By Kasmir Perriman, Sustainability Analyst and Rosemarie Russo, Sustainability Coordinator
"At Rocky Mountain Institute we are practitioners, not theorists. We do solutions, not problems. We do transformation, not incrementalism.”
After meeting Amory Lovins years ago at the Aspen Institutes Environmental Forum, I have been following his work so I was thrilled at the opportunity to tour RMI’s new Innovation Center with CGBG members. In a world or rising energy costs there is an increasing need to find more efficient ways to not only work and live, but to do so in comfort. The Center was designed and constructed with this in mind. As you may know, RMI is an independent nonprofit that drives the efficient and restorative use of resources. Co-founded in 1982 by Amory Lovins its Chief Scientist, RMI has approximately 150 full-time staff, annual operations of $30 million, and serves local, national and international clients. One of the five worldwide RMI offices, the Center located in Basalt is 15,600 square feet, battles a climate zone of 7, and an arid environment. Yet somehow this building is net zero, some may ask how this is possible?
In short: it uses a design that integrates every natural advantage available with a plethora of synthetic technologies and techniques in order to overcome problems of comfort in a passive manner. The whole theme of the building is to focus on the demand, not the supply. In this article we will look at a few design aspects of the RMI Innovation Center that allow it to remain a lively work environment while using little to no energy.
First and foremost an office needs electricity to operate. The roof of RMI is covered in SunPower X21-335 solar modules. These are 21% efficient, making them an industry leader. The combined system generates 83 kW at peak performance, which equates to an average 117,000 kWh per year. RMI actually does not own these panels, as they have worked out a Power Purchase Agreement with a third party financier, such that they are able to receive significant tax rebates on the excess energy produced, which RMI would not receive as a non-profit organization. The electrical energy produced by PV is stored in a 40 kW battery to cushion the PVs against peak energy demand. This system allows RMI to stay constantly below the 50 kW rate class providing financial benefits. While staying constantly below 50 kW, if you were to average energy input over energy output, RMI generates more electricity than it uses over the course of a given day. The system that controls the battery is highly adjustable, allowing it to serve as a test bed for various interactions among solar-electric, electric- vehicles, and the building. It also allows RMI to determine how to use energy storage systems for optimal economics under various utility rate conditions and structures.
The electrical energy used and generated by the Innovation Center is monitored and controlled by software that optimizes efficiency at every turn and displays data in real time to help the occupants understand where inefficiencies lay, and how their choices affect the energy flow of the system. This display can be viewed by the public online at http://buildingdashboard.com/clients/rmi/innovationcenter/ . According to Energy Star, the Innovation Center uses 74% less energy than an average office building and 63% less than a LEED v3.0 base building A typical commercial building uses 90 kBtu/ft2/yr., an average LEED building rates less than 70, while the Center is on track to rate in at 17.2 kBtu/ft2/yr. placing it as one of the most energy efficient building in the coldest climate zone in North America. Across from the display is a beautiful living wall that not only reduces noise and improves the indoor air quality and adds to the biophilic design. Biophilic designs have proven to improve employee alertness, energy levels and overall mood.
The south facing orientation includes a 52% window to wall ratio and a 23% window to wall ratio on the east face to maximize day lighting. The north and west walls have window to wall ratio of less than 20% as windows are less isolative than walls. This set up maximizes both illumination and solar heat gain in the mornings and afternoons while minimizing heat loss in the process. The top floors “butterfly” roof maximizes southern exposure and therefore solar lighting as well. Every light in the building is LED, and they are also automated with photo-sensors and auto dimmers to make sure that only the light that is needed will be produced. Light shelves also line the southern wall to not only provide additional lighting when exterior lighting is low, but to also to reflect solar light onto the roof office when exterior lighting is available. The only problem with sun light is that it has a tendency to cause glare, which can hinder productivity. Workers at the Innovation center can augment glare with, interior sun blinds, however most of the buildings glare protection is found in its design. The light selves mentioned earlier redirect the most intense sunlight to the roof of the building, and not to work spaces. The south face orientation showcases the xeriscape (i.e. drought tolerant native species) landscaping. The site was designed to capture snowmelt and rain water from the roof into bioswales which filter the water.
As many engineers will tell you heating and cooling are the most carbon intensive aspects of any building. This is not true in the case of the Innovation Center as it does not use a furnace, boiler or cooling unit. The comfort problem is as such: the interior air temperature must stay at a level between 70 and 80 degrees while the exterior temperature may range from minus 10 to 100 degrees. During the winter the buildings biggest job is to retain heat as possible, while in the summer it must remain cool. General building codes require a minimum of R-13 walls, R-3 windows and R-38 roofs. RMIs success is largely due to the insulation of its components. RMI boasts an incredible wall structure of R-50, and roof structure of R-71. This is achieved by using extremely thick SIP panels. SIP use foam and wood to make a heavily insulated, air tight and structurally sound siding. The windows at RMI are quadrupled paned and krypton separated, giving them an R - 8. The ground floor of the building is insulated concrete. Insulated concrete has a large specific heat capacity, and therefore gives the building a larger thermal mass. Thermal mass is the ability to store heat. The combination of insulation and thermal mass stops heat from diffusing outside of the perimeter while forcing it into the structure of the building. Phase change gel packs line the walls of the building to add further to the buildings thermal mass. Phase change gel is a solid substance that melts at 77 degrees, and absorbs the heat in the building. When the building starts to cool off, the gel freezes again and the surrounding air will not cool down below 77 degrees until all of the gel is frozen and vice versa for heating. RMI solved this problem by sealing the buildings siding with an airtight foam barrier. Typical commercial buildings have 5 to 7.5 air changes an hour. The Innovation Center clocks in at .36 air changes per hour. That means the air exchange between the building and the environment per hour is about the size of a basketball.
The passive technologies listed above reduce the demand for heating and cooling. However, heat must still be supplied to the building in the winter. The building is oriented to be south facing, in order to maximize its ability to heat using passive solar. Around the building, placed in the floors and walls are a great number of gentle low wattage resistance heaters, so that heat is generated where it is needed, and the building is thus not forced to heat the whole air volume it contains. Winter ventilation is done via air to air heat exchangers. This is a system where fresh air is forced to absorb the heat of the vented air so that the air does not have to be constantly reheated. RMI’s air to air exchange system conveys 90% of the vented heat to the fresh air coming in. During the summer the building must act oppositely as in winter, the air to air exchange must cool the air coming in, which it is also capable of doing. The south facing orientation now becomes the enemy so automated sun blinds sense when the building is heating up past its comfort zone and drops angled blinds that reflect the suns heat while still allowing the sun light to enter. Additionally, highly efficient fans ensure that air circulates within the building. An open office plan has many advantages for creativity and communication; however it also makes it easier to circulate air with ceiling fans and a single ducting system. Singular offices would each require their own duct ways, and their own air supply.
In additional to the efficiency technologies, the designers optimized comfort by a wide range of personal modulators. Every occupant has a “hyper-chair” fitted with personalized air conditioning and seat heating as well as an USB powered fan to circulate the air around them. If ambient lighting is insufficient, workers have LED desk lights to augment visibility.
Following the RMI Tour, several CGBG members toured an equally innovative gem – the Central Rocky Mountain Permaculture Institute. The tour was an impressive display of permaculture, aquaponics and passive building design. The Institute has consulting services and training courses that center on how to incorporate renewable energy and sustainable building technologies to provide optimal growing and living spaces. They also work with local governments and businesses to integrate natural weed and pest management practices that reduce the use of toxic chemical herbicides and pesticides.