Steam is water vapour ( water in the gas phase), often mixed with air and/or an aerosol of liquid water droplets. This may occur due to evaporation or due to boiling , where heat is applied until water reaches the enthalpy of vaporization . Steam that is saturated or superheated (water vapor) is invisible; however, wet steam, a visible mist or aerosol of water droplets, is often referred to as "steam".
30-721: The Willis Avenue Station is a steam production plant used in Detroit 's district steam heating system. The plant is located at 50 West Willis Street, near Woodward Avenue, in the center of the city's Midtown Detroit neighborhood. Built and owned by the Detroit Edison Company, it was listed on the National Register of Historic Places in 1997. Detroit Edison was organized in 1903 to build and operate electric plants in Detroit. The Willis Avenue station
60-477: A piston or turbine to perform mechanical work . The ability to return condensed steam as water-liquid to the boiler at high pressure with relatively little expenditure of pumping power is important. Condensation of steam to water often occurs at the low-pressure end of a steam turbine, since this maximizes the energy efficiency , but such wet-steam conditions must be limited to avoid excessive turbine blade erosion. Engineers use an idealised thermodynamic cycle ,
90-422: A turbine . Also, in thermodynamic cycles energy may be input to the working fluid by means of a compressor . The mathematical formulation for this may be quite simple if we consider a cylinder in which a working fluid resides. A piston is used to input useful work to the fluid. From mechanics, the work done from state 1 to state 2 of the process is given by: where ds is the incremental distance from one state to
120-569: A working fluid is a gas or liquid that primarily transfers force , motion , or mechanical energy . In hydraulics , water or hydraulic fluid transfers force between hydraulic components such as hydraulic pumps , hydraulic cylinders , and hydraulic motors that are assembled into hydraulic machinery , hydraulic drive systems , etc. In pneumatics , the working fluid is air or another gas which transfers force between pneumatic components such as compressors , vacuum pumps , pneumatic cylinders , and pneumatic motors . In pneumatic systems,
150-425: A compressor where its pressure is increased. The compressor therefore inputs work to the working fluid (positive work). The fluid is then transferred to a combustion chamber where this time heat energy is input by means of the burning of a fuel. The air then expands in a turbine thus doing work against the surroundings (negative work). Different working fluids have different properties and in choosing one in particular
180-425: A refrigeration unit, the working fluid is called the refrigerant. Ammonia is a typical refrigerant and may be used as the primary working fluid. Compared with water (which can also be used as a refrigerant), ammonia makes use of relatively high pressures requiring more robust and expensive equipment. In air standard cycles as in gas turbine cycles, the working fluid is air. In the open cycle gas turbine, air enters
210-661: A region of interest by conduction , convection , and/or forced convection (pumped liquid cooling , air cooling , etc.). The working fluid of a heat engine or heat pump is a gas or liquid, usually called a refrigerant , coolant, or working gas, that primarily converts thermal energy (temperature change) into mechanical energy (or vice versa) by phase change and/or heat of compression and expansion. Examples using phase change include water↔steam in steam engines , and refrigerants in vapor-compression refrigeration and air conditioning systems. Examples without phase change include air or hydrogen in hot air engines such as
240-515: A sub-group of steam engines. Piston type steam engines played a central role in the Industrial Revolution and modern steam turbines are used to generate more than 80 % of the world's electricity. If liquid water comes in contact with a very hot surface or depressurizes quickly below its vapour pressure , it can create a steam explosion . Steam is traditionally created by heating a boiler via burning coal and other fuels, but it
270-467: A temperature-entropy diagram or a Mollier diagram shown in this article, may be useful. Steam charts are also used for analysing thermodynamic cycles. In agriculture , steam is used for soil sterilization to avoid the use of harmful chemical agents and increase soil health . Steam's capacity to transfer heat is also used in the home: for cooking vegetables, steam cleaning of fabric, carpets and flooring, and for heating buildings. In each case, water
300-495: A thermodynamic cycle it may be the case that the working fluid changes state from gas to liquid or vice versa. Certain gases such as helium can be treated as ideal gases . This is not generally the case for superheated steam and the ideal gas equation does not really hold. At much higher temperatures however it still yields relatively accurate results. The physical and chemical properties of the working fluid are extremely important when designing thermodynamic systems. For instance, in
330-449: Is also possible to create steam with solar energy. Water vapour that includes water droplets is described as wet steam . As wet steam is heated further, the droplets evaporate, and at a high enough temperature (which depends on the pressure) all of the water evaporates and the system is in vapour–liquid equilibrium . When steam has reached this equilibrium point, it is referred to as saturated steam . Superheated steam or live steam
SECTION 10
#1732798793788360-453: Is also useful in melting hardened grease and oil residues, so it is useful in cleaning kitchen floors and equipment and internal combustion engines and parts. Among the advantages of using steam versus a hot water spray are the facts that steam can operate at higher temperatures and it uses substantially less water per minute. [REDACTED] Wikiversity has steam tables with figures and Matlab code Working fluid For fluid power ,
390-422: Is available in many sorts of large factory, such as paper mills . The locomotive's propulsion used pistons and connecting rods, as for a typical steam locomotive. These locomotives were mostly used in places where there was a risk of fire from a boiler's firebox, but were also used in factories that simply had a plentiful supply of steam to spare. Steam engines and steam turbines use the expansion of steam to drive
420-400: Is heated in a boiler, and the steam carries the energy to a target object. Steam is also used in ironing clothes to add enough humidity with the heat to take wrinkles out and put intentional creases into the clothing. As of 2000 around 90% of all electricity was generated using steam as the working fluid , nearly all by steam turbines. In electric generation, steam is typically condensed at
450-448: Is steam at a temperature higher than its boiling point for the pressure, which only occurs when all liquid water has evaporated or has been removed from the system. Steam tables contain thermodynamic data for water/saturated steam and are often used by engineers and scientists in design and operation of equipment where thermodynamic cycles involving steam are used. Additionally, thermodynamic phase diagrams for water/steam, such as
480-418: Is used for energy storage , which is introduced and extracted by heat transfer, usually through pipes. Steam is a capacious reservoir for thermal energy because of water's high heat of vaporization . Fireless steam locomotives were steam locomotives that operated from a supply of steam stored on board in a large tank resembling a conventional locomotive's boiler. This tank was filled by process steam , as
510-446: Is used in piping for utility lines. It is also used in jacketing and tracing of piping to maintain the uniform temperature in pipelines and vessels. Steam is used across multiple industries for its ability to transfer heat to drive chemical reactions, sterilize or disinfect objects and to maintain constant temperatures. In the lumber industry, steam is used in the process of wood bending , killing insects, and increasing plasticity. Steam
540-620: Is used to accentuate drying of concrete especially in prefabricates. Care should be taken since concrete produces heat during hydration and additional heat from the steam could be detrimental to hardening reaction processes of the concrete. In chemical and petrochemical industries , steam is used in various chemical processes as a reactant. Steam cracking of long chain hydrocarbons produces lower molecular weight hydrocarbons for fuel or other chemical applications. Steam reforming produces syngas or hydrogen . Used in cleaning of fibers and other materials, sometimes in preparation for painting. Steam
570-493: The Rankine cycle , to model the behaviour of steam engines. Steam turbines are often used in the production of electricity. An autoclave , which uses steam under pressure, is used in microbiology laboratories and similar environments for sterilization . Steam, especially dry (highly superheated) steam, may be used for antimicrobial cleaning even to the levels of sterilization. Steam is a non-toxic antimicrobial agent. Steam
600-700: The Stirling engine , air or gases in gas-cycle heat pumps , etc. (Some heat pumps and heat engines use "working solids", such as rubber bands, for elastocaloric refrigeration or thermoelastic cooling and nickel titanium in a prototype heat engine.) Working fluids other than air or water are necessarily recirculated in a loop. Some hydraulic and passive heat-transfer systems are open to the water supply and/or atmosphere, sometimes through breather filters . Heat engines, heat pumps, and systems using volatile liquids or special gases are usually sealed behind relief valves . The working fluid's properties are essential for
630-601: The Edison Illuminating Company. It began operation in 1886. Henry Ford began his career with the Edison Illuminating Company on September 25, 1891 assigned to this substation as a Steam Engineer, working the 6:00pm to 6:00am shift. Steam When liquid water becomes steam, it increases in volume by 1,700 times at standard temperature and pressure ; this change in volume can be converted into mechanical work by steam engines such as reciprocating piston type engines and steam turbines , which are
SECTION 20
#1732798793788660-568: The end of its expansion cycle, and returned to the boiler for re-use. However, in co-generation , steam is piped into buildings through a district heating system to provide heat energy after its use in the electric generation cycle. The world's biggest steam generation system is the New York City steam system , which pumps steam into 100,000 buildings in Manhattan from seven co-generation plants. In other industrial applications steam
690-399: The full description of thermodynamic systems. Although working fluids have many physical properties which can be defined, the thermodynamic properties which are often required in engineering design and analysis are few. Pressure , temperature , enthalpy , entropy , specific volume , and internal energy are the most common. If at least two thermodynamic properties are known, the state of
720-403: The next and F is the force applied. The negative sign is introduced since in this case a decrease in volume is being considered. The situation is shown in the following figure: The force is given by the product of the pressure in the cylinder and its cross sectional area such that Where A⋅ds = dV is the elemental change of cylinder volume. If from state 1 to 2 the volume increases then
750-405: The thermodynamic properties of the fluid. In reality however this can only be done if the process is reversible . If not, the changes in property are represented as a dotted line on a property diagram. This issue does not really affect thermodynamic analysis since in most cases it is the end states of a process which are sought after. The working fluid can be used to output useful work if used in
780-451: The working fluid actually does work on its surroundings and this is commonly denoted by a negative work. If the volume decreases the work is positive. By the definition given with the above integral the work done is represented by the area under a pressure–volume diagram . If we consider the case where we have a constant pressure process then the work is simply given by Depending on the application, various types of working fluids are used. In
810-399: The working fluid can be defined. This is usually done on a property diagram which is simply a plot of one property versus another. When the working fluid passes through engineering components such as turbines and compressors , the point on a property diagram moves due to the possible changes of certain properties. In theory therefore it is possible to draw a line/curve which fully describes
840-443: The working gas also stores energy because it is compressible. (Gases also heat up as they are compressed and cool as they expand; this incidental heat pump is rarely exploited.) (Some gases also condense into liquids as they are compressed and boil as pressure is reduced.) For passive heat transfer , a working fluid is a gas or liquid, usually called a coolant or heat transfer fluid, that primarily transfers heat into or out of
870-620: Was increased as the years passed. By the mid-1940s, there were 42 miles (68 km) of underground mains and serving approximately 1,650 customers. During that time, the Willis Avenue Plant was updated and altered numerous times to serve the heating needs of the community, especially between 1916-1927. The station continues to serve the Cass Farm Survey Area. This station in located near the original location of an electric generating sub-station owned and operated by
900-408: Was the first steam power substation used by Detroit Edison for the production of steam heat. Three other plants serve the central heating district of Detroit. When the plant first went on line in 1904, there were 3,000 feet (910 m) of mains in place, serving only 12 customers. During the summer of that year, an additional 10,000 feet (3,000 m) of mains were constructed, and the infrastructure
#787212