- Hot water reset
Hot water reset is an energy-saving
automatic controlalgorithm for hot water boilers that are typically fired with fueloil or natural gas. A hot water reset control loop measures the outside air temperature; this information is used to estimate demand or heating load as the outdoor temperature varies. The supply hot water temperature is modulated up and down range in an inverse linearratio to outside air temperature. The typical range for conventional boilers is to vary the supply water temperature from 140 to 180°F as the outside temperature varies from 65 to 0°F.
The control system can be made modulate the supply water temperature in two different ways:
#By acting as an operating control on the boiler burners, either modulated on/off, high/low fire, or fully modulating fire, depending on the burner construction. When modulating the actual boiler temperature lower, water temperature needs to have a low limit and be maintained above the
flue gas condensationtemperature for non-condensing type boilers, typically above 140°F. Condensing type boilers can be made to operate at temperatures below the flue gas condensation limit and raise stated efficiencies from the 85% to 95% range.
#By acting as an operating control on a three-way powered mixing valve or proportional injection pump system that modulates the supply distribution hot water temperature. The mixing valve or mixing pump system recirculates the return water temperature and adds proportionally supply hot water from the boiler for tempering to achieve the desired supply water temperature.
Wikimedia Foundation. 2010.
См. также в других словарях:
Boiler — For the Limp Bizkit song, see Boiler (song). A portable boiler (preserved, Poland) … Wikipedia
Life Sciences — ▪ 2009 Introduction Zoology In 2008 several zoological studies provided new insights into how species life history traits (such as the timing of reproduction or the length of life of adult individuals) are derived in part as responses to… … Universalium
metamorphic rock — Any of a class of rocks that result from the alteration of preexisting rocks in response to changing geological conditions, including variations in temperature, pressure, and mechanical stress. The preexisting rocks may be igneous, sedimentary,… … Universalium
PID controller — A block diagram of a PID controller A proportional–integral–derivative controller (PID controller) is a generic control loop feedback mechanism (controller) widely used in industrial control systems – a PID is the most commonly used feedback… … Wikipedia
List of Canada's Worst Handyman 2 episodes — This is a list of episodes from Canada s Worst Handyman 2 , the second season of the Canadian television series that seeks to find the worst handyman in the country. Airdates listed are the first air dates on Discovery Channel Canada the date of… … Wikipedia
Trace heating — Electric Trace Heating, also known as Electric Heat Tracing and Electric Surface Heating, is a system used to maintain or raise the temperature of pipes and vessels. Trace heating takes the form of a electrical like heating element run in… … Wikipedia
Spirit rover — (MER A) Artist s concept of Rover on Mars Operator NASA Mission type Rover Launch date … Wikipedia
Condensing boiler — A condensing boiler utilizes the latent heat of water produced from the burning of fuel, in addition to the standard sensible heat, to increase its efficiency. Contents 1 Principles of work 2 Usage 3 Efficiency 4 … Wikipedia
Snowball Earth — The Snowball Earth hypothesis as it was originally proposedcite book author = Kirschvink, J.L. year = 1992 chapter = Late Proterozoic low latitude global glaciation: The snowball Earth title = The Proterozoic Biosphere: A Multidisciplinary Study… … Wikipedia
Decompression (diving) — Divers decompressing in the water at the end of a dive Decompression in the context of diving derives from the reduction in ambient pressure experienced by the diver during the ascent at the end of a dive or hyperbaric exposure and refers to both … Wikipedia