Search results
Results from the WOW.Com Content Network
An attic fan installed underneath a roof. A powered attic ventilator, or attic fan, is a ventilation fan that regulates the heat level of a building's attic by exhausting hot air. A thermostat is used to automatically turn the fan off and on, while sometimes a manual switch is used. An attic fan can be gable mounted or roof mounted. Additional ...
Institutional heating systems (office buildings or schools, for example) can use low-grade, inexpensive bunker fuel to run their heating plants, but capital cost is high compared to more easily managed liquid fuels. Natural gas is a widespread heating fuel in North America and northern Europe. Gas burners are automatically controlled and ...
Diagramatic operation of a thermal wheel Ljungström Air Preheater by Swedish engineer Fredrik Ljungström (1875–1964). A thermal wheel, also known as a rotary heat exchanger, or rotary air-to-air enthalpy wheel, energy recovery wheel, or heat recovery wheel, is a type of energy recovery heat exchanger positioned within the supply and exhaust air streams of air-handling units or rooftop ...
However, variations such as CAV with reheat, CAV multizone, and CAV primary-secondary systems can serve multiple zones and larger buildings. In mid- to large-size buildings, new central CAV systems are somewhat rare. Due to fan energy savings potential, variable air volume (VAV) systems are more common. However, in small buildings and ...
Dual duct systems provide cool air in one duct and warm air in a second duct to provide an appropriate temperature of mixed supply air for any zone. An extra duct, however, is cumbersome and expensive. Reheating the air from a single duct, using electric or hot water heating, is often a more cost-effective solution. [12]
Underfloor heating systems—electric or hydronic; Wall heating systems; Radiant ceiling panels; Underfloor and wall heating systems often are called low-temperature systems. Since their heating surface is much larger than other systems, a much lower temperature is required to achieve the same level of heat transfer. This provides an improved ...
More complex HVAC systems can interface to Building Automation System (BAS) to allow the building owners to have more control over the heating or cooling units. [3] The building owner can monitor the system and respond to alarms generated by the system from local or remote locations.
A household electric fan A large cylindrical fan. A fan is a powered machine that creates airflow. A fan consists of rotating vanes or blades, generally made of wood, plastic, or metal, which act on the air. The rotating assembly of blades and hub is known as an impeller, rotor, or runner. Usually, it is contained within some form of housing ...