Over the past decade, the construction industry in the UAE has welcomed sustainability like a long-lost son. The transformation from initial reluctance, to understanding, to acceptance, and finally, to the championship has been a marvelous process. Sure, there have been obstacles along the way (when are there not?), but the fact remains that sustainability is now well and truly an integral part of the construction considerations in Dubai.
Widening the lens gives us an idea that the rest of the GCC countries have also caught on to the importance of creating a sustainable world and are slowly, but surely, inching close to a greener path. As the construction industry is literally building our future, it plays a significant role in making sure it is a sustainable one.
Today, the Middle East is experiencing a rapid boom in construction, with the demand for residential, commercial, and educational spaces growing exponentially. However, the environmental regulations and sustainable laws implemented by progressive countries that can see the world heading towards a renewable tomorrow, temper these demands.
You may think, all of this sounds great in generalized terms, but what exactly is the global sustainable scenario? Are there any statistics to prove that the world is indeed moving on to greener buildings? Let’s find out!
Sustainable Building – The Current Global Scenario
According to the World GBC report for 2018, the global green building activity is increasing, but the number of buildings getting the green certification is still less. As a result, we can expect a 20% increase in the buildings with over 60% sustainable components in the next 3 years.
Greater savings, shorter payback periods, and an increase in asset value are some of the chief factors driving investments in green buildings. Client requirements for greener solutions, on account of increased awareness about climate change, are necessitating contractors to think of better alternatives for conventional materials. Similarly, environmental rules and regulations are also having a significant impact on the building’s design process.
Another strong factor that promotes green development, we find, is social reasons. Business owners are more eager to have a workspace that promotes the health and well-being of the employees, increases employee productivity, and creates a sense of community amongst the members of the organization.
The four principal barriers to green buildings include high capital cost, lack of political support and incentives, affordability, and a lack of public awareness.
Nevertheless, all of these observations show that there is a consistent growth towards integrating sustainability into construction in the quest for modern development.
How does this translate into reality though? Let us take a practical case study to see how sustainable green building construction pans out in reality.
Case Study of a Sustainable Villa in Dubai – A Brief Overview
We can best understand the nitty-gritty of green construction with an actual real-life example. And as you know, sustainability begins at home!
So here we take the example of one of our own case studies in Dubai, where we at Consistent Engineering Consultants had to design sustainable considerations in mechanical and electrical services for a G+1+R villa.
The approximate built-up area of the villa was about 225 sq.mt. across two floors with an occupancy of 6 people. The maximum electrical consumption limit was set to 60 kWh/m2/year. This design was based on the standards of DM Green Building Regulations and Specifications, ASHRAE standards, and EGBC compliances.
The idea was to create a theoretical design that would help reduce the consumption of energy and water, making the existing villa significantly more sustainable. Also we considered not just the individual sustainable requirements of the villa but of the community as a whole. This meant taking into account the various parameters that would have an impact on building performance.
Some of the parameters under consideration were:
- Orientation of the building
- Simplicity of Design
- Thermal Mass
- Tight Building Envelope
- Balanced Insulation
- Balanced Ventilation
- Energy-efficient HVAC Equipment
- Solar Domestic Hot Water
- Water-Efficient Appliances
- Efficient Lighting
Let us see how each of these impacts the sustainability of the building.
Parameters Considered for a Sustainable Building
- Orientation of the Building
The orientation of the building plays an important role in establishing the energy graph of the building. Ideally, we need to design the building so that the maximum amount of natural sunlight filters into the room without making it too bright. We seek the balance between adequate light gain and non-excessive heat gain here.
The orientation differs for every building depending on its geographic location, surrounding climate, year-round exposure to sunlight, and other such factors. Usually, in weather conditions like those in Dubai, it is advisable to have at least 50% of the total glazing area in between the east and north-west directions to avoid heat gains.
We have designed the villa in our case study to have minimal glass exposure in the south and south-west directions.
2. Simplicity of Design
When it comes to construction, simplicity is synonymous with efficiency. The simpler the design, the better the energy efficiency of the building as we can utilize every corner of space effectively. Even allowing for the changing architectural trends, simplicity has always been a key feature of the most iconic buildings of all time.
For this villa, we’ve followed the principle of less is more, increasing the aesthetic appeal of the building with its simple structure. Furthermore, keeping the design simple and straightforward allows for minimum heat transfer through the building envelope. The classic layout of the structure helps prevent radiation loads as it avoids exposure to sunlight in the eastern directions.
3. Thermal Mass
The thermal mass of a building is its capability to absorb and store heat energy. Conventional materials like bricks, concrete, and tiles require a lot of heat energy to change the temperature of the building.
Hence, in the dry and arid climate of Dubai, thermal mass is significant in terms of heat transfer from ambient spaces to air-conditioned spaces. To leverage the natural temperature conditions in the region, we store the heat gained through solar radiation as thermal mass by using concrete slabs, precast ceiling panels, and heavyweight mass walls.
On the other hand, when it comes to cooling the building at night, water or air is passed through pipes embedded in slabs to carry the warmer air out and purge the excessive warmth of the building.
4. Tight Building Envelope
A building envelope is a physical separator between the air-conditioned and non-air conditioned areas of the building. It includes things like interior airflows, resistance to air, water, heat, light, and noise pollution.
For this case study, the maximum permissible air leakage was aimed to be 103/hr/m2 in and out of the building at a pressure of 50 Pa. We designed the villa in line with the ASHRAE standards and with a tight envelope to prevent unnecessary loss of energy.
5. Balanced Insulation
Balanced insulation implies reducing the transmission of thermal energy through the walls, ceilings, and floor so that the interior is warm in winter and cool in summer. All building materials have inherent insulation properties that contribute to maintaining the insulation of the envelope. In addition, some materials are integrated specifically to add insulating value to the building.
For this theoretical project, we considered the concepts of the green roof, urban heat island effect, and minimum Light Reflective Value. The green roof contained indigenous plants adapted to Dubai’s climate stretching up to 30% of the total roof area. The rest of the roof, we designed to have a high solar reflective index by reflecting solar lighting to minimize the solar absorption and emitting thermal radiation load. The minimum solar reflective index of the roof was designed to be > 78 for 100 sq.mt., which was 75% of the roof area.
To minimize thermal radiation seeping in from walls, we designed them with a minimum light reflective index of 45%. In addition, we included solar panels on the car park to generate power for the building.
6. Balanced Ventilation
Balanced ventilation systems are necessary to filter out pollutants from the indoor air and maintain clean air within the living space. The term balanced specifically implies that this rate of introduction of fresh air is equal to the rate of expulsion of stale air from the home.
7. Energy-efficient HVAC Equipment
HVAC design is one of the most crucial components which makes sure that sustainability and energy-efficiency are achieved in construction. The HVAC system consumes the maximum amount of energy in the building. Consequently, we need to optimize it to reduce total energy consumption.
Firstly, running a conventional HVAC system in a climate like Dubai’s has an extremely adverse impact on the environment. The high difference in ambient temperature and that within living space necessitates the air conditioner to work at higher power. In turn, this increases energy consumption.
Secondly, in the villa studied, the air-conditioning system suggested has a variable refrigerant flow. A minimum EER of 10.5 at T3 condition is the expected target to reduce energy consumed by the building. For effective operation, we provide each room with a dedicated indoor unit which can be switched off when unoccupied. In order to provide fresh air to the villa, energy recovery ventilators are located on each floor. We route the exhaust air from the toilet and common areas through the recovery section to reduce ambient air temperature. This reduces the overall cooling requirement for the ambient air.
8. Water-Efficient Appliances
Water-efficiency is another important aspect of sustainable infrastructure. Maximum utilization of available water resources, while eliminating wastage of water wherever possible is the idea behind using water-efficient appliances.
One of the ways in which we proposed this for the villa was using recycled water for landscaping, irrigation, flushing. Domestic water, obtained from the incoming main line, we considered using only for primary functions. This used water, we considered, is to be redirected and reused for secondary applications.
The target was to reduce total water consumption by 25%, as compared to the original. To this end, we suggested energy-efficient motors, motion sensor taps, low flow aerators, and restrictors in sanitary fixtures, reducing consumption.
9. Efficient Lighting
Proper orientation of the building and the solar panels installed helps in optimum utilization of the available natural light. For sustainable buildings, we go one step further to install lights with low power consumption and motion sensors.
In the case under question, all internal lighting fixtures are of the LED type. The lighting system is to be equipped with occupancy sensors & daylight sensors to control lights, based on the actual demand.
All exterior lighting must be fitted with automatic controls and photocells to ensure that lights don’t operate during daylight hours.
Apart from this, on-site energy demand is fulfilled using renewable energy generated by the solar panels on the roof floor.
Key Takeaways of the Case Study
With the complete and precise implementation of these parameters, substantial savings in energy consumption can be achieved.
The energy utilization, with these considerations, we can reduce to 31.88 MWh/year.
The total power that can be generated through solar panels is 12.5 MWh/year while the Energy Use Index of the villa goes on to be 87 kWh/m2/year.
The Managing Director of CEC, Mr. Sagar Kulkarni, presented this Case Study to an enthusiastic response at the HVAC Oman Summit in 2019.
Benefits of Sustainable Living
Given the rapid increase in population, sustainable living is the only way to conserve the earth for future generations. Building sustainable homes, like the aforementioned villa, can go a long way in moving towards a greener future. A sustainable lifestyle combines luxury with eco-friendly principles, thereby increasing the eco-efficiency of homes and effectively using available resources.
Innovative heating and cooling system solutions are the need of the hour. Space heating and cooling will account for over 60% of the global energy consumption in the next 30 years. Hence, sustainable construction allows us to satisfy our demands while taking care of the planet as well.
In the book, Transition to Sustainable Buildings, by the International Energy Agency, it is estimated that a combination of sustainability standards, greater use of heat pumps, solar thermal, and co-generation with waste heat and renewables could reduce growth in electricity demand by 2,000 terawatt-hours (TWh) in 2050! That’s huge!
The construction industry is progressing towards a sustainable future, as evinced by everything we’ve seen above. What are your thoughts about making the world a sustainable place? What are the challenges you think you might face in this journey? Share your thoughts with us in the comments section below!