In addition to maximizing insulation, we prioritized airtight construction and low air leakage. There are hundreds, probably thousands, of small actions that all trades involved in the framing and building the walls must get right to achieve airtight construction. For example, the fluid-applied air and water barrier (basically, super thick paint that coats one section of the exterior walls), has to be put on in a way that ensures a perfect seal. This needs to be coordinated with other elements like flashing tape around window openings, the metal flashing at the base of the wall and on top of the concrete slab. We worked to avoid thermal bridging wherever possible by using special fasteners on the exterior of the building to hold the continuous insulation in place — so the fasteners didn’t serve as tiny heat loss pathways throughout the building. We also selected thermally broken window frames in all of our windows. Last but not least, our commissioning agent tested to confirm that our building envelope met the latest standards. A well‑insulated and airtight building plays a huge role in the sizing and selection of the HVAC system, which I’ll tell you about next. Step 5: Ultra efficient HVAC system and commissioning. As an all-electric building, we selected a VRF heat-recovery HVAC system. This is the heart of our approach to providing heating and cooling without using gas combustion. A VRF mechanical system (also called variable refrigerant volume or VRV) is an HVAC heat pump technology that optimizes the use of refrigerant during a heating or cooling period. The Climate Innovation Center’s dedicated outdoor air system (DOAS) provides fresh air throughout the building while the windows are closed and creates a slight pressurization to keep air pollutants out of the building. One innovative function of the DOAS is that it includes an energy recovery ventilation (ERV) system. The ERV transfers energy from the building’s exhaust air into the outside air being brought into the building. Basically, it pretreats the incoming air to reduce the amount of heating and cooling (aka energy) required to bring the incoming air to the desired temperature. In addition, to further reduce summertime electricity demand, we incorporated a highly effective direct evaporative section into the DOAS to pre-cool the air entering the building. For cold winter days, our DOAS includes a small refrigerant coil that assists with pre-heating when outside temperatures are very low. One thing that makes the Climate Innovation Center unique is the natural ventilation mode. When the temperature is optimal in the spring, summer or fall, we don’t want to unnecessarily heat or cool the building if we can accomplish the same effect by opening windows. When the outdoor temperature is within a specified range, a light signal alerts staff who can then place the VRF into “standby” mode, open the windows and turn on the ceiling fans. One essential element of our high-performance HVAC strategy is not a piece of technology, but a process. We brought on a system commissioning agent to work with the mechanical engineer, mechanical contractor and subcontractors. The system commissioning agent monitors and provides technical guidance on the HVAC system from the design stage, through construction, and into the occupancy of the building. The commissioning agent works with various trades to perform functional tests to ensure that the HVAC system is performing as it was designed. Step 6: Solar and battery storage. In Step 3, we worked with our energy modeler to understand what the energy needs of the Climate Innovation Center would be and planned our solar array and battery capacity to meet those needs. While we are connected to the larger electricity grid, we’re powered by the sun 24/7 with help from battery storage. But it was not as simple as you might think. Renovating an office building meant overcoming some very real challenges to get enough solar to provide all of our power needs. Thanks to our partners, we implemented some creative solutions to make it happen. To reach the needed amount of on-site solar, the solar team installed panels at a 5-degree tilt to maximize production while not shading the next row of panels. We also worked with our architect and the solar installers to strategically locate roof penetrations and the HVAC system to fit as many panels on the roof as possible. Our 37.1 kW solar array is comprised of 70 bifacial, 530-watt panels, with 54 on the roof and 16 on a solar canopy. The estimated annual electricity generation is 53,318 kWh, enough to meet our estimated energy consumption plus electricity for charging staff electric vehicles. To ensure the building has clean electricity day and night, we installed a Lithium Iron Phosphate battery with a usable capacity of 90 kWh and a nominal power rating of 30 kW. The battery is enrolled in the local utility’s battery “demand response” program, which allows our building to interact with the electric grid to support grid flexibility. 22 REFLEXION
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