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Precedents from the Past Help Cut Peak AC Load by 50%

March 15, 2018

Dubai is now an alpha+ global city with one of the world’s most attractive construction markets. Its massive growth is impressively balanced by the traditional heritage and history that has underscored the UAE’s development.

In the past, people were able to navigate extreme temperatures through lifestyle accommodations, but contemporary living in the UAE has made air-conditioning a necessary part of life today.

 

The country has grown to such an extent that air-conditioning alone now consumes approximately 75% of all power generated in the UAE.

 

Learning from Traditional Design

 

Traditional architecture can provide us some insight into cooling buildings in hot climates. While global innovations may guide our development, traditional precedents can and should be implemented into modern designs – particularly when it comes to designing and building structures in harmony with the UAE’s environment. Buildings that utilize traditional building concepts in the structure and design can reduce the immense amount of energy consumed by air-conditioning (i.e., using well-shaded and well-insulated structures that take advantage of their thermal mass of concrete), and also capitalize on passive cooling systems when the weather allows.

 

This type of organic yet innovative development, rooted in tradition, has been highlighted as the most effective way to ensure a sustainable path to development.

 

Two sustainability experts, Wissam Yassine and Karim Elgendy, explain in a Carboun Journal article:

 

Passive cooling essentially aims at naturally attaining and sustaining a cool indoor environment. It reduces the dependence on energy-intensive mechanical cooling which saves capital expenditure, reduces energy costs, and improves indoor air quality. Studies by the Abu Dhabi Urban Planning Council have demonstrated that incorporating simple and sensible passive cooling strategies into the design of the built environment can result in as much as 25% reduction in heat gain, which translates into significant savings in cooling electricity consumption...

 

With the regional building industry currently suffering from a lack of innovation, a locally-generated sustainable architecture renaissance in the UAE might be the catalyst it needs for a revival. More importantly, it might be a trigger for the development a more sustainable built environment that would play a role in confronting the global environmental challenges that face our planet. [Excerpted from “Passive Cooling: Responding to Electricity Demand in the UAE,” (2011)].

This is not a call for a landscape replete with wind catchers, or a mandate to apply archetypal structures in design, but it makes sense that precedents of old, and the science behind them, should not be cast aside.

 

Creating cool air in hot climates is not an easy task, and neither is keeping the air cool once it enters a building. Perhaps inspired by traditional concepts of cooling, TermoDeck has developed an innovative system that uses the structure itself as part of the air-conditioning system.

 

Smart Solutions Inspired by Nature

All structures built in Dubai today, from single floor homes to skyscrapers, use concrete slabs. With TermoDeck, air is collected and cooled during the night (higher efficiency) and then stored in these concrete slabs. The slabs work as a medium for storing coolth, relying on the thermal properties of the concrete. The coolth is then radiated by the slabs, which also provide a conduit for air to ventilate the occupied spaces during the day.

 

TermoDeck is an excellent model of using nature in harmony with science, and with buildings in the UAE already constructed and in operation for almost two decades, it has the evidence to back it up. There are over 20 projects in the GCC alone and more than 400 TermoDeck buildings operating worldwide (many award-winning, LEED and BREEAM certified and typically with a 50% reduction in peak AC load compared to conventional buildings).

 

TermoDeck projects are not more expensive to build compared to conventional AC. Primary advantages are significantly reduced operating cost, simplicity of integrating TermoDeck into the design, streamlined construction, and significantly reduced operations & maintenance. TermoDeck uses standard equipment, and works equally well with both precast concrete products, as well as in in-situ concrete construction. In certain situations, we can also retrofit existing structures. 

 

TermoDeck can be combined with all types of AC units, including chilled water systems, packaged units, VRV units, Fan Coil Units, district cooling, etc. From the AC-unit, generally placed on the roof, supply air ducts run in vertical shafts down to each floor inside the building and then to horizontal ducts placed into central corridors usually within false ceilings.

 

The main supply ductwork into the slabs, most often placed in the corridor, is similar in construction to that found in conventional systems. In the TermoDeck system, the entire air volume flows to the AHU, then is filtered, treated, cooled, dehumidified and sent back via hollow core slabs to individual rooms.

 

How Does TermoDeck Stand Up Against Conventional AC

 

The most important difference between conventional AC and TermoDeck is that we take full advantage of the thermal mass of every individual concrete slab, which is supplied with a small quantity of air from the main supply duct, in other words, a small 'feed' duct, every 1200mm along the length of the corridor.

 

Conventional air conditioning systems allow moisture and condensation to build up on duct and coil surfaces when the system is turned off at night, or during holidays or cooler seasons. The metal used in the AC ducts contain organic mineral oils that breed mold, fungus and bacteria that get dispersed into the indoor air once the AC is turned back on. Because its made of metal, the duct itself also acts as a conductor, and is quick to reach the same temperature as incoming air, bringing it closer to the dew point, and making it more likely to produce condensation.

 

Sick building syndrome, airborne fungal toxins, unhealthy indoor air: catch phrases highlighted by media alerting us to the invisible contaminants affecting our immunity, productivity and health. We chip at or bleach away the mold on our walls and accept this as a necessary by product of the humid environment in which we live. But smarter AC does exist and it offers many solutions to the problems that conventional AC can pose on its own. 

 

TermoDeck operates year round, giving very stable internal conditions at all times, with only minor fluctuations of the internal temperatures in the ducts. When cooling is not required, quiet fans run continuously providing internal temperature stability. Air is constantly conditioned and circulated inside the cores of the slabs and kept in a tight temperature range. The dew point remains well below the slab temperature, so no condensation is possible.

 

Superior Health and Air Quality

 

Reports on existing TermoDeck buildings from Envida have measured and proven the IAQ to be superior and occupant comfort to be maximized. The table below, reproduced from a 2016 Envida report, highlights that TermoDeck has no trace of any microbiological organisms of any kind on the concrete surface, and that the air leaving the slab achieves extremely high level of cleanliness, reaching 97% below applicable Dubai Municipality standards.

The benefits from using the system are significant and modifying the slabs to act as coolers within the structure, though simple, is a highly advanced and precise science. Unique innovations that revolutionize whole sectors, like energy and construction, are often thought to be costly or out of reach. It is most often the mindset of individuals that prevent growth, and the construction and design industry has tended until recently to operate along the path of a fixed mindset, specifically when it comes to AC.

 

The disruption that TermoDeck offers is compounded by the idea that this advancement also produces cost savings for owner-developers. Based on one of our recent case studies and applying current DEWA Dubai’s tariff, savings in electricity over 30 years directly due to TermoDeck exceeds the cost of building itself (in this case, for construction of a mall in Dubai exclusively using the TermoDeck system). There is no other technology that can achieve this remarkable achievement. And the capital expenses using TermoDeck are comparable or below the capital costs of constructing a building with a conventional AC system.

 

With the historical benefits, health benefits, environmental benefits and cost-savings of this simple and sensible take on air-conditioning, one good question to ask is whether we can afford to not use this solution in Dubai?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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