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With air curtains, energy efficiency starts at the doorstep

December 19, 2022    3 min.

Among all greenhouse gas (GHG) emission reduction strategies, energy efficiency measures are the logical first step in a structured decarbonization process. There are many ways to optimize the energy performance of buildings – including air curtains. This simple and accessible technology allows for significant energy savings and quick return on investments under the right conditions.

What is an air curtain?

As its name suggests, an air curtain is a device that creates an invisible air barrier at the entrance to a given building or area to reduce heat exchange when doors are open and heating or cooling units are insufficient to maintain the desired temperature. Triggered automatically by the opening of doors, a high-speed blast of pulsed air stops the infiltration of cold air during winter and hot air during summer. It is also very effective in preventing the entry of insects, dust and vehicle fumes into buildings.

Here are some options for installation. Air curtains can be mounted vertically on either side of the entrance when a door is too high for the airflow to reach the floor.

Possibilités d’installation rideaux d'air
Possibilités d’installation rideaux d'air

How does it work?

The mechanical device itself (the ventilation unit) is available in many versions and formats that can accommodate a variety of entryways and usage scenarios, from the drive-through service windows to the entrance to an aircraft hangar, to the doors of office buildings or warehouses. The air stream can be oriented vertically (from top to bottom or from bottom to top) or horizontally, as required.

Efficiency in the air

Studies show that a suitable air curtain, properly installed and used, can provide energy savings of 50% to 85%, which can add up to thousands of dollars every year.

“Of course, you need to assess your needs and how long doors are open for before you invest in an air curtain,” says Feriel Acher, Advisor, Energy Efficiency to Énergir’s DATECH Group. “A business or a factory whose doors are open for a few minutes a day will barely benefit from an air curtain, however, if the doors are open for one or two hours a day in total, an air curtain can be profitable very quickly.”

Energy saving ﹣ Return on investment

1. Data
Province Québec
Region Estrie
Outdoor winter temperature -15 °C (5 °F)
Indoor winter temperature 22 °C (72 °F)

 

2. Building characteristics
Door width 3.7 m (12 pi)
Door height 4.3 m (14 pi)
Annual natural gas consumption 20,000 m³
Cost of natural gas $0.44/m³

 

3. Air curtain features
Number of fans 4
Voltage 575 VAC
Total pulsed air output 5,200 cfm
Cost of air curtain $10,000
Hours of operation per day 1 hour
Days per week 5 days
Weeks per year 28 weeks
Total hours of operation/year 225 h/year

 

4. Results
Consumption without air curtain 20,000 m³
Consumption with air curtain* 9,693 m³
Annual amount saved 10,307 m³
5. Annual savings
Annual savings $4,535
Return on investment (ROI) period 2.2 years
Énergir grant $3,092
Grant/cost of air curtain 30%

For the savings … and the rest

The economic argument of the air curtain, that being reducing building operating costs, is not the only benefit of this technology. It also improves:

  • the comfort of workers and customers;
  • indoor air quality (barrier against pollutants, allergens, fumes, odours, etc.);
  • food safety;
  • foot traffic safety (no visual obstacles);
  • It can also be integrated into a pest management plan (rodents, insects).

Finally, by reducing energy consumption (heating and/or cooling), the air curtain ensures better building energy performance and thus a reduction in its carbon footprint.

Shortening the ROI through Énergir’s grant

As such, Énergir offers a grant for the installation of air curtains as a part of the Studies and Implementation of its energy efficiency program. This grant is conditional on the company using natural gas or renewable natural gas as a source of heating; it allows the company to receive up to $1 per m³ of gas saved for a maximum of $100,000.

“This is a good way to further reduce the return on investment period,” Acher emphasizes.

A simpler and faster process

In addition, to simplify the calculations prior to grant applications, Énergir’s Natural Gas Technology Centre (NGTC) has developed a free air curtain calculator. The calculator is provided to interested clients to estimate the savings associated with equipment installation.

“It’s a useful tool to find out if an air curtain is suitable for their needs and to provide some of the data required for the grant application,” says Feriel Acher.

Technology adapted to our climate

Whether for commercial, institutional or industrial applications, air curtains are an easily deployable energy efficiency measure that can be easily and inexpensively integrated into a global decarbonization strategy. It also contributes directly to the comfort of the building’s occupants and ambient air quality. Finally, air curtains lend themselves particularly well to the Quebec climate – where the difference in indoor and outdoor temperatures is often considerable – by avoiding major heat and cold losses.

 

Cimon Desforges
Senior Energy Advisor
DATECH Group

 

 

* Results based on the calculator developed by Énergir.

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