Fabrication of CaCl2 · 6H2O/Na2SiO3 · 9H2O composite phase change material for floor heating system

In this work, calcium chloride hexahydrate (CaCl2 6H2O) was adopted as phase change material (PCM), and the supercooling degree of CaCl2 6H2O can be reduced to 0.3 °C by adding 5 wt% sodium metasilicate nonahydrate (Na2SiO3 9H2O). Then the composite material of 'CaCl2 6H2O/5 wt% Na2SiO3 9H2O' was added into the floor heating system as the phase change layer to analyze and compare its controlling effect for the indoor temperature under summer and winter conditions. The results showed that the cooling rate of the floor heating system with the phase change layer is lower about 78.7% than that of floor heating system without the phase change layer; the heating rate of the floor heating system with the phase change layer is lower about 70.1% than that of floor heating system without the phase change layer. This result showed that the 'CaCl2 6H2O/5 wt% Na2SiO3 9H2O' composite PCM has a good application prospect in the field of building energy efficiency.