New type of sorption composite for chemical heat pump and refrigeration systems

This paper describes new type of solid sorption composite based on expanded graphite (EXG) and carbon fibers (CF). Process of production (including preparation of the components and molding) of the composite, as well as measurements of its heat transfer coefficient has been presented. Introduction of carbon fibers allowed to obtain thermal conductivity λ of about 13–15 W/mK in comparison to 6.5–9.2 W/mK for expanded graphite based only composites described in available literature. Thermal conductivity of the composite has been measured in cryostat using the axial stationary heat flow method. Temperature profiles for various thermal conductivities (ranging 0.3–16 W/mK) were numerically calculated and compared. The composite has been introduced in experimental single stage sorption heat pump system using CaCl2 – NH3 as working pair.