The energy consumption in buildings has increased in the last years due to the energy demand
for thermal comfort. The improvement of thermal properties in building materials is one of the
key points to achieve a reduction of the energy demand. Thermal energy storage (TES) is an
alternative to save energy that has been investigated extensively in recent years. The addition of
phase change materials (PCM) in a material increases its thermal inertia because PCM are able
to store and release energy in sensible and latent heat. In this paper coatings used in the outer
walls of buildings are studied, in particular single layer mortar. Microencapsulated paraffin
PCM is added into the material to improve the thermal properties of the building envelope. The
use of PCM combined with thermal insulation can reduce the energy consumption of buildings
by absorbing heat gains and reducing the heat flow. Two types of single layer mortar
Weber.Therm.Mineral commerzialized by Weber Saint Gobain incorporating different
percentages of microencapsulated PCM type Micronal® DS5001 (20%, 10% and 0%) in their
formulations are studied in this paper. The main objective of this work is to analyze the effect of
PCM addition on the properties of two single layer mortars. Fresh mortar properties, as well as
fire behavior, physical, mechanical and thermal properties of hardened mortar have been
evaluated. The results show that physical and mechanical properties of single layer mortar are
affected by the addition of microencapsulated PCM. Compressive strength decreases 60% with
the addition of 20% of PCM in the formulation while the formulation with 10% of PCM has
approximately the same compressive strength than a single layer mortar without PCM. The
addition of PCM in the formulation decreases in 35% the adherence of the single layer mortar to
a concrete surface. The presence of PCM in the mortar formulation worsens the fire behavior,
due to the organic, and therefore flammable, composition of Micronal® DS5001. Flammability
increases according to the percentage of PCM added. As a general conclusion, physical and
mechanical properties of the single layer mortar become worse when the percentage of the
added microencapsulated PCM is increased. Nevertheless, an improvement of thermal
properties is expected and the quantification will be done that could justify the addition of PCM
to some extent.
