Transport climate control system with auxilary cooling

A transport climate control system for a climate controlled transport unit, the climate controlled transport unit including a climate controlled space, the transport climate control system comprising:

• a main heat transfer circuit including:
• a compressor to compress a working fluid,
• a condenser downstream of the compressor to cool the working fluid compressed by the compressor with a first process fluid,
• a main expansion valve and a chiller electronic expansion valve (EEV) located in parallel with each other downstream of the condenser to expand the working fluid cooled by the condenser, the main expansion valve being a thermostatic expansion valve,
• a main evaporator and a chiller evaporator located in parallel to each other downstream of the condenser to heat the working fluid expanded by the main expansion valve and the chiller EEV, wherein the working fluid expanded by the main expansion valve is configured to flow through the main evaporator and cool a second process fluid in the main evaporator, wherein the working fluid expanded by the chiller EEV is configured to flow through the chiller evaporator and cool a third process fluid in the chiller evaporator, the chiller EEV controlling flow of the working fluid to the chiller evaporator, and
• an electronic pressure regulator valve downstream of the main evaporator and upstream of the compressor configured to adjust climate control capacity of the main evaporator, the electronic pressure regulator valve is configured to control a pressure of the working fluid discharged from the main evaporator based on an outlet temperature of the third process fluid from the chiller evaporator;
• and
• a chiller heat transfer circuit including:
• the chiller evaporator, the third process fluid is configured to flow through the chiller heat transfer circuit and provide auxiliary cooling within the transport climate control system, wherein
• the second process fluid is configured to cool the climate controlled space.

A method of operating a transport climate control system for a climate controlled transport unit, the transport climate control system including a main heat transfer circuit and a chiller heat transfer circuit, the main heat transfer circuit including a compressor, a condenser, a main evaporator and a chiller evaporator located in parallel to each other downstream of the condenser, and a main expansion valve and a chiller electronic expansion valve (EEV) downstream of the condenser, the method comprising:

• determining a climate control demand for the main heat transfer circuit and a climate control demand for the chiller heat transfer circuit;
• operating in a HVACR and chiller mode when the main heat transfer circuit has the climate control demand and the chiller heat transfer circuit has the climate control demand, wherein operating in the HVACR and chiller mode includes directing working fluid in parallel streams through the main evaporator and the chiller evaporator, wherein the main evaporator cools a first process fluid configured to cool a climate controlled space in the climate controlled transport unit, the main expansion valve or an electronic pressure regulator valve downstream of the main evaporator configured to adjust climate capacity of the main evaporator, wherein the chiller evaporator cools a second process fluid that supplies auxiliary cooling within the transport climate control system, a chiller EEV controlling a flow of the working fluid to and through the chiller evaporator, wherein operating in the HVACR and chiller mode includes shifting the climate control capacity from the main evaporator to the chiller evaporator by one of:
• partially closing the electronic pressure regulator valve, or
• partially closing the main expansion valve that is an electronic expansion valve;
• operating in the HVACR mode when only the main heat transfer circuit has the climate control demand, wherein operating in the HVACR mode includes directing the working fluid through the main evaporator and blocking flow of the working fluid to the chiller evaporator;
• and
• operating in the chiller mode when only the chiller heat transfer circuit has the climate control demand, wherein operating in the chiller mode includes directing the working fluid through the chiller evaporator and blocking flow of the working fluid through the main evaporator.