Refrigeration system condenser fan control

Patent metadata

Field	Value
Publication number	US-10697683-B2
Application number	US-201615553380-A
Country	US
Kind code	B2
Filing date	Feb 26, 2016
Priority date	Feb 27, 2015
Publication date	Jun 30, 2020
Grant date	Jun 30, 2020

Abstract

A method of controlling a refrigeration system having a compressor, a condenser, an evaporator, and a variable speed condenser fan is provided. The method includes determining if a change in an ambient temperature or a compressor suction pressure is greater than a predetermined threshold, determining a near-optimal condensing pressure/temperature if the change in the ambient temperature or the compressor suction pressure is above the predetermined threshold, setting a condensing pressure setpoint based on the determined near-optimal condensing pressure/temperature, and setting a speed of the variable speed condenser fan based on the condensing pressure setpoint.

First claim

The invention claimed is:

1. A method of controlling a refrigeration system having a compressor, a condenser, an evaporator, and a variable speed condenser fan, the method comprising:
determining if a change in an ambient temperature or a compressor suction pressure is greater than a predetermined threshold;
determining a condensing pressure or temperature if the change in the ambient temperature or the compressor suction pressure is above the predetermined threshold;
setting a condensing pressure setpoint based on the determined condensing pressure or temperature; and
setting a speed of the variable speed condenser fan based on the condensing pressure setpoint;
wherein determining the condensing pressure or temperature comprises:
determining the ambient temperature;
determining a saturation temperature leaving the evaporator;
determining a compressor speed; and
determining the condensing pressure or temperature based on a function of the determined ambient temperature, saturation temperature leaving the evaporator, and compressor speed.

2. The method of claim 1 , wherein the condensing pressure or temperature is determined using the equation:
φ opt =f ( T amb ,Ts out,evap )×CF comp ,

where φ opt is the set point of condensing pressure or temperature, T amb is the ambient temperature, Ts out, evap is the saturation temperature at the evaporator outlet, and CF comp is a correction factor with considering the compressor speed.

3. The method of claim 1 , further comprising:
determining a first total power consumption of the refrigeration system and setting as a current minimal power (Wmin);
reducing a speed of the variable speed condenser fan by a predetermined amount;
subsequently determining a second total power consumption of the refrigeration system and setting as a current power (Wcur); and
determining if Wcur is greater than Wmin.

4. The method of claim 3 , further comprising:
increasing the speed of the variable speed condenser fan by a predetermined amount if Wcur is greater than Wmin;
subsequently determining a third total power consumption of the refrigeration system and setting as current power (Wcur); and
determining if Wcur is greater than Wmin.

5. A method of controlling a refrigeration system having a compressor, a condenser, an evaporator, and a multi-speed condenser fan, the method comprising:
determining if a change in the ambient temperature or a suction pressure is greater than a predetermined threshold;
determining a condensing pressure (Pcd) if the change in the ambient temperature or the suction pressure is greater than the predetermined threshold,
determining an upper bound condensing pressure (Pcd_upbound);
determining a lower bound condensing pressure (Pcd_lowbound); and
setting a speed of the multi-speed condenser fan based on the determined condensing pressure Pcd and at least one of the upper bound condensing pressure Pcd_upbound and the lower bound condensing pressure Pcd_lowbound;
wherein determining at least one of the upper bound condensing pressure Pcd_upbound and the lower bound condensing pressure Pcd_lowbound comprises using a pressure table defining pressures at different conditions, wherein the conditions are functions of ambient temperature, evaporator outlet saturation pressure or temperature, and compressor speed.

6. The method of claim 5 , wherein determining the condensing pressure Pcd comprises using a pressure table defining pressures at different conditions, wherein the conditions include ambient temperature, evaporator outlet saturation temperature or box temperature, vehicle run or stop status, and compressor speed.

7. The method of claim 5 , wherein determining the upper bound condensing pressure Pcd_upbound comprises using a pressure table defining pressures at different conditions, wherein the conditions include ambient temperature, evaporator outlet saturation temperature or box temperature, vehicle run or stop status, and compressor speed.

8. The method of claim 5 , wherein determining the lower bound condensing pressure Pcd_lowbound comprises using a pressure table defining pressures at different conditions, wherein the conditions are functions of ambient temperature, evaporator outlet saturation pressure or temperature, and compressor speed.

9. The method of claim 5 , further comprising determining whether Pcd is greater than Pcd_upbound.

10. The method of claim 9 , further comprising operating the multi-speed condenser fan in a high speed mode if Pcd is greater than Pcd_upbound.

11. The method of claim 5 , further comprising determining whether Pcd is greater than Pcd_lowbound.

12. The method of claim 11 , further comprising operating the multi-speed condenser fan in a low speed mode if Pcd is greater than Pcd_lowbound.

13. The method of claim 11 , further comprising turning off the multi-speed condenser fan if Pcd is less than or equal to Pcd_lowbound.

14. A method of controlling a refrigeration system having a compressor, a condenser, an evaporator, a variable speed condenser fan, and a multi-speed condenser fan, the method comprising:
determining if a change in an ambient temperature or a compressor suction pressure is greater than a predetermined threshold;
controlling a speed of the variable speed condenser fan, comprising:
determining a condensing pressure or temperature if the change in the ambient temperature or the compressor suction pressure is above the predetermined threshold;
setting a condensing pressure setpoint based on the determined condensing pressure or temperature; and
setting a speed of the variable speed condenser fan based on the condensing pressure setpoint; and
controlling a speed of the multi-speed condenser fan, comprising:
determining a condensing pressure (Pcd) if the change in the ambient temperature or the suction pressure is greater than the predetermined threshold,
determining an upper bound condensing pressure (Pcd_upbound);
determining a lower bound condensing pressure (Pcd_lowbound), and
setting a speed of the multi-speed condenser fan based on the determined condensing pressure Pcd and at least one of the upper bound condensing pressure Pcd_upbound and the lower bound condensing pressure Pcd_lowbound;
wherein determining at least one of the upper bound condensing pressure Pcd_upbound and the lower bound condensing pressure Pcd_lowbound comprises using a pressure table defining pressures at different conditions, wherein the conditions are functions of ambient temperature, evaporator outlet saturation pressure or temperature, and compressor speed.

Assignees

• Carrier Corp

Inventors

• Sun Jian
• Chen Linhui

Classifications

• F25B41/22

  between evaporator and compressor · CPC title

• Y02B30/70

  Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating · CPC title

• F25B40/00

  Subcoolers, desuperheaters or superheaters · CPC title

• F25B2327/001

  Mechanical Engineering · mapped topic

• F25B27/00

  Machines, plants or systems, using particular sources of energy (F25B30/06 takes precedence) · CPC title