Building Sustainably: Kripalu’s New Annex
By William Bryant
With these questions and answers, one of the lead architects from Rose + Guggenheimer provides a deeper understanding of what makes Kripalu’s new Annex a cutting-edge architectural and environmental project.
What is meant by the word “green”?
The word “green” is often used to describe products, buildings, cities, or landscapes that attempt to minimize their negative impact on the environment. A more descriptive and measurable term is “sustainable,” which alludes to the general goal of the environmental movement to achieve a state in which human practices on Earth can continue indefinitely without leading to the decline or collapse of the Earth’s ecological systems.
What are the general principles of sustainable design?
Sustainable design in architecture aims to reduce the disruption of natural ecosystems, to minimize energy consumption over the course of a building’s lifespan, to utilize renewable and local resources wherever possible, and to encourage building users to relate to the natural environment. These goals have implications both for the users and for the life cycle of each individual building, as well as for the longevity of human life and culture as a whole.
What is LEED certification?
LEED (or Leadership in Energy and Environmental Design) certification is a system of acknowledging and awarding buildings that demonstrate the use of sustainable building practices. Sponsored by the U.S. Green Building Council, the LEED rating system has been instrumental in publicizing the need for responsible green design in this country. Many state and local government agencies have adopted LEED initiatives in an effort to promote sustainability in publicly owned and funded buildings. Participation in LEED for private projects is entirely voluntary, and only projects which choose to track their projects with the LEED rating system are eligible for award. Unfortunately, a side effect of LEED tracking is that projects are saddled with added administrative burdens that manifest in added “soft” costs, costs that are not applied directly to the construction of the building itself. Keeping the basic goals of LEED in mind, many clients choose to forego LEED and instead put their financial resources directly into the creation of a building that exemplifies the principles of sustainable design.
What is Integrated Design?
Integrated Design is a process by which multiple disciplines work together holistically to design and create a building. While this might not sound unusual, in traditional practice, various specialized consultants (structural, mechanical, electrical, plumbing, landscape, etc.) each work independently, and often in isolation, under the general guidance of an architect. Under this model, to account for potential conflicts and unforeseen conditions, consultants tend to incorporate substantial margins of error into their designs, resulting in projects that are overdesigned, costly, and inefficient. Integrated Design is a process that attempts to bridge these traditional gaps in communication, bringing multiple voices into a collaborative unison while eliminating guesswork and contingencies. When practiced effectively, the Integrated Design model saves time, energy, and resources by allowing facts and precision to prevail over approximations and rules of thumb.
While initiatives such as LEED have begun to publicize a more holistic view of building design in the United States, the European community is leading the push toward Integrated Design and sustainable practices in general. The work of the German firm TransSolar, our sustainability consultant on this project, provides many excellent examples of what can be achieved through this collaborative approach (www.transsolar.com).
What are the precise elements in our new building that set it at a high register of sustainability?
Many purportedly “green” projects address sustainability through poorly integrated but high profile add-ons, such as solar panels and planted roofs, which do not necessarily imply sustainable strategies in the building as a whole. With the help of TransSolar and the Integrated Design process, this project employs comparatively modest techniques to produce a building that optimizes the user experience while minimizing energy usage, waste production, and maintenance requirements across its lifespan.
First, every effort has been made to keep the building’s energy requirements to a minimum. Perhaps most importantly, this has been accomplished by making a building that is extremely compact. The overall volume of the Annex is roughly 30% less than a typical building of its type, meaning that there is simply less building to heat, cool, and illuminate. Daylighting is employed extensively to reduce the building’s reliance on artificial light sources. In addition, natural processes and passive systems have been employed wherever possible to provide ventilation, mitigate heat loss in the winter, and heat gain in the summer. For example: the building is heavily insulated and constructed largely of thermally massive concrete, a material that helps to reduce a building’s susceptibility to exterior temperature changes; guest room windows are protected from direct sunlight (and thus unwanted heat gain) by individually operated sliding exterior shading devices; the public corridors on the guest room levels have been tapered and aligned with the prevailing winds to facilitate the natural flow of air in spaces that would more typically be conditioned with energy consuming mechanical systems (the tapered shape is intended to create a Venturi effect that will accelerate air and keep ventilation active).
Where active mechanical systems are required, we have made every effort to ensure that these systems use as little energy as possible. The project boasts a radiant floor system that is used to both heat and cool the building (a technology that is common in Europe, and brand new in the United States). Radiant floor systems are not only more energy efficient than traditional forced air systems, but they also produce a more comfortable environment, reduce indoor air pollutants, eliminate the need for unsightly and space-consuming ductwork, and are virtually silent. The radiant system works by circulating hot or cool water through high strength coiled tubing buried in the concrete slab. Once the building reaches the desired temperature, relatively little energy is required to maintain this temperature as a constant; as we mentioned above, the thermally massive concrete slab is an extremely effective means by which to mitigate temperature swings.
Hot water for the system is drawn from the latent capacity of the existing boiler in Shadowbrook, another means by which energy consumption is reduced. Even the exhaust air system in the building is designed to reduce consumption: a sophisticated heat recovery system has been employed to recycle heat from exhaust air and offset heating loads in the winter months. As a bonus, all of this is done without sacrificing individual comfort and control in the guest rooms. Passive heating/cooling units in each room will allow guests to augment the slab system with additional warm or cool air. These passive units have no moving parts and are again virtually silent.
Finally, within the building, earth-friendly materials are used wherever possible: exposed structural concrete on many walls, floors and ceilings, linoleum in the guest rooms, and recycled carpet in hallways.
