. The investigation has been carried out keeping in view the high energy consumption for cooling applications in the country. The analysis has been done using the overall performance of the system, sensible energy ratio, and cooling and regeneration loads. The main objective of this study is to encourage the implementation of solar thermal cooling systems in the country for the development of sustainable buildings. The economic analysis shows that thermal cooling technology can reduce the cost of cooling units, remarkably. Furthermore, the utilization of the proposed system will decrease the dependence on primary energy resources. The saving factor of the proposed system with 1 ton capacity in comparison to the conventional vapor compression unit is found to be 34.6%. The present study also recommends that the government subsidies and incentives can further improve the development and utilization of solar air conditioning technology in developing countries.

Thermal Management of Li-Ion Batteries With Single-Phase Liquid Immersion Cooling

Development of effective thermal management techniques is essential in enabling further technical advances and wide public acceptance of lithium-ion based battery electrical storage. Both stationary battery arrays and electric vehicle (EV) batteries are pressed to enable charging and discharging at faster C rates, increased amp-hour capacity, longer service life and increased safety. All of these are dependent on more efficient and safer thermal management solutions. Traditional air cooling and indirect liquid cooling (cold plate) methods have limitations in effectiveness and weight. Engineered Fluids has recently completed a series of experiments demonstrating the high efficiency of Single-phase Liquid Immersion Cooling (SLIC) technology for the thermal management of Li-ion batteries. This article reviews the results of these experiments and discusses some of the issues and solutions for battery thermal management, and outlines the proper design of battery thermal management systems. We will discuss such topics as active cooling versus passive cooling, liquid cooling versus air cooling, cooling and heating versus cooling only systems, and relative needs of thermal management for VRLA, NiMH, and Li-Ion batteries.

Electric Vehicle Battery Pack Cooling Technology for Super-Rapid Charging

Electric Vehicle Battery Pack Cooling Technology for Super-Rapid Charging