  Solid-state cooling based on i-caloric effects has shown to be a promising
alternative to the conventional refrigeration devices. Only very recently, the
research on barocaloric materials is receiving a deal of attention due to the
demonstration of giant barocaloric effects in shape-memory alloys. Regarding
polymers, there is still a lack of literature, despite their high caloric
potential. Thus, we present here giant barocaloric effects in natural rubber, a
low-cost and environmental friendly elastomer polymer. The maximum values of
entropy and temperature changes are larger than those previously reported for
any promising barocaloric material. Moreover, the huge normalized temperature
change and refrigerant capacity exhibited by natural rubber confirm its high
potential for cooling applications. We also verify a relevant dependence of the
barocaloric effect on the glass transition in natural rubber. Our findings
suggest that commercial refrigeration devices based on barocaloric effects from
elastomer polymers can be envisaged in the near future.
