The effect of the chilled water temperature on the performance of an experimental air-cooled chiller
Keywords:experimental set-up, air-cooled chiller, coefficient of performance COP, the temperature of chilled water
This paper presents the study results on the effect of the chilled water temperature on the coefficient of performance (COP) of an experimental air-cooled chiller. The measuring sensors and instrument were calibrated, and the uncertainty of the measuring temperature and pressure were evaluated. The uncertainty of measured temperature and pressure at 95% confidence level is 0.12 °C and 1.4 kPa, respectively. The isentropic compression efficiency and the COP of the air-cooled chiller operating at a condensation temperature of 48.05 °C and evaporation temperature of 3.17 °C are 63% and 2.69, respectively. The chilled water temperature has a significant influence on evaporation pressure and the COP of the chiller. If the temperature of the air entering the condenser of the chiller is maintained at 35 °C, the COP of the chiller increases from 2.55 to 2.89 when the temperature of the chiller water increases only 4 K, from 8 °C to 12 °C.
The World Bank. https://data.worldbank.org/indicator/SP.POP.TOTL, (2018).
L. Pérez-Lombard, J. Ortiz, and C. Pout. A review on buildings energy con- sumption information. Energy and Buildings, 40, (3), (2008), pp. 394–398. https:/doi.org/10.1016/j.enbuild.2007.03.007.
Z. Ma and S. Wang. Energy efficient control of variable speed pumps in complex building central air-conditioning systems. Energy and Buildings, 41, (2), (2009), pp. 197–205. https:/doi.org/10.1016/j.enbuild.2008.09.002.
F. W. Yu, W. T. Ho, K. T. Chan, and R. K. Y. Sit. Critique of operating variables importance on chiller energy performance using random forest. Energy and Buildings, 139, (2017), pp. 653–664. https:/doi.org/10.1016/j.enbuild.2017.01.063.
Z. Ma and S. Wang. An optimal control strategy for complex building central chilled water systems for practical and real-time applications. Building and Environment, 44, (6), (2009), pp. 1188–1198. https:/doi.org/10.1016/j.buildenv.2008.08.011.
S. Wang, D.-C. Gao, Y. Sun, and F. Xiao. An online adaptive optimal control strategy for complex building chilled water systems involving intermedi- ate heat exchangers. Applied Thermal Engineering, 50, (1), (2013), pp. 614–628. https:/doi.org/10.1016/j.applthermaleng.2012.06.010.
A. N. Lai. THEPROPER1.10.02 Thermodynamic properties of fluids for science and engineering version 1.10.02. Vietnam Journal of Science, Technology and Engineering, 84, (2011), pp. 80–84.
TCVN 9595-3:2013. Uncertainty of measurement Part 3: Guide to the expression of uncertainty in measurement (GUM:1995).
AHRI Standard 550/590. Standard for performance rating of water-chilling and heat pump water-heating packages using the vapor compression cycle, (2015).