Electrical efficiency, percent

The most popiilar form of motor speed control for adjustable-speed pumping is the voltage-controlled pulse-width-modulated (PWM) frequency synthesizer and AC squirrel-cage induction motor combination. The flexibility of apphcation of the PWM motor drive and its 90 percent- - electric efficiency along with the proven ruggedness of the traditional AC induction motor makes this combination popular. 

The pressurized hybrid cycle provides the basis for the high electric efficiency power system. Applying conventional gas turbine technology, power system efficiencies in the 55 to 60 percent range can be achieved. When the pressurized hybrid system is based on a more complex turbine cycle— such as one that is intercooled, reheated, and recuperated—electric efficiencies of 70 percent or higher are projected. 

Liquid displacement, cu ft/min Theoretical displacement, cu ft/min Electrical horsepower Efficiency, percent... 

Lithium deposited on an anode during a charge is chemically active and reacts with organic electrolytes after deposition. Then, the lithium is consumed during cycling. The cycling efficiency (percent) of a lithium anode (Eff) is basically defined by Eq. (1) [23], where Qp is the amount of electricity needed to plate lithium and <2S is the amount of electricity needed to strip all the plated lithium. As Eff is less than 100 percent, an excess of lithium is included in a practical rechargeable cell to compensate for the consumed lithium. 

D" = Theoretical displacement volume displaced per revolution (s) of driving rotors, cu in./rev d = Impeller diameter, in. dp = Diameter of piston or plunger, in. d, = Diameter of piston rod, in. d = Liquid displacement, cu ft/min d" = Theoretical displacement, cu ft/min eHP = Electrical horsepower E = Efficiency, percent... 

Second, molten carbonate fuel cells have electric efficiencies of 47 to 50 percent or more, which significantly reduces their fuel costs for stationary applications compared with both phosphoric acid and pem fuel cells, whose overall efficiency when running on natural gas might not exceed 35 to 40 percent. Third, high temperatures allow relatively inexpensive nickel to be used as a catalyst rather than pricey platinum, which is required by the lower-temperature fuel cells. Fourth, these fuel cells are far more tolerant of carbon monoxide, which can poison the electrochemical reaction of pem... 

These words are worth bearing in mind throughout this book. We have very little experience with commercial fuel cells, and the only one we do have experience with provides a cautionary tale. In the mid-1990s, the manufacturer of the PC25 promised an electric efficiency of 40 percent, sold the system for 3,ooo/kW (probably at a loss), and projected a price of i,5oo/kW by 2000 as a result of further system optimization and manufacturing economies of scale.10 By 2002, the system efficiency, as measured in more than a... 

High-temperature fuel cells, on the other hand, can offer substantial co2 savings. With electric efficiencies of 50 percent and high-quality heat, molten carbonate fuel cells and sofcs hold the prospect of cutting co2 emissions in factories and buildings by one-third or more. Should hybrid fuel cell and gas turbine systems become economical, they could potentially reduce by half or more the co2 emissions of the systems they replace. 

Fuel Cell Technologies (with Siemens Canada 5kW 2002 5 kW prototype SOFC under test, 40 percent electrical efficiency. Several Field trails... 

Exampie A.3.1 The pressures for three steam mains have been set to the conditions given in Table A.l. Medium- and low-pressure steam are generated by expanding high-pressure steam through a steam turbine with an isentropic efficiency of 80 percent. The cost of fuel is 4.00 GJ and the cost of electricity is 0.07 h. Boiler feedwater is available at 100°C with a heat capacity... 

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