Environmental Resilience and Sustainability
The climate in India and in particular, New Delhi, offers some very significant challenges for the new buildings of the U.S. Embassy compound. These challenges include poor air quality and the scarcity of water along with the poor quality of the existing water. Not only must the design consider how to efficiently deal with very hot conditions for most of the year, as well as high humidity during the monsoon season, the building must be considered in the context of New Delhi’s poor air quality during much of the year.
The project integrates new efficient systems, renewable energy, and sustainable approaches to water collection, treatment, and use in LEED certified designs. The New Office Building (Chancery) and staff housing have been nominated for US Green Building Council (USGBC) Leadership in Energy and Environmental Design (LEED) certification under Green Building Rating System Version 4 and are the basis of the sustainability features for the other office and residential buildings on site. Therefore, the performance of these buildings against the targets are the basis of following energy and water analysis.
On Target for the following LEED Certification Goals:
- LEED v4 Silver certification – New Office Building (Chancery)
- LEED v4 Silver certification – Staff Housing (Apartment)
The nexus between energy and water consumption is a serious consideration for this project as it faces strong headwinds in both directions. Cooling energy dominates the energy performance of the buildings on site and could be improved markedly by adopting water based heat rejection. However, this would lead to a sizeable increase in the quantity of potable water consumed on site even if water recycling options can limit the extent.
In light of this, the proposed buildings incorporate several passive design features to minimize cooling loads. The envelope is improved above American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and Bureau of Overseas Building Operations (OBO) requirements with additional insulation and a high-performance glass specification. The new office building and support annex buildings incorporate pre-cast shading ribs onto the glazing that help protect from solar gains (image, right). A portion of the new office building space is interred under the central green spine to better protect it from hot ambient outdoor air temperatures and reduce solar loads. Additionally, the window to wall ratio of the new office building is kept to a modest 41%, with the openings minimized on east and west facades to protect from hard to shade low angle sun. Improved lighting power density and extensive renewable energy systems also contribute to the energy savings.
The electricity grid in India is mostly coal based, so energy use in buildings greatly contributes to the air quality issues and carbon emissions of the country. Using renewable energy to offset electricity can therefore provide great environmental benefit. The project is targeting 20% of annual building electricity and thermal energy consumption to be offset by on-site renewable energy generation.
The office buildings utilize a large photovoltaic (PV) array (solar panels) located on the roof of the support annex. The 250 kilowatt PV array will help offset nearly 30% of the energy costs. The staff housing building has both 35 kilowatt PV array and 28 kilowatt solar hot water (SHW) arrays on the roof (image, left). The renewable energy will help offset nearly 13% of the energy costs.
On Target for the following Energy Goals:
- 30% energy reduction when measured against ASHRAE 90.1-2010 Baseline Building
- Renewable energy systems to provide a minimum of 20% of the total amount of annual electricity consumed
- Reduce greenhouse gas emissions by 20% compared to the ASHRAE 90.1 baseline model
Water conservation is an important issue for New Delhi. Both the new office building and staff housing exceed OBO’s goal of 50% reduction in outdoor water use and 30% reduction in indoor water use.
At the New Office Building (NOB) the proposed suite of water initiatives shows a total water use demand reduction of 37% and a potable reduction of 74%, while the proposed suite of water initiatives at the staff housing (SDA) shows a water use demand reduction of 42% and a potable water use reduction of 44%.
The project design uses the following suite of initiatives to achieve its water reduction goals:
- Use of highly efficient fixtures and fittings for toilets, urinals, faucets
- Use of efficient kitchen equipment and laundry equipment
- Use of no-low irrigation plant species and subsoil drip irrigation
- Reuse of treated wastewater for irrigation
- Reuse of collected stormwater for the entry fountain, collected in a 1 million gallon storage tank under the fountain (image, left)
On Target for the following Water Goals:
- Reduce indoor potable water consumption by 30% below the LEED baseline
- Reduce outdoor potable water consumption for irrigation by 50% using LEED calculations
The full story of the new embassy design is available in the New U.S. Embassy New Delhi Design Book.