- Instead of water, ORC uses a contained organic fluid.
- Does not need water for cooling.
This article is a continuation of our series about various topics in renewable energy. Waste heat recovery systems collect excess thermal energy that would otherwise be exhausted or vented into the atmosphere. Some heat recovery systems cool hot exhaust from manufacturing processes, capturing excess heat and use it for power generation. What makes this possible is the use of organic working fluids with low vapor points and with high molecular densities. One of the major environmental concerns today is the increasing shortage of usable water. Industry such as lumber mills, utilities, steelworks, cement plants and many more other facilities typically overuse this vital resource. In order to produce materials and goods, each manufacturing process needs heat. The fastest and least expensive way to cool down processes is with the use of water, more specifically, vaporizing or literally, steam generation. Good news: Most of the fast moving water that flashes to steam can be captured, run through a turbine generator, generate electric power, condensed and feed back into the process. A condensing turbine uses the steam to recover energy. Bad news: There are about 2,300 gallons of water being wasted for every megawatt hour of energy being produced. Fresh water is one of the world’s scarcest natural resources. In the US, thermoelectric power accounts for 39% of all water consumption. That consumes more than 200 million of gallons of water each day. The majority of that power is used to cool down heated power production equipment. Why use water to cool down systems and equipment when for more than 50 years, there has been a water free technology that can be used. The Organic Rankine Cycle (ORC) originated from geothermal power and popularized in the late 1960s. It works on the principle as a traditional steam cycle with two notable exceptions: