Multi-zone transport refrigeration system with an ejector system

1. A multi-zone transport refrigeration system for a transport unit having a plurality of zones, the system comprising:

a refrigeration circuit that includes:

a compressor,

a first heat exchanger downstream of the compressor,

a first heat exchange unit downstream of the first heat exchanger, wherein the first heat exchange unit provides independent climate control to a first zone of the plurality of zones of the transport unit,

a second heat exchange unit downstream of the first heat exchanger, wherein the second heat exchange unit provides independent climate control to a second zone of the plurality of zones of the transport unit, and

an ejector system downstream of both the first heat exchange unit and the second heat exchange unit and upstream of the compressor, wherein the ejector system mixes refrigerant exiting the first heat exchange unit with refrigerant exiting the second heat exchange unit, increases the pressure of the mixed refrigerant, and directs the mixed refrigerant to the compressor,

wherein the refrigeration circuit includes a bypass path that directs refrigerant from the first heat exchange unit and the second heat exchange unit to the compressor and bypasses the ejector system, and

wherein the refrigeration circuit includes an ejector system control valve that directs refrigerant from one of the first heat exchange unit and the second heat exchange unit to a primary inlet of the ejector system and directs refrigerant from the other of the first heat exchange unit and the second heat exchange unit to a secondary inlet of the ejector system.

2. The system of claim 1 , wherein the refrigeration circuit includes a first heat exchange unit control valve that directs refrigerant from the first heat exchange unit towards the ejector system in a first position and directs refrigerant from the first heat exchange unit towards the bypass path in a second position, and a second heat exchange unit control valve that directs refrigerant from the second heat exchange unit towards the ejector system in a first position and directs refrigerant from the second heat exchange unit towards the bypass path in a second position.

3. The system of claim 1 , further comprising a controller that compares a first heat exchanger unit evaporator outlet data of refrigerant exiting the first heat exchange unit with a second heat exchanger unit evaporator outlet data of refrigerant exiting the second heat exchange unit, directs refrigerant from the first heat exchange unit and the second heat exchange unit to the bypass path when the first heat exchange unit evaporator outlet data is substantially similar to the second heat exchange unit evaporator outlet data, and directs refrigerant from the first heat exchange unit and the second heat exchange unit to the ejector system when the first heat exchange unit evaporator outlet data is not substantially similar to the second heat exchange unit evaporator outlet data.

4. The system of claim 3 , wherein when the first heat exchange unit evaporator outlet data is not substantially similar to the second heat exchange unit evaporator outlet data, the controller:

directs refrigerant from one of the first heat exchange unit and the second heat exchange unit having a higher evaporator outlet data to a primary inlet of an ejector system;

directing refrigerant from the other of the first heat exchange unit and the second heat exchange unit to a secondary inlet of the ejector system; and

the ejector system mixing refrigerant from the primary inlet with refrigerant of the secondary inlet, increasing the pressure of the mixed refrigerant, and directing the mixed refrigerant towards a suction port of the compressor.

5. A method for operating a multi-zone transport refrigeration system for a transport unit having a plurality of zones, the method comprising:

obtaining a first evaporator outlet data of refrigerant from a first heat exchange unit evaporator;

obtaining a second evaporator outlet data of refrigerant from a second heat exchange unit evaporator;

comparing the first evaporator outlet data with the second evaporator outlet data;

when the first evaporator outlet data is greater than the second evaporator outlet data, directing refrigerant from the first heat exchange unit to a primary inlet of an ejector system and directing refrigerant from the second heat exchange unit to a secondary inlet of the ejector system;

when the first evaporator outlet data is less than the second evaporator outlet data, directing refrigerant from the second heat exchange unit to a primary inlet of an ejector system and directing refrigerant from the first heat exchange unit to a secondary inlet of the ejector system; and

the ejector system mixing refrigerant from the primary inlet with refrigerant of the secondary inlet, increasing the pressure of the mixed refrigerant, and directing the mixed refrigerant towards a suction port of a compressor of the multi-zone transport refrigeration system.

6. The method of claim 5 , further comprising directing refrigerant from the first heat exchange unit and the second heat exchange unit along a bypass path that bypasses the ejector system to the suction port when the first evaporator outlet data is substantially similar to the second evaporator outlet data.

7. The method of claim 6 , wherein directing refrigerant from the first heat exchange unit and the second heat exchange unit along the bypass path includes a controller instructing both a first heat exchange unit control valve and a second heat exchange unit control valve to operate in a second condition.

8. The method of claim 5 , wherein directing refrigerant from the first heat exchange unit to the primary inlet and directing refrigerant from the second heat exchange unit to the secondary inlet includes a controller instructing an ejector system control valve of the multi-zone transport refrigeration system to operate in a first position, and

wherein directing refrigerant from the second heat exchange unit to the primary inlet and directing refrigerant from the first heat exchange unit to the secondary inlet includes the controller instructing the ejector system control valve to operate in a second position.

9. The method of claim 5 , further comprising:

determining whether a power source that supplies power to the compressor is operating safely, and

reducing the amount of refrigerant directed to the compressor when the power source is not operating safely.

10. The method of claim 5 , further comprising:

determining whether there is an unsafe load on the compressor;

determining whether an ambient temperature of air surrounding the transport unit is greater than an ambient temperature threshold; and

turning off the multi-zone transport refrigeration system when it is determined that there is an unsafe load on the compressor and it is determined that the ambient temperature is greater than the ambient temperature threshold.

11. The method of claim 5 , wherein directing refrigerant from the first heat exchange unit to the primary inlet and directing refrigerant from the second heat exchange unit to the secondary inlet includes a controller instructing an ejector system valve to operate in a first position, and

wherein directing refrigerant from the second heat exchange unit to the primary inlet and directing refrigerant from the first heat exchange unit to the secondary inlet includes the controller instructing the ejector system valve to operate in a second position.

12. A refrigerated transport unit comprising:

a transport unit having a plurality of zones; and

a multi-zone transport refrigeration system that provides independent climate control for each of the plurality of zones, the multi-zone transport refrigeration system including:

a refrigeration circuit that includes:

a compressor,

a first heat exchanger downstream of the compressor,

a first heat exchange unit downstream of the first heat exchanger, wherein the first heat exchange unit provides independent climate control to a first zone of the plurality of zones of the transport unit,

a second heat exchange unit downstream of the first heat exchanger, wherein the second heat exchange unit provides independent climate control to a second zone of the plurality of zones of the transport unit, and

an ejector system downstream of both the first heat exchange unit and the second heat exchange unit and upstream of the compressor, wherein the ejector system mixes refrigerant exiting the first heat exchange unit with refrigerant exiting the second heat exchange unit, increases the pressure of the mixed refrigerant, and directs the mixed refrigerant to the compressor,

wherein the refrigeration circuit includes a bypass path that directs refrigerant from the first heat exchange unit and the second heat exchange unit to the compressor and bypasses the ejector system, and

wherein the refrigeration circuit includes an ejector system control valve that directs refrigerant from one of the first heat exchange unit and the second heat exchange unit to a primary inlet of the ejector system and directs refrigerant from the other of the first heat exchange unit and the second heat exchange unit to a secondary inlet of the ejector system.

13. The refrigerated transport unit of claim 12 , wherein the refrigeration circuit includes a first heat exchange unit control valve that directs refrigerant from the first heat exchange unit towards the ejector system in a first position and directs refrigerant from the first heat exchange unit towards the bypass path in a second position, and a second heat exchange unit control valve that directs refrigerant from the second heat exchange unit towards the ejector system in a first position and directs refrigerant from the second heat exchange unit towards the bypass path in a second position.

14. The refrigerated transport unit of claim 12 , wherein the multi-zone transport system includes a controller that compares a first heat exchanger unit evaporator outlet data of refrigerant exiting the first heat exchange unit with a second heat exchanger unit evaporator outlet data of refrigerant exiting the second heat exchange unit, directs refrigerant from the first heat exchange unit and the second heat exchange unit to the bypass path when the first heat exchange unit evaporator outlet data is substantially similar to the second heat exchange unit evaporator outlet data, and directs refrigerant from the first heat exchange unit and the second heat exchange unit to the ejector system when the first heat exchange unit evaporator outlet data is not substantially similar to the second heat exchange unit evaporator outlet data.

15. The refrigerated transport unit of claim 14 , wherein when the first heat exchange unit evaporator outlet data is not substantially similar to the second heat exchange unit evaporator outlet data, the controller:

directs refrigerant from one of the first heat exchange unit and the second heat exchange unit having a higher evaporator outlet data to a primary inlet of an ejector system;

directing refrigerant from the other of the first heat exchange unit and the second heat exchange unit to a secondary inlet of the ejector system; and

the ejector system mixing refrigerant from the primary inlet with refrigerant of the secondary inlet, increasing the pressure of the mixed refrigerant, and directing the mixed refrigerant towards a suction port of the compressor.