中文摘要：

对电热水器2种出水方式的热过程进行解析，导出在有无加热条件下壳体内水温随出流时间的变化关系。在此基础上，提出壳体内水温降至某一值时的出水时间与出水量的预测模型，并通过实测值与计算值对比，验证预测模型的有效性。讨论水容积、加热功率和气温对单人淋浴使用热水器选择的影响，以及气温对不同容量热水器加热设置温度的影响。结果表明：热水器选择宜以当地最低气温、最高设置温度及一次性用水量来确定；对于单人淋浴使用的热水器，为满足一次性加热和用水要求，冬季气温较高和较低的地区宜分别选择较小和较大容量热水器；为了实现节能，热水器在加热过程中设置的温度应根据外气温进行调整。

英文摘要：

Through the analysis of thermal process of electric water heater in two water draining modes,the relationships between water temperature and water draining time are derived under heating and no-heating con-dition,the prediction models of water draining time and volume are put forward when the water temperature falls to certain value,and by comparing the measured values and calculated values,the validity of these predic-tion models is also verified.As the example of the prediction model application,the effects of water capacity, heating power and ambient temperature on the selection of water heater for single person shower are discussed, and the effect of ambient temperature on the set temperature for heating is also discussed for different capacity water heater.It shows that：the selection of water heater should be determined by the local lowest air tempera-ture,the highest set temperature and one time used water volume;for the water heater of one person showe-ring,in order to meet the requirement of one time heating,small water capacity should be chosen for high air temperature in winter,and vice-versa in order to achieve the energy saving,the set temperature should be ad-justed according to the outside air temperature during the heating process of water heater.