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Demand controlled ventilation (DCV) is a feedback control method to maintain indoor air quality that automatically adjusts the ventilation rate provided to a space in response to changes in conditions such as occupant number or indoor pollutant concentration.
Water boiling at 99.3 °C (210.8 °F) at 215 m (705 ft) elevation. The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid [1] [2] and the liquid changes into a vapor.
A tempering valve mixes enough cold water with the hot water from the heater to keep the outgoing water temperature fixed at a more moderate temperature, often set to 50 °C (122 °F). Without a tempering valve, reduction of the water heater's setpoint temperature is the most direct way to reduce scalding.
An electrical resistance heater has a COP of 1.0, which is considerably lower than a well-designed heat pump which will typically have a COP of 3 to 5 with an external temperature of 10 °C and an internal temperature of 20 °C. Because the ground is a constant temperature source, a ground-source heat pump is not subjected to large temperature ...
Control systems grew more sophisticated as automakers gained experience; Volkswagen's "Coolant Controlled Exhaust Gas Recirculation" system of 1973 exemplified this evolution: a coolant temperature sensor blocked vacuum to the EGR valve until the engine reached normal operating temperature. [5]
Heaters are appliances whose purpose is to generate heat (i.e. warmth) for the building. This can be done via central heating. Such a system contains a boiler, furnace, or heat pump to heat water, steam, or air in a central location such as a furnace room in a home, or a mechanical room in a large building.
Escherichia virus T4 is a species of bacteriophages that infect Escherichia coli bacteria. It is a double-stranded DNA virus in the subfamily Tevenvirinae of the family Straboviridae. T4 is capable of undergoing only a lytic life cycle and not the lysogenic life cycle.
Air streams are mixed to save energy and improve energy efficiency by partially recirculating conditioned air.. The most common application for an air-mixing plenum is the mixing of return air (or extract air) with fresh air to provide a supply air mixture for onward distribution to the building or area which the ventilation system is serving. [1]