An apparatus includes a high side heat exchanger, a load, a compressor, a belt, a first bin, a second bin, and a controller. The high side heat exchanger removes heat from a refrigerant. The load uses the refrigerant to cool an enclosed space. The compressor compresses the refrigerant. The first and second bins are coupled to the belt and positioned within the enclosed space. The controller receives a first message, determines that the first bin should be selected, and cycles the belt to move the first bin to a retrieval location within the enclosed space. The controller also receives a second message, determines that the second bin should be selected, and cycles the belt to move the second bin to the retrieval location.