• International Journal of High-Rise Buildings
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• v.12 no.4
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• pp.335-341
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• 2023

This study proposes a novel rotary direct evaporative cooler and investigates the potential of a moisture-wicking fabric as a cooling pad for the proposed evaporative cooler. The rotary direct evaporative cooler rotates the cooling pad to reduce the water and energy consumption of the pump compared to those of existing direct evaporative coolers. A moisture-wicking fabric is considered as the material of the cooling pad, because of its high moisture-wicking property, enhancing water evaporation. Experiments are performed under various inlet air conditions while measuring the air temperature, relative humidity, air velocity, and differential pressure. The evaporative cooling efficiency and impacts of the inlet air temperature and air velocity on the cooling performance are also evaluated. The results demonstrate the potential of the moisture-wicking fabric as cooling pad of direct evaporative cooler.

• Resources Recycling
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• v.11 no.3
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• pp.25-30
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• 2002

Heat transfer occurring in the rotary cooler was analyzed by applying a one-dimensional steady state. The temperature of inlet gas and the measured temperature of outlet gas were used as boundary conditions. Axial temperature distribution of solid, gas and wall were calculated by solving two differential equations and two algebraic equations under the constraint of two point boundary conditions and operating conditions. The temperatures of outer wall calculated in this study were in good agreement with those measured from running rotary cooler.

• Cement Symposium
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• no.17
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• pp.70-76
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• 1989

• Progress in Superconductivity and Cryogenics
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• v.8 no.1
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• pp.54-58
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• 2006

Stirling cryocooler is relatively compact, reliable, commercially available. and uses helium as a working fluid. Over the past decade and a half, there has been rapid development of Stirling cryocooler, mainly for military and space applications. Stirling cryocoolers have been widely used lot the cooling of infrared sensors and high temperature superconducting filters to the temperature of the liquid nitrogen. The Stirling cryocooler with the rotary compressor is applicable to the cooling device for the compact mobile thermal imaging system, because the cryocoolers have the compact structure and light weight. In this paper, integral Stirling cryocooler is designed, manufactured and fabricated, and performance characteristics are investigated. This cooler delivers approximately 0.6W cooling at 80K for 20W of input power from 24V DC power supply.

• The Korean Journal of Ceramics
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• v.5 no.3
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• pp.296-302
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• 1999

The state of the art of the 2-stage swirl calciner is to make 2-stage counter gas flow in a calciner with cooler hot air. Gas flow in the calciner increases retention time of raw mix particles. Simple structure of the 2-stage swirl calciner operated optimally the rotary cement kiln. In this study, in order to decide the entrance type of the cooler air of the optimal calciner model, an entrance cooler air velocity, the input points of raw mix were analyzed in many aspects with cold model experiment and computational fluidized dynamic simulation. It was found that the entrance type of cooler air fully splite 2-stage for the optimal condition of the cold model calciner. The operation conditions were that the input feeding, the cooler air velocity and the air velocity of throat were 0.33kg/$\textrm m$3$, 15m/s and 20m/s respectively. The performance of 150 t/d the pilot plant connected with the kiln rising duct was that volume capacity of the calciner is over 430 kg/$\textrm m$3$-h, decarbonation rate of raw mix apparently 90%, heat consumption 950 kcal/kg-cli and retention time of raw mix 2.4 sec. Its the best operating condition is cooler air velocity 18m/s, the gas velocity of throat 25m/s, feeding rate of raw mix 10t/h. The operating experience of the pilot plant confirmed the success of scale up for over 3000 t-cli/d.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.30 no.3
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• pp.107-115
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• 2018

A design combining the use of a compressor and expander was introduced in order to improve the cycle performance of a $CO_2$ automotive air conditioning system. Both the compressor and expander used were of rotary vane type and were designed to share a common shaft in a housing. Numerical simulation was carried out to evaluate the merit of the combined unit. In a typical automotive air conditioning operating conditions, the COP of the system was improved by 8.7% by the application of the combined unit. The compressor input was reduced by 5.2% through use of the expander output. In addition, about 3.06% increase in the cooling capacity was obtained through isentropic expansion in the expander. Our study noted that, as the pressure difference between the gas cooler and the evaporator becomes larger, the COP of the system improved increases unless the mass flow rate in the expander exceeds that in the compressor.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.1953-1958
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• 2007

This paper presents the results of a series of performance tests for the integral Stirling cryocooler. Infrared sensor systems incorporating cryocoolers are required to be qualified to the appropriate environmental specification. Integral Stirling cryocooler for thermal imaging system have matured to the stage of undergoing formal qualification test program. The thermal environmental test of the Stirling cryocooler is presented in this paper. We performed that low and high temperature keeping test from $-40^{\circ}C$ to $+71^{\circ}C$ and operating test at high and low temperature cyclic range with acceptance tests performed at scheduled intervals. Cooldown time to 80K and steady state input power at 80K were determined as a function of cooler components temperatures at the compressor, hot end and cold tip. Tests performed on this cooler have been successful with a measured cooldown time to 80K of less than 5 minutes 24seconds for $71^{\circ}C$ ambient temperature with input power of 11W

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.893-898
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• 2009

The quantity of discharged oil from a compressor is one of the most important issues for proper operation of refrigeration system. If the oil is increased in the system not only pressure drop is increased in other components, such as evaporator and gas cooler but also heat transfer coefficient in the heat exchangers is decreased. In addition, the lack of oil in the compressor may cause a critical of the system failure. In this study, one stage single rotary compressor is used for measuring oil circulation ratio(OCR). Carbon dioxide and PAG oil are used as refrigerant and lubricant. Using a U-tube densimeter, mixture density is measured. Characteristics of oil circulation ratio have been investigated for $CO_2$ rotary compressor in the range of operation frequency 45 Hz to 63 Hz and the suction temperature range of $0^{\circ}C$ to $15^{\circ}C$. The results obtained indicate that the oil circulation ratio is increased as the suction temperature or compressor operating frequency is increased.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.4
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• pp.505-512
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• 2011

Linear permanent magnet synchronous motors utilize high-energy product permanent magnet to produce high thrust, velocity and acceleration. Such motors are finding applications requiring high positioning accuracy and speed response, for example, machine tools, in the absence of mechanical gears and ball screw systems. A disadvantage of the linear motors is high power loss in comparison with rotary motors. For the application of the linear motors to machine tools, it is required to use water coolers and to improve the thermal behavior through insulation and structure optimization or control strategies. This paper presents the function of the secondary part of the linear synchronous motor as to the thermal behavior and the improving method. The result shows cooling pipe combined with an insulation layer is a suitable design for improving of the thermal behavior.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.1
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• pp.73-79
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• 2011

A portion of oil for lubrication of compressor flows together with refrigerant in the refrigeration system. If the oil discharge from a compressor is increased in the refrigeration system, not only pressure drop is increased in other components, such as evaporator and gas cooler, but also heat transfer coefficient in the heat exchangers is decreased. Oil discharge rate from a compressor may strongly depend on operating conditions of a compressor. In this study, one stage single rotary compressor is employed for measuring oil circulation ratio(OCR). Carbon dioxide and PAG oil are used as refrigerant and lubricant. Using a U-tube densimeter, mixture density is measured. Oil circulation ratio(OCR) can be estimated by measured mixture density. The results obtained indicate that the oil circulation ratio(OCR) is increased as the suction temperature or compressor operating frequency is increased. Oil circulation ratio(OCR) correlation of the compressor is also suggested.