HVAC System

ventilation

Ventilation introduces outdoor air to replenish the oxygen supply and rid building spaces of odors and toxic gases. Ventilation can also be used to pressurize a building to reduce infiltration. While ventilation is required in nearly all buildings, the design of a ventilation system must consider the cost of heating and cooling the ventilation air. …

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humidification

Low humidity can cause problems such as respiratory discomfort and static electricity. Humidifiers can humidify a space either directly or through an air handling system. For satisfactory environmental conditions, the relative humidity of the air should be 30 to 60 percent. In critical areas where explosive gases are present, 50 percent minimum is recommended. Humidification …

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humidity is measured by

The moisture content of air is a significant variable not only in air conditioning for human comfort but also in industrial processing and manufacturing plants, where it can influence the quality of the product. In the spinning of textiles, for example, better results are obtained when humidity is controlled at optimal values. In drying operations, …

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what is a valve

As a mechanical device, a valve should be selected to do the job expected of it and should be properly installed. It will then give long service before it starts to leak or wear out. After installation, and periodically during service, a valve should be checked to ensure that it has the necessary seat tightness …

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artificial ventilation

Where a reliable and positive flow of air for ventilation is required, fans can be installed in a building to extract stale air, which is immediately replaced by fresh air from the outside flowing through gaps around window and door frames, or through purposely designed grilles. Fans in more elaborate ventilation schemes are connected to …

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ventilation in buildings

The simplest ventilation system in a building uses external air as its source, the wind as its motive force, and openings in the external enclosure for fresh air intake on the windward side and stale air extraction on the leeward side . In a tightly constructed building, air infiltration is slow, but in a building …

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stack ventilation

The simplest ventilation system in a building uses external air as its source, the wind as its motive force, and openings in the external enclosure for fresh air intake on the windward side and stale air extraction on the leeward side . In a tightly constructed building, air infiltration is slow, but in a building …

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natural ventilation

The simplest ventilation system in a building uses external air as its source, the wind as its motive force, and openings in the external enclosure for fresh air intake on the windward side and stale air extraction on the leeward side . In a tightly constructed building, air infiltration is slow, but in a building …

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r value units

It is unrealistic to rely on empirical rules to establish forms of constructions which provide satisfactory resistance to heat transfer as well as weather resistance, strength and stability and many of the other performance criteria. Moreover, current construction methods are generally less bulkythan those used years ago, as greatly reduced thicknesses of materials are employed …

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vav system design

Primary Airflow Capabilities All primary air dampers can shut off the primary airflow completely. However, complete shutoff of primary airflow is not recommended if the VAV terminal unit serves a zone that has a heating load If the zone has a heating load, the primary air damper should be specified to have a minimum airflow …

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