Selectively operable heating and cooling system and method of operating thereof

A heating, ventilation, air conditioning, and refrigeration (HVACR) system comprising:

• a hydronic system comprising a first process fluid and a second process fluid for conditioning one or more spaces;
• a first heat transfer circuit, wherein the first heat transfer circuit comprises a first compressor, a first heat exchanger, and a first chiller,
• wherein the first heat exchanger is configured to selectively exchange heat with the first process fluid, wherein the first process fluid further exchanges heat with a heating load in the one or more spaces, or exchanges heat with cooling fluid;
• a second heat transfer circuit, wherein the second heat transfer circuit comprises a second compressor, a cascade heat exchanger, and a second chiller;
• wherein the second chiller is configured to exchange heat between the second process fluid, wherein the second process fluid further exchanges heat with a cooling load;
• a coolant loop including a coolant, the coolant loop configured to thermally communicate thermal energy between the first chiller of the first heat transfer circuit and the cascade heat exchanger of second heat transfer circuit;
• and
• a controller, wherein the controller is configured to selectively operate the HVACR system in:
• a heating mode, wherein the HVACR system is configured to operate the first heat transfer circuit and the second heat transfer circuit in a cascaded operation to heat the first process fluid via heat transfer with the first heat exchanger, wherein the coolant loop is configured to thermally communicate the thermal energy between the cascade heat exchanger of the second heat transfer circuit and the first chiller of the first heat transfer circuit, and
• a cooling mode, wherein the HVACR system is configured to operate the first heat transfer circuit and the second heat transfer circuit in a parallel operation to provide cooling to the second process fluid via heat transfer with the first chiller and the second chiller, wherein the first heat exchanger is configured to exchange heat with the cooling fluid.

A method for heating and/or cooling a system, the system comprising a first heat transfer circuit, wherein the first heat transfer circuit comprises a first compressor, a first heat exchanger, and a second heat exchanger;

• a second heat transfer circuit, wherein the second heat transfer circuit comprises a second compressor, a third heat exchanger, and a fourth heat exchanger;
• a coolant loop including a coolant;
• and a controller, the method comprising selectively operating the system in either one of the following modes:
• operating the system in a heating mode by operating the first heat transfer circuit and the second heat transfer circuit in a cascaded operation to heat a first process fluid via heat transfer with the first heat exchanger, wherein the operating the system in the heating mode includes thermally communicating, via the coolant loop, thermal energy from the third heat exchanger of the second heat transfer circuit and the second heat exchanger of the first heat transfer circuit;
• or
• operating the system in a cooling mode by operating the first heat transfer circuit and the second heat transfer circuit in parallel operation to provide cooling to a second process fluid, wherein the operating the system in the cooling mode includes providing the second process fluid to the fourth heat exchanger and the second heat exchanger.