What are the responsibilities of ASHRAE as we evolve our methods regarding sustainability today?
It's important for architects and engineers to work together to provide very good indoor environments and reduce the energy that's being consumed, not only from operating these buildings, but from constructing the buildings and the embodied energy that's in the materials we select.
How have you seen the relationship between architects and mechanical engineers change over time?
I credit the U.S. Green Building Council with getting architects and engineers to work together at the early stages of project conceptualization to discuss sustainability and understand the impact of the engineering decisions. Through integrated building design, we can make decisions with respect to the proper amount of insulation that reduces the size of the cooling systems and heating systems in buildings. Implementing daylighting in the envelope reduces the amount of power that's going to be required in the lighting. We can design a building that doesn't cost any more, consumes much less energy, and provides good indoor environments.
Credit: Michael Darter
Role: A consulting engineer based in Southern California, Peterson just completed a one-year term as president of the American Society of Heating, Refrigerating and Air- Conditioning Engineers.
More: Last May, he appeared before the U.S. House of Representatives Select Committee on Energy Independence and Global Warming to give testimony on ASHRAE's efforts to provide advanced energy guidance.
A recent New Buildings Institute study notes a gap between building performance and building design. What is ASHRAE doing about this?
Performance is what it's all about. We have to have feedback about building operation, and we lack the benchmarks that would lead to better design tools. ASHRAE has a number of projects under way. One, on building performance measurement protocols, is going to be out this fall. We are working closely with the Chartered Institution of Building Services Engineers on energy benchmarking for different building types. We're working on a database analyzing sustainable and high-performance buildings. Owners are asking for other metrics: productivity in the space, how the space is leased, and what the lease rates are. We have to get these benchmarks, and the only way to do that is to get data in existing buildings and set targets as we design future buildings.
What are the differences between ASHRAE 90.1, which is part of LEED, and the proposed 189.1?
The model energy code is 90.1, and the 2010 version has a 30 percent energy reduction from the 2004 version. ASHRAE 189.1 goes further: It's about energy, indoor environmental quality, and materials. It's setting the baseline and writing code-intended language that a local jurisdiction could adopt.
Mechanical engineering has often been based on a closed-system model—interiors sealed from the out-side to permit maximum control of indoor air quality and temperature. How can we think about mechanical and natural ventilation working together?
A lot of consultants design for peak conditions, but there are many times throughout the year when we can use mixed-mode, natural ventilation to reduce energy consumption. The other issue is how we operate buildings and how occupants interact. If we have a simple control system that turns off the ventilation system and lets people open windows because the conditions are correct, that's the best. People can tolerate other types of conditions for comfort?we don't need to heat the building in the winter to the same temperature that we cool it in the summer. We can use natural ventilation to get cool air to come in and exit at the top. It's an education for the engineering community. It's an education, for the architects and the building operators, on how to use these strategies.
What's necessary to make sure architects and mechanical engineers are working together to move our knowledgebase quickly in order to meet these challenges?
We're starting to look at building science, saying mechanical engineers aren't just there to provide guidance on how to size an HVAC system—they're working with the architect to decide what type of strategy to implement in the building envelope. How can we get daylighting and some passive heating at the same time? How can we get better thermal insulation to reduce the size of the mechanical system and provide a more comfortable space? We don't work just in our single discipline.