30-01-2015, 06:40 PM
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رد: دفاية,سخان متميزين !!!HHOHHU
Also there is CHP, or combined heat and power. The energy efficiency of most thermal power stations is around 30-45%, with the remaining 70-55% of energy simply thrown away as “waste” hot water or saturated steam (info on that and CHP here and here). CHP proposes to use this heat for some useful purpose, such as running some thermal industrial process, or pumping the hot water into a district heating system. Many EU countries already utilize CHP heavily so its proven technology, and the choice of fuels is more varied (from biomass to refuse as well as the more traditional coal and natural gas). Using CHP we can raise the effective efficiency of power generation from its present level (33-45%), to between 60-80%. At present CHP probably represents the easiest and most effective way of reducing carbon emissions, and reducing fossil fuel consumption. Using so-called Tri-Generation (paper on this topic here) it can also be used in conjunction with a heat pump to provide a large cooling load in summer.
Figure 4.9 – High efficiency micro CHP units such as this can be run of off a variety of different fuels, save energy, reduce carbon emissions and serve to diversify electricity generation helping to supplement more intermittent renewable resources [Credit: Lowenergyhouse.com]
However, the CHP plant must be located close to the source of heat demand and most power stations are built some distance away from most cities. Fortunately CHP plant can be sized from multi giga-watt power stations right down to the scale of units to fit a small flat (so called Micro-CHP).
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