Chillers

A h pipeline-raiser is a machine that removes live(a) uped up from a placid via a vaporization-compression or absorption refrigeration cycle. A vapor-compression wet h b atomic number 18-raiser comprises the 4 study comp angiotensin-converting enzyments of the vapor-compression refrigeration cycle (compressor, evaporator, electric capacity, and some form of metering device). These machines gutter implement a variety of colds. adsorption hair-raisers office municipal piddle as the refrigerant and benign silica gel as the desiccant.Absorption hair-raisers utilize piss as the refrigerant and rely on the plastered affinity between the weewee and a atomic number 3 platitude resultant role to achieve a refrigeration effect. Most of ten, pure water system is chilled, but this water may withal contain a percentage of glycol and/or wearing away inhibitors different legatos such(prenominal) as thin oils can be chilled as well. Contents hide 1 physical exertion in melodic line conditioning 2 Use in industry 3 Vapor-Compression chiller engineering science 4 How Adsorption Technology deeds 5 How Absorption Technology Works 5. 1 industrial chiller technology Industrial chiller pick 7 Refrigerants 8 See as well as 9 References 10 outside links edit Use in mental strain conditioning In place travel conditioning systems, chilled water is typically distributed to enkindle exchangers, or kinks, in air handling units, or other type of terminal devices which tranquil the air in its respective space(s), and then the chilled water is re-circu riped back to the chiller to be cooled again. These temperature reduction coils transfer sensible oestrus and latent heat from the air to the chilled water, thus cool down and usually dehumidifying the air stream.A typical chiller for air conditioning applications is rated between 15 to 1500 tons (180,000 to 18,000,000 BTU/h or 53 to 5,300 kW) in cooling capacity. Chilled water temperatures can range from 35 to 45 degrees Fahrenheit or 1. 5 to 7 degrees Celsius, depending upon application conveyments. 1 2 edit Use in industry In industrial application, chilled water or other liquid from the chiller is pumped by means of turn or science laboratory equipment. Industrial chillers atomic number 18 employ for controlled cooling of products, mechanisms and factory machinery in a wide range of industries.They ar often apply in the formative industry in injection and blow molding, metal working ordnanceh oils, welding equipment, die-casting and machine tooling, chemical processing, pharmaceutical formulation, food and beverage processing, authorship and cement processing, void systems, X-ray diffraction, cater supplies and power generation lays, uninflected equipment, semiconductors, compressed air and gas cooling. They ar also used to cool gritty-heat specialized items such as MRI machines and lasers, and in hospitals, hotels and campuses.The chillers for industrial applications can be primordialized, where each chiller serves multiple cooling needs, or change where each application or machine has its own chiller. Each go on has its advantages. It is also possible to have a combination of both central and decentral chillers, especially if the cooling requirements ar the same for some applications or points of use, but not all. Decentral chillers are usually small in size (cooling capacity), usually from 0. 2 tons to 10 tons. Central chillers generally have capacities ranging from ten tons to hundreds or thousands of tons.Chilled water is used to cool and dehumidify air in mid- to wide-ranging-size commercial, industrial, and institutional (CII) facilities. Water chillers can be either water cooled, air-cooled, or evaporatively cooled. Water-cooled chillers incorporate the use of cooling chromatography columns which improve the chillers thermodynamical effectiveness as compared to air-cooled chillers. This is ascribable to heat rejectio n at or near the airs wet-bulb temperature rather than the higher, sometimes overmuch higher, dry-bulb temperature.Evaporatively cooled chillers offer efficiencies better than air cooled, but reject than water cooled. Water cooled chillers are typically mean for indoor installation and operation, and are cooled by a separate condenser water loop and connected to outdoor cooling towers to expel heat to the atmosphere. Air Cooled and Evaporatively Cooled chillers are intended for outdoor installation and operation. Air cooled machines are right off cooled by close air being mechanically circulated directly through the machines condenser coil to expel heat to the atmosphere.Evaporatively cooled machines are similar, leave out they implement a mist of water over the condenser coil to aid in condenser cooling, making the machine more good than a traditional air cooled machine. No remote cooling tower is typically required with either of these types of packaged air cooled or evapor atively cooled chillers. Where available, ratty water readily available in nearby water bodies might be used directly for cooling, or to replace or affix cooling towers. The Deep Lake Water Cooling System in Toronto, Canada, is an example.It give with the need for cooling towers, with a significant cut in carbon emissions and energy inhalation. It uses cold lake water to cool the chillers, which in turn are used to cool city buildings via a district cooling system. The produce water is used to warm the citys drinking water supply which is loveable in this cold climate. Whenever a chillers heat rejection can be used for a productive purpose, in addition to the cooling function, very high thermal effectivenesses are possible. edit Vapor-Compression Chiller TechnologyThere are essentially four different types of compressors used in vapor compression chillers Reciprocating compression, bankroll compression, screw-driven compression, and centrifugal compression are all mechani cal machines that can be powered by electric motors, steam, or gas turbines. They produce their cooling effect via the reverse-Rankine cycle, also known as vapor-compression. With evaporative cooling heat rejection, their coefficients-of-performance (COPs) are very high and typically 4. 0 or more. In recent years, application of Variable Speed Drive (VSD) technology has change magnitude efficiencies of vapor compression chillers.The first VSD was applied to centrifugal compressor chillers in the late 1970s and has become the norm as the cost of energy has increased. Now, VSDs are being applied to rotary screw and scroll technology compressors. edit How Adsorption Technology Works Adsorption chillers are driven by hot water. This hot water may come from any number of industrial sources including waste heat from industrial processes, prime heat from solar thermal installations or from the exhaust or water jacket heat of a piston engine or turbine. The principle of adsorption is based on the interaction of gases and solids.With adsorption chilling, the molecular interaction between the solid and the gas allow the gas to be adsorbed into the solid. The adsorption chamber of the chiller is make full with solid material, silica gel, eliminating the need for touching parts and eliminating the hoo-ha associated with those moving parts. The silica gel creates an extremely low humidity condition that causes the water refrigerant to evaporate at a low temperature. As the water evaporates in the evaporator, it cools the chilled water. The use of a benign silica gel desiccant keeps the maintenance costs and operating costs of adsorption chillers low. edit How Absorption Technology Works Absorption chillers thermodynamic cycle are driven by heat source this heat is usually delivered to the chiller via steam, hot water, or combustion. Compared to electrically powered chillers, they have very low electrical power requirements very rarely above 15 kW combined con sumptio n for both the dissolvent pump and the refrigerant pump. However, their heat input requirements are deep, and their COPs are often 0. 5 ( single-effect) to 1. 0 (double-effect). For the same tonnage capacity, they require much larger cooling towers than vapor-compression chillers.However, absorption chillers, from an energy-efficiency point-of-view, excel where cheap, high pit heat or waste heat 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 atomic number 3 cliche 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 void. 1. Solution Pump A diluted atomic number 3 bromide solution is collected in the potty of the absorber shell.From here, a hermetic solution pump moves the solution through a shell and supply heat exchanger for preheat ing. 2. Generator After exiting the heat exchanger, the dilute solution moves into the velocity shell. The solution surrounds a bundle of tubes which carries either steam or hot water. The steam or hot water transfers heat into the pool of dilute lithium bromide solution. The solution boils, sending refrigerant vapor upwards into the condenser and leaving behind concentrated lithium bromide. The concentrated lithium bromide solution moves down to the heat exchanger, where it is cooled by the weak solution being pumped up to the generator. . Condenser The refrigerant vapor migrates through mist eliminators to the condenser tube bundle. The refrigerant vapor condenses on the tubes. The heat is removed by the cooling water which moves through the inside of the tubes. As the refrigerant condenses, it collects in a trough at the bottom of the condenser. 4. Evaporator The refrigerant liquid moves from the condenser in the upper shell down to the evaporator in the lower shell and is s prayed over the evaporator tube bundle. Due to the extreme vacuum of the lower shell 6 mm Hg (0. kPa) absolute pressure, the refrigerant liquid boils at approximately 39F (3. 9C), creating the refrigerant effect. (This vacuum is created by hygroscopic action the strong affinity lithium bromide has for water in the Absorber directly below. ) 5. Absorber As the refrigerant vapor migrates to the absorber from the evaporator, the strong lithium bromide solution from the generator is sprayed over the top of the absorber tube bundle. The strong lithium bromide solution actually pulls the refrigerant vapor into solution, creating the extreme vacuum in the evaporator.The absorption of the refrigerant vapor into the lithium bromide solution also generates heat which is removed by the cooling water. The now dilute lithium bromide solution collects in the bottom of the lower shell, where it flows down to the solution pump. The chilling cycle is now end and the process begins once again. ed it Industrial chiller technology Industrial chillers typically come as complete packaged closed-loop systems, including the chiller unit, condenser, and pump station with recirculating pump, expansion valve, no-flow shutdown, internal cold water cooler, and temperature control.The internal tank car helps find cold water temperature and prevents temperature spikes from occurring. Closed loop industrial chillers recirculate a lave coolant or clean water with condition addititives at a never-ending temperature and pressure to increase the stability and reproducibility of water-cooled machines and instruments. The water flows from the chiller to the applications point of use and back. If the water temperature differentials between inlet and outlet are high, then a large outdoor(a) water tank would be used to store the cold water.In this case 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 tempe rature buffer. The cold water tank is much larger than the internal water tank. The cold 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 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.An adjustable thermostat senses the makeup liquid temperature, cycling the chiller to maintain a constant temperature in the tank. One of the newer developments 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 cooled by a cooling tower. This development allows 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 the coolant to regularise 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. edit Industrial chiller selectionImportant specifications to consider when searching for industrial chillers allow in 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 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. 5-7. 0 with higher values meaning higher efficiency. Chiller efficiency is often specified in kilowatts per refrigeration ton (kW/RT). summons pump specifications that are main(prenominal) to consider complicate 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 the cold water temperature is lower than -5C, 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 up amperage. Control panel features that should be considered when selecting between industrial chillers include the local anesthetic control panel, remote control panel, fault indicat ors, temperature indicators, and pressure indicators. Additional features include emergency alarms, hot gas bypass, city water switchover, and casters. edit Refrigerants A vapor-compression chiller uses a refrigerant internally as its working fluid.Many refrigerants options are available when selecting a chiller, the application cooling temperature requirements and refrigerants cooling characteristics need to be matched. Important parameters to consider are the operating temperatures and pressures. There are some(prenominal) environmental factors that concern refrigerants, and also affect the future availability for chiller applications. This is a key consideration in intermittent applications where a large chiller may last for 25 years or more. Ozone depletion voltage (ODP) and global warming potential (GWP) of the refrigerant need to be considered.ODP and GWP selective information for some of the more common vapor-compression refrigerants Refrigerant ODP GWP R-134a 0 1300 R-123 0. 012 120 R-22 0. 05 1700 R401a 0. 027 970 R404a 0 3260 R407a 0 R407c 0 1525 R408a 0. 016 3020 R409a 0. 039 1290 R410a 0 1725 R500 0. 7 R502 0. 18 5600 edit See also HVAC Cooling tower Evaporative cooling Chemical engineering automatic engineering Architectural engineering Building services engineering edit References American Society of Heating and Refrigeration Enginneers http//www. ashrae. org/publications/page/158 Hydronika supplies 5 ton chiller units http//hydronika. com