Using statistical tests to compare the coefficient of performance of air source heat pump water heaters
DOI:
https://doi.org/10.17159/2413-3051/2022/v33i1a7943Keywords:
Air source heat pump (ASHP) water heater, Coefficient of performance (COP), p-value, Significance level, one-way ANOVA test and Kruskal-Wallis testAbstract
The study compared the coefficient of performance (COP) of two residential types of air source heat pump (ASHP) water heaters using statistical tests. The COPs were determined from the controlled volume of hot water (150, 50 and 100 L) drawn off from each tank at different time of use (morning, afternoon and evening) periods during summer and winter. Power meters, flow meters, and temperature sensors were installed on both types of ASHP water heater to measure the data needed to determine the COPs. The results showed that the mean COPs of the split and integrated type ASHP water heaters were 2.965 and 2.652 for summer and 2.657 and 2.202 for winter. In addition, the p-values of the groups COPs for the split and integrated type ASHP water heaters during winter and summer were 7.09 x 10-24 and 1.01 x 10-11, based on the one-way ANOVA and the Kruskal-Wallis tests. It can be concluded that, despite the year-round performance of both the split and integrated type ASHP water heaters, there is a significant difference in COP at 1% significance level among the four groups. Furthermore, both statistical tests confirmed these outcomes in the comparisons of the mean COPs among the four groups based on the multiple comparison algorithm.
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References
Breiman, L., Friedman, J.H., Olshen, R.A. and Stone, C.J., 2017. Classification and regression trees. Routledge. DOI: https://doi.org/10.1201/9781315139470
Collins, L.M., Schafer, J.L. and Kam, C.M., 2001. A comparison of inclusive and restrictive strategies in modern miss-ing data procedures. Psychological Methods, 6(4): 330. DOI: https://doi.org/10.1037/1082-989X.6.4.330
Gang, P., Guiqiang, L. and Jie, J., 2011. Comparative study of air-source heat pump water heater systems using the instantaneous heating and cyclic heating modes. Applied Thermal Engineering, 31(2-3): 342-347. DOI: https://doi.org/10.1016/j.applthermaleng.2010.09.020
Guo, J.J., Wu, J.Y., Wang, R.Z. and Li, S., 2011. Experimental research and operation optimization of an air-source heat pump water heater. Applied Energy, 88(11): 4128-4138. DOI: https://doi.org/10.1016/j.apenergy.2011.04.012
Harvey, L.D., 2012. A handbook on low-energy buildings and district-energy systems: Fundamentals, techniques and examples. Routledge. DOI: https://doi.org/10.4324/9781849770293
Hepbasli, A. and Kalinci, Y., 2009. A review of heat pump water heating systems. Renewable and Sustainable Energy Reviews, 13(6-7): 1211-1229. DOI: https://doi.org/10.1016/j.rser.2008.08.002
Huberty, C.J. and Morris, J.D., 1992. Multivariate analysis versus multiple univariate analyses. In Kazdinm A.E. (Ed.), Methodological Issues and Strategies in Clinical Research: 351–365. American Psychological Association. https://doi.org/10.1037/10109-030 DOI: https://doi.org/10.1037/10109-030
Ibrahim, O., Fardoun, F., Younes, R. and Louahlia-Gualous, H., 2014. Review of water-heating systems: General selec-tion approach based on energy and environmental aspects. Building and Environment, 72: 259-286. DOI: https://doi.org/10.1016/j.buildenv.2013.09.006
Jaglin, S. and Dubresson, A., 2016. Eskom: Electricity and technopolitics in South Africa. Juta.
Johnson, R.A. and Wichern, D.W., 2014. Applied multivariate statistical analysis (Vol. 6). London, UK: Pearson.
Kivevele, T. and Huan, Z., 2014. A review on opportunities for the development of heat pump drying systems in South Africa. South African Journal of Science, 110(5-6): 01-11. DOI: https://doi.org/10.1590/sajs.2014/20130236
Kulinskaya, E., Staudte, R.G. and Gao, H., 2003. Power approximations in testing for unequal means in a one-way ANOVA weighted for unequal variances. Communications in Statistics-Theory and Methods, 32(12): 2353-2371. DOI: https://doi.org/10.1081/STA-120025383
Laird, N.M. and Mosteller, F., 1990. Some statistical methods for combining experimental results. International Jour-nal of Technology Assessment in Health Care, 6(1): 5-30. DOI: https://doi.org/10.1017/S0266462300008916
Morrison, G.L., Anderson, T. and Behnia, M., 2004. Seasonal performance rating of heat pump water heaters. Solar Energy, 76(1-3): 147-152. DOI: https://doi.org/10.1016/j.solener.2003.08.007
Ozgener, O. and Hepbasli, A., 2005. Experimental performance analysis of a solar assisted ground-source heat pump greenhouse heating system. Energy and Buildings, 37(1): 101-110. DOI: https://doi.org/10.1016/j.enbuild.2004.06.003
Tangwe, S., Simon, M. and Meyer, E., 2014. Mathematical modeling and simulation application to visualize the per-formance of retrofit heat pump water heater under first hour heating rating. Renewable Energy, 72: 203-211. DOI: https://doi.org/10.1016/j.renene.2014.07.011
Tangwe, S.L., 2018. Demonstration of residential air source heat pump water heaters performance in South Africa: Systems monitoring and modelling. Doctoral dissertation, University of Sunderland.
Tangwe, S.L. and Simon, M., 2019. Quantification of the viability of residential air source heat pump water heaters as potential replacement for geysers in South Africa. Journal of Engineering, Design and Technology, 17(2): 456-470. DOI: https://doi.org/10.1108/JEDT-05-2017-0042
Theodorsson-Norheim, E., 1986. Kruskal-Wallis test: BASIC computer program to perform nonparametric one-way analysis of variance and multiple comparisons on ranks of several independent samples. Computer Methods and Programs in Biomedicine, 23(1): 57-62. DOI: https://doi.org/10.1016/0169-2607(86)90081-7
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