Gaviotas is a 200 people sustainable living community based in Colombia. In the hospital, a community solar cooker has been installed. It consists in an exterior hole tube solar collector, located in the building's roof, where cotton seed oil is heated. In sunny days, the oil may reach 180 ºC. In the storage tank, the difference in temperature creates a natural circulation: hot oil is sucked in the tank while colder oil, lower in the tank, goes into the collector to be heated. The tank includes two more holes (a superior inlet and an inferior outlet) to allow for oil transportation to the building. To take the heated oil to the interior of the building, a little 40 w pump (solar powered by the photovoltaic collectors and battery system) is used. The oil passes through 6 coils that surround the stainless steel pressure cookers where cooking takes place. Then, cool oil comes back to the storage tank. Both the tank and the pipes are thermically insulated. The oil is kept hot so it is possible to cook at night or in bad weather conditions (clouds, rain).