The invention provides a heat pump system and method heat pump system comprising a first Shape-Memory Alloy (SMA) or Negative Thermal Expansion (NTE) elastocaloric material core positioned in a housing and adapted to change state in response a temperature change supplied by a fluid. A second Shape-Memory Alloy (SMA) or Negative Thermal Expansion (NTE) elastocaloric material core positioned in a housing and adapted to change state in response a temperature change supplied by the fluid. A pump mechanism connected in a fluid communication with the first core and second core and adapted to control delivery of the fluid to the first and second core.