River Ice is a small-scale Garman river turbine directly connected to an open refrigeration compressor. Polyethylene bags which contain filtered water produce ice blocks through the energy of the currant. Garman river turbines (or the very similar Tyson- and VHL-turbines) are well known technologies. Their typical power output is 300 – 500 W and they are mainly used for house lightning, cellphone recharging, etc. In contrast to the conventional turbines, the River Ice turbine is connected directly to a mechanical compressor, which cools down through polyethylene bags containing water, thus producing ice blocks.
For this system to work, a river must have a minimum depth of 1.7m and a flow rate of at least 0.6 m/sec. If the energy flow of a river surpasses 12 kWh/day, it is sufficient to produce more than 250 kg/24 h of ice in tropical areas with temperatures of 30ºC or higher. According to Aprotec, the River Ice plant allows a direct cost saving of about 66%, compared to usual ice production methods.
According to WHO estimation, an average of 30% of all food is spoiled due to inadequate storage options in developing countries. This figure rises to 50% in tropical regions. Particularly affected is fresh fish, as an estimated 40 % of the stock rots before it can be processed. Cooling devices are not available and the hygiene is insufficient. Many rural communities in proximity to rivers e.g. the Amazon River, the Orinoco River, the Zambezi, Congo and the Nile, live on fishing and fish trade without the possibility of maintaining stocks. In these regions cooling is often as important as electricity.
River Ice is a cooling system which operates around the year, independent of the supply of conventional fuels. It will improve the livelihood of villagers living near to tropical rivers.The social impact is especially high with regard to the improvement of local living conditions and a better commercial exploitation of local fishing. The possibility of keeping their fish cooled, will lead to greater job potential in the communities. Job creation can also be expected from distribution, installation and maintenance of the River Ice plants. Moreover, water current turbines are a reliable and ecologically friendly technology. Overall, the River Ice plant could pave the way for other technologies: The system could be supplemented by a small PV-driven ultrafiltration plant and as a result produce absolutely clean and germ-free water for the ice blocks from the river water.