DOI QR코드

DOI QR Code

Precision Control of Water Bath Temperature using Air Cooled Variable Refrigerant Flow Chiller

공랭식 변유량 냉매 냉동기를 적용한 수조 온도의 정밀 제어

  • Jeong, Kwang-Ju (Graduate Seoul of Energy and Environment, Seoul National University of Science & Technology) ;
  • Kim, Young Il (School of Architecture, Seoul National University of Science & Technology)
  • 정광주 (서울과학기술대학교 에너지환경대학원) ;
  • 김영일 (서울과학기술대학교 건축학부)
  • Received : 2018.09.28
  • Accepted : 2018.11.02
  • Published : 2018.12.01

Abstract

This study compared constant water bath performances of conventional water-cooled refrigerator and electric heater with an air-cooled VRF chiller and electric heater equipped with optimal control algorithm. In heating mode, the air cooled VRF chiller and electric heater combination reduced the set temperature arrival time by an average of 42 minutes, and energy was also reduced by 18%. In cooling mode, the two systems took 70 minutes to reach the set temperature and showed no difference. Energy was reduced by 33.5% with the new system. For constant temperature maintaining experiment, after reaching the set temperature of $15^{\circ}C$, $20^{\circ}C$ and $22^{\circ}C$, temperature deviations were all in the range of $-0.2^{\circ}C$ to $+0.1^{\circ}C$. Energy was reduced by an average of 84.9%. Through this study, possibility of precise temperature control by an air cooled VRF chiller system was confirmed.

Keywords

JOOJBH_2018_v14n4_27_f0001.png 이미지

Fig. 1. Diagram of a refrigerator and VRF system.

JOOJBH_2018_v14n4_27_f0003.png 이미지

Fig. 2. Temperature and load characteristics of conven-tional water bath.

JOOJBH_2018_v14n4_27_f0004.png 이미지

Fig. 3. Temperature and electric heater power characteristics of refrigerator and electric heater system for various set temperature conditions.

JOOJBH_2018_v14n4_27_f0005.png 이미지

Fig. 4. Load characteristics of conventional refrigerator and electric heater system.

JOOJBH_2018_v14n4_27_f0006.png 이미지

Fig. 5. algorithm of VRF.

JOOJBH_2018_v14n4_27_f0007.png 이미지

Fig. 6. Diagram of the VRF and electric heater system.

JOOJBH_2018_v14n4_27_f0008.png 이미지

Fig. 7. Temperature and electric heater power characteristics of VRF and electric heater system for various set temperature conditions.

Table 1. Refrigerator and VRF system

JOOJBH_2018_v14n4_27_t0001.png 이미지

Table 2. Load and device power for constant temperature condition (15℃)

JOOJBH_2018_v14n4_27_t0002.png 이미지

Table 3. Control algorithm of VRF and electric heater system

JOOJBH_2018_v14n4_27_t0003.png 이미지

Table 4. Comparison of time and power consumption for change of set temperature

JOOJBH_2018_v14n4_27_t0004.png 이미지

Table 5. Comparison of temperature deviation and power consumption for constant temperature condition

JOOJBH_2018_v14n4_27_t0005.png 이미지

Acknowledgement

Supported by : 한국연구재단

References

  1. Choi, B. Y., Lee, S. H., Kim, S. C., and Lee, D. W., 2005, An Instance Application of Thermal Storage Type Heat Pump System by Using Air Heat-source, SAREK, 2005-S-056, pp. 343-349.
  2. Kim, O. J., Song, C. H., Jang, H. Y., and Park, M. S., 2014, An Experimental Study on the Electric Heat Pump Performance with Ice and water Storage Tank, SAREK, 2014-W-005, pp. 16-19.
  3. Kim, O. J., 2010, State of the Arts and Technical Road Map of Air to Water Heat Pump, SAREK, 2010-W-053, pp. 306-312.
  4. Lee, J. Y., Kim, J. H., Yeon, C. K., and Jeong, C. S., 2013, Design Examples for Green Data Centers, SAREK, 2013-W-53, pp. 239-244.
  5. Cha, D. A., and Kwon, O. K., 2010, An experimental study on semiconductor process chiller for dual channel, SAREK, Vol. 22, No. 11, pp. 760-766.
  6. Cha, D. A., Kwon, O. K., Yun, J. H., and Kim, D. H., 2010, An experimental study on semiconductor process chiller for energy saving, Proceeding of the KSME Spring Annual Conference, pp. 371-376.
  7. Cha, D. A., Kwon, O. K., and Oh, M. D., 2010, An experimental study on process chiller for semiconductor temperature control, Trans of the KSME(B), Vol. 35, No. 5, pp. 459-465.