Solar walls have been studied for decades as a way of heating building from a renewable energy source. A key ingredient of these wall is their storage capacity. However, this increases their weight and volume, which limits theirs integration into existing building. To aleviate this problem, storage mass is replaced by a phase change materials. These allow to store a large amount of energy in a small volume, which brings the possibility of retrofit trough use of light prefabricated module. This article presents an experimental study of a small-scale Trombe composite solar wall. In this case, the phase change material was inserted into the wall in the form of a brick-shaped package. While this material can store more heat than the same volume of concrete (for the same temperature range), it shows a very different thermal behavior under dynamic conditions. A particular attention is focused on the delay between the absorption of solar radiation and the energy supplied to the room. The energy performance of the wall from heat flux measurements and enthalpy balances are also presented. (C) 2011 Elsevier Ltd. All rights reserved.