The changing and increasing needs of developers, architects, tenants and cities are challenging the way we design building services for tall buildings.
How do we maximise floorspace to improve returns without compromising design and comfort? And how do we incorporate developing technologies and adapt to shifts in building practices to maximize performance and increase economic benefits?
Key considerations include:
- Identification of services spatial requirements
- Rationalisation of services arrangements
- Efficiency of core design including size and number of lifts, number and location of services risers
- Vertical continuity of services
- Simplicity of services routes
- Evaluation of options to achieve compliance with the NCC/BCA
By using innovative building services strategies such as distributed pumping, CFD modeling, EC windows, vertical city approach and renewable energy analysis, it is possible to reduce the size required for plant space allowances, and reduce the core risers sizes and number whilst always maintaining the buildings performance and quality.
A conventional system uses a pump designed for full load pushing against a brake (motorized control valve). The distributed pumping system utilizes a pump with a variable speed drive connected to the temperature sensor in place of the brake. As the demand across the coil is increased or decreased the pump speeds up or down accordingly.
This system can be used for heating or cooling and saves 22 per cent energy on peak load days and 49 per cent on normal days. It costs no more to install than the conventional system.
When the system is commissioned, there is no need to allow three to four months to balance all of the 90 floors. The distributed pumping system with its smart controller and variable speed drives balance automatically.
Computational fluid design (CFD)
When it comes to CFD modelling in high rise buildings, most people think about wind loading on the structure. CFD modeling can also inform the sizing of our mechanical systems. By using a model, we can simulate the indoor environment using the façade type and performance and match it with the appropriately sized mechanical system. This reduces cost due to over-design of mechanical output, saves space on reduced mechanical plant and reduces the core riser requirements.
Electrochromatic (EC) windows
This is an emerging technology that allows the transparency level of the glass to be altered. Smart glass controls the amount of light transmission. When activated, the glass changes from transparent to translucent, blocking some of the light wavelengths and leading to a reduction in heating, cooling and lighting costs as well as the need to install and maintain motorized light screens, blind or curtains.
Using this technology in conjunction with the CFD modeling of the façade, you can reduce the size of the mechanical system, saving construction expenditure as well as operational costs.
I look at super-tall buildings as vertical cities, by extending the medium-voltage primary distribution to as close to the load centre as possible. This reduces the material required to distribute power while also reducing distribution power losses.
The zoning within super-tall or high-rise buildings lends itself to configuration through multiple electrical feeds, which inherently increases the system reliability and redundancy. In this way, it is a similar concept to the horizontal distribution of cities with the redundant power coming from on-site generators combined with a photovoltaic system.
Renewable energy systems
Integrated photovoltaic panels on the façade, which use alternating upward-angled spandrel panels to maximize sun exposure for energy collection and downward-angled viewing panels, can minimize sun glare and heat gain, thereby reducing the cooling load.
We have the ability to use a CFD model to run an optimization analysis for the positioning and placement of these panels to support the maximum amount of energy that would be collected to generate power for the tower’s electrical systems.
Using this information, we can suggest certain portions of exterior wall spandrel panels be fitted with active photovoltaic panels to maximize performance and to increase economic benefit
Innovative fire engineering solutions
This can be particularly beneficial in high-rise buildings. Where buildings are very tall, it is important to consider all aspects of fire safety and how the tall nature of the building will impact on the occupants and fire fighters. Applying the Deemed to Satisfy (DtS) provisions of the BCA isn’t necessarily appropriate in these very tall buildings.
One aspect of fire safety design recently adopted into the BCA is the use of lift as part of the evacuation strategy. This doesn’t work in lower rise buildings, but in high rise residential buildings this can provide a very efficient strategy for evacuating occupants.
In addition to occupants escaping from the building, carrying out effective firefighting operations in the building is an important consideration. The best approach is to ensure systems are designed to allow effective firefighting operations to take place from inside the building.