Refrigeration control system for optimum demand operation

• US 4,084,388 A
• Filed: 11/08/1976
• Issued: 04/18/1978
• Est. Priority Date: 11/08/1976
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Nelson, Lorne W.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US05/739,405
• Time in Patent Office: 526 Days
• Field of Search: 236/1 E, 165/22, 62/229, 62/175, 62/152, 62/196 A, 62/207, 307/39
• US Class Current: 62/152
• CPC Class Codes: F25B 2400/075 with parallel compressors
• CPC Class Codes: F25B 2400/22 Refrigeration systems for supermarkets
• CPC Class Codes: F25B 41/22 between evaporator and compressor
• CPC Class Codes: F25B 49/022 Compressor control arrangements
• CPC Class Codes: F25B 5/02 arranged in parallel
• CPC Class Codes: F25D 21/002 Defroster control
• CPC Class Codes: F25D 21/02 Detecting the presence of frost or condensate
• CPC Class Codes: F25D 21/08 by electric heating
• CPC Class Codes: G05D 23/1912 whose output amplitude can take more than two discrete values
• CPC Class Codes: G05D 23/24 the sensing element having a resistance varying with temperature, e.g. a thermistor

Abstract

A control sysem for controlling a plurality of refrigeration compressors has an input circuit for receiving a plurality of control signals from control devices for a plurality of evaporators connected to the refrigeration compressors with means for controlling the control signal of the evaporator having the greatest load to control the total operating capacity of the refrigeration compressors. Each of the input circuits has means for rendering the control signal input ineffective from a particular evaporator when the evaporator is in a defrosting cycle to allow the signal from the evaporator having the greatest load control the operating capacity of the refrigeration compressors.

Claims

1. In an energy conservation control system for controlling a plurality of refrigeration compressors to maintain the operating capacity of the operating compressors at a level to satisfy the load to each of a plurality of evaporators controlled by a control device thereby maintaining the total operating capacity dependent upon the load of the evaporator having the greatest load comprising;

a control having an input adapted to be connected to the control device of each of the evaporators wherein a control signal from each control device is indicative of the cooling load of the evaporator and an output adapted to be connected to each of the refrigeration compressors,

said input comprising means for selecting the control signal of the control device of the evaporator having the greatest load to control said output,

said output being adapted to selectively energize the refrigeration compressors dependent upon the magnitude of said control signal to maintain the total operating refrigeration capacity sufficient to satisfy the load of the evaporator having the greatest demand,

said control device is a temperature controlled valve to control the flow of refrigerant of each evaporator to maintain the temperature at a predetermined value,

said control signal of each control device is an electric signal proportional to the flow of refrigerant of the evaporator so that as the flow increases to a maximum said control signal is a maximum,

said means for selecting a signal of said input comprising a diode to allow the largest of said control signals to pass to said output, and

said output being an electric signal providing for the control of the total operating capacity of the refrigeration compressors proportional to said control signal passing to said input,

said output comprising a circuit for a sequential operator for energizing the plurality of refrigeration compressors in sequence, said output increasing the number of compressors in operation depending on the magnitude of said control signal passing through said diode from the control device of the evaporator having the greatest load, and

said circuit comprising circuit means adapted to be controlled by means responsive to a need of defrost of the evaporator to disconnect said input from the control device of the evaporator being defrosted to allow another control signal of a control device to control the operating capacity of the refrigeration compressors.