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For residential buildings, which mostly rely on infiltration for meeting their ventilation needs, a common ventilation rate measure is the air change rate (or air changes per hour): the hourly ventilation rate divided by the volume of the space (I or ACH; units of 1/h). During the winter, ACH may range from 0.50 to 0.41 in a tightly air-sealed ...
Passive cooling covers all natural processes and techniques of heat dissipation and modulation without the use of energy. [1] Some authors consider that minor and simple mechanical systems (e.g. pumps and economizers) can be integrated in passive cooling techniques, as long they are used to enhance the effectiveness of the natural cooling process. [7]
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.
[7] [8] [9] The system cooling effectiveness (natural or mechanical ventilation) depends on the air flow rate that can be established, the thermal capacity of the construction and the heat transfer of the elements. During cold periods the cooling power of outdoor air is large. The risk of draughts is also important.
The quality of air it introduces in buildings may be polluted for example due to proximity to an urban or industrial area (although this can also be a factor in wind-driven ventilation) Natural ventilation in buildings can rely mostly on wind pressure differences in windy conditions, but buoyancy effects can a) augment this type of ventilation ...
Use of passive natural ventilation is an integral component of passive house design where ambient temperature is conducive—either by singular or cross ventilation, by a simple opening or enhanced by the stack effect from smaller ingress with larger egress windows and/or clerestory-operable skylight.
The US Standard ASHRAE 62.1-2007: Ventilation for Acceptable Indoor Air Quality, only requires 4% of net floor area to be operable. This creates the potential for increased energy consumption where natural ventilation is provided by operable windows where supplemental air conditioning is provided, in addition to generally poor control over ventilation rates during hot summer or cold winter ...
Underfloor air distribution (UFAD) is an air distribution strategy for providing ventilation and space conditioning in buildings as part of the design of a HVAC system. UFAD systems use an underfloor supply plenum located between the structural concrete slab and a raised floor system to supply conditioned air to supply outlets (usually floor ...