Misting Devices for Cooling Outdoor Space

About this pattern

Misting devices can be highly effective in cooling outdoor spaces.  Dry misting has been used extensively in public open space in Keyaki, Japan and now in Toronto, Canada.  Misting installations can also provide attractive, interesting features into public spaces including renovations of public parks, helping to increase their use. In some instances, municipal authorities can commission misting devices and misting fans as permanent or temporary art installations, which help to generate higher footfall for local restaurants and retail businesses (Roe, n.d.)

Although seemingly a misnomer, ‘dry mist’ is formed when water is pushed through a fine aperture at high pressure; the mist is so fine it evaporates, feeling dry, and lowers the temperature by up to 30°F.  Misting fans are energy and water efficient, readily available and easily installed.  Depending on the types and placement of plants, misting systems can double as watering systems, keeping plants lush and green.

Misting Pumps

The most expensive part of the system is the high-pressure pump because fine water droplets required for quick evaporation cannot be achieved by low water pressure. Solar panels can supply the energy needed.

When installed and used properly, mist cooling systems can reduce temperatures by as much as 30°F depending on the efficiency of the misting system, relative humidity, and outdoor temperature. Evaporative cooling is remarkably energy and water efficient.

Misting devices cannot use stored on-site water. The misting nozzle requires mains water in order to ensure there is no particulate matter to block it. There are also public health considerations if stored tank or run-off water is used for misting.

Pattern Conditions

Enablers:

• Misting devices are relatively inexpensive and can be deployed temporarily in public spaces, allowing seasonal use and reassignment to other spaces. 

Constraints:

• Governance is required when used in public open space. There are some health implications.
• May not be effective in areas of high humidity.

Commoning Concerns

Misting devices facilitate the coolth for ‘cool commons’; those spaces that offer cooler temperatures than surrounding areas and that are used by, and are accessible to, a community of commoners who, to some degree, care for, take responsibility for, and benefit from this coolness.

Access: Unrestricted and restricted.

Use: Outdoor recreation in reduced temperatures. 

Benefit: Cool outdoor space.

Care: Local Government, Body Corporate, community.

Responsibility: Local Government and Body Corporate.

Ownership: Community groups, Body Corporate, sometimes Local Authorities.