Horsepower compressor problem

Refrigerant composition (refrigeration systems), 231-234, 241 speed-limited, 232-233 horsepower-limited, 233 accumulator relief valve, 233-234 minimum suction pressure, 234 Refrigerant condenser problems (evaporating problems), 240 Refrigeration systems, 227-241 efficiency, 227-229 diagnosing compressor problems, 229—231 refrigerant composition, 231—234 ... 

Figure 16-16 shows the performance characteristic of a split-shaft turbine where the only power output limitation is the maximum allowable temperature at the inlet of the turbine section. In actual practice a torque limit, increased exhaust temperature, loss of turbine efficiency, aud/or a lubrication problem on the driven equipment usually preclude operating at very low power turbine speeds. The useful characteristic of the split-shaft engine is its ability to supply a more or less constant horsepower output over a wide range of power turbine speeds. The air compressor essentially sets a power level and the output shaft attains a speed to pnivide the required torque balance. Compressors, pumps, and various mechanical tinvc systems make very good applications for split-shaft designs. 

Figure El 3.4b shows two different forms for the annualized capital cost of the compressors. Line A indicates the cost is a linear function of horsepower [ 70.00/(hp)(year)] with the line passing through the origin, whereas line B assumes a linear function of horsepower with a fixed initial capital outlay [ 70.00/(hp)(year) + 10,000] to take into account installation costs, foundation, and so on. For fine A, the objective function in dollars per year for the example problem is...

This formula will permit one to differentiate between compressor deficiencies and losses in refrigeration from evaporator or condenser problems. A reduction in horsepower for a steam-driven centrifugal compressor is caused by one of four factors ... 

If high exhaust steam pressure is the problem, increasing the flow of driver steam will not provide much of an increase in refrigeration compressor horsepower. 

The required engine horsepower, but not the volumetric capacity, of a two-stage reciprocating compressor is affected by the intercooler outlet temperature. As a rule of thumb, each increment of 12 F increases the engine horsepower load by 1%. Frequently, all that is needed to minimize this problem is an occasional external water wash of the intercooler aerial fin-tube cooler. 

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