Restaurants use about five to seven times more energy per square foot than other commercial buildings. High-volume quick-service restaurants (QSRs) may even use up to 10 times more energy per square foot than other commercial buildings. Restaurants generally use the most electricity for refrigeration, followed by lighting, then cooling. i
January last year, ASHRAE released the latest version of its benchmark energy efficiency standard, ANSI/ASHRAE/IES Standard 90.1-2022, Energy Efficiency Standard for Sites and Buildings Except Low-Rise Residential Buildings. The latest version includes an expanded scope for building sites and major additions appearing for the first time in a minimum-efficiency U.S. model energy standard or code. ii
The standard is for new construction or major renovation. It doesn’t apply to an existing building. Local jurisdictions also are not going to immediately adopt it. iii
Figure 1 Prototype QSR Building. vi
This article attempts to quantify the potential energy saving impact of adopting the new standard across the different US climate zones for quick service restaurants.
The Simulation Model
To simulate this effect, the Quick Service Restaurant model from the DOE Commercial Building Benchmark Models was used. iv The energy analysis was done using the latest publicly available version of EnergyPlus (23.1.0) which was also developed by the DOE and the National Renewable Energy Laboratory (NREL). v
Figure 2 Commercial product minimum efficiency requirements before 1/1/2023 and after. vii
The main change resulting from adopting the new standard in the energy analysis was for equipment capacity ≥ 65,000 < 135,000 BTU. For such equipment, the efficiency before vs. after were 11.0 EER/ after 14.6 IEER (~3.22 COP before / 4.28 COP after). Figure 2 below summarizes the minimum efficiency requirements under the new standard.
The Results
A total of sixteen different US climate zones were modeled as shown in Figure 3 below.
Figure 3 Climate zone classification. viii
The data was captured for 365 days a year, 24 hours a day and in 10 minutes intervals each hour, for 16 climate zones with two energy standard options: a total of about 1.7 million data points.
Figure (4) below illustrates the annual electricity consumption under the different standards based on the energy simulations. As expected, the analysis clearly illustrates the savings in energy consumption.
Figure 4. Annual Electricity Consumption. (Courtesy of ENERGY STAR)
Conclusion
Most quick-service restaurants create heat when they cook, but even when they are not cooking, equipment such as refrigerators are constantly creating heat. This means that HVAC accounts for 25 to 30 percent of the overall energy use in a quick-service restaurant at a minimum, and it could be more than 40 percent.
[i] U.S. Environmental Protection Agency and U.S. Department of Energy. Energy Star Energy Savings Tips for Small Businesses: Restaurants. August 27, 2020.
[ii] Karen Buckley Washington. Newly Released ASHRAE 90.1-2022 Includes Expanded Scope for Building Sites. ASHRAE. January 25, 2023.
[iii] Dave Lubach. Impact of ASHRAE 90.1 Standard Changes. Facilities Net. March 13, 2023.
[iv] Torcellini, P. et al. (2008). DOE Commercial Building Benchmark Models. National Renewable Energy Laboratory. https://www.energycodes.gov/development/commercial/prototype_models
[v] EnergyPlus, U.S. Department of Energy’s (DOE) Building Technologies Office (BTO) and National Renewable Energy Laboratory (NREL). https://energyplus.net/
[vi] Technical Support Document: 50% Energy Savings for Quick-Service Restaurants. U.S. Department of Energy. PNNL-19809. 2010.
[vii] Philip Smyth. 2023 Regulatory Requirements Guidebook. Johnson Controls. January 2022.
[viii] Deru, M. et al. (2011). U.S. Department of Energy Commercial Reference Building Models of the National Building Stock. National Renewable Energy Laboratory.
[i] Chloe Arrojado. How Restaurants Can Reduce HVAC Expenses by Up to 60 Percent. QSR Magazine. March 19, 2021.
Energy efficiency measures as outlined in the new ANSI/ASHRAE/IES Standard 90.1-2022 can help these restaurants save money and align with more environmentally conscious values.
[i] Chloe Arrojado. How Restaurants Can Reduce HVAC Expenses by Up to 60 Percent. QSR Magazine. March 19, 2021.
