5-6.BUILDING INTEGRATY
1.Building integrated photovoltaics (qualitative &quantitative)
2.Whole building performance overview
Technologies Implemented:Overview
1.Building integrated photovoltaics
The integration of photovoltaic’s (PV’s) in building design, where the PV elements become an integral part of the building envelope, often serving as the exterior weather skin, is growing worldwide. Building Integrated Photovaltaic’s (BIPV’s) is the integration of PV’s into the building envelope rather than as an applied extra feature. The PV modules on the Pearl River Tower serve the dual function of building skin (spandrel panels) and power generator. By avoiding the cost of conventional spandrel panels, the incremental cost of PV’s is reduced and its life-cycle cost is improved. BIPV systems often have lower overall costs compared to PV systems requiring separate, dedicated, mounting systems.
The solar radiation on the Pearl River Tower was carefully studied (Figure 1). It was determined that the use of PV cells could be productive if used on certain portions on building’s envelope. The distribution of the BIPV’s directly correlates with where they would optimize the solar power offered by the sun, You will see (Figure 2) that they are asymmetrically located at roof level in order to achieve best performance rather than nonspecific architectural criteria.
The system not only provides an electrical supply for the building, it also functions a solar shade for that part of the building most susceptible to the negative impacts of direct solar radiation.
Figure 1 :Incident solar radiation stress analysis(Frechette&Gilchrist,2008)
Figure 3 Building integrated photovoltaics (quantitative)
Figure 2: Integrated photovoltaics ((Frechette&Gilchrist,2008))
SOM also is taking advantage of the tropical sun, using two kinds of solar electric panels on the east and west façades. At the crown of the tower, the design calls for photovoltaic (PV) technology integrated into more than 16,000 ft2 (1500 m2) of the façade glass itself. Another 16,000 ft2 (1500 m2) of PV will be mounted onto the fixed solar shading feature on the west façade. In all, the tower’s PV technology will have a 300,000 kWh capacity (about 2% of the building’s needs). The wind and photovoltaic systems not only reduce the amount of electricity needed from the power grid to operate the building, but also create a more efficient system altogether. SOM’s initial design also included the capability of producing power on-site using micro-turbine technology. Conventionally, power generation starts at the power plant, sends electricity along lines to a transformer, and finally to the building’s wall receptacles. Energy is lost along every step of the way, making that energy pathway about 30% efficient. Generating electricity at the site where it will be used reduces the losses that come from handling and distributing it. According to Frechette, the Pearl River Tower systems, with heat recovery, would be able to use about 80% of the energy that is produced, much more efficient than “importing” electricity from the utility.
2. Whole building performance overview
Project Initiation and Purpose
Chinese government goal of reducing carbon emissions by 10% by 2010
Guangzhou was focus of this policy
China National Tobacco Company (CNTC) decided to locate their new headquarters in
Guangzhou
CNTC asked for submissions for “High Performance Super Tower”
A U.S. Company Skidmore, Owings, & Merrill LLP (SOM) responded with a Net
Zero Proposal
Project Approach
SOM believes in uniqueness of each project and environment
Analyzed wind speed, wind direction, solar angles, air quality, temperature, and humidity profiles which all impacted the design
Generated team of experts in various specialties
Integrated the architecture, structural, mechanical and electrical systems which were previously thought to be independent layers.
SOM’s Proposal
Reduction
Reclamation
Absorption
Generation
Reduction
Reduced the building’s energy consumption by
reducing HVAC and Lighting needs by
addressing:
Site Orientation – to the East
High Performance Building Envelope
Day-lighting
Building Control Systems
Absorption and Reclamation
Reclaims energy by using thermal barrier of hot
air for mechanical floor for passive
dehumidification
Chilled Slab concrete vaulted ceilings
Enhances daylight
Cools for underfloor ventilation system
Wide-scale PV System
Reusing harvested energy
Generation
3 Power Generating Technologies
Wind
Integrated PV
Micro Turbines
Curvelinear structure forces air through turbines
Increases speed of air 1.5-2.5 times
Results in 15x more power than freestanding wind turbine
