Solid-state heating or cooling systems, devices, and methods

A heating/cooling system comprising:

• a plurality of modules, each of the modules comprising one or more structures formed of shape memory alloy, the shape memory alloy being constructed to convert from a first crystal phase to a second crystal phase upon application of a first stress and to release latent heat in converting from the first crystal phase to the second crystal phase;
• at least one loading device coupled to the modules and configured to apply a force thereto;
• a fluid network coupled to a heat source and a heat sink;
• at least one pump configured to move heat transfer fluid through the fluid network;
• and
• a controller operatively coupled to the fluid network, the at least one loading device, and the at least one pump and configured to control the heating/cooling system such that:
• during a first part of a cycle, a first of the plurality of modules rejects heat to the heat sink while a second of the plurality of modules absorbs heat from the heat source, and
• during a second part of the cycle, the first and second modules are connected together to transfer heat therebetween.