How to Cool a Warehouse With Roof Vents
A large building, such as a warehouse, can absorb large amounts of direct solar heat, hot air infiltration from outside, and internal heat production from machines, appliances and people. Installing large electric ventilation systems can work but these are quite costly. Other methods, using passive solar energy, can make a noticeable difference in cooling a building and can save money as well. Using natural convection currents, the Venturi principle, and other methods can help to efficiently cool and ventilate a building.
Open roof vents and windows at ground level. By opening roof vents and windows low on the structure of a building, you can use natural convection currents to assist in cooling and ventilating a warehouse or large building. This method of cooling is called the "stack effect" The stack effect takes advantage of hot air being less dense, rising and then exiting a building through openings towards the ceiling. When hot air rises due to natural convection currents, it leaves behind an area of slightly less air pressure. As the pressure and temperature want to reach equilibrium, new, fresh air will suction into the building through windows that are at or near ground level. The greater the difference in height between the point of air intake and exit, the greater the convection current, ventilation and cooling.
Install smaller windows on the windward side of the building. By installing smaller openings or windows on the windward side of the building, you can use the Venturi effect. When a breeze is fed through a confined opening, the Venturi effect states that the air will speed up. Bernoulli's principle further states that when air speeds up, its pressure decreases. As air tends to move from higher to lower pressure, a slight suction can be initiated on the inside of a small windward window, creating a higher flow of air into the building. When this is paired with a convection current, it increases the flow of air from lower, smaller windows and up through roof vents.
Install a solar chimney on top of roof vents to further increase the convection current that pulls hot air out of a building. The greater the distance between cool-air intake and hot-air exit, the greater the convection flow. A solar chimney is a chimney designed to feed hot air up and out of a building. If a solar chimney is black or a dark color, it will absorb more solar light and therefore heat. Insulating the solar chimney will further heat it. As this air temperature further increases within the solar chimney, the convection current will increase. Install a spinning wind turbine on top of the solar chimney that uses openings opposite the wind to further increase the suction of hot air outside the roof of the building.
Install a wind scoop on top of the roof vents. If the warehouse is surrounded by wind-obstructing objects, such as other buildings or hills, a wind scoop can be used to capture a heavy wind at or above roof level. This method is used in densely populated areas in Africa and the Middle East to siphon cool winds down from above roof level. The air and wind at this level is also more free of contaminants, such as dust, found at ground level. A wind scoop will not be effective in areas without prevalent winds.