The JGC Corporation is now striving to develop a new solar thermal energy system based on a solar chemical heat pump. Solar thermal energy has not been applied to industry due to the low energy density and the uncertainty of solar energy. To solve these problems the authors propose a solar energy system combined with chemical heat pump. A combined system could collect low-temperature solar energy efficiently, upgrade its energy level, and store this energy without heat loss. In 1993 the authors completed the construction of a pilot plant and succeeded in demonstrating the world`s first chemical heat pump that utilizes catalytic reactions. The pilot plant specifications, the results of the demonstration experiments, and the technical items they have to solve before this heat pump can be applied practically to the solar energy system are summarized in this paper.