Method and apparatus for controlling capacity of a multiple-stage cooling system

Claim 2

A refrigeration system having in a closed loop connection a compressor for compressing a refrigerant, condensing means for condensing the compressed refrigerant from the compressor and discharging the condensed refrigerant at a discharge pressure into an outlet of said condensing means, said system further comprising: (a) a pre-selected number of condenser fans, at least one condenser fan being adapted to operate between a maximum and a minimum operating speed; (b) discharge pressure selection means for establishing a first and second discharge pressure range, each said discharge pressure range having an upper and a lower limit, the first discharge pressure range being associated with the variable speed fan and the second discharge pressure range being associated with the remaining fans; (c) detection means for sensing the discharge pressure and for cooperating with the discharge pressure selection means to provide an increase speed signal when the discharge pressure exceeds the upper limit of the first discharge pressure range, a decrease speed signal when the discharge pressure falls below the lower limit of the first discharge pressure range, an increase capacity signal when the discharge pressure exceeds the upper limit of the second discharge pressure range and when the variable speed fan is operating at the maximum speed, and a decrease capacity signal when the discharge pressure falls below the lower limit of the second pressure range and when the variable speed fan is operating at the minimum speed; and (d) selection means for receiving the increase speed and decrease speed signals and in respective response thereto increasing and decreasing the speed of the variable speed fan, and for receiving the increase capacity and decrease capacity signals and in respective response thereto energizing and deenergizing a fan of the refrigeration compressor system.

Claim 3

A refrigeration system having in a closed loop connection at least one compressor for compressing a refrigerant, condensing means for condensing the compressed refrigerant from the compressor and discharging the condensed refrigerant into an outlet of said condensing means, said system further comprising: (a) a pre-selected number of condenser fans, at least one condenser fan being adapted to operate between a maximum and a minimum operating speed; (b) temperature selection means for establishing a first and a second temperature range, each said temperature range having an upper and a lower limit, wherein the first temperature range being associated with the variable speed fan and the second temperature range being associated with the remaining fan; (c) detection means for sensing the temperature of the refrigerant at the outlet of the condensing means and for cooperating with the discharge temperature selection means to provide an increase speed signal when the refrigerant temperature exceeds the upper limit of the first temperature range, a decrease speed signal when the refrigerant temperature falls below the lower limit of the first temperature range, an increase capacity signal when the refrigerant temperature exceeds the upper limit of the second temperature range and when the variable speed fan is operating at the maximum speed, and a decrease capacity signal when the temperature falls below the lower limit of the second temperature range and when the variable speed fan is operating at the minimum speed; and (d) selection means for receiving the increase speed and decrease speed signals and in respective response thereto increasing and decreasing the speed of the variable speed fan, and for receiving the increase capacity and decrease capacity signals and in respective response thereto energizing and deenergizing a fan of the refrigeration compressor system.

Claim 4

A refrigeration system having in a closed loop connection at least one compressor for compressing a refrigerant, condensing means for condensing the compressed refrigerant from the compressor and discharging the condensed refrigerant into an outlet of said condensing means, said system further comprising: (a) a pre-selected number of condenser fans, at least one condenser fan being adapted to operate between a maximum and a minimum operating speed; (b) temperature selection means for establishing a first and a second temperature range, each said temperature range having an upper and a lower limit, wherein the first temperature range being associated with the variable speed fan and the second temperature range being associated with the remaining fan; (c) detection means for sensing the temperature of the refrigerant at the outlet of the condensing means and for cooperating with the discharge temperature selection means to provide an increase speed signal when the refrigerant temperature exceeds the upper limit of the first temperature range, a decrease speed signal when the refrigerant temperature falls below the lower limit of the first temperature range, an increase capacity signal when the refrigerant temperature exceeds the upper limit of the second temperature range and when the variable speed fan is operating at the maximum speed, and a decrease capacity signal when the temperature falls below the lower limit of the second temperature range and when the variable speed fan is operating at the minimum speed; and (d) selection means for receiving the increase speed and decrease speed signals and in respective response thereto increasing and decreasing the speed of the variable speed fan, and for receiving the increase capacity and decrease capacity signals and in respective response thereto energizing and deenergizing a fan of the refrigeration compressor system.

Claim 5

A refrigeration system comprising: (a) a predetermined number of commonly piped compressors having a common suction pressure for compressing a refrigerant, and wherein at least one compressor being adapted to operate between a maximum and a minimum operating speed; (b) condensing means for condensing the compressed refrigerant from the compressors and for discharging the condensed refrigerant at a discharge pressure into an outlet of the condensing means; (c) a predetermined number of fans placed near the condensing means for aiding in the condensation of said compressed refrigerant wherein at least one fan being adapted to operate between a maximum and a minimum operating speed; (d) pressure selection means for establishing a first and a second suction pressure range, each said pressure range having an upper and lower limit, the first pressure range being associated with the variable speed compressor and the second pressure range being associated with the remaining compressors; (e) detection means for sensing the suction pressure and for cooperating with the pressure selection means to provide an increase speed signal when the suction pressure exceeds the upper limit of the first pressure range, a decrease speed signal when the suction pressure falls below the lower limit of the first pressure range, an increase capacity signal when the suction pressure exceeds the upper limit of the second pressure range and that the variable speed compressor is operating at the maximum speed, and a decrease capacity signal when the suction pressure falls below the lower limit of the second pressure range and that the variable speed compressor is operating at the minimum speed; (f) selection means for receiving the increase speed and decrease speed signals and in respective response thereto increasing and decreasing the speed of the variable speed compressor, and for receiving the increase capacity and decrease capacity signals and in respective response thereto energizing and deenergizing a compressor of the refrigeration compressor system; (g) discharge pressure selection means for establishing a first and second discharge pressure range, each said discharge pressure range having an upper and a lower limit, wherein the first discharge pressure range being associated with the variable speed fan and the second discharge pressure range being associated with the remaining fans; (h) detection means for sensing the discharge pressure and for cooperating with the discharge pressure selection means to provide an increase speed signal when the discharge pressure exceeds the upper limit of the first discharge pressure range, a decrease speed signal when the discharge pressure falls below the lower limit of the first discharge pressure range, an increase capacity signal when the discharge pressure exceeds the upper limit of the second discharge pressure range and when the variable speed fan is operating at the maximum speed, and a decrease capacity signal when the discharge pressure falls below the lower limit of the second pressure range and when the variable speed fan is operating at the minimum speed; and (i) selection means for receiving the increase speed and decrease speed signals and in respective response thereto increasing and decreasing the speed of the variable speed fan, and for receiving the increase capacity and decrease capacity signals and in respective response thereto energizing and deenergizing a fan of the refrigeration compressor system.

Claim 6

A refrigeration system comprising: (a) a predetermined number of commonly piped compressors having a common suction pressure for compressing a refrigerant, and wherein at least one compressor being adapted to operate between a maximum and a minimum operating speed; (b) condensing means for condensing the compressed refrigerant from the compressors and for discharging the condensed refrigerant at a discharge pressure into an outlet of the condensing means; (c) a predetermined number of fans placed near the condensing means for aiding in the condensation of said compressed refrigerant wherein at least one fan being adapted to operate between a maximum and a minimum operating speed; (d) pressure selection means for establishing a first and a second suction pressure range, each said pressure range having an upper and lower limit, the first pressure range being associated with the variable speed compressor and the second pressure range being associated with the remaining compressors; (e) detection means for sensing the suction pressure and for cooperating with the pressure selection means to provide an increase speed signal when the suction pressure exceeds the upper limit of the first pressure range, a decrease speed signal when the suction pressure falls below the lower limit of the first pressure range, an increase capacity signal when the suction pressure exceeds the upper limit of the second pressure range and that the variable speed compressor is operating at the maximum speed, and a decrease capacity signal when the suction pressure falls below the lower limit of the second pressure range and that the variable speed compressor is operating at the minimum speed; (f) selection means for receiving the increase speed and decrease speed signals and in respective response thereto increasing and decreasing the speed of the variable speed compressor, and for receiving the increase capacity and decrease capacity signals and in respective response thereto energizing and deenergizing a compressor of the refrigeration compressor system; (g) discharge pressure selection means for establishing a first and second discharge pressure range, each said discharge pressure range having an upper and a lower limit, wherein the first discharge pressure range being associated with the variable speed fan and the second discharge pressure range being associated with the remaining fans; (h) detection means for sensing the discharge pressure and for cooperating with the discharge pressure selection means to provide an increase speed signal when the discharge pressure exceeds the upper limit of the first discharge pressure range, a decrease speed signal when the discharge pressure falls below the lower limit of the first discharge pressure range, an increase capacity signal when the discharge pressure exceeds the upper limit of the second discharge pressure range and when the variable speed fan is operating at the maximum speed, and a decrease capacity signal when the discharge pressure falls below the lower limit of the second pressure range and when the variable speed fan is operating at the minimum speed; and (i) selection means for receiving the increase speed and decrease speed signals and in respective response thereto increasing and decreasing the speed of the variable speed fan, and for receiving the increase capacity and decrease capacity signals and in respective response thereto energizing and deenergizing a fan of the refrigeration compressor system.

Claim 7

A refrigeration system comprising: (a) a predetermined number of commonly piped compressors having a common suction pressure for compressing a refrigerant, and wherein at least one compressor being adapted to operate between a maximum and a minimum operating speed; (b) condensing means for condensing the compressed refrigerant from the compressors and for discharging the condensed refrigerant into an outlet of the condensing means; (c) a predetermined number of fans placed near the condensing means for aiding in the condensation of said compressed refrigerant wherein at least one fan being adapted to operate between a maximum and a minimum operating speed; (d) pressure selection means for establishing a first and a second suction pressure range, each said pressure range having an upper and a lower limit, the first pressure range being associated with the variable speed compressor and the second pressure range being associated with the remaining compressors; (e) detection means for sensing the suction pressure and for cooperating with the pressure selection means to provide an increase speed signal when the suction pressure exceeds the upper limit of the first pressure range, a decrease speed signal when the suction pressure falls below the lower limit of the first pressure range, an increase capacity signal when the suction pressure exceeds the upper limit of the second pressure range and that the variable speed compressor is operating at the maximum speed, and a decrease capacity signal when the suction pressure falls below the lower limit of the second pressure range and that the variable speed compressor is operating at the minimum speed; (f) selection means for receiving the increase speed and decrease speed signals and in respective response thereto increasing and decreasing the speed of the variable speed compressor, and for receiving the increase capacity and decrease capacity signals and in respective response thereto energizing and deenergizing a compressor of the refrigeration compressor system; (g) temperature selection means for establishing a first and a second temperature range, each said temperature range having an upper and a lower limit, the first pressure range being associated with the variable speed fan and the second temperature range being associated with the remaining fans; (h) detection means for sensing the temperature of the discharged refrigerant and for cooperating with the temperature selection means to provide an increase speed signal when the refrigerant temperature exceeds the upper limit of the first temperature range, a decrease speed signal when the refrigerant temperature falls below the lower limit of the first temperature range, an increase capacity signal when the refrigerant temperature exceeds the upper limit of the second temperature range and when the variable speed fan is operating at the maximum speed, and a decrease capacity signal when the refrigerant temperature falls below the lower limit of the second pressure range and when the variable speed fan is operating at the minimum speed; and (i) selection means for receiving the increase speed and decrease speed signals and in respective response thereto increasing and decreasing the speed of the variable speed fan, and for receiving the increase capacity and decrease capacity signals and in respective response thereto energizing and deenergizing a fan of the refrigeration compressor system.

Claim 8

A refrigeration system comprising: (a) a predetermined number of commonly piped compressors having a common suction pressure for compressing a refrigerant, and wherein at least one compressor being adapted to operate between a maximum and a minimum operating speed; (b) condensing means for condensing the compressed refrigerant from the compressors and for discharging the condensed refrigerant into an outlet of the condensing means; (c) a predetermined number of fans placed near the condensing means for aiding in the condensation of said compressed refrigerant wherein at least one fan being adapted to operate between a maximum and a minimum operating speed; (d) pressure selection means for establishing a first and a second suction pressure range, each said pressure range having an upper and a lower limit, the first pressure range being associated with the variable speed compressor and the second pressure range being associated with the remaining compressors; (e) detection means for sensing the suction pressure and for cooperating with the pressure selection means to provide an increase speed signal when the suction pressure exceeds the upper limit of the first pressure range, a decrease speed signal when the suction pressure falls below the lower limit of the first pressure range, an increase capacity signal when the suction pressure exceeds the upper limit of the second pressure range and that the variable speed compressor is operating at the maximum speed, and a decrease capacity signal when the suction pressure falls below the lower limit of the second pressure range and that the variable speed compressor is operating at the minimum speed; (f) selection means for receiving the increase speed and decrease speed signals and in respective response thereto increasing and decreasing the speed of the variable speed compressor, and for receiving the increase capacity and decrease capacity signals and in respective response thereto energizing and deenergizing a compressor of the refrigeration compressor system; (g) temperature selection means for establishing a first and a second temperature range, each said temperature range having an upper and a lower limit, the first pressure range being associated with the variable speed fan and the second temperature range being associated with the remaining fans; (h) detection means for sensing the temperature of the discharged refrigerant and for cooperating with the temperature selection means to provide an increase speed signal when the refrigerant temperature exceeds the upper limit of the first temperature range, a decrease speed signal when the refrigerant temperature falls below the lower limit of the first temperature range, an increase capacity signal when the refrigerant temperature exceeds the upper limit of the second temperature range and when the variable speed fan is operating at the maximum speed, and a decrease capacity signal when the refrigerant temperature falls below the lower limit of the second pressure range and when the variable speed fan is operating at the minimum speed; and (i) selection means for receiving the increase speed and decrease speed signals and in respective response thereto increasing and decreasing the speed of the variable speed fan, and for receiving the increase capacity and decrease capacity signals and in respective response thereto energizing and deenergizing a fan of the refrigeration compressor system.

Claim 11

Apparatus for controlling the capacity of a refrigeration system having one variable speed compressor adapted to operate at variable speeds between a maximum and minimum speed and a plurality of equal capacity compressors, said compressors also having a common suction pressure, said system comprising: (a) a pressure selecting means for establishing an operating suction pressure range; (b) a detection means for sensing the suction pressure and cooperating with said pressure selecting means to generate an increase speed signal when the suction pressure exceeds the suction pressure range, a decrease speed signal when the suction pressure falls below the suction pressure range, an increase capacity signal when the suction pressure exceeds the suction pressure range and that the variable speed compressor is at the maximum speed, and a decrease capacity signal when the suction pressure falls below the suction pressure range and that the variable speed compressor is at the minimum speed; and (c) selection means for receiving the increase speed signal and decrease speed signals and in respective response thereto increasing and decreasing the speed of the variable speed compressor, and for receiving the increase capacity and decrease capacity signal and in respective response thereto selectively energizing and de-energizing compressors from said plurality of compressors so that the compressor that has been turned-off the longest is the first to be energized and the compressor that has been turned-on the longest is the first to be de-energized.

Claim 12

Apparatus for controlling the capacity of a refrigeration system having one variable speed compressor adapted to operate at variable speeds between a maximum and minimum speed and a plurality of equal capacity compressors, said compressors also having a common suction pressure, said system comprising: (a) a pressure selecting means for establishing an operating suction pressure range; (b) a detection means for sensing the suction pressure and cooperating with said pressure selecting means to generate an increase speed signal when the suction pressure exceeds the suction pressure range, a decrease speed signal when the suction pressure falls below the suction pressure range, an increase capacity signal when the suction pressure exceeds the suction pressure range and that the variable speed compressor is at the maximum speed, and a decrease capacity signal when the suction pressure falls below the suction pressure range and that the variable speed compressor is at the minimum speed; and (c) selection means for receiving the increase speed signal and decrease speed signals and in respective response thereto increasing and decreasing the speed of the variable speed compressor, and for receiving the increase capacity and decrease capacity signal and in respective response thereto selectively energizing and de-energizing compressors from said plurality of compressors so that the compressor that has been turned-off the longest is the first to be energized and the compressor that has been turned-on the longest is the first to be de-energized.

Claim 13

Apparatus for controlling the capacity of a refrigeration system having variable speed compressors adapted to operate at variable speeds between a maximum and a minimum operating speed and a plurality of unequal capacity compressors, said compressors also having a common suction pressure, said system comprising: (a) a pressure selecting means for establishing and operating suction pressure range; (b) a detection means for sensing the suction pressure and cooperating with said pressure selecting means to generate an increase speed signal when the suction pressure exceeds the suction pressure range, a decrease speed signal when the suction pressure falls below the suction pressure range, an increase capacity signal when the suction pressure exceeds the suction pressure range and that the variable speed compressor is at the maximum speed, and a decrease capacity signal when the suction pressure falls below the suction pressure range and that the variable speed compressor is at the minimum speed; and (c) selection means for receiving the increase speed signal and decrease speed signals and in respective response thereto increasing and decreasing the speed of the variable speed compressor, and for receiving the increase capacity and decrease capacity signal and in respective response thereto energizing and de-energizing a compressor from said plurality of compressors in a way that most closely matches the system compressor capacity with the refrigeration load of the refrigeration system.

Claim 14

Apparatus for controlling the capacity of a refrigeration system having variable speed compressors adapted to operate at variable speeds between a maximum and a minimum operating speed and a plurality of unequal capacity compressors, said compressors also having a common suction pressure, said system comprising: (a) a pressure selecting means for establishing and operating suction pressure range; (b) a detection means for sensing the suction pressure and cooperating with said pressure selecting means to generate an increase speed signal when the suction pressure exceeds the suction pressure range, a decrease speed signal when the suction pressure falls below the suction pressure range, an increase capacity signal when the suction pressure exceeds the suction pressure range and that the variable speed compressor is at the maximum speed, and a decrease capacity signal when the suction pressure falls below the suction pressure range and that the variable speed compressor is at the minimum speed; and (c) selection means for receiving the increase speed signal and decrease speed signals and in respective response thereto increasing and decreasing the speed of the variable speed compressor, and for receiving the increase capacity and decrease capacity signal and in respective response thereto energizing and de-energizing a compressor from said plurality of compressors in a way that most closely matches the system compressor capacity with the refrigeration load of the refrigeration system.