• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.1219-1224
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• 2006

This paper presents the friction and anti-wear characteristics of nano-oil with n mixture of a refrigerant oil and carbon nano-particles in the thrust slide-bearing of scroll compressors. Frictional loss in the thrust slide-bearing occupies a large part of total mechanical loss in scroll compressors. The characteristics of friction and anti-wear Lising nano-oil is evaluated using the thrust bearing tester for measuring friction surface temperature and the coefficient of friction at the thrust slide-bearing as a function of normal loads up to 4,000 N and orbiting speed up to 3,200 rpm. It is found that the coefficient of friction increases with decreasing orbiting speed and normal force. The friction coefficient of carbon nano-oil is 0.015, while that of pure oil is 0.023 under the conditions of refrigerant gas R-22 at the pressure of 5 bars. It is believed that carbon nano-particles can be coated on the friction surfaces and the interaction of nano-particles between surfaces can be improved the lubrication in the friction surfaces. Carbon nano-oilenhances the characteristics of the anti-wear and friction at the thrust slide-bearing of scroll compressors.

• Proceedings of the SAREK Conference
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• 2003.07a
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• pp.119-119
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• 2003

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.7
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• pp.551-556
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• 2003

The present study concerns an experiment on the heating characteristics of a system air-conditioner (A/C) using PWM method or inverter method at low temperature con-ditions. The compressors used are digital scroll type and BLDC inverter type. Under the low outside temperature condition, -5$^{\circ}C$, -1$0^{\circ}C$, -15$^{\circ}C$, heating capacities and COPs are mea-sured by the psychometric calorimeter using air enthalpy method. Also, outlet air temperatures at heating operation mode are measured at -5$^{\circ}C$, -1$0^{\circ}C$ and -15$^{\circ}C$. Experimental results show that COPs of the system A/C using a PWM method are more effective than those of the inverter method at heating operation mode. Although the heater is on, COPs of PWM method are similar to those of BLDC inverter method. Moreover, the heating capacities of PWM method at -5$^{\circ}C$, -1$0^{\circ}C$ and -15$^{\circ}C$ are larger about 10~20% and outlet air tempe-rature at -15$^{\circ}C$ is larger about 10%, compared to the inverter method.

• International Journal of Air-Conditioning and Refrigeration
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• v.8 no.1
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• pp.29-39
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• 2000

A series of tests were performed to verify the transient characteristics of heat pump in heating and cooling mode when operating speed was varied over the 30 to 102Hz. One of the major issues that has not been addressed so far is transient characteristics during speed modulation. The model for cycle simulation has been developed to predict the cycle performance under conditions of decreasing drive frequency and the results of the theoretical study were compared with the results of the experimental study. The simulated results were in good agreement with the experimental result within 10%. The transient cycle migration of the liquid state refrigerant causes significant dynamic change in system. Thus, the migration of refrigerant was the most important factor whenever do experimental results analysis or develop simulation model.