| 摘要 |
<p>An improvement is provided in a system comprising (i) a source of fresh hot water, (ii) a source of waste hot water fed from the fresh hot water, and (iii) a drain for discharging the waste hot water. The improvement comprises a hot water heat recovery system interposed between the source of waste hot water and the drain, comprising: (a) a water/water heat exchanger; (b) conduit means automatically controllably continuously and selectively passing the waste hot water to the heat exchanger before the waste hot water passes to the drain; (c) conduit means automatically controllably continuously selectively passing the cool fresh water to the heat exchanger to be preheated and pipe means connecting to said heat exchanger to said shource of fresh hot water and for continuously withdrawing the preheated water from the heat exchanger, and contuit means automatically controllably, continuously and selectively simultaneously passing the waste hot water to the heat exchanger in heat exchange contact only with the cool fresh water; and (d) temperature control means associated with the conduit means to shunt the waste hot water from the heat exchanger to the drain and simultaneously to shunt the flow of cool fresh water from the heat exchanger when the water temperature drops below a selected value. By these means, the waste heat in hot water is recovered and is used to preheat incoming cool water before it proceeds to the hot water heater and the waste hot water does not enter the heat exchanger unless it is hot enough. Thus plugging of the heat exchanger by sedimentation and precipitation of solids out of cooler water is minimized.</p> |
