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AssigneeBorg-Warner Corporation
InventorsKenneth J. Kountz, Richard A. Erth, Dean K. Norbeck
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The control system disclosed herein regulates a centrifugal compressor which has inlet guide vanes adjustable to vary the compressor capacity. A variable speed motor is connected to drive the compressor, and variation of this motor speed provides another input for regulating the compressor capacity. A control system achieves optimum energy efficiency, while avoiding surge, by the manner in which the motor speed and the inlet guide vane positions are regulated. To do this, a control signal must be derived to indicate the compressor head value. This signal is achieved by providing two signals, one related to the absolute condenser pressure, and the second related to the absolute evaporator pressure. The control system operates on these two signals to provide a third signal which is a function of a ratio, in which the numerator is the difference between the condenser and evaporator pressures, and the denominator is the evaporator pressure. Alternative measurement and processing techniques are described. This signal affords a very good indication of the compressor head and thus achieves increased efficiency of system operation, with consequent energy conservation, especially at lighter loads and low heads.
A control system for a refrigeration system including a compressor, a condenser and an evaporator, all connected in a closed refrigeration circuit, which compressor includes an adjustable capacity control means, means for regulating the adjustable capacity control means, an electrical prime mover connected to drive the compressor, and means for regulating the speed of the prime mover, which control system includes means for sensing the absolute condenser pressure and the absolute evaporator pressure and for regulating the adjustable capacity control means and the electrical prime mover in an energy-conservation manner while avoiding compressor surge in accordance with a control signal varying as a function of the expression (Pcd-Pev/Pev), where Pcd is the absolute condenser pressure and Pev is the absolute evaporator pressure.
A control system for a refrigeration system including a compressor, a condenser and an evaporator, all connected in a closed refrigeration circuit, which compressor includes an adjustable capacity control means, means for regulating the adjustable capacity control means, an electrical prime mover connected to drive the compressor, and means for regulating the speed of the prime mover, which control system comprises:
The method of controlling a refrigeration system having a compressor, a condenser, and an evaporator, all connected in a closed refrigeration circuit, which compressor includes adjustable inlet guide vanes to vary the compressor capacity, and an electrical adjustable speed motor connected to drive the compressor, such that motor speed adjustment also varies the capacity, comprising the steps of:
The method of controlling a refrigeration system having a compressor, a condenser, and an evaporator, all connected in a closed refrigeration circuit, which compressor includes adjustable inlet guide vanes to vary the compressor capacity, and an electrical adjustable speed motor connected to drive the compressor, such that motor speed adjustment also varies the capacity, comprising the steps of:
Dependencies are inferred from the claim text.