Pumpable heat transfer composition

The invention relates to pumpable heat transfer compositions wherein a solid polymeric porous structure having absorbed therein a polar or non-polar phase change material is incorporated with a heat transfer carrier liquid, with the phase change material being present in an amount sufficient to increase the heat capacity and/or heat transfer coefficient of the carrier liquid. The invention also relates to the method of increasing the heat capacity and/or heat transfer coefficient of a heat transfer carrier liquid by adding thereto a solid polymeric porous structure having absorbed therein a polar or non-polar phase change material.