| 摘要 |
In most homes today, when a person turns on a hot water faucet, he or she must wait for residual cold water to flow out of the hot water pipe as hot water travels from the water heater to the faucet. That residual cold water typically goes down the drain. In some buildings, recirculating hot water systems keep hot water flowing in a loop, thereby making hot water immediately available and eliminating the waste of residual hot water, but these systems waste energy from thermal radiation in the hot water pipes at times when no hot water is being utilized. The invention conserves both water and energy by controlling the recirculation of residual cold water by means of momentary activation of any hot water faucet, and also by programmed time-of-day intervals, whereupon the pump replaces the residual cold water with hot water and recirculates the residual cold water, and then turns off so as to avoid energy waste from running hot water through the loop at times it is not needed. The invention provides for fast installation of the pump, detector, and controller on the hot water outlet side of the water heater. It can be used in buildings that have separate hot water return pipes, and it can also be used in configurations where existing cold water pipes are used for the return of hot water.
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