This paper presents experimental results obtained with a prototype of a solar heat storage absorption process using the KCOOH/H2O couple. The process principle and the prototype tested are described, and both charging and discharging results are presented and discussed. The parameters influencing the results the most are water and solution flow on the reactor heat exchangers as well as the heat source and sink temperatures. The system's main limitation is the wetting of the exchanger plates. However, the tests prove the interest of the KCOOH/H2O couple in this type of low-temperature heat storage process.