www.heatingandventilating.net Benefits
¡ Allows ‘open door trading’ invitation to customers ¡ Increases comfort for customers and staff ¡ Increases available useable space ¡ Increased productivity ¡ Reduces employee absenteeism
¡ Reduces product spoilage Applications
Air curtain units have been used in a range of buildings, including: ¡ Airports
¡ Distribution establishments ¡ Educational centres ¡ Care homes ¡ Factories ¡ Galleries ¡ Hospitality ¡ Hospitals ¡ Hotels
¡ Leisure complexes ¡ Museums ¡ Retail ¡ Shopping centres ¡ Showrooms
Energy effectiveness of an air E is the energy effectiveness
Qa is the energy exchange through an open doorway WITH an air curtain unit fitted plus the power consumed by the air curtain units
Qb is the energy exchange through an open doorway WITHOUT an air curtain unit fitted The closer the energy effectiveness is to 1 (unity) the better the energy effectiveness with, 1 = Ultimate Barrier (equivalent to a closed door, if Qa = 0)
0 = Bad (equivalent to an open doorway with no air curtain units, if Qa = 1) The energy effectiveness could also become a negative figure, if
building entrance and suitable controls need to be fitted to adjust the heat output and air stream characteristics if necessary.
Energy exchange loss
A good air curtain unit installation could be up to 70% effective at controlling the original energy exchange loss through a doorway without an air curtain unit. To a significant extent it does this by disrupting the
natural convection (buoyant flow) effect of warm air spilling out of the top of the open doorway and being replaced by cold air in at the bottom. The new “lower” energy exchange (30% of the original) is added to the power consumed by the air curtain unit and the energy effectiveness then calculated.
Controls
Occupant comfort and energy efficiency do not have to be mutually exclusive. Controls with the air curtain unit are essential to prevent unnecessary
energy usage. They can, if necessary, also be used to adjust the air stream characteristics and to optimise penetration across the doorway. For convenience, user operated controls are mounted remotely and configured to satisfy the needs of the building occupants. At the simplest control level only manual operation of the fan(s) and fan speed may be required, however more advanced control options may be included such as:
¡ Thermostatic control ¡ Timer On/Off control
¡ Step or modulating control of electric or water heating ¡ BMS control interface ¡ Energy management ¡ Automatic door activation
¡ Optimisation controls for on/off and temperature adjustment
Installation and maintenance
Specifying the correct air curtain unit size and performance is part of the building design. What follows is installing the air curtain unit correctly and commissioning it to optimise performance. Thereafter, as the units will be working 10 to
24 hours a day, every day, they do need checking periodically for safety, cleanliness and operational efficiency.
This vital stage of regular service and maintenance is often ignored, yet it does impact the credentials of organisations that make ESG key measures of performance within their company’s stated objectives. The Air Curtain Industry Group is a member of
the Federation of Environmental Trade Associations (FETA). Further information can be obtained from manufacturers who will be able to provide the most suitable product for individual applications.
DOWNLOAD THE HVR APP NOW February 2023 13
curtain unit (HVACR application) The energy effectiveness of an air curtain unit installation over an open doorway can be described by the following equation: where,
Low carbon buildings
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