Preliminary Modeling, Testing, and Analysis of a Gas Tankless Water Heater. Preprint.

Burch, J. ; Thornton, J. ; Hoeschele, M. ; Springer, D. ; Rudd, A.

Technical Information Center Oak Ridge Tennessee

关键词: Solar energy;    Water heaters;    Simulation;    Burners;    Oscillations;   

RP-ID  :  DE2008932897

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

Today's gas tankless water heaters offer significant energy savings over conventional gas storage tank water heaters, but savings depends on the draw pattern. A one-node model incorporating heat exchanger mass is used to address this and other issues. Key model parameters are determined from least-squares regression on short-term data, including burner efficiency, thermal capacitance, and thermal loss coefficient. The calibrated model agrees with data to approximately 5% on Qgas, with temperature RMS deviation of approximately 4 degrees C. Efficiency with a standard realistic draw is 71%, compared to 81% predicted from standard energy-factors. Adding a small tank controlled by the tankless heater solves issues of oscillations with solar pre-heat, low-flow and hot-water-delay issues. Future work includes model refinements and developing optimal data protocols for model parameter extraction.