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:
- Instead of water, ORC uses a contained organic fluid.
- Does not need water for cooling.
ORC captures exhaust and cools it with the use of an environment friendly refrigerant which moves through a closed loop system, turns from liquid to steam and back to gas. The process generates continuous power, is totally self sustainable and with a lifespan of 20 years. Oil fields, cement plants, paper mills, steel mills are few of the large industrial facilities that both use waste heat and great amount of electricity. Through the use of waste heat recovery, the operations of these easily reduced their demand for traditional water cooling steam plants. This saves water by millions of gallons each year. The end product is clean energy that feeds back into the plant. In today’s economy, business owners must make business decisions that help the environment and actually help their businesses as well. One way to succeed is doing more with less. Using less means paying less. That is what waste heat recovery is all about. It helps equipment to use less resource while it saves business money. Across the United States, more and more industrial and power plant operators have worked with project developers on waste heat recovery systems. There are more than 25 completed projects already in the US alone with many more ongoing projects being developed.