Thermal performance of concrete masonry units containing insulation and phase change material

The stationary thermal performance requirements of building energy codes are mainly met by compounding insulation materials in building envelope or adding air interlayers. However, with the transformation of building envelope to lightweight and hollow, its thermal capacity value decreases significantly, which causes the indoor thermal environment to fluctuate with the outdoor space. The introduction of phase change materials is a potential solution to improve the transient performance. However, since the thermal properties of phase change materials vary with several environmental factors, it is a complex problem to rationalize the use of phase change materials, including their location in enclosures, the selection of types, quantities, and how to couple with insulation materials, so that the enclosures can achieve high stationary and transient performance simultaneously. In this study, a thermal environment simulator was built for the investigation of a series of triple concrete masonry unit blocks (bricks) equipped with insulation materials or/and phase change materials using dynamic testing method. The experiments were conducted under three typical boundary conditions reflecting different orientations of walls. A complete specification of the thermal performance of the walls with different configurations is summarized. It is found that the performance of insulation materials is stable, while the performance of phase change materials is influenced by the type and quantity of materials, indoor and outdoor temperatures, and the location in envelope. Phase change materials can show much higher thermal performance than insulation materials if under appropriate conditions. A series of construction optimization cases that can significantly improve the thermal performance of envelope are summarized, and general construction principles for envelopes with high thermal performance are given. From the influence laws of thermal performance to the improvement measures and the general rules of envelope configuration, this study provides the theoretical basis, optimization cases, and guidance rules for thermal applications of insulation-phase change building envelopes.