Refrigeration PDF

DOMRAC Domestic Refrigeration and Air Conditioning  Difference Between Air Conditioning and Refrigeration  High Temperature Reservoir How does it work? Heat Rejected R Work Input...

DOMRAC Domestic Refrigeration and Air Conditioning  Difference Between Air Conditioning and Refrigeration  High Temperature Reservoir How does it work? Heat Rejected R Work Input Heat Absorbed Low Temperature Reservoir  Difference Between Air Conditioning and Refrigeration Air Conditioning Refrigeration The circulation system is designed to keep The circulation system is designed to keep the cooled air out of the unit the cool air within the unit Two individual units are present. One unit for One single unit encompasses the evaporator, the evaporator and the other unit houses the compressor and condenser compressor and the condenser. The in-built chemicals within the unit absorb The air is supplied to the unit through pipes air into the system Fan is required No fan is required They are used to cool the room to maintain They are used to cool the food for food humidity preservation  Different Types of RAC Units 1. Chillers Chillers typically cool water, which is then circulated to provide comfort cooling throughout a building or other location. Chillers can be classified by compressor type, including centrifugal, reciprocating, scroll, screw, and rotary compressors. Chillers used to cool industrial processes. 2. Cold Storage Warehouses Cold storage warehouses store meat, produce, dairy products, and other perishable goods. The majority of cold storage warehouses in the United States use ammonia as the refrigerant in a vapor compression cycle, although some rely on other refrigerants. 3. Commercial Ice Machines Commercial ice machines are used in commercial establishments (e.g., hotels, restaurants, convenience stores) to produce ice for consumer use. Ice machines produce ice in various sizes and shapes, and with different retrieval mechanisms (e.g., dispensers or self- retrieval from bins). Ice makers that are part of a refrigerator-freezer are considered part of the latter end-use, while equipment that is solely used to make ice, even if used in a domestic setting, is considered part of the commercial ice machine’s end-use. 4. Household Refrigerators and Freezers Household refrigerators and freezers are intended primarily for residential use, although they may be used outside the home. Household freezers only offer storage space at freezing temperatures. Products with both a refrigerator and freezer in a single unit are most common. Small refrigerated household appliances may also include chilled kitchen drawers, wine coolers, and mini fridges. 5. Ice Skating Rinks Ice skating rinks are used by the general public for recreational purposes and also include professional rinks. These systems frequently use secondary loop refrigeration systems. 6. Industrial Process Air Conditioning Industrial process air-conditioning units, which are distinct from commercial and residential air conditioning, provide comfort cooling for operators and protect process equipment. This end- use is often used when ambient temperatures approach 200°F (93°C) and corrosive conditions exist. 7. Industrial Process Refrigeration Industrial process refrigeration systems cool process streams in industrial applications. The choice of substitute for specific applications depends on ambient and required operating temperatures and pressures 8. Motor Vehicle Air Conditioning Motor vehicle air-conditioning systems (MVACs) provide comfort cooling for passengers in light-duty cars and trucks, buses, trains, and other forms of transportation. 9. Non-Mechanical Heat Transfer Systems Non-mechanical heat transfer systems include cooling systems that do not rely on a vapor compression cycle, such as those using convection to remove heat from an area. Two types of such systems are recirculating coolers, i.e., systems with fluid pumps, and thermosiphons, i.e., those that rely on natural convection currents. This end-use also includes Organic Rankine Cycle (ORC) devices that typically pump refrigerant to recover and utilize energy from lowertemperature heat rejected from other processes. 10. Residential and Light Commercial Air Conditioning and Heat Pumps This end-use includes equipment that cools enclosed spaces in households and commercial industries, but excludes chillers―which include room air conditioning such as window units, packaged terminal air conditioners (PTAC) and heat pumps (PTHP), and portable air conditioners; central air conditioners (i.e., ducted); non-ducted systems (both mini and multi splits); packaged rooftop units; water- source and ground-source heat pumps; and other products. Residential and light commercial air conditioning and heat pumps are often distinguished from chillers by the fact that they condition the air directly, rather than cool (or heat) water that is then used to condition air. 11. Residential Dehumidifiers Residential dehumidifiers are primarily used to remove water vapor from ambient air or directly from indoor air for comfort or material preservation purposes. While air-conditioning systems often combine cooling and dehumidification, this application serves only the latter purpose. 12. Refrigerated Transport Refrigerated transport moves products (e.g., perishable goods) from one place to another by various modes of transportation while maintaining necessary temperatures, including refrigerated ship holds, truck trailers, railway freight cars, ships, and other shipping containers. 13. Retail Food Refrigeration Retail food refrigeration, or commercial refrigeration, includes equipment designed to store, display, process, or dispense chilled or frozen goods for commercial sale. This end-use includes these categories of equipment: standalone equipment, remote condensing units, supermarket systems, and refrigerated food processing and dispensing equipment. 14. Vending Machines Vending machines are self- contained units that dispense goods that must be kept cold or frozen 15. Very Low Temperature Refrigeration Very low temperature refrigeration systems require maintaining temperatures at approximately -80 degrees Fahrenheit (-62 degrees Celsius) or lower. Examples include medical freezers and freeze-dryers, which generally require extremely reliable refrigeration cycles to maintain low temperatures and must meet stringent technical standards that do not normally apply to refrigeration systems. 16. Water Coolers Water coolers are self-contained units providing chilled water, and possibly heated water, for drinking. They may or may not feature detachable containers of water.