High resolution time-series modeling of domestic hot water heating systems




Li, Bo

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This thesis evaluates domestic water heating systems in conjunction with energy saving technologies such as solar water heating, drain water heat recovery, and heat pump water heating. Five dynamic models are developed using Matlab Simulink® with a time-step of one minute. Using minute resolution hot water flow, hourly solar radiation data and ambient temperature, the performance of various configurations are assessed when operating in Victoria, Kamloops, and Williams Lake, B.C. Twelve different demand profiles on a summer day and winter day are simulated. Some specific metrics, such as conventional energy consumption, system energy factor, and equivalent CO2 emissions are used as the basis of evaluating the system efficiency. Results indicate the potential improvements in system performance over a conventional domestic water heating system in lower conventional energy consumption and lower CO2 emissions when applying any one of the three energy saving technologies mentioned above. For example, on a representative summer day (Day 228) in Victoria with a load profile of a low-use two-person family on a weekday, the system‟s energy factor can be improved from 0.50 to up to 2.84, and the corresponding conventional energy consumption and the CO2 emissions decrease from 9.86 kwh to 1.67 kwh, and 1.77 kg/day to 0.06 kg/day, respectively depending on which energy saving technology is applied. The modeling tool developed in this research can be used to guide the design of domestic water heating systems with various system configurations.



solar water heating, drain water, heat recovery, heat pump