ASHRAE-90.1-2022- - Page 017
Extracted Content
ductwork: a system of ducts for distribution and extraction of air.
dwelling unit: a single unit providing complete independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking, and sanitation.
direct-expansion dedicated outdoor air system units (DX-DOAS units): a type of air-cooled, water-cooled, or water-source factory-assembled product that dehumidifies 100% outdoor air to a low dew point and includes reheat that is capable of controlling the supply dry-bulb temperature of the dehumidified air to the designed supply air temperature. This conditioned outdoor air is then delivered directly or indirectly to the conditioned spaces . It may precondition outdoor air by containing an enthalpy wheel, sensible wheel, desiccant wheel, plate heat exchanger, heat pipes, or other heat or mass transfer apparatus.
dynamic glazing: any glazing system /glazing infill that has the fully reversible ability to change its performance properties, including U-factor, solar heat gain coefficient, or visible transmittance . This includes (but is not limited to) shading systems between the glazing layers and chromogenic glazing.
east-oriented: facing within 45 degrees of true east to the south and within less than 22.5 degrees of true east to the north in the northern hemisphere; facing within 45 degrees of true east to the north and within less than 22.5 degrees of true east to the south in the southern hemisphere.
economizer, air: a duct and damper arrangement and automatic control system that together allow a cooling system to supply outdoor air to reduce or eliminate the need for mechanical cooling during mild or cold weather.
economizer, fluid: a system by which the supply air of a cooling system is cooled indirectly with a fluid that is itself cooled by heat or mass transfer to the environment without the use of mechanical cooling . Examples of commonly used fluids are water, glycol mixtures, and refrigerants.
effective panel surface: see thermally effective panel surface .
efficacy (of a lamp): the ratio of the total luminous output of a lamp to the total power input to the lamp, typically expressed in lm/W.
efficiency: performance at specified rating conditions.
electric resistance: see resistance, electric.
emittance: the ratio of the radiant heat flux emitted by a specimen to that emitted by a blackbody at the same temperature and under the same conditions.
enclosed space: a volume substantially surrounded by solid surfaces, such as walls, floors, roofs, and openable devices, such as doors and operable windows.
energy: the capacity for doing work. It takes a number of forms that may be transformed from one into another such as thermal (heat), mechanical (work), electrical, and chemical (Btu).
energy cost budget: the annual energy cost for the budget building design intended for use in determining minimum compliance with this standard.
energy efficiency ratio (EER): the ratio of net cooling capacity (Btu/h) to total rate of electric input in watts under designated operating conditions. ( Informative Note: EER2 reflects the new higher static effective 1/1/2023.)
energy factor (EF): a measure of water heater overall efficiency .
envelope performance factor: the trade-off value for the building envelope performance compliance option, expressed in annual energy cost, calculated using the procedures specified in Section 5.6. For the purposes of determining building envelope requirements, the classifications are defined as follows:
base envelope performance factor: the building envelope performance factor for the base design.
proposed envelope performance factor: the building envelope performance factor for the proposed design .
energy recovery ratio, series (SERR): the difference between the dry-bulb air temperatures leaving the series energy recovery unit and leaving the dehumidifying coil divided by the difference between 75°F and the dry-bulb temperature of the air leaving the dehumidifying cooling coil.
energy recovery, series: a three-step process in which the first step is to remove energy from a single airstream without the use of mechanical cooling . In the second step, the airstream is mechanically cooled for the purpose of dehumidification. In the third step, the energy removed in step one is reintroduced to the airstream.
ANSI/ASHRAE/IES Standard 90.1-2022 (I-P) 15