To predict the long-term performance of solar domestic hot water (SDHW) systems requires computational models that can characterize the systems under a range of operating conditions. The development of detailed fundamental models that suitably describe the operation of systems with natural convection heat exchangers is, however, difficult and time consuming. The fact that the natural convection flow through the heat exchanger is intrinsically self-controlling and temperature dependent complicates the analysis. One approach to modeling this type of system is to use performance characteristics, empirically derived from experimental data, to predict the performance of the heat exchanger under typical operating conditions. Unfortunately, a significant number of tests may be required to characterize the full operation of the device. This paper presents a simplified test method that was developed to allow pre-configured SDHW systems that use natural convection heat exchangers, to be characterized. The results of this test method produce performance coefficients for simple empirical expressions that describe the fluid flow and heat transfer in the heat-exchange loop. These empirically derived coefficients are an input to a general simulation routine that allows overall system performance to be determined for various loads and climatic conditions. In this paper, data is presented for a typical heat exchanger under a range of operational conditions. Copyright

Solar 2006: Renewable Energy - Key to Climate Recovery, Including 35th ASES Annual Conference, 31st ASES National Passive Solar Conference, 1st ASES Policy and Marketing Conference and ASME Solar Energy Division International Solar Energy Conference
Department of Mechanical and Aerospace Engineering

Cruickshank, C, & Harrison, S.J. (Stephen J.). (2006). Experimental characterization of a natural convection heat exchanger for solar domestic hot water systems. In American Solar Energy Society - Solar 2006: 35th ASES Annual Conf., 31st ASES National Passive Solar Conf., 1st ASES Policy and Marketing Conf., ASME Solar Energy Division Int. Solar Energy Conference (pp. 1327–1333).