The invention provides heat pump system a Shape-Memory Alloy (SMA) or Negative Thermal Expansion (NTE) or elastocaloric material core positioned in a housing and adapted to absorb thermal heat and store energy in response to a first fluid inputted at a first temperature. The housing is configured to receive the fluid at the first temperature via an inlet to cause the SMA or NTE or elastocaloric material core to change state. A device is configured to apply stress on the SMA or NTE or elastocaloric core in the housing to cause the SMA or NTE or elastocaloric core to change state. A support system is configured to engage with the material in the core to prevent the material buckling when the stress is applied wherein the support system comprises a series of buckling supports positioned along at least one length of the SMA or NTE or elastocaloric material core. The support system provides a mechanical buckling support and heat transfer optimisation for fluid flow in a SMA heat pump during compression.