CAS storage tanks are intended for installation in central heating systems next to solid fuel boilers in order to accumulate thermal energy and more economical and efficient operation of the boiler. They are made in 8 sizes (volumes 325, 475, 740, 940, 1450, 2160, 2960, 3820 and 5055 liters) and 4 versions: as an accumulation tank (CAS), with built-in stainless steel boiler for domestic hot water preparation ), with built-in tubular heat exchanger for connecting solar collectors (CAS-S) and with built-in stainless steel water heater and tube heat exchanger (CAS-BS). Such designs enable the simultaneous use of several renewable energy sources, which makes them environmentally and energetically very acceptable. With built-in CAS tanks, heating can be planned at an acceptable time, and in the case of milder outdoor temperatures, space heating and domestic hot water heating without boiler heating is possible for several days. The tanks are made of certified materials in accordance with ISO 9001 and ISO 14001.