How does the solar wall-integrated ventilator differ?
Sojol's wall ventilator is designed to allow solar ventilation to be applied to facades of buildings, such as apartments or office blocks. It provides heating and cooling to the interior of the building without any ducting system. It seamlessly integrates into a wall cavity and has been developed to accommodate some variations in the width of any given cavity.
At only one meter wide it has little impact on natural lighting, yet significantly increases the solar heating and cooling potential from the solar facing surfaces.
From the exterior, it appears like a window with a water-proofing vent above and below the glass. From the interior it is barely noticeable except for a lower and upper interior vent. The exterior vents have excellent water-proofing properties while allowing for more than sufficient air flow requirements.
It is also designed for all parts to be easily accessible from the interior for periodic maintenance. Because the area between the absorbing panel and the glass is well sealed, this maintenance is expected to be only every four years. A washable pre-filter is accessible from the inside.
It works like the roof mounted solar ventilator. Warm solar heated air flows into the building in winter, stale air is removed from the building during the day in summer, and cool air flows back into the building during summer nights. Its effectiveness partly depends on strategically located vents to allow cross ventilation through the building. An intelligent system switches between modes based on temperatures inside and outside the building and pressure sensors to ensure a slightly positively pressurized building.
In a similar way to our roof-mounted solar ventilator and system, Sojol’s wall-integrated solar ventilator is accompanied by a system that completes the heating and cooling requirements of a building in the form of a wall-mounted air heater to supplement the supply of solar fresh heated air during non solar periods.
Overcoming the barriers to the development of a wall-integrated solar ventilator
Challenges in its development have included many practical considerations such as:
sealing the absorbing space between the glass and absorbing panel in order to keep this area free of dust for long term efficiency thereby reducing the frequency to access and clean.
ease of access to dismount the unit from inside the building in order to periodically maintain.
allowing the unit to continue to ventilate and cool in summer as well as heat in winter
preventing the solar ventilator from heating the building interior in summer through excellent insulation
allowing the solar ventilator to self-cool if there is no air to draw from inside the building, thereby avoiding negative pressure within the building and the solar ventilator from over-heating
seamlessly integrating the unit to its surrounds inside the building despite varying widths of wall cavity
meeting water-proofing requirements at the intake and outlet of fresh air.
But the greatest challenge and barrier in the development and design of our wall-integrated solar ventilator had been the difficulty finding a fan capable of a high flow rate, quiet and with good pressure and that can be accommodated within a restricted space with the correct flow direction. Even though it has been shown that there is considerable upwards air pressure resulting from natural thermal siphoning in both winter and summer, it is still important for other times to provide sufficient air supply when adequate filtration is installed.
Sojol has now developed its own unique fan. A prototype has been built and tested. For the flow rate required now for our wall-integrated we would only need 2 fans. This provides us with a significant improvement from an equivalent of 7 centrifugal fans of the same size for the same task.