1. Accumulator – Accumulator is a storage tank which prevents the liquid refrigerant (from the evaporator) to flow into the suction before evaporating.
  2. Adiabatic Compression – Adiabatic Compression is the process by which we can compress the refrigerant gas without adding or subtracting heat.
  3. AHU – Air Handler Unit (AHU) is the interior of an air conditioning system that comprises of the blower, evaporator coil and the heater.
  4. ARI – Air-Conditioning and Refrigeration Institute (ARI) is a non-profit institution that publishes heat pump rating and testing & air conditioner standards.
  5. AHRI – Air Conditioning, Heating and Refrigeration Institute (AHRI) is an association that creates standards for the measurement and certification of the performance of products.
  6. Absorption Chiller – Absorption Chiller is defined as low pressure refrigeration equipment that creates chilled water with the help of chemicals and heat source.
  7. Air Balance – Air Balance is the process of measuring air flow from the supply diffusers in an air conditioning system. It is expressed in CFM (Cubic feet per minute).
  8. Absolute Temperature – Absolute Temperature is the temperature scale that is expressed in Fahrenheit or Celsius using absolute zero as the base value.
  9. Absolute Zero – Theoretically, Absolute Zero is the temperature at which the molecular activity is bound to stop completely (-456.69 degrees F or -273.16 degrees C).
  10. Air Cooled Heat Exchanger– Is a type of heat exchanger that uses fan to generate air to repel heat. This system is very suitable for those areas with a limited space.
  11. Automatic Expansion Valve – Automatic Expansion Value is a control valve that is used to maintain uniform pressure in the evaporator of the refrigeration system.
  12. BTU – British Thermal Unit (BTU) is defined as the amount of heat an air conditioner isneeded to raise one pound of pure water by one degree Fahrenheit.
  13. Compressor – In a refrigerating process, compressor is the pump that exerts low pressure on the cooling side of the refrigerant cycle and exerts high pressure thereby compressing the gas in the condensing side of the cycle.
  14. Condenser Coil – Condenser Coil is exterior portion of a split air conditioner. It converts the refrigerant gas into liquid form to expel the heat outside.
  15. CFM – Cubic feet per minute (CFM) is a standard measurement unit of the airflow in a typical air conditioning system.
  16. Cooling Capacity – Cooling Capacity is the amount of cooling provided by an air conditioner. It is the number of BTUs per hour of heat that can be removed by the system.
  17. COP – Coefficient of Performance (COP) is used to measure the performance of the refrigeration cycles and is the ratio of desired output to the required input.Higher COP value means lower operating cost.
  18. Compressor Compression Ratio – At the saturated conditions, the compression ratio of a refrigerator is defined as the ratio of discharge pressure to the suction pressure.
  19. Central Air-Conditioning – Central air-conditioning or the central A/C is a system in which the central location of the building is cooled down and distributed either ways from rooms.
  20. Cooling Anticipator – Cooling Anticipator is a resistance heater that is connected parallel to the cooling circuit and it reduces the off cycle by adding on heat to the system.
  21. Centrifugal Chiller – Centrifugal Chiller is low-pressure power refrigeration unit that provides chilled water to air conditioning systems. This unit comprises of refrigerant evaporator, compressor and water cooled condenser. Understand more about compressor here.
  22. Condensing Unit Capacity – Condensing unit capacity is defined as the refrigerating effect that is produced by the difference in the total enthalpy of refrigerant leaving and entering the unit.
  23. Capacity Factor – Capacity Factor is the ratio of average load on the system to the capacity rating on the system over a particular duration of time.
  24. Cooling Load – Cooling Load is referred to theamount of heat that need to be removed to maintain a constant temperature and humidity in a certain space.
  25. Discharge Line – Discharge Line is a tube that supplies the compressed vapour of the refrigerant from compressor to the condenser unit.
  26. Dielectric Strength –Dielectric Strength is the indicator of moisture content in the refrigerator and ideally it should be high.
  27. Department of Energy (DOE) – The U.S. Department Of Energy (DOE) is an agency which monitors the energy consumption and sets the efficiency standards for cooling unit industries in the U.S.
  28. Dry-Charged Unit – Dry-Charged Unit is a heat pump or an air-conditioner that is shipped dry as the name suggests. It is charged with refrigerant once it at the time of installation.
  29. Ductwork – Ductwork is defined as the systematic cluster of ducts (tubes) that supply air from heating, ventilation & air-conditioning (HVAC) machinery throughout the stretch of your home.
  30. DAT – Discharge Air Temperature (DAT) is the temperature of air that is emitted from the air ducts of air conditioning systems.
  31. Evaporator – Evaporator is a device in which the liquid form of refrigerator changes into vapour form when superheating takes place.
  32. Electronic Air Cleaner – Electronic Air Cleaner makes use of electrically charged filters to clean the air passing through the cooling system to trap the harmful particles.
  33. ENERGY STAR – ENERGY STAR is a program started by the U.S. Environmental Protection Agency (EPA) that was framed with the motive of helping the consumers and organizations to adopt energy-efficient products and technology.
  34. Energy Saver Switch – An energy saver switch is used to cycle air conditioner fan and compressor on and off together and thus reducing the use of energy for this purpose. Find this article on 51 cold room energy saving tips.
  35. Freon – Freon is the trade name of R-22 chlorofluorocarbon (CFC) refrigerant used in air conditioning systems and refrigerators.
  36. FCU – Fan Coil Unit (FCU) is a device that is used to cool a room with the help of a coil and fan without making connection with the ductwork.
  37. Flash gas – Flash gas is formed by instantaneous evaporation of refrigerant in the system due to drop in pressure which helps to cool down the remaining refrigerant to the desired temperature.
  38. GWP – Global Warming Potentials (GWP) measures the relative average of radiation by a harmful greenhouse gas. GWP values are applied to all the units of mass.
  39. HCFC – Hydro Chlorofluorocarbon (HCFC) is a class of refrigerants that belong to the Halogenated Chlorofluorocarbon family of the refrigerants.
  40. Heat Exchange– Heat exchange is a mechanism that heat is being absorbed or transferred by fluid (liquid or gas) from one medium to another.
  41. Heat Rejection – Heat Rejection is defined as the extra heat in a cooling system that is rejected by the condenser (transfer of energy from cool to warm side).
  42. HVAC&R – Heating, Ventilation, Air-conditioning and Refrigerating (HVAC&R) is the combination of processes that equalizes to all the functions performed by air-conditioning.
  43. HVAC Damper – HVAC Damper, better known as the duct damper is located in the ductwork. It used to channel the flow of air and direct it specific regions of the home.
  44. HVAC Zoning System – HVAC Zoning System is a cooling system with customized temperature that uses duct dampers to regulate the flow of air to particular regions in the house.
  45. Heat Pump – Heat Pump is a device that works on similar grounds like an air conditioner in the cooling mode but opposite in the heating mode.
  46. Inverter – In an air conditioner, the inverter controls the conditioned temperature by regulating the compressor motor speed resulting in variable refrigerant flow in the system.
  47. Induction Ratio – Induction Ratio (I) of an air conditioning system is defined as the ratio of air flow rate to the primary air flow rate.
  48. Intercooling – Intercooling is the process of cooling between two stages of compression. This reduces the task of compressing and increases the output manifold.
  49. Load Estimate – Load Estimate is the detailed study of the determination of cooling requirements of a house or an institution.
  50. MERV Rating – Minimum Efficiency Reporting Value (MERV) is the measurement of the extent to which your air filter (in air conditioner) can remove dust particles from air.Higher MERV value means finer filtration, lesser dust particles can pass through the filter.
  51. Matched System – Matched System has both the features of a cooling and heating device that are certified to provide you with comfort when used together.
  52. NRE – Net Refrigeration Effect (NRE) is the amount of heat that every pound of refrigerant can extract from the refrigerated space to result in effective cooling.
  53. Precharged Lines – Precharged lines are the refrigerator’s line that comprises of refrigerant sealed from either ends. These seals break down when the refrigerator lines are installed.
  54. Pumpdown – Pumpdown is the process of pumping refrigerator out of the evaporator and suction line when the on-cycle of the system comes to an end. The compressor thereby shuts down by the low pressure.
  55. Ref