**6.1 The Bullitt Center**

*Zero-Energy Buildings - New Approaches and Technologies*

improvements in the energy efficiency.

energy requirement needed in this step.

C. Renewable energy measures

systems, and other sources.

and help in shifting the peak load.

above 25 mph (11.2 m/s).

sensors.

ventilation.

design, applying factors to reasonable baseline cases, and using simulation to model the design and predict the optimized requirements. In the simulation, part load performance should be considered which would come useful when using variable volume systems, variable speed drives, variable capacity boilers, variable capacity chiller systems, and variable capacity pumping systems as well. In addition to this, the designer should consider using high-efficiency lighting and control systems such as LED lights, high-performance ballasts, dual circuited task lighting, occupancy sensors, and daylighting dimming

The designer should shift electric loads during peak demand which would optimize the energy consumption. Some recommendations for optimizing the HVAC loads are (1) using heat recovery chillers, (2) using underfloor air distribution systems, (3) using high-efficiency chillers, (4) using passive cooling, (5) applying thermal storage using phase-change materials (PCMs),

(6) using combined heating and power (CHP), and (7) using natural

Go green! Maximizing the energy sources are done through the first two measures, the building envelope which promotes using less energy and the efficient utilities and equipment measures. The renewable energy measures are more expensive than these two measures, and for that designers should start with the first two measures and optimize their design which would reduce the

There are various renewable energy resources, such as solar which can be used for generating electricity, storing energy, and heating water, wind, biomass

Solar water heating systems include roof-mounted solar collectors that heat a fluid which would be used to heat water stored in a cylinder. Two collector types are usually used: the flat plate and the evacuated tube type. Flat plate collectors are usually cheaper. The solar water collectors heat the water that would be stored in a cylinder directly or indirectly by heating another fluid that would heat the water. Photovoltaic systems can be used to store energy

Wind systems provide energy a very effective cost if the wind is continuous and steady and its speed above 10 mph (4.47 m/s), but it is recommended to be

At the end of the construction phase, commissioning is a crucial step to ensure the building is performing as the intended design and is meeting its objectives. Commissioning phase verifies that the building's energy-related systems are installed and calibrated and perform according to the owner's project requirements, basis of design, and construction documents. The commissioning phase should cover at least the HVAC systems and controls, lighting and daylighting controls, domestic hot water system and any renewable system such as wind and solar. Building commissioning can reduce energy use, lower operating costs, reduce contractor callbacks, and improve occupant productivity. Successful implementation of the commissioning process can yield 5–10%

**50**

The Bullitt Center in Seattle was opened on Earth Day on April 22, 2013. The building is shown in **Figures 4** and **5** and is rated as the greenest commercial

#### **Figure 4.**

*Seattle's net-zero energy building (Bullitt Center) [17].*

**Figure 5.** *Seattle's net-zero energy building (Bullitt Center).*

building in the world. It is a six-story building and has a total area of 52,000 ft2 (4800 m2 ). The building is energy and carbon neutral, but its cost reaches as high as \$18.5 million which yields \$355 per square foot (per 0.09 m2 ). The center's energy efficiency is 83% better than a typical office in Seattle with many efficient and sustainable energy sources including a 242 kW photovoltaic array, ground source geothermal heat exchange system, radiant floor heating and cooling, and retractable external blinds that block heat from warming the building. For water usage aspect, the center is 80% more efficient than a typical office in Seattle with live rainwaterto-portable water system that can collect up to 56,000 gallons (211,948 L) of rainwater [16]. The building also uses gray water reclamation using compositing foam flush toilets that save up to 96% of water as compared to traditional flush toilets. The building has also green roof and wetlands.
