In this research work, hierarchical porous carbon foams (CFs) with high surface area and three dimensionally (3D) interconnected macro/meso/microporous structures were prepared through pyrolysis of stabilized poly (acrylonitrile-co-divinylbenzene) P(AN-co-DVB) polyHIPE foams at 900 degrees C under nitrogen atmosphere. The prepared CFs revealed high surface area (540 m(2) g(-1)), semi-ordered nanoporosity, high electrical conductivity (470 S m(-1)) and high graphitization degree. Further, HR-TEM observation of CFs revealed the formation of graphitic domains in the structures. The obtained CFs were employed for encapsulation of phase change materials (PCMs) e.g. paraffin (PA) and polyethylene glycol (PEG). The prepared PCMs composites revealed the excellent reversible thermal/chemical stability after frequent 200 heating/cooling cycles. Black CF/PA and CF/PEG composites can be promising structures to be driven either by applying a small voltage (3-3.6 V) with high electric-to thermal efficiency (up to 85%) or by irradiating with sunlight with high photo-to thermal efficiency (up to around 91%).