Method and apparatus for improving efficiency of a pulsed expansion valve heat pump
First Claim
1. In a heat pump system for cooling a conditioned space having a pulsed solenoid expansion valve controlled by a discharge temperature based PI algorithm the method of improving efficiency of operation which comprises the steps of:
- interrupting the discharge temperature sensor control of the pulsed expansion valves during start up;
pulsing the expansion valve during start up at a predetermined constant duty cycle; and
terminating the constant duty cycle and reestablishing discharge temperature sensor control thereof upon reaching a predetermined compressed refrigerant discharge temperature.
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Accused Products
Abstract
During start up of a heat pump compressor that is controlled by a pulsed expansion valve system the discharge temperature sensor control of the pulse system is interrupted and a predetermined constant pulse is applied to the expansion valve increasing capacity and reducing loss of suction pressure resulting in improved cyclic system efficiency. The constant pulse control is applied only during start up until the discharge temperature reaches a predetermined level at which point control is returned to the discharge temperature sensor.
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Citations
10 Claims
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1. In a heat pump system for cooling a conditioned space having a pulsed solenoid expansion valve controlled by a discharge temperature based PI algorithm the method of improving efficiency of operation which comprises the steps of:
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interrupting the discharge temperature sensor control of the pulsed expansion valves during start up; pulsing the expansion valve during start up at a predetermined constant duty cycle; and terminating the constant duty cycle and reestablishing discharge temperature sensor control thereof upon reaching a predetermined compressed refrigerant discharge temperature. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In a heat pump system for cooling a conditioned space having a pulsed solenoid expansion valve controlled by a discharge temperature based PI algorithm
apparatus for controlling the operation of a heat pump compressor which comprises: -
a solenoid operated expansion valve connected to the compressor and cooling coil of the heat pump; a temperature sensor positioned to sense refrigerant discharge temperature; first means for pulsing said expansion valve at a first predetermined rate; second means responsive to said temperature sensor for pulsing said expansion valve at a second predetermined rate; and control means for selecting said first or second means for pulsing said expansion valve, depending on the discharge temperature. - View Dependent Claims (8, 9, 10)
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Specification