| 摘要 |
There is herein described a peak-power reducing domestic hot water heater comprising: a closed tank having a predetermined water holding capacity, a hot water outlet in a top end wall of said tank, a cold water inlet in a side wall of said tank adjacent a bottom wall thereof, three spaced apart resistive heating elements projecting substantially horizontally in said tank, each of said resistive heating elements having a temperature sensing element to enable a control of their respective activation; a bottom one of said resistive heating elements extending in said tank spaced slightly above said bottom wall and having a lowest power rating, said bottom resistive heating element being turned on when water is flowing into said cold water inlet and drawn out of said hot water outlet during a peak-power demand time period; a middle one of said resistive heating elements extending in said tank at a level which is calculated to be equal or above an average maximum daily water consumption volume drawn out during the peak power demand time periods; and a top one of said resistive heating elements extending between said middle element and said top end wall of said tank and having a highest power rating; said middle and said bottom resistive heating elements being activated simultaneously only when said top resistive heating element is inactive.
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