Abstract: In a natural gas liquefaction system having a refrigerant storage circuit, a refrigerant circulation circuit in fluid communication with the refrigerant storage circuit, and a natural gas liquefaction circuit in thermal communication with the refrigerant circulation circuit, a method for liquefaction of natural gas in which pressure in the refrigerant circulation circuit is adjusted to below about 175 psig by exchange of refrigerant with the refrigerant storage circuit. A variable speed motor is started whereby operation of a compressor is initiated. The compressor is operated at full discharge capacity. Operation of an expansion valve is initiated whereby suction pressure at the suction pressure port of the compressor is maintained below about 30 psig and discharge pressure at the discharge pressure port of the compressor is maintained below about 350 psig.

Abstract: A method and apparatus for dispensing compressed natural gas and for maximizing the mass of compressed gas dispensed into a gas storage cylinder is disclosed. Pressure and temperature transducers are provided as a part of the apparatus to emit data signals to a control processor of the pressure and temperature of a supply of compressed gas delivered to a gas dispenser, as well as the ambient temperature at the dispenser and the pressure of the compressed gas within the cylinder, respectively. A mass flow meter is also provided for emitting a data signal to the control processor of the mass of compressed gas injected into the storage cylinder.

Abstract: A method and apparatus for dispensing compressed natural gas and for maximizing the mass of compressed gas dispensed into a gas storage cylinder is disclosed. Pressure and temperature transducers are provided as a part of the apparatus to emit data signals to a control processor of the pressure and temperature of a supply of compressed gas delivered to a gas dispenser, as well as the ambient temperature at the dispenser and the pressure of the compressed gas within the cylinder, respectively. A mass flow meter is also provided for emitting a data signal to the control processor of the mass of compressed gas injected into the storage cylinder.

Abstract: A method and apparatus for dispensing natural gas into the natural gas vehicle cylinder of a motor vehicle is disclosed. The natural gas dispensing system includes a pressure transducer and a temperature transducer for measuring the pressure and temperature, respectively, of the supply gas as it is passed toward a dispenser, a second pressure transducer for measuring the pressure within the natural gas vehicle cylinder, an ambient air temperature transducer for measuring ambient air temperatures at the dispensing site, and a mass flow meter for measuring the gas mass injected into the vehicle cylinder. Each transducer and the mass flow meter emits a data signal to a control processor which automatically dispenses compressed gas to the vehicle cylinder, as well as maximizing the amount of gas mass injected into the cylinder.

Abstract: A method and apparatus for dispensing natural gas into the natural gas vehicle cylinder of a motor vehicle is disclosed. The natural gas dispensing system includes a pressure transducer and a temperature transducer for measuring the pressure and temperature, respectively, of the supply gas as it is passed toward a dispenser, a second pressure transducer for measuring the pressure within the natural gas vehicle cylinder, an ambient air temperature transducer for measuring ambient air temperatures at the dispensing site, and a mass flow meter for measuring the gas mass injected into the vehicle cylinder. Each transducer and the mass flow meter emits a data signal to a control processor which automatically dispenses compressed gas to the vehicle cylinder, as well as maximizing the amount of gas mass injected into the cylinder.

Abstract: A method and apparatus for dispensing natural gas into the natural gas vehicle cylinder of a motor vehicle is disclosed. The natural gas dispensing system includes a pressure transducer and a temperature transducer for measuring the pressure and temperature, respectively, of the supply gas as it is passed toward a dispenser, a second pressure transducer for measuring the pressure within the natural gas vehicle cylinder, an ambient air temperature transducer for measuring ambient air temperatures at the dispensing site, and a mass flow meter for measuring the gas mass injected into the vehicle cylinder. Each transducer and the mass flow meter emits a data signal to a control processor which automatically dispenses compressed gas to the vehicle cylinder, as well as maximizing the amount of gas mass injected into the cylinder.

Abstract: A method and system for charging a container with a pressurized gaseous fuel. The gaseous fuel is transferred from a gas supply through a heat exchanger to a fueling dispenser. The gaseous fuel is cooled as a function of one or both of a fueling station pressure availability or a container pressure rating. This method and system ensure that a pressurized gas cylinder can be completely charged regardless of the ambient temperature.

Abstract: An apparatus and system for the fast-filling of cylinders for natural gas powered vehicles, employing a simplified physical arrangement and an improved control method to obtain maximum safe filling of the cylinders, which takes into account the presence of residual gas in the cylinders.

Abstract: An apparatus and method for the fast-filling of cylinders for natural gas powered vehicles, employing a simplified physical arrangement and an improved control method to obtain maximum safe filling of the cylinders, which takes into account the presence of residual gas in the cylinders.

Abstract: A heat pump system using a non-azeotropic refrigerant mixture comprising a main refrigeration circuit, an engine coolant circuit, and a refrigerant rectifier circuit interfacing with main refrigeration circuit, and the engine coolant circuit. The refrigerant rectifier circuit comprises in order of decreasing relative elevation a condenser, a storage vessel in communication with a condenser, a rectifier in communication with a storage tank and a condenser, a receiver vessel in communication with a rectifier, and a boiler in communication with the rectifier and the receiver vessel. The refrigerant rectifier circuit is used to adjust the relative concentrations of lower boiling point refrigerant, and higher boiling point refrigerant in the non-azeotropic refrigerant mixture thereby changing the cooling or heating capacity of the heat pump system.

Abstract: A heat exchange system for a heat pump in which the cooled fluid and the cooling fluid are maintained in a counterflow heat exchange relationship in a heat exchanger in both the heating and cooling modes of operation of the heat pump. The heat exchange system comprises a refrigeration coil, a liquid distributor, a vapor distributor, an outlet manifold, expansion means, vapor refrigerant/inlet distributor valve means, vapor refrigerant/outlet manifold valve means, liquid refrigerant/inlet distributor valve means and liquid refrigerant/outlet manifold valve means.

Abstract: A self-optimizing, capacity control system for a refrigeration system including a compressor, a condenser, and an evaporator, all connected in a closed refrigeration circuit is provided. The compressor includes a plurality of adjustable inlet guide vanes, a motor connected to regulate the inlet guide vanes position and an electrical speed motor connected to drive the compressor. The self-optimizing capacity control system includes a microprocessor responsive to continual measurements of a PRV signal, a compressor head signal, a motor current signal and a motor speed signal for determining both the compressor speed and the position of the inlet guide vanes to define a current operating point in an initial surge surface array stored in a random-access memory. The microprocessor will initiate a "learning" mode in which the compressor motor speed will continually be decreased incrementally and the PRV will be moved to a more open position until an operating point is found where the compressor is surging.

Abstract: A capacity control system for a refrigeration system including a compressor, a condensor, and an evaporator, all connected in a closed refrigeration circuit is provided. The compressor includes a plurality of adjustable inlet guide vanes, a motor connected to regulate the inlet guide vanes position, and an electrical speed motor connected to drive the compressor. The capacity control system includes a microprocessor responsive to continual measurements of a PRV signal, a compressor head signal and a suction flow signal for calculating a current operating point. The microprocessor determines whether the operating point is sufficiently away from a surge surface. The microprocessor will cause the operating point to move to a new operating point of a lower compressor speed and a more open PRV position if the operating point is sufficiently away from surge.

Abstract: An adjustable surge and capacity control system for matching a capacity control system to an inverter-driven centrifugal compressor based liquid chiller having unknown surge characteristics. The necessary adaptation of the capacity control circuit to a particular chiller is attained by the provision of two potentiometers which are adjustable to develop a functional which avoids surge and operates the system in an efficient manner at all feasible operating point loads and heads. The use of a circuit employing a pair of potentiometers permits the formation of the appropriate functional with two degrees of shaping flexibility.

Abstract: A control system for a rotary helical screw compressor of the variable speed type includes a variable speed motor driving the compressor for varying the compressor capacity and a slide valve member which is adjusted optimally for varying the volume of gas trapped in the working chamber prior to discharge as a function of the pressure ratio across the compressor. There is also provided a control system for a rotary helical screw compressor of the fixed speed type which include a first slide valve member for varying the compressor capacity through modulating the volume of gas trapped in the working chamber prior to compression and a second slide valve member for adjusting optimally the volume of gas trapped in the working chamber prior to discharge as a function of the pressure ratio across the compressor.

Abstract: 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.

Abstract: An evaporator inlet water temperature control system for controlling the inlet water temperature of an evaporator utilized in an inverter driven centrifugal chiller. The system creates the proper chilled water set point at the evaporator outlet needed to maintain the inlet water at its set point for greater efficiency of operation. Control is accomplished by generating an electrical error signal which is a function of an inlet water set point voltage and the actual inlet water temperature. A logic signal is produced as a function of the error signal detected by the circuit and establishes a dead zone band representing a range in which the error signal is acceptable. Output of the control system is passed to the capacity control circuit of an inverter driven centrifugal compressor chiller.

Abstract: An adjustable surge and capacity control system for matching a capacity control system to an inverter-driven centrifugal compressor based liquid chiller having unknown surge characteristics. The necessary adaptation of the capacity control circuit to a particular chiller is attained by the provision of two potentiometers which are adjustable to develop a function which avoids surge and operates the system in an efficient manner at all feasible operating point loads and heads. The use of a circuit employing a pair of potentiometers permits the formation of the appropriate function with two degrees of shaping flexibility.

Abstract: An apparatus and method for controlling continuously and discretely the speed of a heat pump compressor as a function of load conditions to run at least up to 150% of its rate-speed when operated in the heating mode to provide initial supplemental heating prior to turning on of electric heaters. The speed of the indoor condenser fan is maintained at its full rated-speed. The operation of the apparatus is controlled by a microprocessor with a program to provide improved performance and minimize energy consumption.

Abstract: An apparatus and method for controlling continuously and discretely the speed of an indoor evaporator fan motor and the speed of the compressor as a function of the fan speed for regulating the dry bulb temperature and relative humidity of a conditioned space includes a programmed control device which produces a first signal for driving a fan inverter connected to the evaporator fan motor. A second signal, which is a function of the first signal, is also provided by the control device to drive a compressor inverter coupled to the compressor. A microprocessor having a program is operatively connected to the programmed control device for controlling its operation to effect the measured temperature of the conditioned space.