Preparation and Performance Study of CaCl₂ Composite Adsorbent Based on Rock Wool Board Suitable for Continuous Heat Storage/Release of Trombe Wall

Abstract

As a passive solar design technology, the Trombe wall can improve buildings’ energy efficiency and thermal comfort. However, the traditional Trombe wall heating efficiency is low and cannot meet the needs of continuous night heating of the building. To solve these problems, a new type of sheet-like composite adsorbent is proposed in this study, prepared from calcium chloride supported by a rock wool board, a high-porosity building material. The high adaptability of rock wool board to the building wall makes it possible for the composite adsorbent to be directly applied to the Trombe wall. The results show that the macroporous structure of the rock wool board provides a wealth of space for loading hydrated salts. The smaller the density and thickness, the more calcium chloride the rock wool board can carry, speeding up the absorption/deportation process. The rock wool slab-based calcium chloride composite adsorbent has a maximum adsorption capacity of 51% and a heat storage density of about 838 J/g. Achieving the desorbed balance within 8 h and applying it to the Trombe wall is expected to attain continuous heating of buildings and has significant potential in building energy conservation.

Keywords

• thermochemical energy storage
• sorption storage
• salt hydrate
• composite materials
• Trombe wall