Support surface with phase change material or heat tubes

A support surface for general skin cooling, or reducing the incidence and promoting the healing of bedsores, includes:(a) at least one thermal layer comprising: a phase change material having a melting point of between about 18 and 32 degrees Centigrade; a gel or viscous fluid carrier in which the phase change material is substantially evenly distributed; and a fluid-impermeable, conformable envelope surrounding the phase change material and the carrier;(b) at least one conformable compression support layer beneath and adjacent to the thermal layer;(c) at least one conformable base support layer beneath and adjacent to the compression layer, the base support layer having a higher indentor load deflection (ILD) than the compression layer. A preferred embodiment, with or without the thermal layer, includes a heat tube layer. Another preferred embodiment includes an envelope containing phase change material in a carrier material, without either of the support layers.