A novel design for a molten salt solar central receiver is presented and investigated with regard to its thermal efficiency. The new receiver is for a surrounding heliostat field and consists of many hexagonal pyramid-shaped elements that are arranged alveolarly with their apexes pointing to the heliostats. Concentrated solar radiation is absorbed on the surfaces while the elements are cooled by a molten salt flow on the inside. As most of the radiative losses are re-absorbed by the neighboring pyramids, the system can almost be considered as a radiation trap. The new receiver's efficiency has been investigated using coupled CFD-simulations for the radiation and for the heat transfer into the molten salt flow. Presuming a concentrated incident power of 1 MW/m(2), a thermal efficiency of 91.2% was obtained. Losses by reflection could be reduced to 1.3% of the incoming radiation, while losses by emission accounted for 2.8%. The efficiency was compared to literature values of existing solar receivers, showing that the new concept is promising from the heat transfer point of view. Further simulations were performed to investigate part load behavior and the influence of geometry variations. (C) 2012 Elsevier Ltd. All rights reserved.