The 2 challenges

The two key challenges of building underground residences are lighting and ventilation. Sure, we can install numerous lights and use powerful air-conditioning like what we have in our underground MRT stations and shopping centres. However, that would negate the savings in electricity that underground buildings are said to bring (remember the temperature stability and lower energy requirements to heat/cool them?). I’m sure our immediate response in a basement carpark is to get out of that place as soon as we can, find the nearest door to air-con! At three storeys below ground, the air is just humid, stagnant and warm.  If we are to switch on all the lights and air-conditioning units at full power every single day, 24/7, think about the crazy energy usage! We might as well be better off squeezing on the surface. Besides, living in a windowless environment with ‘white light’ all the time isn’t healthy for us in the long run. Just imagine living in your office or tutorial rooms, that kind of man-made feeling might just drive us to depression. That’s why we need an energy-efficient ventilation system and natural light.

One energy-saving ventilation system currently used by the Ewha Campus Centre building in Seoul, South Korea is the thermal ventilation system. In such a system, there will be an underground labyrinth where air from outside can be forced in and heat is lost to the ground (Song et al., 2014). The cool air can then be enjoyed by occupants of the building. This system has been proven to be effective as the yearly energy demand for conditioning outdoor air decreased by 31.3% (Song et al, 2014). Engineers can also consider pumping air underground to ensure good ventilation. By allowing air to enter low enough, it can be sufficiently cooled by the earth and sink below to reach the people. Meanwhile, warm air generated by the population can rise up via another set of shafts. Hopefully more innovative technologies will come about as more and more governments consider underground structures.  

Natural light from the sun has many benefits: it increases visual performance, hence heightening alertness and concentration, it soothes the mind and it induces the skin to produce vitamin D which is important for calcium and phosphorus absorption from food (Hughes, 1987). As such, if we are able to simulate natural light, replacing artificial fluorescent lamps with lighting that emits rays of similar wavelengths as that of the sun, then we can achieve maximum bodily functions and comfort. It is not too difficult to simulate natural light as we only need to select the correct wavelengths. Also, the “remote skylight” technology proposed by Ramey in the Lowline can be combined with natural simulation to create a pleasantly lighted environment for the underground dwellers. 

Picture taken from Lowline (2014)

Other forms of renewable energy sources such as solar or even kinetic can be considered to power the lights in the underground building as well.

If you ever miss the natural breeze and sunlight, you can always take the elevator (or stairs, if you’re not that deep into the ground) to the surface where nature would be more beautiful since there would be less tall buildings fighting for space.

Literature cited:

Hughes, P. C. (1987) The use of simulated natural light in the design of earth-sheltered environment. Tunnelling and underground space technology. 2 (1). p.75-81.

Song, S. Y., Song, J. H. & Lim, J. H. (2014) Effectiveness of a thermal labyrinth ventilation system using geothermal energy: A case study of an educational facility in South Korea. Energy for Sustainable Development. 23. p.150-164.