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The Mitsubishi model was the first air conditioner with a cross-flow fan. [64] [65] [66] In 1969, the first mini-split air conditioner was sold in the US. [67] Multi-zone ductless systems were invented by Daikin in 1973, and variable refrigerant flow systems (which can be thought of as larger multi-split systems) were also invented by Daikin in ...
The ASHRAE Handbook is the four-volume flagship publication of the nonprofit technical organization ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers [a]). This Handbook is considered the most comprehensive and authoritative repository of practical knowledge on the various topics that form the field of heating ...
The EU standard test conditions for an air source heat pump is at dry-bulb temperature of 20 °C (68 °F) for and 7 °C (44.6 °F) for . [9] Given sub-zero European winter temperatures, real world heating performance is significantly poorer than such standard COP figures imply.
It was originally defined as the rate of heat transfer that results in the freezing or melting of 1 short ton (2,000 lb; 907 kg) of pure ice at 0 °C (32 °F) in 24 hours. [1] [2] The modern definition is exactly 12,000 Btu IT /h (3.516853 kW). Air-conditioning and refrigeration equipment capacity in the U.S. is often specified in "tons" (of ...
Clean air delivery rate (CADR) is the amount of clean air an air cleaner provides to a room or space. When determining CADR, the amount of airflow in a space is taken into account. For example, an air cleaner with a flow rate of 30 cubic metres (1,000 cu ft) per minute and an efficiency of 50% has a CADR of 15 cubic metres (500 cu ft) per minute.
An air handler, or air handling unit (often abbreviated to AHU), is a device used to regulate and circulate air as part of a heating, ventilating, and air-conditioning system. [1] An air handler is usually a large metal box containing a blower , furnace or A/C elements, filter racks or chambers, sound attenuators , and dampers . [ 2 ]
Variable refrigerant flow (VRF), also known as variable refrigerant volume (VRV), is an HVAC technology invented by Daikin Industries, Ltd. in 1982. [1] Similar to ductless mini-split systems, VRFs use refrigerant as the primary cooling and heating medium, and are usually less complex than conventional chiller-based systems.
Packaged terminal air conditioner installed in a residential apartment. A packaged terminal air conditioner (PTAC) is a type of self-contained heating and air conditioning system intended to be mounted through a wall. [1] The first practical semi-portable air conditioning unit invented by engineers at Chrysler Motors. It entered the market in ...