DEFINICION:
Es cualquier cuerpo o sustancia que actúa como agente de enfriamiento absorbiendo calor de otro cuerpo o sustancia.
Con respecto al ciclo compresión-vapor, el refrigerante es el fluido de trabajo del ciclo el cuál alternativamente se vaporiza y se condensa absorbiendo y cediendo calor, respectivamente. Para que un refrigerante sea apropiado y se le pueda usar en el ciclo antes mencionado, debe poseer ciertas propiedades físicas, químicas y termodinámicas que lo hagan seguro durante su uso.
No existe un refrigerante “ideal” ni que pueda ser universalmente adaptable a todas las aplicaciones. Entonces, un refrigerante se aproximará al “ideal”, solo en tanto que sus propiedades satisfagan las condiciones y necesidades de la aplicación para la que va a ser utilizado.
Diferentes tipos de refrigerantes (características)
Amoníaco
Aunque el amoníaco es tóxico, algo inflamable y explosivo bajo ciertas condiciones, sus excelentes propiedades térmicas lo hacen ser un refrigerante ideal para fábricas de hielo, para grandes almacenes de enfriamiento, etc., donde se cuenta con los servicios de personal experimentado y donde su naturaleza tóxica es de poca consecuencia.
El amoníaco es el refrigerante que tiene mas alto efecto refrigerante por unidad de peso.
El punto de ebullición del amoníaco bajo la presión atmosférica estándar es de -2,22°C, las presiones en el evaporador y el condensador en las condiciones de tonelada estándar es de -15°C y 30°C son 34,27 libras por pulgada* y 169,2 libras por pulgada* abs. , respectivamente, pueden usarse materiales de peso ligero en la construcción del equipo refrigerante. La temperatura adiabática en la descarga es relativamente alta, siendo de 98,89°C para las condiciones de tonelada estándar, por lo cuál es adecuado tener enfriamiento en el agua tanto en el cabezal como en el cilindro del compresor.
En la presencia de la humedad el amoníaco se vuelve corrosivo para los materiales no ferrosos.
El amoníaco no es miscible con el aceite y por lo mismo no se diluye con el aceite del cárter del cigüeñal del compresor. Deberá usarse un separador de aceite en el tubo de descarga de los sistemas de amoníaco.
El amoníaco es fácil de conseguir y es el mas barato de los refrigerantes.
Su estabilidad química, afinidad por el agua y no-miscibilidad con el aceite, hacen al amoníaco un refrigerante ideal pare ser usado en sistemas muy grandes donde la toxicidad no es un factor importante.
Refrigerante 22
Conocido con el nombre de Freón 22, se emplea en sistemas de aire acondicionado domésticos y en sistemas de refrigeración comerciales e industriales incluyendo: cámaras de conservación e instalaciones para el procesado de alimentos: refrigeración y aire acondicionado a bordo de diferentes transportes; bombas de calor para calentar aire y agua. Se pude utilizar en compresores de pistón, centrífugo y de tornillo.
El refrigerante 22 (CHCIF ) tiene un punto de ebullición a la presión atmosférica de 40,8°C. Las temperaturas en el evaporador son tan bajas como 87°C. Resulta una gran ventaja el calor relativamente pequeño del desplazamiento del compresor.
La temperatura en la descarga con el refrigerante22 es alta, la temperatura sobrecalentada en la succión debe conservarse en su valor mínimo, sobre todo cuando se usan unidades herméticas motor-compresor. En aplicaciones de temperatura baja, donde las relaciones de compresión altas, se recomienda tener en enfriamiento con agua al cabezal y a los cilindros del compresor. Los condensadores enfriados por aire empleados con el refrigerante 22, deben ser de tamaño generoso.
Aunque el refrigerante 22 es miscible con aceite en la sección de condensación a menudo suele separársele del aceite en el evaporador.
No se han tenido dificultades en el retorno de aceite después del evaporador cuando se tiene el diseño adecuado del serpentín del evaporador y de la tubería de succión.
Siendo un fluorcarburo, el refrigerante 22 es un refrigerante seguro.
Se comercializa en cilindros retornables (CME) de 56,7 Kg, cilindros desechables de 22,68 kg, cilindros desechables de 13,61 kg y cajas de 12 latas de 5,10 kg cada una.
Refrigerante 123
Es un sustituto viable para el freón 11 como refrigerante.
Las propiedades termodinámicas y físicas del refrigerante 123 en conjunto con sus características de no-inflamabilidad lo convierte en un reemplazo eficiente del Freón 11 en chillers centrífugos.
El refrigerante 123 fue diseñado para trabajar en equipos nuevos existentes. Cuando se considere u reacondicionamiento para refrigerante 123 de un equipo existente, debe considerarse el ciclo de vida útil del equipo, la diferencia de costo de operación y mantenimiento y el costo de reacondicionamiento.
Los equipos nuevos que han sido diseñados para trabajar con el refrigerante 123 tienen menor costo de operación comparados con los equipos existentes.
Debido a que tiene un olor tan leve que no se puede detectar por medio del olfato es necesaria una verificación frecuente de fugas y la instalación de detectores de fugas por áreas cerradas utilizadas por el personal. Se comercializa en tambores de 283,5kg, tambores de 90,72kg y tambores de 45,36kg. Su composición en peso es de 100% HFC-123.
Refrigerante 134-a
El refrigerante marca Suva134a, ha sido introducido por DuPont, como reemplazo de los clorofluorocarbonos (CFC) en muchas aplicaciones. La producción de CFC es reemplazada por el hidrofluorucarbono HFC-134ª.
Este refrigerante no contiene cloro y puede ser usado en muchas aplicaciones que actualmente usan CFC-12. Sin embargo en algunas ocasiones se requieren cambios en el diseño del equipo para optimizar el desempeño del Suva 134ª en esta aplicaciones.
Las propiedades termodinámicas y físicas del Suva 134ª y su baja toxicidad lo convierten en un reemplazo seguro y muy eficiente del CFC-12 en muchos segmentos de la refrigeración industrial mas notablemente en el aire acondicionado automotriz, equipos domésticos, equipo estacionario pequeño, equipo de supermercado de media temperatura y chillers, industriales y comerciales. El Suva134a ha mostrado que es combustible a presiones tan bajas como 5,5 psig a 177°C cuando se mezclan con aire a concentraciones generalmente mayores al 60% en volumen de aire. A bajas temperaturas se requieren mayores presiones para la combustibilidad. No deben ser mezclados con el aire para pruebas de fuga. En general no se debe permitir que estén presentes con altas concentraciones de aire arriba de la presión atmosférica. Se comercializan en cilindros retornables (CME) de 56,7kg, cilindros desechables de 13,61kg, y cajas de 12 latas de 3,408kg cada una. Temperatura del evaporador -7°C a 7°C. Su composición en peso es de 100% HFC-134ª.
Refrigerante 407c/410 a
DuPont los comercializa con el nombre de Suva 9100 respectivamente.
Reemplazan el HCFC-22 en el aire acondicionado doméstico en aplicaciones en el calentamiento de bombas. El Suva 9000 sirve para equipos nuevos o en servicio, tiene un desempeño similar del HCFC-22 en el aire acondicionado. El Suva 9100 sirve solo para equipos nuevos y es un reemplazo del Freón 22 de mayor capacidad. Se comercializa en cilindros desechables de 6,8kg y en cajas de 12 latas de 3,408kg cada una. Su composición en peso es de 60% HCFC-22, 23% HFC-152ª y 27% HCFC-124.
Refrigerante 401ª
Comercializado por DuPont con el nombre de Suva MP39. Algunas aplicaciones de este refrigerante son refrigeradores domésticos, congeladores, equipos de refrigeración para alimentos de media temperatura de humidificadores, máquinas de hielo y máquinas expendedoras de bebidas.
Tiene capacidades y eficiencia comparables a las del Freón 12, en sistemas que operan con una temperatura de evaporación de -23°C (-10°F) y superiores.
Se comercializan en cilindros retornables (CGT) de 771kg, cilindros retornables de 56,7kg, cilindros desechables de 6,8kg y cajas de 12 latas de 3,408kg cada una. Su composición en peso es de 60% HCFC-22, 13% HCF-152ª y 27% HCFC-124.
Refrigerante 401-b
Comercializado por DuPont con el nombre de Suva MP66, provee capacidades comparables al CFC-12 en sistemas que operan a temperatura de evaporación debajo de los -23°C (-10°F), haciéndolo adecuado para el uso en equipos de transporte refrigerado y en congeladores domésticos y comerciales. También puede sr utilizado para reemplazar en equipos que usan R-500. Se comercializa en cilindros retornables (CGT) de 771kg, cilindros retornables de 56,7kg y cilindros desechables de 13,61kg. Sus composición en peso es de 60% HCFC-22, 13% HFC-152ª y 27% HCFC-124.
Refrigerante 402ª
Comercializado por DuPont con el nombre de Suva HP80, reemplaza al R-502 en sistemas de media y baja temperatura. Tiene aplicaciones muy variadas en la industria de la refrigeración. Es usado ampliamente en aplicaciones de supermercados, almacenamiento y transporte de alimentos en sistemas de cascada de temperatura. Ofrece buena capacidad y eficiencia sin sufrir los incrementos de presión y temperatura en la descarga del compresor, lo cuál si sucede cuando un equipo es convertido HCFC-22. Se comercializa en cilindros retornables (CME) de 49,9kg y cilindros desechables de 13.25 kg. Su composición en peso es de 60% HCFC-22, 38,5% HFC-125 y 2% de propano.
Refrigerante 402b
Comercializado por DuPont con el nombre de Suva HP81, todos los refrigerantes designados HP fueron diseñados para reemplazar al R-502 en sistemas de refrigeración de temperatura media y baja. Está diseñado para el reacondicionamiento de equipos como máquinas de hielo. Además ofrece mas alta eficiencia comparado con el R-502 y una capacidad relativamente mejor. Sin embargo el mayor contenido de HCFC-22 resulta en temperaturas de descarga de compresor en un rango de 14°C (25°F). Se comercializa en cilindros desechables de 5,9kg. Su composición en peso es de 60% HCFC-22, 38% HFC-125 y 2% de propano.
Hidrocarburos directos
Los hidrocarburos directos son un grupo de fluidos compuestos en varias proporciones de los dos elementos hidrógeno y carbono. Algunos son el Metano, etano, butano, etileno e isobutano. Todos son extremadamente inflamables y explosivos. Aunque ninguno de estos compuestos absorben humedad en forma considerable, todos son extremadamente miscibles en aceite para todas las condiciones. Su uso ordinariamente está limitado a aplicaciones especiales donde se requieren los servicios de personal especializado.
Medio ambiente
Una de las propiedades más importantes es que no debe contaminar el medio ambiente.
Los estudios demostraron que los químicamente inalterables CFC son poco estables hacia la radiación UV-C, se produce una reacción fotoquímica que da lugar a la liberación de átomos de cloro, los cuáles son muy reactivos y colisionan con los átomos de ozono produciendo monóxido de cloro y oxígeno molecular. El monóxido de cloro puede reaccionar con los átomos de oxígeno y se regenera el cloro atómico. Los átomos de cloro liberados cierran el llamado “ciclo cloro catalítico del ozono”. Se estima que un solo átomo liberado de un CFC puede dar origen a una reacción en cadena que destruya 100000moléculas de ozono. Este ciclo puede ser bloqueado por dióxido de nitrógeno, que puede secuestrar monóxido de cloro mediante una reacción química en la que se forma nitrato de cloro, esta reacción es conocida como “reacción de interferencia”, porque bloquea la degradación del ozono producida por derivados del CFC.
Los HCFC continúan destruyendo la capa de ozono, aunque algo menos que los CFC, y tanto los HCFC como los HFC son gases de invernadero potente.
Debido a que los HCFC destruyen el ozono, solo son considerados “compuestos de transición” lo que significa que tendrán que ser reemplazados a su vez por compuestos mas aceptables desde el punto de vista ambiental. Lo mismo puede decirse con respecto a los HFC, que por su elevado potencial de calentamiento global han sido incluidos en el protocolo de Kioto. El absurdo paso intermedio entre los HCFC o HFC doblará los costes de los nuevos equipos, de los cambios en las líneas de producción y del entrenamiento del personal. Las actuales fechas de eliminación de los HCFC, CFC y bromuro de metilo son inadecuadas para la producción de Ozono.
Toxicidad
Debido a que todos los fluidos no son otra cosa que aire tóxico, en el sentido que pueden causar sofocación cuando se tienen en concentraciones suficientemente altas que evitan tener el oxígeno necesario para sustentar la vida, la toxicidad es un término relativo el cuál tiene significancia solo cuando se especifica el grado de concentración y tiempo de exposición requeridos para producir efectos nocivos.
El grado de peligro en que se incurre con el uso de refrigerantes tóxicos depende de varios factores, tales como la cantidad de refrigerante usado con relación al tamaño del espacio dentro del cuál se pueden tener fugas de refrigerante, del tipo de ocupación, de sí se tengan fiamas o fuego y de si el personal experimentado tenga la obligación de atender al equipo.
Los refrigerantes tóxicos (incluyendo productos de descomposición) despiden olores muy peculiares que tienden a dar aviso de su presencia. Son peligrosos para el caso de niños y personas que por razones de enfermedad o confinamiento son incapaces de escapar de los humos.
De acuerdo a su toxicidad el american Standard Safety Code for Mechanichal Refrigeration (código Americano Estándar de Seguridad para la refrigeración Mecánica) y la norma ASHRAE 12-58 agrupan los refrigerantes en tres clases. Puesto que muchos de ellos no se utilizan, solo describiremos los de uso más corriente.
Refrigerantes del grupo 1:
Son los de toxicidad e inflamabilidad despreciables. De ellos, los refrigerantes 11, 113 y 114 se emplean en compresores centrífugos.
Los refrigerantes 12, 22, 500 y 502 se usan normalmente en compresores alternativos y en los centrífugos de elevada capacidad.
Refrigerantes del grupo 2:
Son los tóxicos o inflamables, o ambas cosas.
El grupo incluye el Amoníaco, Cloruro de etilo, Cloruro de metilo y Dióxido de azufre, pero solo el Amoníaco (r-717) se utiliza aún en cierto grado.
Refrigerantes del grupo 3:
Estos refrigerantes son muy inflamables y explosivos. A causa de su bajo costo se utilizan donde el peligro está siempre presente y su uso no agrega otro peligro, como por ejemplo, en las plantas petroquímicas y en las refinerías de petróleo.
El grupo incluye el Butano, Propano, Isobutano, Etano, Etileno, Propileno y Metano.
Estos refrigerantes deben trabajar a presiones mayores que la atmosférica para evitar que aumente el peligro de explosión. Las presiones mayores que las atmosféricas impiden la penetración de aire por pérdidas porque es la mezcla aire-refrigerante la que resulta potencialmente peligrosa.
DEFINITION:Is any body or substance that acts as a cooling agent by absorbing heat from another body or substance.With respect to the vapor-compression cycle, the refrigerant is the cycle working fluid alternately on which is condensed and vaporized by absorbing and releasing heat, respectively. To an appropriate cooling and was suitable for use in the abovementioned cycle, must possess certain physical properties, chemical and thermodynamic safe to do so during use.There is no coolant "ideal" or that can be universally adaptable to all applications. Then, a refrigerant will approach the "ideal", just as their properties meet the conditions and needs of the application for which will be used.
Different types of refrigerants (Features)
AmmoniaAlthough ammonia is toxic, which is flammable and explosive under certain conditions, excellent thermal properties make him an ideal coolant for ice factories, department stores for cooling, etc.., Which has the services of experienced and where his toxic nature is of little consequence.The ammonia is the refrigerant which has higher cooling effect per unit weight.The boiling point of ammonia under standard atmospheric pressure is from -2.22 ° C, pressures in the evaporator and condenser under conditions of standard ton is -15 ° C and 30 ° C are 34.27 pounds per inch * and 169.2 pounds per inch * abs. , Respectively, can be used lightweight materials in the construction of equipment refrigerant. The adiabatic temperature at the discharge is relatively high, being of 98.89 ° C for standard ton conditions, so what is adequate cooling water having both the head and the cylinder of the compressor.In the presence of moisture ammonia becomes corrosive to the non-ferrous materials.Ammonia is not miscible with the oil and therefore not diluted with oil from the compressor crankcase. Should be used an oil separator in the discharge pipe systems ammonia.Ammonia is readily available and is the cheapest of refrigerants.Chemical stability, affinity for water and non-miscible with the oil, ammonia make an ideal refrigerant stops be used in very large systems where toxicity is an important factor.
Refrigerant 22Known as Freon 22, is used in air conditioning systems, domestic and commercial and industrial refrigeration including cold storage facilities for food processing: refrigeration and air conditioning on board of different transport, heat pumps heating air and water. It could be used in reciprocating compressors, centrifugal and screw compressors.The coolant 22 (CHCIF) has a boiling point at atmospheric pressure 40.8 ° C.Temperatures in the evaporator are as low as 87 ° C. A great advantage is the relatively small heat of displacement of the compressor.The temperature in the discharge with the refrigerante22 is high, the superheated in the suction temperature should be kept at its minimum value, especially when using hermetic motor-compressor units. In low temperature applications where high compression ratios, we recommend you in the head with water cooling and compressor cylinders. The air-cooled condensers with refrigerant 22 employees, should be generously sized.Although the coolant is miscible with oil 22 in the condensation section often usually separable oil in the evaporator.There have been difficulties in the oil return after the evaporator when you have the proper design of the evaporator coil and suction line.Being a fluorocarbon, the coolant 22 is a safe coolant.It is sold in returnable cylinders (CME) of 56.7 kg, 22.68 kg disposable cylinder, 13.61 kg of disposable cylinders and boxes of 12 cans of 5.10 kg each.
Refrigerant 123It is a viable replacement for Freon 11 as coolant.The thermodynamic and physical properties of refrigerant 123 in conjunction with their non-flammability characteristics makes it an efficient replacement of Freon 11 in centrifugal chillers.Refrigerant 123 was designed to work in new equipment available. When considering or retrofit refrigerant 123 from an existing team, should consider the life cycle of the equipment, the difference in cost of operation and maintenance and overhaul costs.New equipment that are designed to work with refrigerant 123 are lower operating costs compared with existing equipment.Because it smells so slight that it can be detected by smell is often necessary leak testing and installing leak detectors enclosed areas used by staff. It is available in drums of 283.5 kg, 90.72 kg drums and drums of 45.36 kg. Its composition by weight is 100% HFC-123.
134-a refrigerantThe refrigerant Suva134a brand has been introduced by DuPont as a replacement for chlorofluorocarbons (CFCs) in many applications. The production of CFCs is replaced by HFC-134 hidrofluorucarbono th.This refrigerant does not contain chlorine and can be used in many applications that currently use CFC-12. But sometimes requires changes in equipment design to optimize the performance of Suva 134 th in this application.The thermodynamic and physical properties of Suva 134a and its low toxicity make it a safe replacement and highly efficient CFC-12 in many segments of the industrial refrigeration most notably in the automotive air conditioning, domestic equipment, stationary equipment small team of supermarket medium temperature and chillers, industrial and commercial. The Suva134a has shown that is combustible at pressures as low as 5.5 psig to 177 ° C when mixed with air at concentrations generally greater than 60% by volume of air. At low temperatures, higher pressures are required for combustibility. They should not be mixed with air for leak testing. In general should not be allowed to be present with high concentrations of air above atmospheric pressure. They are sold in returnable cylinders (CME) of 56.7 kg, 13.61 kg of disposable cylinders, and boxes of 12 cans of 3.408 kg each. Evaporator temperature -7 ° C to 7 ° C. Its composition by weight is 100% HFC-134a.
Coolant 407c/410 toDuPont's marketed as Suva 9100 respectively.Replace HCFC-22 in air conditioning applications in domestic heating pumps. The 9000 Suva used for new equipment or service has a similar performance of HCFC-22 in air conditioning. The 9100 Suva serves only to new equipment and is a replacement for Freon 22 with greater capacity. It is sold in disposable cylinders of 6.8 kg and in boxes of 12 cans of 3.408 kg each. Its composition by weight is 60% HCFC-22, HFC-152 23% th and 27% HCFC-124.
Refrigerant 401 thMarketed by DuPont under the name of Suva MP39. Some applications of this refrigerant are domestic refrigerators, freezers, food refrigeration medium temperature of humidifiers, ice machines and beverage machines.Has capabilities and efficiencies comparable to those of Freon 12, in systems operating with an evaporation temperature of -23 ° C (-10 ° F) and above.They are sold in returnable cylinders (CGT) of 771kg, returnable cylinders of 56.7 kg, 6.8 kg of disposable cylinders and boxes of 12 cans of 3.408 kg each. Its composition by weight is 60% HCFC-22, HFC-152 13% th and 27% HCFC-124.
Refrigerant 401-bMarketed by DuPont under the name of Suva MP66, provides capabilities comparable to CFC-12 in systems operating at evaporation temperature below -23 ° C (-10 ° F), making it suitable for use in refrigerated transportation equipment and in domestic and commercial freezers. You can also used to replace sr equipment using R-500. It is sold in returnable cylinders (CGT) of 771kg, returnable cylinders of 56.7 kg and 13.61 kg disposable cylinder. Its composition by weight is 60% HCFC-22, HFC-152 13% 27% th and HCFC-124.
Refrigerant 402 thMarketed by DuPont under the name of Suva HP80 replaces R-502 in medium and low temperature. It has numerous applications in the refrigeration industry. Is widely used in supermarket applications, storage and transport of food temperature cascade systems.It offers good capacity and efficiency without suffering increases pressure and temperature in the compressor discharge, so what if it happens when a computer is converted to HCFC-22. It is sold in returnable cylinders (CME) of 49.9 kg and 13.25 kg disposable cylinder. Its composition by weight is 60% HCFC-22, 38.5% HFC-125 and 2% propane.
Refrigerant 402bMarketed by DuPont under the name of Suva HP81, all refrigerants designated HP were designed to replace R-502 in refrigeration systems for low and medium temperature. It is designed for reconditioning of equipment such as ice machines. It also offers higher efficiency compared to the R-502 and a relatively better. However, the higher content of HCFC-22 results in compressor discharge temperatures in a range of 14 ° C (25 ° F). It is sold in disposable cylinders of 5.9 kg. Its composition by weight is 60% HCFC-22, HFC-125 38% and 2% propane.
Direct hydrocarbonDirect hydrocarbon fluids are a group of compounds in various proportions of the two elements hydrogen and carbon. Some are methane, ethane, butane, ethylene and isobutane. All are extremely flammable and explosive. While none of these compounds absorb moisture considerably, all are highly miscible in oil to all conditions. Its use is usually limited to special applications which require the services of specialized personnel.Environment
One of the most important properties is not to contaminate the environment.The studies demonstrated that the CFCs are unchanged chemically unstable to UV-C, a photochemical reaction occurs which results in the release of atoms of chlorine, which are very reactive and collide with atoms of chlorine monoxide producing ozone and molecular oxygen. Chlorine monoxide can react with the oxygen atoms and chlorine atom is regenerated. The chlorine atoms released close the so-called "chlorine catalytic cycle of ozone." It is estimated that a single atom released from a CFC can give rise to a chain reaction that destroys ozone 100000moléculas. This cycle can be blocked by nitrogen dioxide, which can sequester chlorine monoxide through a chemical reaction in which chlorine nitrate is formed, this reaction is known as "reaction interference", because it blocks the degradation of the ozone produced by derivatives of CFCs.HCFCs continue to destroy the ozone layer, although somewhat less than CFCs, HCFCs and therefore as HFCs are potent greenhouse gases.Because ozone-depleting HCFCs, are only considered "compounds of transition" which means they will have to be replaced in turn by compounds more acceptable environmentally. The same is true with respect to HFCs, which because of their high global warming potential have been included in the Kyoto Protocol. The absurdity intermediate step between HCFC or HFC will double the cost of new equipment, changes in production lines and personnel training. The current phase-out dates for HCFCs, CFCs and methyl bromide are inadequate for the production of ozone.Toxicity
Because all fluids are nothing but air toxic, in that it can cause suffocation when concentrations are high enough to avoid having the necessary oxygen to sustain life, toxicity is a relative term which has the significance only when specifying the degree of concentration and exposure time required to produce harmful effects.The degree of risk incurred by the use of toxic refrigerants depends on several factors such as the amount of refrigerant used with the size of the space within which refrigerant may leak, the type of occupation, in itself is fiamas have no fire and whether the experienced staff is required to meet the team.Toxic refrigerants (including breakdown products) emit peculiar odors that tend to give notice of their presence. They are dangerous for children and people who for reasons of illness or confinement are unable to escape the fumes.According to the American Standard toxicity for Mechanichal Refrigeration Safety Code (American Standard Code of Safety for Mechanical Refrigeration) and ASHRAE 12-58 refrigerants grouped into three classes. Since many of them are not used, only describe the most commonly used.
Refrigerants group 1:Are negligible toxicity and flammability. Of these, Refrigerant 11, 113 and 114 are used in centrifugal compressors.Refrigerants 12, 22, 500 and 502 are normally used in reciprocating compressors and the high capacity centrifugal.
Group 2 refrigerants:Are toxic or flammable or both.The group includes ammonia, ethyl chloride, methyl chloride and sulfur dioxide, but only ammonia (R-717) is still used to some degree.
Group 3 refrigerants:These refrigerants are highly flammable and explosive. Because of its low cost is used where the danger is always present and its use does not add another danger, for example, petrochemical plants and oil refineries.The group includes Butane, Propane, Isobutane, Ethane, Ethylene, Propylene and Methane.These refrigerants have to work at pressures greater than atmospheric pressure to avoid increasing the danger of explosion. Pressures greater than atmospheric prevent the penetration of air is lost because the air-refrigerant mixture which is potentially dangerous.
Different types of refrigerants (Features)
AmmoniaAlthough ammonia is toxic, which is flammable and explosive under certain conditions, excellent thermal properties make him an ideal coolant for ice factories, department stores for cooling, etc.., Which has the services of experienced and where his toxic nature is of little consequence.The ammonia is the refrigerant which has higher cooling effect per unit weight.The boiling point of ammonia under standard atmospheric pressure is from -2.22 ° C, pressures in the evaporator and condenser under conditions of standard ton is -15 ° C and 30 ° C are 34.27 pounds per inch * and 169.2 pounds per inch * abs. , Respectively, can be used lightweight materials in the construction of equipment refrigerant. The adiabatic temperature at the discharge is relatively high, being of 98.89 ° C for standard ton conditions, so what is adequate cooling water having both the head and the cylinder of the compressor.In the presence of moisture ammonia becomes corrosive to the non-ferrous materials.Ammonia is not miscible with the oil and therefore not diluted with oil from the compressor crankcase. Should be used an oil separator in the discharge pipe systems ammonia.Ammonia is readily available and is the cheapest of refrigerants.Chemical stability, affinity for water and non-miscible with the oil, ammonia make an ideal refrigerant stops be used in very large systems where toxicity is an important factor.
Refrigerant 22Known as Freon 22, is used in air conditioning systems, domestic and commercial and industrial refrigeration including cold storage facilities for food processing: refrigeration and air conditioning on board of different transport, heat pumps heating air and water. It could be used in reciprocating compressors, centrifugal and screw compressors.The coolant 22 (CHCIF) has a boiling point at atmospheric pressure 40.8 ° C.Temperatures in the evaporator are as low as 87 ° C. A great advantage is the relatively small heat of displacement of the compressor.The temperature in the discharge with the refrigerante22 is high, the superheated in the suction temperature should be kept at its minimum value, especially when using hermetic motor-compressor units. In low temperature applications where high compression ratios, we recommend you in the head with water cooling and compressor cylinders. The air-cooled condensers with refrigerant 22 employees, should be generously sized.Although the coolant is miscible with oil 22 in the condensation section often usually separable oil in the evaporator.There have been difficulties in the oil return after the evaporator when you have the proper design of the evaporator coil and suction line.Being a fluorocarbon, the coolant 22 is a safe coolant.It is sold in returnable cylinders (CME) of 56.7 kg, 22.68 kg disposable cylinder, 13.61 kg of disposable cylinders and boxes of 12 cans of 5.10 kg each.
Refrigerant 123It is a viable replacement for Freon 11 as coolant.The thermodynamic and physical properties of refrigerant 123 in conjunction with their non-flammability characteristics makes it an efficient replacement of Freon 11 in centrifugal chillers.Refrigerant 123 was designed to work in new equipment available. When considering or retrofit refrigerant 123 from an existing team, should consider the life cycle of the equipment, the difference in cost of operation and maintenance and overhaul costs.New equipment that are designed to work with refrigerant 123 are lower operating costs compared with existing equipment.Because it smells so slight that it can be detected by smell is often necessary leak testing and installing leak detectors enclosed areas used by staff. It is available in drums of 283.5 kg, 90.72 kg drums and drums of 45.36 kg. Its composition by weight is 100% HFC-123.
134-a refrigerantThe refrigerant Suva134a brand has been introduced by DuPont as a replacement for chlorofluorocarbons (CFCs) in many applications. The production of CFCs is replaced by HFC-134 hidrofluorucarbono th.This refrigerant does not contain chlorine and can be used in many applications that currently use CFC-12. But sometimes requires changes in equipment design to optimize the performance of Suva 134 th in this application.The thermodynamic and physical properties of Suva 134a and its low toxicity make it a safe replacement and highly efficient CFC-12 in many segments of the industrial refrigeration most notably in the automotive air conditioning, domestic equipment, stationary equipment small team of supermarket medium temperature and chillers, industrial and commercial. The Suva134a has shown that is combustible at pressures as low as 5.5 psig to 177 ° C when mixed with air at concentrations generally greater than 60% by volume of air. At low temperatures, higher pressures are required for combustibility. They should not be mixed with air for leak testing. In general should not be allowed to be present with high concentrations of air above atmospheric pressure. They are sold in returnable cylinders (CME) of 56.7 kg, 13.61 kg of disposable cylinders, and boxes of 12 cans of 3.408 kg each. Evaporator temperature -7 ° C to 7 ° C. Its composition by weight is 100% HFC-134a.
Coolant 407c/410 toDuPont's marketed as Suva 9100 respectively.Replace HCFC-22 in air conditioning applications in domestic heating pumps. The 9000 Suva used for new equipment or service has a similar performance of HCFC-22 in air conditioning. The 9100 Suva serves only to new equipment and is a replacement for Freon 22 with greater capacity. It is sold in disposable cylinders of 6.8 kg and in boxes of 12 cans of 3.408 kg each. Its composition by weight is 60% HCFC-22, HFC-152 23% th and 27% HCFC-124.
Refrigerant 401 thMarketed by DuPont under the name of Suva MP39. Some applications of this refrigerant are domestic refrigerators, freezers, food refrigeration medium temperature of humidifiers, ice machines and beverage machines.Has capabilities and efficiencies comparable to those of Freon 12, in systems operating with an evaporation temperature of -23 ° C (-10 ° F) and above.They are sold in returnable cylinders (CGT) of 771kg, returnable cylinders of 56.7 kg, 6.8 kg of disposable cylinders and boxes of 12 cans of 3.408 kg each. Its composition by weight is 60% HCFC-22, HFC-152 13% th and 27% HCFC-124.
Refrigerant 401-bMarketed by DuPont under the name of Suva MP66, provides capabilities comparable to CFC-12 in systems operating at evaporation temperature below -23 ° C (-10 ° F), making it suitable for use in refrigerated transportation equipment and in domestic and commercial freezers. You can also used to replace sr equipment using R-500. It is sold in returnable cylinders (CGT) of 771kg, returnable cylinders of 56.7 kg and 13.61 kg disposable cylinder. Its composition by weight is 60% HCFC-22, HFC-152 13% 27% th and HCFC-124.
Refrigerant 402 thMarketed by DuPont under the name of Suva HP80 replaces R-502 in medium and low temperature. It has numerous applications in the refrigeration industry. Is widely used in supermarket applications, storage and transport of food temperature cascade systems.It offers good capacity and efficiency without suffering increases pressure and temperature in the compressor discharge, so what if it happens when a computer is converted to HCFC-22. It is sold in returnable cylinders (CME) of 49.9 kg and 13.25 kg disposable cylinder. Its composition by weight is 60% HCFC-22, 38.5% HFC-125 and 2% propane.
Refrigerant 402bMarketed by DuPont under the name of Suva HP81, all refrigerants designated HP were designed to replace R-502 in refrigeration systems for low and medium temperature. It is designed for reconditioning of equipment such as ice machines. It also offers higher efficiency compared to the R-502 and a relatively better. However, the higher content of HCFC-22 results in compressor discharge temperatures in a range of 14 ° C (25 ° F). It is sold in disposable cylinders of 5.9 kg. Its composition by weight is 60% HCFC-22, HFC-125 38% and 2% propane.
Direct hydrocarbonDirect hydrocarbon fluids are a group of compounds in various proportions of the two elements hydrogen and carbon. Some are methane, ethane, butane, ethylene and isobutane. All are extremely flammable and explosive. While none of these compounds absorb moisture considerably, all are highly miscible in oil to all conditions. Its use is usually limited to special applications which require the services of specialized personnel.Environment
One of the most important properties is not to contaminate the environment.The studies demonstrated that the CFCs are unchanged chemically unstable to UV-C, a photochemical reaction occurs which results in the release of atoms of chlorine, which are very reactive and collide with atoms of chlorine monoxide producing ozone and molecular oxygen. Chlorine monoxide can react with the oxygen atoms and chlorine atom is regenerated. The chlorine atoms released close the so-called "chlorine catalytic cycle of ozone." It is estimated that a single atom released from a CFC can give rise to a chain reaction that destroys ozone 100000moléculas. This cycle can be blocked by nitrogen dioxide, which can sequester chlorine monoxide through a chemical reaction in which chlorine nitrate is formed, this reaction is known as "reaction interference", because it blocks the degradation of the ozone produced by derivatives of CFCs.HCFCs continue to destroy the ozone layer, although somewhat less than CFCs, HCFCs and therefore as HFCs are potent greenhouse gases.Because ozone-depleting HCFCs, are only considered "compounds of transition" which means they will have to be replaced in turn by compounds more acceptable environmentally. The same is true with respect to HFCs, which because of their high global warming potential have been included in the Kyoto Protocol. The absurdity intermediate step between HCFC or HFC will double the cost of new equipment, changes in production lines and personnel training. The current phase-out dates for HCFCs, CFCs and methyl bromide are inadequate for the production of ozone.Toxicity
Because all fluids are nothing but air toxic, in that it can cause suffocation when concentrations are high enough to avoid having the necessary oxygen to sustain life, toxicity is a relative term which has the significance only when specifying the degree of concentration and exposure time required to produce harmful effects.The degree of risk incurred by the use of toxic refrigerants depends on several factors such as the amount of refrigerant used with the size of the space within which refrigerant may leak, the type of occupation, in itself is fiamas have no fire and whether the experienced staff is required to meet the team.Toxic refrigerants (including breakdown products) emit peculiar odors that tend to give notice of their presence. They are dangerous for children and people who for reasons of illness or confinement are unable to escape the fumes.According to the American Standard toxicity for Mechanichal Refrigeration Safety Code (American Standard Code of Safety for Mechanical Refrigeration) and ASHRAE 12-58 refrigerants grouped into three classes. Since many of them are not used, only describe the most commonly used.
Refrigerants group 1:Are negligible toxicity and flammability. Of these, Refrigerant 11, 113 and 114 are used in centrifugal compressors.Refrigerants 12, 22, 500 and 502 are normally used in reciprocating compressors and the high capacity centrifugal.
Group 2 refrigerants:Are toxic or flammable or both.The group includes ammonia, ethyl chloride, methyl chloride and sulfur dioxide, but only ammonia (R-717) is still used to some degree.
Group 3 refrigerants:These refrigerants are highly flammable and explosive. Because of its low cost is used where the danger is always present and its use does not add another danger, for example, petrochemical plants and oil refineries.The group includes Butane, Propane, Isobutane, Ethane, Ethylene, Propylene and Methane.These refrigerants have to work at pressures greater than atmospheric pressure to avoid increasing the danger of explosion. Pressures greater than atmospheric prevent the penetration of air is lost because the air-refrigerant mixture which is potentially dangerous.
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