As many cities and states establish carbon neutrality goals, electrification of commercial buildings is becoming more popular as a way to reduce associated carbon emissions. Electrification is the process of replacing fossil-fuel burning equipment in a building with electric equipment and intended to lower the building’s long-term carbon footprint. Unfortunately, electrification is not as simple as performing standalone, like-for-like equipment replacement.
The process should begin with a feasibility study to determine whether the building is a good candidate for electrification and identify the best path forward. There are several components to consider.
Identify all gas consuming equipment
The first step is to identify end uses that need replacement or modification. This step can include examining the space heating system, domestic hot water heating, cooking equipment and laundry. In most commercial buildings, the space heating system accounts for most of the gas consumption, although, especially in older buildings, legacy domestic water systems can also be substantial.
Minimize heating loads and water temperatures
For all heating equipment, right sizing is the next step to ensure the weight, added electrical load and overall cost of the new units are minimized. As part of this effort, system modifications like resizing zone hot water coils and implementing advanced control sequences (such as in your Building Automation System, or BAS) should be considered to reduce the heating loads and required water temperatures at the building.
Identify replacement equipment options
For most appliance-sized pieces of equipment (stoves, washing machines, small to midsize water heaters) selecting replacement equipment is straight-forward and there are plenty of options. For larger space heating equipment like heating hot water boilers and package units with gas furnaces, there may be additional considerations like electrical service, weight, and refrigerant choice.
- Unitary systems (like package units with gas furnaces) can be replaced like-for-like with heat pump package units. The primary criterium is whether or not the building’s electric infrastructure can supply the required amperage needed for the heat pump. If the replacement heat pump is a physically larger unit than the existing package unit, a structural analysis may also be required – especially for wooden roofs. As an alternative, a VRF system may be a preferred option for some buildings.
- Heating hot water boilers can be replaced with air-to-water heat pumps. Larger units are relatively new to the North American market and can come in a variety of configurations as needed to meet the heating loads and required water temperatures. In addition to modifications to the electrical infrastructure to serve this equipment, available space and structural support for multiple, heavy pieces of equipment are required. In some situations, dual source heat pumps can make use of the heating and cooling capacities of the system, at least for parts of the year.
- Domestic water heating can also be switched to heat pumps. If your loads are small, like most office buildings, you can consider heat pump water heaters to replace residential-style gas water heaters. Or if sinks are your main load, you can get by with small point-of-use instant electric resistance water heaters. For larger applications (hospitals, laundries, lodging for example) you’ll need to look at larger heat pump applications similar to the heating hot water options described above.
- Consider the refrigerant you choose for your new equipment.Heat pumps all use a reversible refrigeration cycle to produce heat efficiently. Refrigerants used by heat pumps are often potent global warming gases themselves and are under increasing regulations and market changes. Make sure that when you choose a heat pump, you’re picking an option that doesn’t undo the environmental impact you’re trying to make through electrification, and that the refrigerant you pick is going to be available throughout the expected life of your equipment.
Determine new power requirements and required modifications
Electrical space heating equipment will add substantial electrical demand to the building. At a minimum, modifications to the existing electrical panels (such as adding or upsizing additional breakers and running wire) will be required. In most scenarios, electrical switchgear will need to be added and/or the capacity expanded.
Determine the new electrical load
The calculated demand of the new equipment will add to the existing building demand. The existing demand can best be determined using meter data, installing monitoring equipment, or by performing detailed electrical load calculations. The resulting total building demand (including new loads) must be compared to the maximum capacity of the service agreement with your electric utility. If the new need exceeds the service agreement terms, you can try to lower loads by selecting different equipment, implementing energy efficiency measures, or by requesting additional service capacity from the utility.
Consider your electrical rate terms
Electric rates are complex, and the increased loads could mean that your old electrical rate is no longer the best choice for you. Rates across the U.S. have gotten increasingly focused on the magnitude and timing of your monthly peak demand (typically measured as the highest 15 minutes of consumption or peak kW draw). The added demand of new electrical equipment merits a re-examination of the best rate tariff for you, based on the new peak demands, when they occur, and your new expected service requirements. You may even want to look at potential long-term rate savings by purchasing your own transformer (taking service at a higher voltage is typically cheaper) especially if you’re essentially already paying for it through a service upgrade charge at the utility.
If you’re part of a Bay Area government, you may be eligible for free technical assistance to identify and implement electrification or other carbon reduction projects. You can find out more in this post.
Getting started with electrification of commercial buildings
To achieve your intended environmental impacts, while continuing to keep your buildings safe and comfortable, and not breaking the bank in the process, will take some careful planning. At kW, we’ve spent over 20 years helping clients finding cleaner (and usually cheaper) ways of meeting the heating and cooling needs of commercial buildings. Let us know if you need a hand.