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54-401: When used as a refrigerant, R-114 is classified as a medium pressure refrigerant. The U.S. Navy uses R-114 in its centrifugal chillers in preference to R-11 to avoid air and moisture leakage into the system. While the evaporator of an R-11 charged chiller runs at a vacuum during operation, R-114 yields approximately 0 psig operating pressure in the evaporator. Manufactured and sold R-114

108-454: A heat exchanger to cool equipment, or another process stream (such as air or process water). As a necessary by-product, refrigeration creates waste heat that must be exhausted to ambience, or for greater efficiency, recovered for heating purposes. Vapor compression chillers may use any of a number of different types of compressors. Most common today are the hermetic scroll, semi-hermetic screw, or centrifugal compressors. The condensing side of

162-407: A chiller in an air conditioning or cooling plant is typically distributed to heat exchangers, or coils , in air handlers or other types of terminal devices which cool the air in their respective space(s). The water is then recirculated to the chiller to be recooled. These cooling coils transfer sensible heat and latent heat from the air to the chilled water, thus cooling and usually dehumidifying

216-400: A chiller, the application cooling temperature requirements and refrigerant's cooling characteristics need to be matched. Important parameters to consider are the operating temperatures and pressures. There are several environmental factors that concern refrigerants, and also affect the future availability for chiller applications. This is a key consideration in intermittent applications where

270-421: A clean coolant or clean water with condition additives at a constant temperature and pressure to increase the stability and reproducibility of water-cooled machines and instruments. The water flows from the chiller to the application's point of use and back. If the water temperature differentials between inlet and outlet are high, then a large external water tank would be used to store the cold water. In this case

324-481: A further power boost. This technique was first employed on an experimental gas turbine in Norway in 1903. There are many successful systems in operation today. Several gas turbine manufactures offer both fogging and wet compression systems. Systems are also available from third-party manufacturers. The evaporative cooler is a wetted rigid media where water is distributed throughout the header and where air passes through

378-715: A large chiller may last for 25 years or more. Ozone depletion potential (ODP) and global warming potential (GWP) of the refrigerant need to be considered. ODP and GWP data for some of the more common vapor-compression refrigerants (noting that many of these refrigerants are highly flammable and/or toxic): R12 is the ODP reference. CO 2 is the GWP reference The refrigerants used in the chillers sold in Europe are mainly R410a (70%), R407c (20%) and R134a (10%). Turbine inlet air cooling#Vapour compression chiller Turbine inlet air cooling

432-436: A mechanical compression chiller technology, the coolant is circulated through a chilling coil heat exchanger that is inserted in the filter house, downstream from the filtering stage. Downstream from the coil, a droplet catcher is installed to collect moisture and water drops. The mechanical chiller can increase the turbine output and performance better than wetted technologies due to the fact that inlet air can be chilled below

486-542: A mist of water over the condenser coil to aid in condenser cooling, making the machine more efficient than a traditional air-cooled machine. No remote cooling tower is typically required with either of these types of packaged air-cooled or evaporatively cooled chillers. Where available, cold water readily available in nearby water bodies might be used directly for cooling, replacing or supplementing cooling towers. The deep water source cooling system in Toronto, Ontario , Canada ,

540-443: A reduction in energy requirements by more than 15% and also allows a significant reduction in the size of the chiller, due to the small surface area of the water-based condenser and the absence of fans. Additionally, the absence of fans allows for significantly reduced noise levels. Most industrial chillers use refrigeration as the media for cooling, but some rely on simpler techniques such as air or water flowing over coils containing

594-446: A semi-hermetic or hermetic configuration is the most common method of driving the compressors since electric motors can be effectively and easily cooled by the refrigerant, without requiring fuel supply or exhaust ventilation and no shaft seals are required as the motor can operate in the refrigerant, reducing maintenance, leaks, operating costs and downtime, although open compressors are sometimes used. They produce their cooling effect via

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648-429: A separate condenser water loop and connected to outdoor cooling towers to expel heat to the atmosphere. Air-cooled and evaporative cooled chillers are intended for outdoor installation and operation. Air-cooled machines are directly cooled by ambient air being mechanically circulated directly through the machine's condenser coil to expel heat to the atmosphere. Evaporative cooled machines are similar, except they implement

702-603: A single chiller serves multiple cooling needs, or decentralized where each application or machine has its own chiller. Each approach has its advantages. It is also possible to have a combination of both centralized and decentralized chillers, especially if the cooling requirements are the same for some applications or points of use, but not all. Chilled water is used to cool and dehumidify air in mid- to large-size commercial, industrial, and institutional (CII) facilities. Liquid chillers can be liquid-cooled, air-cooled, or evaporatively cooled. Water or liquid-cooled chillers incorporate

756-424: A specific manufacturer, or be open drive--allowing the connection to another type of mechanical connection. Compressors can also be either hermetic (welded closed) or semi-hermetic (bolted together). In recent years, application of variable-speed drive (VSD) technology has increased efficiencies of vapor compression chillers. The first VSD was applied to centrifugal compressor chillers in the late 1970s and has become

810-453: Is a group of technologies and techniques consisting of cooling down the intake air of the gas turbine . The direct consequence of cooling the turbine inlet air is power output augmentation. It may also improve the energy efficiency of the system. This technology is widely used in hot climates with high ambient temperatures that usually coincides with on-peak demand period. Gas turbines take in filtered, fresh ambient air and compress it in

864-713: Is an example. It uses cold lake water to cool the chillers, which in turn are used to cool city buildings via a district cooling system. The return water is used to warm the city's drinking water supply, which is desirable in this cold climate. Whenever a chiller's heat rejection can be used for a productive purpose, in addition to the cooling function, very high thermal effectiveness is possible. A vapor compression chiller typically uses one of four types of compressor: Reciprocating compression, scroll compression, screw-driven compression, and centrifugal compression are all mechanical machines that can be powered by electric motors , steam , or gas turbines . Using electric motors in

918-414: Is low and chillers have better performance. Another advantage is the reduction of the chilling plant capacity and operational cost in comparison with an on-line chilling system, which produce delays during periods of low demand. In areas where there is demand cooling, daily summer on-peak periods coincide with the highest atmospheric temperatures, which may reduce the efficiency and power gas turbines. With

972-400: Is often in turn cooled by a cooling tower . The expansion device ( TEV ) or refrigerant metering device (RMD) restricts the flow of the liquid refrigerant causing a pressure drop that vaporizes some of the refrigerant; this vaporization absorbs heat from nearby liquid refrigerant. The RMD is located immediately prior to the evaporator so that the cold gas in the evaporator can absorb heat from

1026-466: Is readily available. In extremely sunny climates, solar energy has been used to operate absorption chillers. The single-effect absorption cycle uses water as the refrigerant and lithium bromide as the absorbent. It is the strong affinity that these two substances have for one another that makes the cycle work. The entire process occurs in almost a complete vacuum. Industrial chillers typically come as complete, packaged, closed-loop systems, including

1080-418: Is the least expensive gas turbine inlet air cooling option and has low operating costs, particularly when one accounts for the fact that fog systems impose only a negligible pressure drop on the inlet airflow when compared to media-type evaporative coolers. Fog nozzle manifolds are typically located in the inlet air duct just downstream of the final air filters but other locations can be desirable depending on

1134-415: Is usually leftover steam coming from combined cycle, and it is bypassed to drive the cooling system. Compared to mechanical chillers, absorption chillers have a low coefficient of performance , however, it should be taken into consideration that this chiller usually uses waste heat, which decreases the operational cost. A thermal energy storage tank is a naturally stratified thermal accumulator that allows

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1188-407: The compressor stage. The compressed air is mixed with fuel in the combustion chamber and ignited. This produces a high-temperature and high-pressure flow of exhaust gases that enter in a turbine and produce the shaft work output that is generally used to turn an electric generator as well as powering the compressor stage. As the gas turbine is a constant volume machine, the air volume introduced in

1242-400: The reverse-Rankine cycle , also known as vapor-compression. With evaporative cooling heat rejection, their coefficients of performance (COPs) are very high; typically 4.0 or more. Current vapor-compression chiller technology is based on the "reverse-Rankine" cycle known as vapor-compression. See the attached diagram which outlines the key components of the chiller system. Key components of

1296-417: The additional water vapor quenches hot spots in the combustors of the gas turbine. Fog systems can be used to produce more power than can be obtained by evaporative cooling alone. This is accomplished by spraying more fog than is required to fully saturate the inlet air. The excess fog droplets are carried into the gas turbine compressor where they evaporate and produce an intercooling effect, which results in

1350-431: The air flow). Each condenser has a different material cost and they vary in terms of efficiency. With evaporative cooling condensers, their coefficients-of-performance (COPs) are very high; typically 4.0 or more. Air cooled condensers are installed and operated outdoors and are cooled with outside air, that is often forced through the condenser using electric fans . Water or liquid cooled condensers are cooled with water that

1404-588: The air stream. A typical chiller for air conditioning applications is rated between 50  kW (170 thousand  BTU / h ) and 7 MW (24 million BTU/h), and at least two manufacturers (York international and LG) can produce chillers capable of up to 21 MW (72 million BTU/h) cooling. Chilled water temperatures (leaving from the chiller) usually range from 1 to 7 °C (34 to 45 °F), depending upon application requirements. Commonly, chillers receive water at 12°C (entering temperature), and cool it to 7°C (leaving temperature). When

1458-517: The airflow. Fog systems typically produce a water spray, with about 90% of the water flow being in droplets that are 20 microns in diameter or smaller. Inlet fogging has been in commercial use since the late 1980s and is a popular retrofit technology. As of 2015, there were more than 1000 inlet fog systems installed around the world. Inlet fog systems are, “simple, easy to install and operate” and less expensive than other power augmentation systems such as evaporative coolers and chillers. Inlet fogging

1512-419: The chilled water is not going directly from the chiller to the application, but goes to the external water tank which acts as a sort of "temperature buffer." The cold water tank is much larger than the internal water goes from the external tank to the application and the return hot water from the application goes back to the external tank, not to the chiller. The less common open loop industrial chillers control

1566-678: The chiller can be either air or water cooled. Even when liquid cooled, the chiller is often cooled by an induced or forced draft cooling tower . Absorption and adsorption chillers require a heat source to function. Chilled water is used to cool and dehumidify air in mid- to large-size commercial, industrial, and institutional facilities. Water cooled chillers can be liquid-cooled (through cooling towers), air-cooled, or evaporatively cooled. Water or liquid-cooled systems can provide efficiency and environmental impact advantages over air-cooled systems. In air conditioning systems, chilled coolant, usually chilled water mixed with ethylene glycol , from

1620-869: The chiller is pumped through process or laboratory equipment. Industrial chillers are used for controlled cooling of products, mechanisms and factory machinery in a wide range of industries. They are often used in the plastic industries, injection and blow molding, metalworking cutting oils, welding equipment, die-casting and machine tooling, chemical processing, pharmaceutical formulation, food and beverage processing, paper and cement processing, vacuum systems, X-ray diffraction, power supplies and gas turbine power generation stations (see Turbine inlet air cooling#Vapour compression chiller ), analytical equipment, semiconductors, compressed air and gas cooling. They are also used to cool high-heat specialized items such as MRI machines and lasers in hospitals, hotels, and campuses. Chillers for industrial applications can be centralized, where

1674-404: The chiller unit, condenser , and pump station with recirculating pump, expansion valve, no-flow shutdown, internal cold water control. Compressors can be of two types - scroll and screw depending on the budget and the performance expected from a chiller. The internal tank helps maintain cold water temperature and prevents temperature spikes from occurring. Closed-loop industrial chillers recirculate

1,2-Dichlorotetrafluoroethane - Misplaced Pages Continue

1728-567: The chiller: Refrigeration compressors are essentially a pump for refrigerant gas. The capacity of the compressor, and hence the chiller cooling capacity, is measured in kilowatts input (kW), Horse power input (HP), or volumetric flow (m /h, ft /h). The mechanism for compressing refrigerant gas differs between compressors, and each has its own application. Common refrigeration compressors include reciprocating, scroll, screw, or centrifugal. These can be powered by electric motors, steam turbines, or gas turbines. Compressors can have an integrated motor from

1782-437: The chillers can have a great bearing on the system parasitic power consumption. The series counterflow configuration can reduce the compressor work needed on each chiller, improving the overall chiller system by as much as 8%. Other options such a steam driven compression are also used in industry. In vapor-absorption chillers technology, thermal energy is used to produce cooling instead of mechanical energy. The heat source

1836-431: The chillers for air conditioning systems are not operable or they are in need of repair or replacement, emergency chillers may be used to supply chilled water. Rental chillers are mounted on a trailer so that they can be quickly deployed to the site. Large chilled water hoses are used to connect between rental chillers and air conditioning systems. In industrial applications, chilled water or other coolant liquid from

1890-535: The climate conditions, which may decrease the output power ratings by up to 40%. To operate the turbine at ISO conditions and recover performance, several inlet air cooling systems have been promoted. Different technologies are available in the market. Each particular technology has its advantages and inconveniences according to different factors such as ambient conditions, investment cost and payback time, power output increase and cooling capacity. Inlet air fogging consists of spraying finely atomized water (fog) into

1944-657: The cold water temperature is lower than −5 °C, then a special pump needs to be used to be able to pump the high concentrations of ethylene glycol. Other important specifications include the internal water tank size and materials and full load current. Control panel features that should be considered when selecting between industrial chillers include the local control panel, remote control panel, fault indicators, temperature indicators, and pressure indicators. Additional features include emergency alarms, hot gas bypass, city water switchover, and casters. Demountable chillers are also an option for deployment in remote areas and where

1998-401: The combustion chamber after the compression stage is fixed for a given shaft speed (rpm). Thus the air mass flow in is directly related to the density of air , and the introduced volume. where m {\displaystyle m} is the mass, ρ {\displaystyle \rho } is the density and V {\displaystyle {V}} is the volume of

2052-438: The conditions may be hot and dusty. If noise levels of the chiller are acoustically unacceptable, noise control engineers will implement sound attenuators to reduce chiller noise levels. Larger chillers will typically require an array of sound attenuators sometimes known as a silencer bank. A vapor-compression chiller uses a refrigerant internally as its working fluid. Many refrigerants options are available; when selecting

2106-721: The coolant to regulate temperature. Water is the most commonly used coolant within process chillers, although coolant mixtures (mostly water with a coolant additive to enhance heat dissipation) are frequently employed. Important specifications to consider when searching for industrial chillers include the total life cycle cost, the power source, chiller IP rating, chiller cooling capacity, evaporator capacity, evaporator material, evaporator type, condenser material, condenser capacity, ambient temperature, motor fan type, noise level, internal piping materials, number of compressors, type of compressor, number of fridge circuits, coolant requirements, fluid discharge temperature, and COP (the ratio between

2160-614: The cooling capacity in RT to the energy consumed by the whole chiller in kW). For medium to large chillers this should range from 3.5 to 7.0, with higher values meaning higher efficiency. In the US, chiller efficiency is often specified in kilowatts per refrigeration ton (kW/RT). Process pump specifications that are important to consider include the process flow, process pressure, pump material, elastomer and mechanical shaft seal material, motor voltage, motor electrical class, motor IP rating and pump rating. If

2214-557: The design of the inlet duct and the intended use of the fog system. On a hot afternoon in a desert climate, it is possible to cool by as much as 40 °F (22.2 °C), while in a humid climate hot-afternoon cooling potential can be just 10 °F (5.6 °C) or less. Nevertheless, there are many successful inlet-fogging installations in humid climates such as Thailand, Malaysia and the American Gulf States. Inlet fogging reduces emissions of Oxides of nitrogen (NOx) because

1,2-Dichlorotetrafluoroethane - Misplaced Pages Continue

2268-428: The gas. As the volume V {\displaystyle {V}} is fixed, only density ρ {\displaystyle \rho } of the air can be modified to vary air mass. The density of the air depends on the relative humidity , altitude , pressure drop and temperature. where: The performance of a gas turbine, its efficiency ( heat rate ) and the generated power output strongly depend on

2322-450: The inlet airflow of a gas turbine engine. The water droplets evaporate quickly, which cools the air and increases the power output of the turbine. Demineralized water is typically pressurized to 2000 psi (138 bar) then injected into the inlet air duct through an array of stainless steel fog nozzles. Demineralized water is used in order to prevent fouling of the compressor blades that would occur if water with mineral content were evaporated in

2376-406: The norm as the cost of energy has increased. Now, VSDs are being applied to rotary screw and scroll-technology compressors. Condensers can be air-cooled, liquid-cooled, or evaporative. The condenser is a heat exchanger which allows heat to migrate from the refrigerant gas to either water or air. Air cooled condenser are manufactured from copper tubes (for the refrigerant flow) and aluminium fins (for

2430-411: The refrigerant can absorb large amounts of heat without changing temperature. The thermodynamic cycle of an absorption chiller is driven by a heat source; this heat is usually delivered to the chiller via steam, hot water, or combustion. Compared to electrically powered chillers, an absorption chiller has very low electrical power requirements – very rarely above 15 kW combined consumption for both

2484-403: The solution pump and the refrigerant pump. However, its heat input requirements are large, and its COP is often 0.5 (single-effect) to 1.0 (double-effect). For the same cooling capacity, an absorption chiller requires a much larger cooling tower than a vapor-compression chiller. However, absorption chillers, from an energy-efficiency point of view, excel where cheap, low-grade heat or waste heat

2538-428: The storage of chilled water produced during off-peak time, to use this energy later during on-peak time to chill the turbine inlet air and increment its power output. A thermal energy storage tank reduces operational cost and refrigerant plant capacity. One advantage is the production of chilled water when demand is low, using the excess of power generation, which usually coincides with the night, when ambient temperature

2592-403: The temperature of a liquid in an open tank or sump by constantly recirculating it. The liquid is drawn from the tank, pumped through the chiller and back to the tank. In industrial water chillers is the use of water cooling instead of air cooling. In this case the condenser does not cool the hot refrigerant with ambient air, but uses water that is cooled by a cooling tower . This development allows

2646-484: The use of cooling towers which improve the chillers' thermodynamic effectiveness as compared to air-cooled chillers. This is due to heat rejection at or near the air's wet-bulb temperature rather than the higher, sometimes much higher, dry-bulb temperature. Evaporatively cooled chillers offer higher efficiencies than air-cooled chillers but lower than liquid-cooled chillers. Liquid-cooled chillers are typically intended for indoor installation and operation and are cooled by

2700-405: The vapor mechanical compression technologies, cooling can be used during these periods so that the performance and the power output of the turbine may be less affected by ambient conditions Another benefit is the lower cost per extra inlet-cooling kilowatt compared to newly installed gas turbine kilowatt . Moreover, the extra inlet-cooling kilowatt uses less fuel than the new turbine kilowatt due to

2754-464: The water in the evaporator. There is a sensor for the RMD on the evaporator outlet side which allows the RMD to regulate the refrigerant flow based on the chiller design requirement. Evaporators can be plate type or shell and tube type. The evaporator is a heat exchanger which allows the heat energy to migrate from the water stream into the refrigerant gas. During the state change of the remaining liquid to gas,

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2808-411: The wet bulb temperature, indifferent to the weather conditions. Compression chiller equipment has higher electricity consumption than evaporative systems. Initial capital cost is also higher, however turbine power augmentation and efficiency is maximized, and the extra-cost is amortized due to increased output power. The majority of such systems involve more than one chiller unit and the configuration of

2862-433: The wet porous surface. Part of the water is evaporated, absorbing the sensible heat from the air and increasing its relative humidity. The air dry-bulb temperature is decreased but the wet-bulb temperature is not affected. Similar to the fogging system, the theoretical limit is the wet bulb temperature, but performance of the evaporative cooler is usually around 80%. Water consumption is less than that of fogging cooling. In

2916-498: Was usually mixed with the non symmetrical isomer 1,1-dichlorotetrafluoroethane (CFC-114a), as separation of the two isomers is difficult. Aside from its immense environmental impacts, R114, like most chlorofluoroalkanes, forms phosgene gas when exposed to a naked flame. Chiller A chiller is a machine that removes heat from a liquid coolant via a vapor-compression , adsorption refrigeration , or absorption refrigeration cycles. This liquid can then be circulated through

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