The green revolution has advanced several areas of the automotive, power, and appliance industries. Two refrigerators in the appliance category could change the face of the green industry in the kitchen. One is a futuristic concept called the Bio Robot Refrigerator, which would use gel to preserve food, and the other, a complete product, is a solar-powered refrigerator that stores vaccines in developing countries.  

The Bio Robot Refrigerator is an idea in its earliest stages by Electrolux's Design Lab competition semifinalist Yuriy Dmitriev, and is supposed to be a zero-energy refrigerator that uses a gel-like substance that is odor-free to preserve and cool food. It is four times smaller than a traditional refrigerator, but possesses maximized storage space and the absence of doors, which "allows horizontal or vertical placement and displays food in plain view."

What would make the Bio Robot Refrigerator zero-energy is that it would not contain a motor, compressor or any other electrical constituents. What would keep the food cool is a "green, biopolymer gel that uses luminescence to preserve food." The food item is pressed into the gel, and the gel closes in around it suspending the item in place. A "separate capsule" is created for each additional piece of food that is placed into the gel.

This design has raised some questions regarding how much weight the gel can hold and how the gel can affect different foods in terms of temperature and texture. But this concept is one of the first contemporary redesigns of the traditional refrigerator since freon-based models in the 1950's. 

While the gel concept contributes a zero-energy appliance, it is still a ways off from becoming a realistic part of any household. On the other hand, a solar-powered refrigerator provides both zero-energy cooling and is currently saving the lives of those who "are limited by a lack of available refrigeration for the storage of vaccines."

The solar-powered refrigerator was developed by Appropriate Technology Collaborative (ATC), which is a non-profit organization that works to develop technologies to "improve the lives of people in developing countries." ATC works to insure that the systems they develop can be made by local engineers from locally available materials. 

The ATC solar-powered vaccine refrigerator was made for certain parts of the world that require vaccines but have no source of refrigeration to keep them from spoiling. Due to this lack of refrigeration, more than half of the vaccines go bad before they're even administered, which leads to the death of millions of lives and the loss of billions of dollars. 

This refrigerator requires no electricity and contains no valves or moving parts, making maintenance an easy task. The inexpensive design provides cold storage for vaccines in developing countries, depending solely on sunlight to make it freeze. According to the ATC, the "ATC Solar Vaccine Refrigerator is a robust, easy to maintain technology that can be made in the country or region where it is to be used" and "is made out of simple materials that can be found in most cities like steel, charcoal and ethanol or methanol."

The ATC Solar Vaccine Refrigerator has been entered in the NASA Tech Briefs Create The Future Contest.