From improving life quality to solar panels that decrease temperature, researchers at the Department of Environmental Design in the Faculty for the Built Environment (University of Malta) have come up with some ingenious ideas to strengthen modern building design. Natasha Padfield learns more.
Fluid Mechanics: a crash-course
‘Fluid’ is an umbrella term for liquids and gases. Fluid mechanics studies their behaviour. Studies involve many variables and there are a few simple rules. Micallef’s research is based on fluid mass, momentum, and energy conservation equations that describe the fluid behaviour. The equations cannot be solved using direct mathematical techniques and scientists needs computers to crunch the large calculations.
The modern house is a machine. Twenty-first century living demands air conditioning, ventilation, insulation, and heating. Buildings are no longer simply walls and windows. Intelligent systems have brought brick and mortar skeletons to life powered by science.
The science behind modern building design and how it interacts with the outside environment is the subject area of Dr Daniel Micallef (Department of Environmental Design, Faculty for the Built Environment, University of Malta). He specialises in Computational Fluid Dynamics (CFD) and wind engineering. He uses computers to understand how fluids (such as air) flow in and around whole buildings or parts of them. Using specialised programs, he models airflow around and within buildings. Humans are constantly affected by fluid dynamics, whether they are shying away from a draft or wondering why their bathroom is stuffy. Our comfort and safety rests on understanding how airflow works.
CFD converts the building’s environment into a mathematical model. The geometry of the building as well as wind speeds, atmospheric pressures, and wall properties are inputted into the program. The program then generates massive volumes of data interpreted using special graphs (contour plots). From these graphs, Micallef can extract information about air velocities and pressures acting on different parts of a building or elements like wind turbines. To verify modelling results they are checked against real-world experiments.
This research can lead to more comfortable, safer, and energy efficient urban environments. Information on wind speeds and drafts is used to see if a proposed development is comfortable for humans. Using these methods, architects can ensure a building has good ventilation when the building is being planned. Inadequate ventilation can aggravate asthma and lead to poor health. In the past, building ventilation could only be tested after construction was completed. Sub-standard buildings were either unsafe to live in or subjected to expensive, time-consuming modifications.
The models can enhance a building’s energy efficiency. They can assess a building’s insulation to estimate the amount of heat flowing into and out of the building. Planning alterations ensure maximum efficiency, saving money and the environment. CFD can also be used to assess the potential of a rooftop wind turbine. Modelling helps perfect a building before it is built, maximising the latest technology.
Building a model
The geometry of the problem is defined. For example, the dimensions of the building and the photovoltaic system, and their positions relative to each other.
The model gets divided into sub-sections for detailed computer processing.
Set Boundary Conditions
Input wind speed, atmospheric pressure, and wall conditions.
Run the program to obtain estimates.
Hot solar, hot ideas
Solar panels could decrease indoor air temperature. Micallef’s research has shown that panels can funnel air providing cooling airflows over the roof. Implementing his studies could help change solar panel positioning to reduce heating and perhaps cool a building instead. With solar energy gaining popularity in the Mediterranean, this research could lead to more innovation to synergise the other beneficial and indirect effects of solar energy systems in the built environment.
Just how important are these tools and the insights they give? Micallef is emphatic, ‘Long gone are the days when architects and engineers used (only) generic rules of thumb when designing […] This scientific research builds our knowledge step by step. This could seem useless in isolation but when worldwide research is combined we can develop a useful system for the construction industry. If we learn what happens in nature we can then use this knowledge to build better buildings […]. I would like to see a more scientific approach towards building energy efficiency. I think buildings have almost become a machine. We cannot simply design a building with techniques used 100 years ago.’ Modern buildings need the application of modern science.
Alternative energy has a big role to play in building efficiency. For his Ph.D., Micallef worked on improving the performance and the modelling of wind turbine blades. The improvements have a relatively small effect on singular turbines but lead to huge savings in wind farms. In urban areas wind is even more complex to study because buildings change its direction. In such areas Micallef is researching rooftop flows.
“If Malta were to completely ignore the potential of wind energy, it would be disastrous.”
Malta’s energy infrastructure is experiencing an overhaul with a newly installed interconnector and replacement of heavy oil power stations with gas. Malta’s renewable energy generation hovers slightly short of 5%,but where is wind power? ‘If Malta were to completely ignore the potential of wind energy, it would be disastrous.’ Micallef concedes that wind farms can be a visual scar and that Malta has limited onshore or near-shore sites appropriate for development, which leaves offshore wind farms as the only option. ‘Malta should not miss the boat by failing to invest in on-going research related to these new deep offshore technologies.’ Malta needs to think ahead and invest in research and then build these wind farms. Wind energy can complement solar energy. Both would give a more stable and complete energy package for Malta. There have been plenty of discussions in the past ten years or so on the concept of a renewable energy mix. This seems to have been forgotten given the predominance of solar energy uptake.
In the next few decades, with the right investment and regulations, our buildings will continue to become greener, smarter, and safer. Research like Micallef’s is forging a healthy relationship between our natural environment, building requirements, and cutting-edge technologies—our ever-increasing demandson building performance beg for turning mud into bricks into a modern smart home.