PDX_18_HVAC Part 2 Flashcards
This system incorporates outdoor air when it becomes cool enough, about 60°F, reducing the energy required for refrigeration. A mechanical substitution for an open window, and filtered air improves quality.
Economizer cycle
Energy used by HVAC accounts for __% of overall consumption
40 to 60%
This system increases efficiency by having varying sized chillers and operating the best sized chiller for the load
Dual Condenser Chillers
Commonly powered by gas, higher initial cost, but can be more efficient for buildings in areas where electricity costs are high, and low cost heat sources like steam are available
Gas-fired absorption chillers
More efficient absorption chiller powered by hot water from standard flat plate solar collectors. Operation costs can be less than compressive type chillers.
Solar powered absorption cooling
Heat water bypassing hot gases, by way of fluegases containing sensible and latent heat, through water. He exchanger on the combustion chamber reclaims any heat lost in chamber. Good for applications were hot water is needed constantly.
Direct contact water heater
We cover sensible latent heat this preheats the cold water entering the boiler. This he would typically be discharged to the atmosphere. Clue gases are also cool enough to achieve condensation.
Recuperative gas boilers
Aire distribution systems where supply air originates at the floor and rises to return in grills in the ceiling. Improves indoor air quality and energy savings. Most systems use and access for system for ductwork
Displacement ventilation
And cooling systems that use a series of heat pumps for different zones in the building. Waterloop is maintained at a temperature range of 60° to degrees Fahrenheit and can simultaneously heat or cool zones with no additional energy. Reduces piping costs for two and four pipe systems.
Water Loop Heat Pumps
Uses water, ice, or rock beds to store excess heat or cool mist for use in the future. Thanks vantage of temperature swings and off-peak energy consumption to manage Goldings energy needs.
Thermal energy storage
These methods are based on the concept of the heat exchange from a source where heat or cool this is not wanted, to a place where it is desired.
Heat transfer methods
This heat transfer method reclaims waste energy from the exhaust air Stream and uses it to condition the incoming fresh air. Energy can be reduced from 60 to 70%. Efficient and climates where indoor/outdoor temperature differentials are high.
Energy Recovery Ventilators
air to air heat exchangers
This energy recovery ventilator, or air to air heat exchanger, must have two separate ducts for incoming air and exhaust air separated by a thin heat transfer wall
Flat-plate heat recovery units
This energy recovery ventilator, or air to air heat exchanger, transfers heat to heat exchanger wheel with small openings where air passed through.
Energy transfer wheels
Enthalpy heat exchanger
This energy recovery ventilator, or air to air heat exchanger, passes hot exhaust air over the heat pipe and vaporizes a refrigerant inside the pipe, which passes to the area of cool incoming air. As the refrigerant condenses, it gives off heat, warming the incoming air. Outgoing and incoming streams must be adjacent to one another.
Heat pipes
