Dish washing machine with heat exchangers

A dish washing machine comprising:

• a housing having an interior wash space for washing dishes, the housing having a liquid inlet for adding a liquid to the dish washing machine and a liquid outlet for removing dirty liquid from the dish washing machine;
• at least one spray nozzle for spraying the liquid onto dishes positioned within the interior wash space;
• a heating tank for heating the liquid which is supplied to the at least one spray nozzle for spraying onto the dishes in the interior wash space;
• and
• at least one heat exchange system within the housing, the at least one heat exchange system transferring heat from the liquid heated by the heating tank to the liquid added to the dish washing machine from the liquid inlet;
• the at least one heat exchange system includes a first heat exchange system comprising a pipe system defining a first path therethrough and a second path therethrough, with the first heat exchange system transferring heat from liquid in the second path to liquid in the first path;
• the first path being located between the liquid inlet and the heating tank;
• the second path being located between a drain for the interior wash space and the liquid outlet of the housing;
• a first surface portion of the pipe system of the first path engaging the liquid in the first path having a greater thermal conductivity than a second surface portion of the pipe system of the second path engaging the liquid in the second path;
• the pipe system comprising an inner pipe defining the second path therethrough and an outer pipe defining the first path between the inner pipe and the outer pipe;
• and
• the inner pipe being stainless steel with a copper coating on an outer surface thereof.