System for head pressure control

1. A cooling system comprising:

a heat exchanger;

a thermal expansion valve configured to control the delivery of liquid phase refrigerant to the heat exchanger;

a condenser fluidly coupled to the thermal expansion valve and configured to condense gas phase refrigerant to liquid phase refrigerant, the condenser including:

a gas header configured to receive gas phase refrigerant, the gas header separated into at least two sections, a first section and a second section, each section having an inlet port;

a liquid header disposed downstream from the gas header, the liquid header separated into at least two sections, a third section and a fourth section, which correspond to the first section and the second section of the gas header, respectively, each section of the at least two sections having an outlet port in fluid communication with the heat exchanger;

parallel tubes extending between the gas header and the liquid header;

a head pressure control valve positioned downstream and in between the outlet port of the third section and the outlet port of the fourth section of the liquid header; and

a pressure sensor positioned downstream from the outlet port of the third section of the liquid header; and

a controller coupled to the control valve and the pressure sensor, the controller being configured to place the control valve in a closed state to close off fluid communication between the outlet port of the third section of the liquid header and the outlet port of the fourth section of the liquid header when a pressure of the outlet port of the third section of the liquid header as determined by the pressure sensor is below a predetermined value, and configured to place the control valve in an open state to allow fluid communication between the outlet port of the third section of the liquid header and the outlet port of the fourth section of the liquid header when a pressure of the outlet port of the third section of the liquid header as determined by the pressure sensor is above the predetermined value, wherein the open state of the control valve enables liquid phase refrigerant from the outlet port of the third section of the liquid header to enter the outlet port of the fourth section of the liquid header.

2. The cooling system of claim 1 , wherein one section of the first section and the second section of the liquid header has an internal volume that is of a different size than an internal volume of the other section of the first section and the second section.

3. The cooling system of claim 1 , wherein the outlet port of the first section of the liquid header is configured to be fluidly coupled to the thermal expansion valve, and the control valve is configured such that the outlet port of the second section of the liquid header is in selective fluid communication with the thermal expansion valve.

4. The cooling system of claim 3 , wherein the control valve is configured to direct liquid phase refrigerant to the outlet port of the second section of the liquid header when the pressure of liquid phase refrigerant exiting the outlet port of the first section exceeds a predetermined value.

5. The cooling system of claim 3 , wherein the first section of the liquid header is configured to have a smaller internal volume than an internal volume of the second section of the liquid header.

6. The cooling system of claim 3 , wherein the first section of the liquid header is configured to have a larger internal volume than an internal volume of the second section of the liquid header.

7. The cooling system of claim 3 , wherein the first section of the gas header is fluidly coupled to the first section of the liquid header by a first series of parallel tubes, and the second section of the gas header is fluidly coupled to the second section of the liquid header by a second series of parallel tubes.

8. The cooling system of claim 7 , wherein the first section of the gas header, the first section of the liquid header, and the first series of parallel tubes has an internal volume of from about 25% to about 50% of a total internal volume of the condenser.

9. The cooling system of claim 3 , further comprising a receiver configured to store liquid phase refrigerant and positioned in between the condenser and the thermal expansion valve such that the outlet port of the first section of the liquid header is fluidly coupled to the receiver and the outlet port of the second section of the liquid header is in selective fluid communication with the receiver.

10. The cooling system of claim 1 , wherein the condenser is configured as an air-cooled condenser and the system further comprises at least one air mover configured to direct air over the condenser.

11. The cooling system of claim 10 , wherein the air mover includes at least one variable speed fan.

12. The cooling system of claim 1 , wherein the controller further is configured to allow liquid phase refrigerant to flow out of the outlet port of the fourth section of the liquid header through the control valve to join liquid phase refrigerant exiting the outlet port of the third section of the liquid header.