Economic, prime movers

A more economical alternative is found in a submersible pump where the pump, directly coupled with the prime mover, is slid into the tubewell through narrow pipes. Narrow pipes are easy to sink into rocky terrain or very deep water levels. They are less expensive and are easy to install due to the elimination of the need for a pump house. Once the unit is slid into the well it requires little maintenance. (See Figures 7.5-7.7.) Such pumps have a standard centrifugal multistage arrangement, and the motors are required to work under water or any other liquid. These motors have an exclusive application for submersible pumps. 

A friction loss of 37.125 m In a total length of 1000 m is quite high and will require a larger motor. Therefore, a 150 mm main pipeline will offer a better and more economical design compared to a 125 mm pipeline such as the reduced cost of the prime mover and lower power consumption during the life of pumping system, in addition to a longer life span of a 150 mm pipe compared to a 125 mm pipe. 

Gas turbines are used as prime movers for pumps, electric generators, and large rotating machinery. Their main economic advantage is driving... 

The preceding section reviewed the application of popular prime movers for the generation of electrical power only. In the conversion of fuel energy to electricity it is shown that heat is rejected, either in the exhaust of a diesel or gas turbine or, alternatively, in the condenser of a thermal power plant. It can be seen that by applying these machines to provide both heat and electricity the total energy recovery can be much greater and efficiency thereby improved. Combined heat and power (CHP) schemes of this nature are well-established methods of producing both heat and power efficiently and economically. 

The increment size of the prime mover, starting loads, and sales value of fuel gas must be taken into consideration. Space/weight consideration determines whether individual gas-turbine drivers or a central power-generation station will be more economical. 

Speed Reducer. Economically, it is normally better to use a small, high-speed prime mover and gear-reducer combination than a larger, low-speed power source. 

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