Refrigerant flow rate control based on suction line temperature

• US 5,415,008 A
• Filed: 03/03/1994
• Issued: 05/16/1995
• Est. Priority Date: 03/03/1994
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Bessler, Warren F.
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US08/205,857
• Time in Patent Office: 439 Days
• Field of Search: 62/210, 62/211, 62/212, 62/222, 62/224, 62/225, 62/113, 62/513
• US Class Current: 62/212
• CPC Class Codes: F25B 2700/2103 near a heat exchanger
• CPC Class Codes: F25B 2700/21151 at the suction side of the compressor
• CPC Class Codes: F25B 40/00 Subcoolers, desuperheaters or superheaters
• CPC Class Codes: F25B 41/347 with the valve member being opened and closed cyclically, e.g. with pulse width modulation
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

Pulse width modulation is used to control the flow rate through a solenoid expansion valve in a refrigeration system. A device for sensing suction line temperature is provided, and a controller is included for controlling the duty cycle of the pulse width modulated solenoid valve. The controller receives input from the suction line temperature sensing device as a basis for controlling the duty cycle. The suction line temperature sensing device may be a temperature sensor disposed on the suction line at the midpoint of the heat exchanger between the suction line and the liquid line. Alternatively, the suction line temperature sensing device may include a first temperature sensor disposed on the liquid line at one end of the heat exchanger and a second temperature sensor disposed on the liquid line at another end of the heat exchanger.

Claims

1. A refrigerator system for cooling at least one compartment, said refrigerator system comprising:

an evaporator disposed in said compartment and having an inlet and an outlet;

a compressor connected to said outlet of said evaporator by a suction line;

a pulse width modulated solenoid valve connected to said inlet of said evaporator;

a condenser connected to said pulse width modulated solenoid valve by a liquid line, said liquid line and said suction line being in thermal contact to form a heat exchanger therebetween;

a first temperature sensor disposed on said liquid line at one end of said heat exchanger;

a second temperature sensor disposed on said liquid line at another end of said heat exchanger; and

a controller for controlling the duty cycle of said pulse width modulated solenoid valve, said controller having inputs connected to said first temperature sensor and said second temperature sensor.

2. A refrigerator system comprising:

an evaporator having an inlet and an outlet;

a compressor connected to said outlet of said evaporator by a suction line;

a pulse width modulated solenoid valve connected to said inlet of said evaporator;

a condenser connected to said pulse width modulated solenoid valve by a liquid line, said liquid line and said suction line being in thermal contact to form a heat exchanger therebetween;

a first temperature sensor disposed on said liquid line at one end of said heat exchanger;

a second temperature sensor disposed on said liquid line at another end of said heat exchanger; and

a controller for controlling the duty cycle of said pulse width modulated solenoid valve, said controller having inputs connected to said first temperature sensor and said second temperature sensor.

3. A method of controlling refrigerant flow rate in a refrigeration system having a liquid line, a suction line and a pulse width modulated solenoid valve, said liquid line and said suction line being in thermal contact to form a heat exchanger therebetween, said method comprising the steps of:

sensing the temperature at one end of said heat exchanger;

sensing the temperature at another end of said heat exchanger; and

adjusting the duty cycle of said pulse width modulated solenoid valve based on the two temperatures.