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  2. Water timer - Wikipedia

    en.wikipedia.org/wiki/Water_timer

    The solenoid/diaphragm timer uses more battery power throughout the "on" cycle because the solenoid must be actuated the entire time that the water flow is "on". The ball valve timer using the motor and gear actuator only uses more battery power during the few seconds that motor is used to turn the water flow on or off.

  3. Heat recovery ventilation - Wikipedia

    en.wikipedia.org/wiki/Heat_recovery_ventilation

    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 ...

  4. Constant air volume - Wikipedia

    en.wikipedia.org/wiki/Constant_air_volume

    [2] The terminal reheat system cools the air in the air handling unit down to the lowest possible needed temperature within its zone of spaces. This supplies a comfortable quality to the space, but wastes energy. The mixed air system has two air streams, typically one for the coldest and one for the hottest needed air temperature in the zone.

  5. Air-mixing plenum - Wikipedia

    en.wikipedia.org/wiki/Air-mixing_plenum

    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] The air transferred from the return air stream to the supply air stream is termed recirculated air.

  6. Heat recovery steam generator - Wikipedia

    en.wikipedia.org/wiki/Heat_recovery_steam_generator

    They can use a gas turbine to produce high-reliability electricity for campus use. The HRSG can recover the heat from the gas turbine to produce steam/hot water for district heating or cooling. [1] Large ocean vessels (e.g., Emma Maersk) make use of heat recovery so that their oil-fired boilers can be shut down while underway. [1]

  7. Process duct work - Wikipedia

    en.wikipedia.org/wiki/Process_Duct_Work

    See above photo of round duct elbows, transitions, and stiffeners. The duct elbow radius is from 1 1/2 to 2 times the duct diameter. The round duct has ovaling, and shipping rings at 20 foot nominal spacing, and larger support rings at supports. The Y split has suction stiffeners at the duct intersection.

  8. Heating, ventilation, and air conditioning - Wikipedia

    en.wikipedia.org/wiki/Heating,_ventilation,_and...

    Most modern hot water boiler heating systems have a circulator, which is a pump, to move hot water through the distribution system (as opposed to older gravity-fed systems). The heat can be transferred to the surrounding air using radiators, hot water coils (hydro-air), or other heat exchangers. The radiators may be mounted on walls or ...

  9. Automatic balancing valve - Wikipedia

    en.wikipedia.org/wiki/Automatic_balancing_valve

    In a variable primary chilled-water system, the design flow rate is determined by the water flow velocity in the tube of the coils. At typical conditions, 6–7 feet per second (1.8–2.1 m/s) Maximum 12 ft/s (3.7 m/s) Minimum 1.5 ft/s (0.46 m/s) (based on a Reynolds number of 7500) Minimum flow is typically 50% or less of the design flow. [1]