It is estimated that 15% of the total energy used in the United States is used in building HVAC systems, split between both residential and commercial uses. With an estimated 5.7 million commercial buildings and 100 million single-family residences, the task of decarbonizing this sector is an enormous one. While decarbonizing the electric grid is progressing, leading to fewer emissions, there is still significant work to be done in building and retrofitting more energy-efficient buildings while also working towards site electrification to reduce on-site fossil fuel use. Due to the scale of the system and the long lifespan of the underlying buildings and equipment, taking a modular approach to retrofitting existing buildings will be essential in reducing the cost and impact of the transition.
Designing around a modular transition has several important benefits. Phasing the changeover will allow the capital costs to be spread out over multiple budget years and will allow building owners to take advantage of cost reductions as new technology matures and economies of scale ramp up. It will also allow the grid time to adapt and grow to meet the increased demand. Finally, the technology of today may not be the ultimate technology to support the changeover, so by using a modular solution, the building owner can be flexible as new technologies become available.
Flexibility is key in this approach. In some cases, fossil fuels such as natural gas may play a transitional role in building heating. For example, a transition from steam to hot water may utilize natural gas boilers in the short term. Capital upgrades for the electrification of the building are being done and lay the groundwork for a low-temperature hot water system built around electric-based sources of heating.
To best utilize this approach, it is important to have a road map with an end goal to work towards. The first step is to build a master plan that identifies current and future likely sources of energy demand. As well as current building limitations and with that come up with a roadmap of projects needed to electrify the building. Enabling projects will likely be needed to lay the groundwork for the transition. Enabling projects may include things like upgrading the building's electrical service or taking measures to convert a high-temperature hot water system to a low-temperature hot water system. Additionally, bridging projects should be identified if existing equipment will need to be replaced before enabling projects are ready. The more existing systems that are impacted, the more strategic these enabling projects need to be in execution. In some cases, the required changes are more than a plug and play equipment swap and will require reconfiguration of major building systems to optimize for the new operating parameters.
Once enabling projects have been completed, the work of transitioning to the new system can begin. By using a modular approach, the central plant can be expanded as older terminal equipment and air handlers are decommissioned and replaced. This will ensure that the heating/cooling load is always finely balanced and spread the cost over successive years of equipment replacement.
Utilizing this approach, it is possible to begin transitioning our building infrastructure in a way that doesn’t break the bank for owners and leverages transitions happening in other sectors of the economy. An engineering firm well-versed in planning for the energy transition can be invaluable for this process. Be sure to read our upcoming guide to see how F&T can help with these planning goals.
Written By:
Aaron Valentine
Mechanical Project Leader
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