Shell and tube isolation in heat exchanger

A chiller system comprising:

• a refrigerant circuit having a flow of refrigerant circulating therethrough;
• a fluid circuit having a flow of heat transfer fluid circulating therethrough, the fluid circuit operably connected to the refrigerant circuit at a heat exchanger assembly to transfer thermal energy between the flow of refrigerant and the fluid circuit, the heat exchanger assembly comprising:
• a heat exchanger shell formed from a first metal material;
• a plurality of heat exchanger tubes extending through a plurality of tube openings in the heat exchanger shell, the plurality of heat exchanger tubes formed from a second metal material different from the first metal material;
• and
• a galvanic isolator disposed at each tube opening of the plurality of tube openings, radially between the tube opening and the corresponding evaporator tube of the plurality of heat exchanger tubes, the galvanic isolator configured to mitigate a galvanic reaction between the heat exchanger shell and the plurality of heat exchanger tubes.

A method of assembling a heat exchanger comprising:

• defining a heat exchanger shell formed from a first metal material, the heat exchanger shell having a plurality of tube openings formed therein;
• providing a plurality of heat exchanger tubes formed from a second metal material different from the first metal material;
• installing a non-metallic galvanic isolator to one of an opening wall of the plurality of tube openings or the plurality of heat exchanger tubes;
• and
• installing the plurality of heat exchanger tubes into the plurality of tube openings, such that the galvanic isolator is disposed radially between the heat exchanger tube and the opening wall.