1988/04/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria
According to Brissounneau Lotz Marine (BLM) this type of refrigerators can be very useful in the Third World, where there is no electric energy for the conservation of medicines and vaccines.
The system uses two substances: methanol and active carbon. Use the difference between night and day. During the day, the sun warms the solar panel containing both substances. Heat aromatizes methanol and becomes high-pressure gas. The gas enters through a valve, at the back of the panel, in the shade, in a zigzag condenser tube. In the tube, the gaseous methanol condenses and passes through another valve to the evaporator, where at low pressure the liquid becomes gas again. The latent heat required under low pressure conditions is extracted from the storage chamber and cooled.
At night, the steam in the panel cools and as the methanol is liquidated, it extracts the steam from the evaporator to compensate for the vacuum generated. This also keeps pressure down on the evaporator and continues the cycle. Methanol condenses as it enters the panels and is absorbed by coal.