摘要:
A method of optimizing the design of a chiller involves placing more emphasis on the chiller's performance at part load than at full load and rating the chiller accordingly. In some embodiments, compressor speed and impeller diameter are chosen to optimize the chiller's performance at part load. With the chosen impeller diameter, operation at full load is then achieved by increasing compressor speed, opening inlet guide vanes, and perhaps sacrificing some efficiency. If necessary, an inverter over speeds the compressor by driving it at a speed beyond that which the compressor would normally run if it were driven at the nominal line frequency of the electrical power feeding the inverter.
摘要:
An adaptive control apparatus and a method for automatically controlling a refrigeration system as a function of cooling load and head. A control panel controls the operation of a hot gas bypass valve so as to avoid surging of the compressor in response to cooling load and head. The control apparatus and method also allow for automatic self calibration.
摘要:
A compressor for use in a refrigerator, which has a rotary shaft supported by bearings to be lubricated by a liquid refrigerant and is adapted to permit the rotary shaft to continue rotating for a while after a liquid refrigerant pump is stopped at, for example, a power failure, thereby preventing the bearings from being damaged. To that end the compressor has a reservoir liquid tank for storing high pressure liquid refrigerant to be supplied to the bearing and a gas storage tank for storing high pressure gas. There is a valve system connected between the gas storage tank and the reservoir liquid tank which is operable upon a power failure to supply high pressure gas to the liquid storage tank.
摘要:
A centrifugal type refrigerant compressor comprises at least one impeller (17, 18), electric motor (27) and drive shaft (22) mounted on non-lubricated radial bearings, such as magnetic or foil gas bearings (23, 24), with axial locating means (26) associated with the shaft (22) to restrict axial movement thereof with respect to the compressor housing (12). The housing (12) encases the motor (27) and the compressor and defines the gas inlet (31) and the gas outlet (16) passageways. Gas throttling means (34) is provided in the inlet (31), and a control means (30) varies the speed of the motor (27) and the throttling means (34) to control the compression ratio and mass flow through the compressor in accordance with the refrigeration load.
摘要:
A single motor drives both oil and refrigerant pumps in a refrigeration chiller, the motor and oil pump being disposed in the chiller's oil supply tank and the refrigerant pump being disposed exterior thereof. The refrigerant pump pumps liquid refrigerant to the chiller's compressor section so as to cool the motor by which the compressor is driven while the oil pump pumps oil to chiller locations that require lubrication when the chiller is in operation.
摘要:
A closed loop vapor cycle refrigeration system an expander-compressor is disclosed. A portion of the liquid refrigerant in the system is expanded into gas. This gas is used to operate a compressor. The compressor compresses the low pressure gas from the evaporator and discharges the compressed gas either to a primary compressor or the condenser. A novel expander-compressor device is also disclosed for use in the refrigeration system.
摘要:
In a motor driven centrifugal compressor having a diffuser containing a movable wall for varying the width of the diffuser passage, control equipment is provided for continually changing the wall position in response to changes in motor current.
摘要:
A surge detection apparatus for use in a refrigeration system having a centrifugal compressor driven by an electric motor includes a first pressure transducer for sensing a condenser pressure and a second pressure transducer for sensing an evaporator pressure. A first bandpass digital filter responsive to the condenser pressure and the evaporator pressure is provided for generating a first signal representative of the rate of change of the pressure developed across the compressor. A current transformer is used to sense a current in the electric motor driving the compressor. A second bandpass digital filter responsive to the motor current is provided for generating a second signal representative of the rate of change of the RMS current being drawn by the compressor drive motor. A third signal representative of a differential pressure threshold and a fourth signal representative of a first motor current threshold and a second motor current threshold are provided. A computing device responsive to the first through fourth signals indicates when a valid surge is occurring in the compressor.
摘要:
In a turbo-refrigerator apparatus provided with a compressor in the form of a turbocompressor, a speed increasing gear system capable of switching from one speed increase ratio to another at least in two stages is located between the turbocompressor and an electric motor, so that a speed increase ratio suitable for the conditions of outdoor air can be selected to operate the apparatus with high efficiency. Housings of the turbocompressor, electric motor and speed increasing gear system are connected together in such a manner that a shaft supporting an impeller of the turbocompressor, an output shaft of the electric motor and shafts of the speed increasing gear system are located within the respective housings to render the apparatus hermetic to avoid extension of the rotary shafts through the housings, thereby avoiding leak of the working fluid of the turborefrigerator apparatus to outside.
摘要:
A method and apparatus to prevent oil pump cavitation in a hermetically sealed vapor compression refrigeration system are disclosed. A hermetically sealed housing containing the refrigeration compressor transmission and oil supply reservoir is connected to the suction side of the compressor to equalize the pressure in the housing and the suction to the compressor is constructed with a restriction such as an orifice or a venturi to create a pressure drop or is of a size small enough to create a pressure drop when refrigerant flows through the line. The pressure drop is sensed by a pressure differential switch to anticipate sharp drops in pressure in the housing. The flow of refrigerant to the compressor is throttled in response to predetermined pressure drops to prevent a sharp drop in pressure within the transmission housing and thus prevent vigorous boiling of refrigerant from the oil reservoir. Prevention of vigorous boiling of the refrigerant from the oil prevents oil pump cavitation and loss of oil to the transmission and bearings of the compressor.