Misplaced Pages

#707292

102-400: In 1915 DSM decided to build a new cooling tower in order to cool water that was used at their coal-fired electrical power station. DSM director and engineer Frederik van Iterson made a new design of a concrete hyperboloid natural draught cooling tower, which evolved into the standard design that is used at modern power plants . The design was patented by Van Iterson and Gerard Kuypers in

204-449: A pultruded fiber-reinforced plastic (FRP) structure, FRP cladding , a mechanical unit for air draft , and a drift eliminator. With respect to the heat transfer mechanism employed, the main types are: In a wet cooling tower (or open circuit cooling tower), the warm water can be cooled to a temperature lower than the ambient air dry-bulb temperature, if the air is relatively dry (see dew point and psychrometrics ). As ambient air

306-422: A stub . You can help Misplaced Pages by expanding it . This article about a specific mine is a stub . You can help Misplaced Pages by expanding it . Cooling tower A cooling tower is a device that rejects waste heat to the atmosphere through the cooling of a coolant stream, usually a water stream, to a lower temperature. Cooling towers may either use the evaporation of water to remove heat and cool

408-651: A vertical beam or overhead beam , and sometimes simply referred as a "beam", was another early adaptation of the beam engine, but its use was confined almost entirely to the United States. After its introduction, the walking beam quickly became the most popular engine type in American waters for inland waterway and coastal service, eventually making its way into American transoceanic steamships as well. The type proved to have remarkable longevity, with walking beam engines still being occasionally manufactured as late as

510-417: A beam (i.e. walking beam, side-lever or grasshopper) engine. The later definition only uses the term for engines that apply power directly to the crankshaft via the piston rod and/or connecting rod. Unless otherwise noted, this article uses the later definition. Unlike the side-lever or beam engine, a direct-acting engine could be readily adapted to power either paddlewheels or a propeller. As well as offering

612-464: A centrally located crankshaft. Back-acting engines were another type of engine popular in both warships and commercial vessels in the mid-19th century, but like many other engine types in this era of rapidly changing technology, they were eventually abandoned for other solutions. There is only one known surviving back-acting engine—that of the TV Emery Rice (formerly USS  Ranger ), now

714-460: A chiller coefficient of performance (COP) of 4.0. This COP is equivalent to an energy efficiency ratio (EER) of 14. Cooling towers are also used in HVAC systems that have multiple water source heat pumps that share a common piping water loop . In this type of system, the water circulating inside the water loop removes heat from the condenser of the heat pumps whenever the heat pumps are working in

816-486: A chimney stack much shortened vertically (20 to 40 ft. high) and very much enlarged laterally. At the top is a set of distributing troughs, to which the water from the condenser must be pumped; from these it trickles down over "mats" made of wooden slats or woven wire screens, which fill the space within the tower". A hyperboloid cooling tower was patented by the Dutch engineers Frederik van Iterson and Gerard Kuypers in

918-492: A common, T-shaped crosshead. The vertical arm of the crosshead extended down between the two cylinders and was attached at the bottom to both the crankshaft connecting rod and to a guide block that slid between the vertical sides of the cylinders, enabling the assembly to maintain the correct path as it moved. The Siamese engine was invented by British engineer Joseph Maudslay (son of Henry ), but although he invented it after his oscillating engine (see below), it failed to achieve

1020-553: A compound engine gave a significant increase in fuel efficiency, so allowing steamships to out-compete sail on the route from the UK to China, even before the opening of the Suez Canal in 1869. A triple-expansion engine is a compound engine that expands the steam in three stages, e.g. an engine with three cylinders at three different pressures. A quadruple-expansion engine expands the steam in four stages. However, as explained above,

1122-468: A compound walking beam type, compound being the cylinder technology, and walking beam being the connection method. Over time, as most engines became direct-acting but cylinder technologies grew more complex, engines began to be classified solely according to cylinder technology. More commonly encountered marine steam engine types are listed in the following sections. Note that not all these terms are exclusive to marine applications. The side-lever engine

SECTION 10

#1732775418708

1224-434: A deep pan with holes or nozzles in its bottom is located near the top of a crossflow tower. Gravity distributes the water through the nozzles uniformly across the fill material. Cross Flow V/s Counter Flow Advantages of the crossflow design: Disadvantages of the crossflow design: In a counterflow design, the air flow is directly opposite to the water flow (see diagram at left). Air flow first enters an open area beneath

1326-430: A different design operating at only 90 psi (620 kPa). This was insufficient to fully realise the economic benefits of triple expansion. Aberdeen was fitted with two double ended Scotch type steel boilers, running at 125 psi (860 kPa). These boilers had patent corrugated furnaces that overcame the competing problems of heat transfer and sufficient strength to deal with the boiler pressure. This provided

1428-474: A lower profile, direct-acting engines had the advantage of being smaller and weighing considerably less than beam or side-lever engines. The Royal Navy found that on average a direct-acting engine (early definition) weighed 40% less and required an engine room only two thirds the size of that for a side-lever of equivalent power. One disadvantage of such engines is that they were more prone to wear and tear and thus required more maintenance. An oscillating engine

1530-514: A method for steam recapture. The steam is charged using an ion beam, and then captured in a wire mesh of opposite charge. The water's purity exceeded EPA potability standards. An HVAC (heating, ventilating, and air conditioning) cooling tower is used to dispose of ("reject") unwanted heat from a chiller . Liquid-cooled chillers are normally more energy efficient than air-cooled chillers due to heat rejection to tower water at or near wet-bulb temperatures . Air-cooled chillers must reject heat at

1632-729: A ship's economy or its speed. Broadly speaking, a compound engine can refer to a steam engine with any number of different-pressure cylinders—however, the term usually refers to engines that expand steam through only two stages, i.e., those that operate cylinders at only two different pressures (or "double-expansion" engines). Note that a compound engine (including multiple-expansion engines, see below) can have more than one set of variable-pressure cylinders. For example, an engine might have two cylinders operating at pressure x and two operating at pressure y, or one cylinder operating at pressure x and three operating at pressure y. What makes it compound (or double-expansion) as opposed to multiple-expansion

1734-407: A side-rod, extended down each side of the cylinder to connect to the end of the side-lever on the same side. The far ends of the two side-levers were connected to one another by a horizontal crosstail, from which extended a single, common connecting rod which operated the crankshaft as the levers rocked up and down around the central pin. The main disadvantage of the side-lever engine was that it

1836-416: A small amount of the water to be lost as windage or drift (W) and some of the water (E) to evaporate . The heat required to evaporate the water is derived from the water itself, which cools the water back to the original basin water temperature and the water is then ready to recirculate. The evaporated water leaves its dissolved salts behind in the bulk of the water which has not been evaporated, thus raising

1938-511: A small, low-profile engine like the trunk engine to power the U.S. Federal government's monitors , a type of warship developed during the American Civil War that had very little space for a conventional powerplant. The trunk engine itself was, however, unsuitable for this purpose, because the preponderance of weight was on the side of the engine that contained the cylinder and trunk—a problem that designers could not compensate for on

2040-415: A smaller, lighter, more efficient design. In a steeple engine, the vertical oscillation of the piston is not converted to a horizontal rocking motion as in a beam engine, but is instead used to move an assembly, composed of a crosshead and two rods, through a vertical guide at the top of the engine, which in turn rotates the crankshaft connecting rod below. In early examples of the type, the crosshead assembly

2142-534: A typical 700 MW th coal-fired power plant with a cooling tower amounts to about 71,600 cubic metres an hour (315,000 US gallons per minute) and the circulating water requires a supply water make-up rate of perhaps 5 percent (i.e., 3,600 cubic metres an hour, equivalent to one cubic metre every second). If that same plant had no cooling tower and used once-through cooling water, it would require about 100,000 cubic metres an hour A large cooling water intake typically kills millions of fish and larvae annually, as

SECTION 20

#1732775418708

2244-493: Is a steam engine that is used to power a ship or boat . This article deals mainly with marine steam engines of the reciprocating type, which were in use from the inception of the steamboat in the early 19th century to their last years of large-scale manufacture during World War II . Reciprocating steam engines were progressively replaced in marine applications during the 20th century by steam turbines and marine diesel engines . The first commercially successful steam engine

2346-457: Is a design in which the airflow is directed perpendicular to the water flow (see diagram at left). Airflow enters one or more vertical faces of the cooling tower to meet the fill material. Water flows (perpendicular to the air) through the fill by gravity. The air continues through the fill and thus past the water flow into an open plenum volume. Lastly, a fan forces the air out into the atmosphere. A distribution or hot water basin consisting of

2448-417: Is a relatively more important issue for package type cooling towers. Facilities such as power plants, steel processing plants, petroleum refineries, or petrochemical plants usually install field-erected type cooling towers due to their greater capacity for heat rejection. Field-erected towers are usually much larger in size compared to the package type cooling towers. A typical field-erected cooling tower has

2550-462: Is also an alternative name for the steeple engine (below). Many sources thus prefer to refer to it by its informal name of "square" engine to avoid confusion. Additionally, the marine crosshead or square engine described in this section should not be confused with the term " square engine " as applied to internal combustion engines , which in the latter case refers to an engine whose bore is equal to its stroke . The walking beam, technically known as

2652-655: Is based on the type of air induction into the tower: the main types of cooling towers are natural draft and induced draft cooling towers. Cooling towers vary in size from small roof-top units to very large hyperboloid structures that can be up to 200 metres (660 ft) tall and 100 metres (330 ft) in diameter, or rectangular structures that can be over 40 metres (130 ft) tall and 80 metres (260 ft) long. Hyperboloid cooling towers are often associated with nuclear power plants , although they are also used in many coal-fired plants and to some extent in some large chemical and other industrial plants. The steam turbine

2754-574: Is defined as the removal of 12,000 British thermal units per hour (3.5 kW). The equivalent ton on the cooling tower side actually rejects about 15,000 British thermal units per hour (4.4 kW) due to the additional waste-heat–equivalent of the energy needed to drive the chiller's compressor. This equivalent ton is defined as the heat rejection in cooling 3 US gallons per minute (11 litres per minute) or 1,500 pounds per hour (680 kg/h) of water by 10 °F (5.6 °C), which amounts to 15,000 British thermal units per hour (4.4 kW), assuming

2856-400: Is drawn past a flow of water, a small portion of the water evaporates, and the energy required to evaporate that portion of the water is taken from the remaining mass of water, thus reducing its temperature. Approximately 2,300 kilojoules per kilogram (970 BTU/lb) of heat energy is absorbed for the evaporated water. Evaporation results in saturated air conditions, lowering the temperature of

2958-452: Is not an issue with marine engines , it forms a significant limitation for many land-based systems. By the turn of the 20th century, several evaporative methods of recycling cooling water were in use in areas lacking an established water supply, as well as in urban locations where municipal water mains may not be of sufficient supply, reliable in times of high demand, or otherwise adequate to meet cooling needs. In areas with available land,

3060-630: Is supplied by other means, usually from separate boilers . Industrial cooling towers can be used to remove heat from various sources such as machinery or heated process material. The primary use of large, industrial cooling towers is to remove the heat absorbed in the circulating cooling water systems used in power plants , petroleum refineries , petrochemical plants, natural gas processing plants, food processing plants, semi-conductor plants, and for other industrial facilities such as in condensers of distillation columns, for cooling liquid in crystallization, etc. The circulation rate of cooling water in

3162-401: Is that the engine could be easily started from any crank position. Like the conventional side-lever engine however, grasshopper engines were disadvantaged by their weight and size. They were mainly used in small watercraft such as riverboats and tugs . The crosshead engine, also known as a square , sawmill or A-frame engine, was a type of paddlewheel engine used in the United States. It

Staatsmijn Emma - Misplaced Pages Continue

3264-438: Is that there are only two pressures , x and y. The first compound engine believed to have been installed in a ship was that fitted to Henry Eckford by the American engineer James P. Allaire in 1824. However, many sources attribute the "invention" of the marine compound engine to Glasgow 's John Elder in the 1850s. Elder made improvements to the compound engine that made it safe and economical for ocean-crossing voyages for

3366-761: Is the 210 metres (690 ft) tall cooling tower of the Pingshan II Power Station in Huaibei , Anhui Province, China. These types of cooling towers are factory preassembled, and can be simply transported on trucks, as they are compact machines. The capacity of package type towers is limited and, for that reason, they are usually preferred by facilities with low heat rejection requirements such as food processing plants, textile plants, some chemical processing plants, or buildings like hospitals, hotels, malls, automotive factories, etc. Due to their frequent use in or near residential areas, sound level control

3468-523: Is what necessitates the cooling tower. Although these large towers are very prominent, the vast majority of cooling towers are much smaller, including many units installed on or near buildings to discharge heat from air conditioning . Cooling towers are also often thought to emit smoke or harmful fumes by the general public and environmental activists, when in reality the emissions from those towers mostly do not contribute to carbon footprint , consisting solely of water vapor . Cooling towers originated in

3570-417: The beam engine . The typical side-lever engine had a pair of heavy horizontal iron beams, known as side-levers, each secured in the centre by a pin near the base of the engine, allowing the levers to pivot through a limited arc. The engine cylinder stood vertically between this pair of levers at one end, with the piston rod attached to a horizontal crosshead above, from each end of which a vertical rod, known as

3672-471: The screw propeller , and the introduction of iron and later steel hulls to replace the traditional wooden hull allowed ships to grow ever larger, necessitating steam power plants that were increasingly complex and powerful. A wide variety of reciprocating marine steam engines were developed over the course of the 19th century. The two main methods of classifying such engines are by connection mechanism and cylinder technology . Most early marine engines had

3774-524: The 1830s and the type was perfected in the early 1840s by the Scottish shipbuilder David Napier . The steeple engine was gradually superseded by the various types of direct-acting engine. The Siamese engine, also referred to as the "double cylinder" or "twin cylinder" engine, was another early alternative to the beam or side-lever engine. This type of engine had two identical, vertical engine cylinders arranged side-by-side, whose piston rods were attached to

3876-504: The 1940s. In marine applications, the beam itself was generally reinforced with iron struts that gave it a characteristic diamond shape, although the supports on which the beam rested were often built of wood. The adjective "walking" is believed to have originated from a corruption of the technical term "working beam". Walking beam engines were a type of paddlewheel engine and were rarely used for powering propellers. They were used primarily for ships and boats working in rivers, lakes and along

3978-511: The 19th century through the development of condensers for use with the steam engine . Condensers use relatively cool water, via various means, to condense the steam coming out of the cylinders or turbines. This reduces the back pressure , which in turn reduces the steam consumption, and thus the fuel consumption, while at the same time increasing power and recycling boiler water. However, the condensers require an ample supply of cooling water, without which they are impractical. While water usage

4080-497: The M-Cycle HMX for air conditioning, through engineering design this cycle could be applied as a heat- and moisture-recovery device for combustion devices, cooling towers, condensers, and other processes involving humid gas streams. The consumption of cooling water by inland processing and power plants is estimated to reduce power availability for the majority of thermal power plants by 2040–2069. In 2021, researchers presented

4182-731: The Netherlands on August 16, 1916. The first hyperboloid reinforced concrete cooling towers were built by the Dutch State Mine (DSM) Emma in 1918 in Heerlen . The first ones in the United Kingdom were built in 1924 at Lister Drive power station in Liverpool , England. On both locations they were built to cool water used at a coal-fired electrical power station. According to a Gas Technology Institute (GTI) report ,

Staatsmijn Emma - Misplaced Pages Continue

4284-523: The Netherlands on August 16, 1916. The first Van Iterson cooling tower was built and put to use on the DSM Emma terrain in 1918. A whole series of the same and later evolved designs would follow. The towers were so iconic the Dutch State Mines decided to use them in their logo. [REDACTED] Media related to Staatsmijn Emma at Wikimedia Commons This Dutch Limburg location article is

4386-609: The UK patent (108,863) for Improved Construction of Cooling Towers of Reinforced Concrete . The patent was filed on 9 August 1917, and published on 11 April 1918. In 1918, DSM built the first hyperboloid natural-draft cooling tower at the Staatsmijn Emma , to his design. Hyperboloid (sometimes incorrectly known as hyperbolic ) cooling towers have become the design standard for all natural-draft cooling towers because of their structural strength and minimum usage of material. The hyperboloid shape also aids in accelerating

4488-514: The United States and in Ericsson's native country of Sweden, and as they had few advantages over more conventional engines, were soon supplanted by other types. The back-acting engine, also known as the return connecting rod engine , was another engine designed to have a very low profile. The back-acting engine was in effect a modified steeple engine, laid horizontally across the keel of a ship rather than standing vertically above it. Instead of

4590-526: The acceptable range of cycles of concentration. Concentration cycles in the majority of cooling towers usually range from 3 to 7. In the United States, many water supplies use well water which has significant levels of dissolved solids. On the other hand, one of the largest water supplies, for New York City , has a surface rainwater source quite low in minerals; thus cooling towers in that city are often allowed to concentrate to 7 or more cycles of concentration. Marine steam engine A marine steam engine

4692-570: The accumulation of dissolved minerals in the recirculating cooling water. Discharge of draw-off (or blowdown) is used principally to control the buildup of these minerals. The chemistry of the make-up water, including the amount of dissolved minerals, can vary widely. Make-up waters low in dissolved minerals such as those from surface water supplies (lakes, rivers etc.) tend to be aggressive to metals (corrosive). Make-up waters from ground water supplies (such as wells ) are usually higher in minerals, and tend to be scaling (deposit minerals). Increasing

4794-420: The amount of minerals present in the water by cycling can make water less aggressive to piping; however, excessive levels of minerals can cause scaling problems. As the cycles of concentration increase, the water may not be able to hold the minerals in solution . When the solubility of these minerals have been exceeded they can precipitate out as mineral solids and cause fouling and heat exchange problems in

4896-412: The assembly maintained the correct path as it moved. The engine's alternative name—"A-frame"—presumably derived from the shape of the frames that supported these guides. Some crosshead engines had more than one cylinder, in which case the piston rods were usually all connected to the same crosshead. Because the cylinder was above the crankshaft in this type of engine, it had a high center of gravity, and

4998-488: The centerpiece of a display at the American Merchant Marine Museum . As steamships grew steadily in size and tonnage through the course of the 19th century, the need for low profile, low centre-of-gravity engines correspondingly declined. Freed increasingly from these design constraints, engineers were able to revert to simpler, more efficient and more easily maintained designs. The result was

5100-457: The close of the 19th century. Because they became so common, vertical engines are not usually referred to as such, but are instead referred to based upon their cylinder technology, i.e. as compound, triple-expansion, quadruple-expansion etc. The term "vertical" for this type of engine is imprecise, since technically any type of steam engine is "vertical" if the cylinder is vertically oriented. An engine someone describes as "vertical" might not be of

5202-431: The coast. The first successful transatlantic crossing by a steamship occurred in 1819 when Savannah sailed from Savannah, Georgia to Liverpool, England . The first steamship to make regular transatlantic crossings was the sidewheel steamer Great Western in 1838. As the 19th century progressed, marine steam engines and steamship technology developed alongside each other. Paddle propulsion gradually gave way to

SECTION 50

#1732775418708

5304-640: The coastline, but were a less popular choice for seagoing vessels because the great height of the engine made the vessel less stable in heavy seas. They were also of limited use militarily, because the engine was exposed to enemy fire and could thus be easily disabled. Their popularity in the United States was due primarily to the fact that the walking beam engine was well suited for the shallow- draft boats that operated in America's shallow coastal and inland waterways. Walking beam engines remained popular with American shipping lines and excursion operations right into

5406-435: The conservatism of American domestic shipbuilders and shipping line owners, who doggedly clung to outdated technologies like the walking beam and its associated paddlewheel long after they had been abandoned in other parts of the world. The steeple engine, sometimes referred to as a "crosshead" engine, was an early attempt to break away from the beam concept common to both the walking beam and side-lever types, and come up with

5508-477: The cooling mode, then the externally mounted cooling tower is used to remove heat from the water loop and reject it to the atmosphere . By contrast, when the heat pumps are working in heating mode, the condensers draw heat out of the loop water and reject it into the space to be heated. When the water loop is being used primarily to supply heat to the building, the cooling tower is normally shut down (and may be drained or winterized to prevent freeze damage), and heat

5610-529: The cooling tower or the heat exchangers . The temperatures of the recirculating water, piping and heat exchange surfaces determine if and where minerals will precipitate from the recirculating water. Often a professional water treatment consultant will evaluate the make-up water and the operating conditions of the cooling tower and recommend an appropriate range for the cycles of concentration. The use of water treatment chemicals, pretreatment such as water softening , pH adjustment, and other techniques can affect

5712-424: The crankshaft rotated—hence the term, oscillating . Steam was supplied and exhausted through the trunnions. The oscillating motion of the cylinder was usually used to line up ports in the trunnions to direct the steam feed and exhaust to the cylinder at the correct times. However, separate valves were often provided, controlled by the oscillating motion. This let the timing be varied to enable expansive working (as in

5814-410: The early 20th century. Although the walking beam engine was technically obsolete in the later 19th century, it remained popular with excursion steamer passengers who expected to see the "walking beam" in motion. There were also technical reasons for retaining the walking beam engine in America, as it was easier to build, requiring less precision in its construction. Wood could be used for the main frame of

5916-412: The engine in the paddle ship PD Krippen ). This provides simplicity but still retains the advantages of compactness. The first patented oscillating engine was built by Joseph Maudslay in 1827, but the type is considered to have been perfected by John Penn . Oscillating engines remained a popular type of marine engine for much of the 19th century. The trunk engine, another type of direct-acting engine,

6018-526: The engine, at a much lower cost than typical practice of using iron castings for more modern engine designs. Fuel was also much cheaper in America than in Europe, so the lower efficiency of the walking beam engine was less of a consideration. The Philadelphia shipbuilder Charles H. Cramp blamed America's general lack of competitiveness with the British shipbuilding industry in the mid-to-late 19th century upon

6120-466: The entire system is then: Since the evaporated water (E) has no salts, a chloride balance around the system is: and, therefore: From a simplified heat balance around the cooling tower: Windage (or drift) losses (W) is the amount of total tower water flow that is entrained in the flow of air to the atmosphere. From large-scale industrial cooling towers, in the absence of manufacturer's data, it may be assumed to be: Cycle of concentration represents

6222-443: The fill media, and is then drawn up vertically. The water is sprayed through pressurized nozzles near the top of the tower, and then flows downward through the fill, opposite to the air flow. Advantages of the counterflow design: Disadvantages of the counterflow design: Common aspects of both designs: Both crossflow and counterflow designs can be used in natural draft and in mechanical draft cooling towers. Quantitatively,

SECTION 60

#1732775418708

6324-404: The first Royal Navy steam vessel in 1820 until 1840, 70 steam vessels entered service, the majority with side-lever engines, using boilers set to 4psi maximum pressure. The low steam pressures dictated the large cylinder sizes for the side-lever engines, though the effective pressure on the piston was the difference between the boiler pressure and the vacuum in the condenser. The side-lever engine

6426-550: The first time. To fully realise their benefits, marine compound engines required boiler pressures higher than the limit imposed by the United Kingdom 's Board of Trade , who would only allow 25 pounds per square inch (170 kPa). The shipowner and engineer Alfred Holt was able to persuade the authorisation of higher boiler pressures, launching SS  Agamemnon in 1865, with boilers running at 60 psi (410 kPa). The combination of higher boiler pressures and

6528-424: The growing dominance of the so-called "vertical" engine (more correctly known as the vertical inverted direct acting engine). In this type of engine, the cylinders are located directly above the crankshaft, with the piston rod/connecting rod assemblies forming a more or less straight line between the two. The configuration is similar to that of a modern internal combustion engine (one notable difference being that

6630-716: The gunboat type exists in the Western Australian Museum in Fremantle . After sinking in 1872, it was raised in 1985 from the SS ; Xantho and can now be turned over by hand. The engine's mode of operation, illustrating its compact nature, could be viewed on the Xantho project's website. The vibrating lever, or half-trunk engine, was a development of the conventional trunk engine conceived by Swedish - American engineer John Ericsson . Ericsson needed

6732-436: The heat into the atmosphere instead, so that wind and air diffusion spreads the heat over a much larger area than hot water can distribute heat in a body of water. Evaporative cooling water cannot be used for subsequent purposes (other than rain somewhere), whereas surface-only cooling water can be re-used. Some coal-fired and nuclear power plants located in coastal areas do make use of once-through ocean water. But even there,

6834-499: The higher boiler pressures that became prevalent in the latter half of the 19th century due to the difficulty of maintaining a steam seal around the trunk, and builders abandoned them for other solutions. Trunk engines were normally large, but a small, mass-produced, high-revolution, high-pressure version was produced for the Crimean War. In being quite effective, the type persisted in later gunboats. An original trunk engine of

6936-440: The higher dry-bulb temperature , and thus have a lower average reverse– Carnot-cycle effectiveness. In hot climates, large office buildings, hospitals, and schools typically use cooling towers in their air conditioning systems. Generally, industrial cooling towers are much larger than HVAC towers. HVAC use of a cooling tower pairs the cooling tower with a liquid-cooled chiller or liquid-cooled condenser. A ton of air-conditioning

7038-402: The hot process streams which need to be cooled or condensed, and the absorbed heat warms the circulating water (C). The warm water returns to the top of the cooling tower and trickles downward over the fill material inside the tower. As it trickles down, it contacts ambient air rising up through the tower either by natural draft or by forced draft using large fans in the tower. That contact causes

7140-402: The indirect–dew-point evaporative-cooling Maisotsenko Cycle (M-Cycle) is a theoretically sound method of reducing a working fluid to the ambient fluid’s dew point, which is lower than the ambient fluid’s wet-bulb temperature. The M-cycle utilizes the psychrometric energy (or the potential energy) available from the latent heat of water evaporating into the air. While its current manifestation is as

7242-500: The literature of the early period then, an engine can generally be assumed to be simple-expansion unless otherwise stated. Compound engines were a method of improving efficiency. Until the development of compound engines, steam engines used the steam only once before it was recycled back to the boiler. A compound engine first recycles the steam into one or more larger, lower-pressure secondary cylinders, to use more of its heat energy. Compound engines could be configured to increase either

7344-459: The location of the lever pivot and connecting rod are more or less reversed, with the pivot located at one end of the lever instead of the centre, while the connecting rod is attached to the lever between the cylinder at one end and the pivot at the other. Chief advantages of the grasshopper engine were cheapness of construction and robustness, with the type said to require less maintenance than any other type of marine steam engine. Another advantage

7446-419: The material balance around a wet, evaporative cooling tower system is governed by the operational variables of make-up volumetric flow rate , evaporation and windage losses, draw-off rate, and the concentration cycles. In the adjacent diagram, water pumped from the tower basin is the cooling water routed through the process coolers and condensers in an industrial facility. The cool water absorbs heat from

7548-673: The number of expansion stages defines the engine, not the number of cylinders, e.g. the RMS Titanic had four-cylinder, triple-expansion engines. The first successful commercial use was an engine built at Govan in Scotland by Alexander C. Kirk for the SS  Aberdeen in 1881. An earlier experiment with an almost identical engine in SS Propontis in 1874 had had problems with the boilers. The initial installation, running at 150 psi (1,000 kPa) had to be replaced with

7650-414: The offshore discharge water outlet requires very careful design to avoid environmental problems. Petroleum refineries may also have very large cooling tower systems. A typical large refinery processing 40,000 metric tonnes of crude oil per day (300,000 barrels (48,000 m ) per day) circulates about 80,000 cubic metres of water per hour through its cooling tower system. The world's tallest cooling tower

7752-621: The organisms are impinged on the intake screens . A large amount of water would have to be continuously returned to the ocean, lake or river from which it was obtained and continuously re-supplied to the plant. Furthermore, discharging large amounts of hot water may raise the temperature of the receiving river or lake to an unacceptable level for the local ecosystem. Elevated water temperatures can kill fish and other aquatic organisms (see thermal pollution ), or can also cause an increase in undesirable organisms such as invasive species of zebra mussels or algae . A cooling tower serves to dissipate

7854-432: The salt concentration in the circulating cooling water. To prevent the salt concentration of the water from becoming too high, a portion of the water is drawn off or blown down (D) for disposal. Fresh water make-up (M) is supplied to the tower basin to compensate for the loss of evaporated water, the windage loss water and the draw-off water. Using these flow rates and concentration dimensional units: A water balance around

7956-595: The same cylinder technology (simple expansion, see below) but a number of different methods of supplying power to the crankshaft (i.e. connection mechanism) were in use. Thus, early marine engines are classified mostly according to their connection mechanism. Some common connection mechanisms were side-lever, steeple, walking beam and direct-acting (see following sections). However, steam engines can also be classified according to cylinder technology (simple-expansion, compound, annular etc.). One can therefore find examples of engines classified under both methods. An engine can be

8058-455: The same widespread acceptance, as it was only marginally smaller and lighter than the side-lever engines it was designed to replace. It was however used on a number of mid-century warships, including the first warship fitted with a screw propeller, HMS  Rattler . There are two definitions of a direct-acting engine encountered in 19th-century literature. The earlier definition applies the term "direct-acting" to any type of engine other than

8160-475: The side-to-side motion of the connecting rod, which links a gudgeon pin at the piston head to an outside crankshaft. The walls of the trunk were either bolted to the piston or cast as one piece with it, and moved back and forth with it. The working portion of the cylinder is annular or ring-shaped, with the trunk passing through the centre of the cylinder itself. Early examples of trunk engines had vertical cylinders. However, ship builders quickly realized that

8262-406: The small monitor warships. Ericsson resolved this problem by placing two horizontal cylinders back-to-back in the middle of the engine, working two "vibrating levers", one on each side, which by means of shafts and additional levers rotated a centrally located crankshaft. Vibrating lever engines were later used in some other warships and merchant vessels, but their use was confined to ships built in

8364-436: The steam engine is double acting, see below, whereas almost all internal combustion engines generate power only in the downward stroke). Vertical engines are sometimes referred to as "hammer", "forge hammer" or "steam hammer" engines, due to their roughly similar appearance to another common 19th-century steam technology, the steam hammer . Vertical engines came to supersede almost every other type of marine steam engine toward

8466-422: The systems took the form of cooling ponds ; in areas with limited land, such as in cities, they took the form of cooling towers. These early towers were positioned either on the rooftops of buildings or as free-standing structures, supplied with air by fans or relying on natural airflow. An American engineering textbook from 1911 described one design as "a circular or rectangular shell of light plate—in effect,

8568-404: The technical solution that ensured that virtually all newly built ocean-going steamships were fitted with triple expansion engines within a few years of Aberdeen coming into service. Multiple-expansion engine manufacture continued well into the 20th century. All 2,700 Liberty ships built by the United States during World War II were powered by triple-expansion engines, because the capacity of

8670-411: The triangular crosshead assembly found in a typical steeple engine however, the back-acting engine generally used a set of two or more elongated, parallel piston rods terminating in a crosshead to perform the same function. The term "back-acting" or "return connecting rod" derives from the fact that the connecting rod "returns" or comes back from the side of the engine opposite the engine cylinder to rotate

8772-543: The type was compact enough to lay horizontally across the keel . In this configuration, it was very useful to navies, as it had a profile low enough to fit entirely below a ship's waterline , as safe as possible from enemy fire. The type was generally produced for military service by John Penn. Trunk engines were common on mid-19th century warships. They also powered commercial vessels, where—though valued for their compact size and low centre of gravity—they were expensive to operate. Trunk engines, however, did not work well with

8874-582: The upward convective air flow, improving cooling efficiency. These designs are popularly associated with nuclear power plants . However, this association is misleading, as the same kind of cooling towers are often used at large coal-fired power plants and some geothermal plants as well. The steam turbine is what necessitates the cooling tower. Conversely, not all nuclear power plants have cooling towers, and some instead cool their working fluid with lake, river or ocean water. Typically lower initial and long-term cost, mostly due to pump requirements. Crossflow

8976-420: The vertical inverted direct-acting type, unless they use the term "vertical" without qualification. A simple-expansion engine is a steam engine that expands the steam through only one stage, which is to say, all its cylinders are operated at the same pressure. Since this was by far the most common type of engine in the early period of marine engine development, the term "simple expansion" is rarely encountered. In

9078-407: The water flow causing splashing. Film fill is composed of thin sheets of material (usually PVC ) upon which the water flows. Both methods create increased surface area and time of contact between the fluid (water) and the gas (air), to improve heat transfer. With respect to drawing air through the tower, there are three types of cooling towers: On 16 August 1916, Frederik van Iterson took out

9180-422: The water processed by the tower to a value close to wet-bulb temperature , which is lower than the ambient dry-bulb temperature , the difference determined by the initial humidity of the ambient air. To achieve better performance (more cooling), a medium called fill is used to increase the surface area and the time of contact between the air and water flows. Splash fill consists of material placed to interrupt

9282-444: The working fluid to near the wet-bulb air temperature or, in the case of dry cooling towers , rely solely on air to cool the working fluid to near the dry-bulb air temperature using radiators . Common applications include cooling the circulating water used in oil refineries , petrochemical and other chemical plants , thermal power stations , nuclear power stations and HVAC systems for cooling buildings. The classification

9384-686: The world's "first practical steamboat ", the Charlotte Dundas , in 1802. Rivaling inventors James Rumsey and John Fitch were the first to build steamboats in the United States. Rumsey exhibited his steamboat design in 1787 on the Potomac River; however, Fitch won the rivalry in 1790 after his successful test resulted in a passenger service on the Delaware River. In 1807, the American Robert Fulton built

9486-582: The world's first commercially successful steamboat, simply known as the North River Steamboat , and powered by a Watt engine. Following Fulton's success, steamboat technology developed rapidly on both sides of the Atlantic . Steamboats initially had a short range and were not particularly seaworthy due to their weight, low power, and tendency to break down, but they were employed successfully along rivers and canals, and for short journeys along

9588-491: Was a paddlewheel engine and was not suitable for driving screw propellers . The last ship built for transatlantic service that had a side-lever engine was the Cunard Line 's paddle steamer RMS  Scotia , considered an anachronism when it entered service in 1862. The grasshopper or 'half-lever' engine was a variant of the side-lever engine. The grasshopper engine differs from the conventional side-lever in that

9690-406: Was a type of direct-acting engine that was designed to achieve further reductions in engine size and weight. Oscillating engines had the piston rods connected directly to the crankshaft, dispensing with the need for connecting rods. To achieve this, the engine cylinders were not immobile as in most engines, but secured in the middle by trunnions that let the cylinders themselves pivot back and forth as

9792-466: Was developed by Thomas Newcomen in 1712. The steam engine improvements brought forth by James Watt in the later half of the 18th century greatly improved steam engine efficiency and allowed more compact engine arrangements. Successful adaptation of the steam engine to marine applications in England would have to wait until almost a century after Newcomen, when Scottish engineer William Symington built

9894-464: Was large and heavy. For inland waterway and coastal service, lighter and more efficient designs soon replaced it. It remained the dominant engine type for oceangoing service through much of the first half of the 19th century however, due to its relatively low centre of gravity , which gave ships more stability in heavy seas. It was also a common early engine type for warships, since its relatively low height made it less susceptible to battle damage. From

9996-404: Was originally developed as a means of reducing an engine's height while retaining a long stroke . (A long stroke was considered important at this time because it reduced the strain on components.) A trunk engine locates the connecting rod within a large-diameter hollow piston. This "trunk" carries almost no load. The interior of the trunk is open to outside air, and is wide enough to accommodate

10098-619: Was rectangular in shape, but over time it was refined into an elongated triangle. The triangular assembly above the engine cylinder gives the engine its characteristic "steeple" shape, hence the name. Steeple engines were tall like walking beam engines, but much narrower laterally, saving both space and weight. Because of their height and high centre of gravity, they were, like walking beams, considered less appropriate for oceangoing service, but they remained highly popular for several decades, especially in Europe, for inland waterway and coastal vessels. Steeple engines began to appear in steamships in

10200-474: Was the first type of steam engine widely adopted for marine use in Europe . In the early years of steam navigation (from c1815), the side-lever was the most common type of marine engine for inland waterway and coastal service in Europe, and it remained for many years the preferred engine for oceangoing service on both sides of the Atlantic . The side-lever was an adaptation of the earliest form of steam engine,

10302-406: Was the most common type of engine in the early years of American steam navigation. The crosshead engine is described as having a vertical cylinder above the crankshaft, with the piston rod secured to a horizontal crosshead, from each end of which, on opposite sides of the cylinder, extended a connecting rod that rotated its own separate crankshaft. The crosshead moved within vertical guides so that

10404-433: Was therefore deemed unsuitable for oceangoing service. This largely confined it to vessels built for inland waterways. As marine engines grew steadily larger and heavier through the 19th century, the high center of gravity of square crosshead engines became increasingly impractical, and by the 1840s, ship builders abandoned them in favor of the walking beam engine. The name of this engine can cause confusion, as "crosshead"

#707292