Kuwait is hot and arid. Most people complain that the sun prevents any kind of outdoor or pedestrian activity during most of the year. How can we manipulate the weather in such a way as to create microclimates that can produce tolerable and even pleasant local weather?
The weather in the winter is very pleasant, and can be controlled through appropriate clothing. The challenge is how to design for the summer. The three major obstacles are:
- Intense summer heat
- Lack of precipitation
In a way, we can count ourselves lucky that we are not in a hot/humid region. As you can see in the above graphs, the humidity levels drop sharply during the summer months. This gives us an incredible advantage in that we can use the process of evaporative cooling to cool our buildings and ourselves. Our bodies regulate heat by many processes, one of them being the secretion of sweat. The sweat evaporates from skin and cools down the body. One of the properties of water is that when it evaporates, it requires a lot of heat energy, and it absorbs this heat from the area that surrounds it. The problem in hot/humid regions is that the air is usually saturated with water molecules. You still sweat, but it never evaporates. This means that you can’t regulate the heat generated by your body and you feel hotter still.
We can use this process to cool down our buildings and outdoor spaces. One of the easiest ways to do this is through water misting. These are simple water sprays that shower an outdoor space with small water droplets. The droplets begin to evaporate into the air and will slowly cool down the space. This can also be used to cool down roofs and walls by adding sprinkler systems, but the water waste becomes a problem as well.
Plants and trees can be used to control both heat gain and dust. They act as a natural air filter, trapping dust particles and filtering the air while adding oxygen too. They shade the ground underneath it and cool the air that passes through it. Trees absorb water from the soil which passes through it and eventually evaporates from stomata in its leaves. This process is called evapotranspiration and it cools down the air around the leaves in the same way as sweat.
Different materials absorb and reflect heat radiation at vastly different rates. Aluminum would heat up so much faster than concrete, which heats up faster than grass. The air that passes through these materials will heat up accordingly. The space around a building has to take all these factors into account. Hot air passing through trees will cool down considerably.
Hot air is lighter than cold air. This means that hot air rises and cool air drops low. A courtyard home therefore has an incredible advantage in that it creates pockets of space where cool air will collect. This property along with a well shaded space means that you can naturally and passively cool down a courtyard to a tolerable level even in the most intensely hot summer days.
There are many drought tolerant species of plants and trees that are able to survive and thrive in Kuwait. The example below is Bougainvillea, locally known as al-Majnuna. It is a flowering vine that is able to be trained to grow on trellises and along pergolas and arbors. It is fairly disease and pest free and requires little maintenance and watering. A courtyard entirely shaded with this vine would create a wonderfully pleasant microclimate where families can enjoy a private outdoor gathering in the hottest summer day while the sunlight filters through the beautiful colors of the flowers.
The cooler air dropping from above will be cooled further by the vines, which would trap all the dust that is in the air. The filtered cool air would collect in the courtyard and any air that heats up will rise and escape. I would suggest a large fountain, or a pool with a waterfall be added to the landscape of the courtyard so that a water misting effect is created to cool the space even further.
A courtyard home is not a luxury. It should become the template in which all homes in Kuwait are based on. We must remember how our ancestors used to live and adapt those methods to our contemporary, modern lifestyles. We cannot hide from these challenges in our sealed refrigerators. We have to take control.
The data used in this post was taken from this meteorological study: http://apps1.eere.energy.gov/buildings/energyplus/weatherdata/2_asia_wmo_region_2/KWT_Kuwait.Intl.AP_KISR.stat