The market
The global market for refrigeration equipment in 2010 was estimated at $27.1 billion. It is expected to grow by nearly 5% annually until 2012, reaching approximately $30 billion. The strongest growth is expected in Latin America and Asia, with China leading the way. However, the manufacturing industry remains largely dominated by Europe, the United States, and Japan. Global demand for household refrigerators is projected to exceed 90 million units this year. The Asian market (excluding Japan) is 2.5 times larger than the North American market in terms of units sold, and 20% larger than the combined market for Eastern and Western Europe. The electricity generated to power refrigerators in the United States contributes to over 100 million tons of carbon emissions annually. While developing countries are making progress in refrigeration, this advancement primarily benefits the middle class, where owning a refrigerator has become a status symbol. However, the real need for refrigeration lies in medicine and food preservation, and it fosters agricultural development and ensures public health. Milk and fish can be kept for several days at a temperature of 4 to 6 degrees Celsius, although they spoil in less than 24 hours at room temperature. A consistently cold environment preserves the effectiveness of vaccines. Industry has been working on solutions, including solar refrigerators. However, solar systems require a minimum of five hours of direct sunlight to function properly. Therefore, designers include a backup battery to ensure performance. The main drawback of this system is its cost. At a minimum of $5,000 per unit, this solution is beyond the reach of communities in the developing world. It relies on aid or subsidies and is therefore not sustainable.
Innovation
Making something hot out of something cold is easy. The key to a predictable cooling process is the exchange of energy as vapor turns into liquid and liquid turns into vapor. The most common approach is to compress a gas and turn it into a liquid, which heats it. When the pressure is released, the gas cools and condenses back into a liquid. As the liquid moves toward an area of low pressure, it expands more rapidly and vaporizes, creating cold by absorbing heat from the surroundings. Much research has been done to harness solar energy for refrigeration. Einstein pioneered this idea. The sun raises the temperature, which causes the pressure to rise. At high pressure, the refrigerant gas condenses into a liquid. If the heat is reduced, the pressure drops, and the liquid evaporates back into a gas, cooling the surroundings. Using solar energy directly to trigger this condensation and evaporation cycle is more efficient than converting it into electricity using photovoltaic panels, which then powers a compressor that transforms the refrigerant gas into a liquid. Emily Cummins, a 24-year-old British student, is taking the logic of evaporative cooling to the next level with a simple, inexpensive, and ingenious system. Emily uses no photovoltaics, no electricity, no chemical refrigerants, and no moving parts to produce the desired cooling effect. It's one of the most fundamental applications of the laws of physics and a prime example of the innovative principles of the blue economy: "substituting something with nothing." Emily applies the well-established evaporation system, relying solely on the heat generated by the sun. It's an ideal setup for villages in the developing world that lack electricity and the money to spend on expensive photovoltaics. Her refrigeration device consists of two cylinders, one inside the other. Emily studied the geometry and impact of drilling holes in the outer cylinder to allow for optimal access to direct sunlight. While the inner cylinder is made of metal, the outer cylinder can be made of wood, plastic, or even cardboard. The space between the inner and outer cylinders is filled with compacted wool, cotton, sand, raw earth—whatever is locally available. It even works with shredded newspaper. Food or medicine is placed inside the cylinder in the center. Water is poured into the space between the two cylinders until the filling (cotton, sand, raw earth, etc.) is saturated. It doesn't have to be pure drinking water; seawater and greywater work just as well. When the sun heats the outer cylinder, the water evaporates, removing heat, and as the filling touches the metal of the inner cylinder, it absorbs that heat. The more compact and conductive the filling and inner cylinder are, the more quickly heat is extracted from the inside of the cylinder. The inner chamber becomes very cold. A single infusion of water keeps the interior at 5-6 degrees Celsius for days.
The first cash flow
The system is brilliant because it is simple and has predictable performance. No backup is needed. By saturating the filling (cotton, sand, soil, etc.) with water, which absorbs heat from the inner cylinder, the cooling process continues. Emily first tested her invention in Namibia and concluded that, with an average of 10 hours of sunshine per day, the locations that would be ideal candidates for a $5,000 solar-powered refrigerator offer perfect conditions for her invention. The main criticism is that sunlight is rarely guaranteed, and this low-tech, eco-friendly refrigerator relies solely on nature to keep the interior cold. We propose integrating Las Gaviotas' expertise to substitute the sun's heating effect for light (see case 15). This would allow for the design of a refrigeration system that would operate year-round, especially where sunlight is at its peak.
The opportunity
Combining two fundamental areas of knowledge yields the desired result, grounded in practical experience of how two elements cool and heat each other. Emily's refrigeration system preserves medicines and food, and could even create ambient comfort in homes, while the water heaters offer comfort similar to underfloor heating while controlling bacteria by heating the water. Since Las Gaviotas has refined luminescent water heating over the past 35 years, to the point of offering a 25-year warranty, imagine now applying its luminescence technology to the external cylinder of Emily's invention. In this case, and with the appropriate choice of materials for the inner cylinder, a vast platform for entrepreneurship is created that redefines refrigeration in the tropics once and for all. It simply doesn't make sense to consider other solutions—even free ones—that cost thousands of dollars when the same effect can be achieved—as expected—for just $10! Emily proved herself in Southern Africa and then decided to offer her ideas as an open-source solution, publishing the data so anyone could use her ideas to create a cheaper, competitive solution at a fraction of the cost. It's no surprise that Emily was recently selected by Junior Chamber International as one of the World's Ten Outstanding People for her leadership in business and entrepreneurship.
