Compressors power requirements

While theoretical compressor power requirements are reduced slightly by going to lower evaporating temperatures, the volume of vapor to be compressed and hence compressor size and cost increase so rapidly that low-temperature operation is more expensive than high-temperature operation. The requirement of low temperature for fruit-juice concentration has led to the development of an evaporator... 

The compressor train is driven by the motor/generator, which has a pair of clutches that enable it to act as a motor when the compressed air is being generated for storage in the cavern, declutches it from the expander train, and connects it to the compressor train. The compressor train consists of a three-section compressor each section having an intercooler to cool the compressed air before it enters the other section, thus reducing the overall compressor power requirements. 

Gas temperature is an important quantity when designing gas transmission lines, since pipelines are designed for large flows and their consequent higher compressor requirements. The compressor power required at each station depends to a great extent on the gas temperature. Rowing gas temperature must be controlled to a... 

In summary, increasing the number of beds in series for the system shown in Figure 12 decreases the volume of recycle somewhat more than proportionately to the number of beds, decreases the recycle compressor power requirements somewhat, and has no effect on the catalyst volume. On balance, it would appear that the capital savings achieved by increasing the number of beds will be minimal. 

Natural gas (methane) is transported through an uninsulated 6 in. ID commercial steel pipeline, 1 mi long. The inlet pressure is 100 psi and the outlet pressure is 1 atm. What are the mass flow rate of the gas and the compressor power required to pump it T) = 70°F, /rgas = 0.02 cP. 

An engine operates on the closed Brayton cycle (Fig 4.8) and has a compression ratio of 8. Helium enters the engine at 47°C and 200 kPa. The mass flow rate of helium is 1.2 kg/sec and the amount of heat addition is 1 MJ/kg. Determine the highest temperature of the cycle, the turbine power produced, the compressor power required, the back-work ratio, the rate of heat added, and the cycle efficiency. 

Determine temperature of all states of the cycle, compressor power required, power produced by turbine 1, power produced by turbine 2, and cycle efficiency. 

Determine the power required by the compressor, power required by pumps 1 and 2, power produced by turbines 1, 2, and 3, rate of heat added by the nuclear reactor, net power produced by the Brayton gas turbine plant, net power produced by the Rankine plant, rate of heat removed by coolers 1 and 2, rate of heat exchanged in the heat exchanger, rate of heat added in the gas burner, mass rate flow of helium in the Brayton cycle, mass rate flow of steam extracted to the feed-water heater (mixing chamber), cycle efficiency of the Brayton plant, cycle efficiency of the Rankine plant, and cycle efficiency of the combined Brayton-Rankine plant. 

Determine the COP, horsepower required, and cooling load of a Carnot vapor refrigeration cycle using R-12 as the working fluid and in which the condenser temperature is 100°F and the evaporation temperature is 20°F. The circulation rate of fluid is O.llbm/sec. Determine the compressor power required, turbine power produced, net power required, cooling load, quality at the inlet of the evaporator, quality at the inlet of the compressor, and COP of the refrigerator. 

A steady-flow ideal 0.4 ton refrigerator uses refrigerant R-134a as the working fluid. The evaporator pressure is 120 kPa. The condenser pressure is 600 kPa. Determine (a) the mass rate flow, (b) the compressor power required, (c) the rate of heat absorbed... 

Find the compressor power required, cooling load, and COP for a refrigerator that uses R-12 as the working fluid and is designed to operate at an evaporator temperature of 5°C and a condenser temperature of 30°C. The mass flow rate of R-12 is 0.22kg/sec. 

Consider an ideal heat pump which uses R-12 as the working fluid. The saturation temperature of the refrigerant in the evaporator is 6°C and in the condenser it is 58°C. The refrigerant is circulated at the rate of 0.021 kg/sec. Determine the compressor power required, quality of the refrigerant at the end of the throttling process, heating load, and COP of the heat pump. 

In the air-conditioning mode, a domestic air-conditioning and heat-pump system as shown in Fig. 6.22 uses R-134a as the refrigerant. The refrigerant-saturated vapor is compressed from 140 to 700 kPa. Summer ambient air at 30°C is to be cooled down to 17°C. Find the compressor power required, heat removed from the ambient air in the heat exchanger, COP of the system, and mass rate of air flow per unit of mass rate of refrigerant flow. 

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