With buildings contributing close to half of the energy use in the United States, and energy use being the number one contributor to global warming, an obvious means to mitigate climate change is to design low or no-energy use buildings.
To do so means going back to basics and looking carefully at how to design a building to optimize the particular features of a specific site and minimize the potential of extreme energy use.
In a nutshell, designers will need to:
- Perform a site analysis. Determine the weather patterns, climate, soil types, wind speed and direction, heating degree days and path of the sun. Look at the water flows, habitat and geology of the site. Document each with a qualified team of professionals to understand the ramifications of building in that specific place.
- Layout the building on the site. Using the general program, through an integrative team process, use a basic massing of the building layout to determine specifically on site the most optimal location for the building to be situated. Factors to consider here are access to infrastructure, staying at least 100 feet clear of any watershed, not building within a floodplain and/or in a habitat with endangered species. Ask: what trees and other existing geological features should be avoided? How does the water flow across the site dictate the location of the building?
- It’s all about the sun - orient the building based upon cardinal directions. The goal here is to maximize the amount of sun that heats the space in the winter (hence using less energy to mechanically heat) and decrease the amount of sun that cooks in the summer (hence using less energy to mechanically cool).
- Select the appropriate window areas and glazing types based on orientation. South facing facades should utilize a window area appropriate to its orientation and glazing should utilize a double or triple paned glass with a low-e coating to minimize the amount of heat transmitted into the space in the hottest months, while keeping heat inside during the cooler winter months. For example, a south facing glass window wall will cook the occupants inside during the hot summer months if care is not taken on this façade.
- Building envelope design varies greatly by geographic area. When designing the envelope of the building, factors such as insulation, vapor barriers and air barriers will vary radically depending on whether the project is in the cold, snowy north, the hot and humid south or the arid desert.
- Minimize the building footprint. Question the true needs of the program – do you really need that much space? Are there ways that spaces can become multi-functional? Do we really need that many private offices if some staff can telecommute occasionally and share offices? Once your team is set on the minimize program, take a look at the size of your footprint. Is it possible to add extra stories to make the footprint smaller? That way, the building will have less excavation cost, and more wall area that can benefit from the warming effects of the sun and an increase in natural daylighting.
- Design for natural ventilation. Since warm air rises, a building can be cooled by designing for stack ventilation by drawing cooler air from openings low in the building, while carrying heat away through openings in the top of the space. The rate at which the air moves is a function of the vertical distance between the inlets and outlets, their size and the difference in temperature over the height of the room.
- Relax the occupants comfort standards. Most buildings in this day and age are designed to keep occupants fairly comfortable – around 78 degrees farenheit. However, with climate responsive design, reducing the amount of energy used to cool and heat the building can result in using natural systems – the sun and the wind. With these, if building occupants are open to adding or removing layers during the seasons, it’s amazing how much energy can be saved. Adding a sweater in the winter or relaxing the company dress code to shorts in the summer can be enough to eliminate mechanical heating and cooling all together – saving a bundle of money and the environment.
- Conduct modeling and analysis. Energy modeling, lighting models, daylighting studies, computational fluid dynamics are all tools that designers can and should use to understand how the design best integrates with the local climate and micro-climate features specific to the site. Again, having the right team members with modeling expertise and software is the trick to keeping costs down while exploring the best options for the design.
- Perform multiple iterations. If at first you don’t succeed - try again! It will take the design team multiple passes of just these basic layouts in your pre-design or schematic design phase to hone in the lowest energy use possible, optimized for your specific site. However, it’s better to spend more time in the early phases of design to model the project which is far less costly than making changes in the field or later on in the design process. Keep at the trials and eventually your building will be responding directly to the climate specific to the project site! Congrats!