Technical Support Document: 50% Energy Savings for Quick-Service Restaurants

Abstract

Building Technologies Program (DOE/BTP). According to DOE, buildings account for over 40% of total energy use and over 70% of electricity use in the United States. To reduce building energy usage, DOE/BTP established a strategic goal to significantly improve the energy efficiency of new and existing commercial buildings across the nation.In direct support of DOE's goal, the objective of this work is to develop a package of energy efficiency measures (EEMs) that demonstrates the feasibility of achieving at least 50% energy savings for quick-service restaurants (QSRs) with a simple payback of five years or less. As defined, the 50% goal involves reducing site energy usage in all eight U.S. climate zones, relative to buildings constructed to just meet minimal code-compliant requirements of ANSI/ASHRAE/IESNA Standard 90. 2 ) QSR building model that was based on actual floor plans in prototypical QSR design drawings. PNNL used EnergyPlus, a state-of-art energy simulation program, to determine the energy savings provided by the EEM package. The prototype building was analyzed in all eight U.S. climate zones that were further divided into moist, dry, and marine regions in which 16 representative climate cities were identified. The TSD establishes the baseline energy use by end-use category in a typical QSR, and provides the site energy and energy cost savings from implementation of the recommended EEMs. Finally, this TSD provides an estimate of the incremental first costs and simple payback years for an energy-efficient QSR in various climate locations. Table ES.1 summarizes the recommended EEMs for QSRs. Implementation of these EEMs can achieve a weighted-average energy savings of 45% across the nation, ranging from 41% to 52% by climate zone. Cost-effectiveness analysis to implement the EEMs shows a payback period ranging from 1.5 years to 3.5 years, depending on the climate location. These results are summarized for the 16 representative cities in Table ES.2.The project goal was to enable QSRs to achieve whole-building energy savings of at least 50% across all eight U.S. climate zones. Although we found that a national-weighted-average energy savings of 45% can be achieved, only the two coldest climates were able to reach the 50% energy-saving target. The key reason is that QSR is a special building type in which energy use is driven by very intensive process loads (i.e., the energy used for food preparation and storage). Process loads constitute 45% to 65% of wholebuilding energy consumption in a typical QSR. We have achieved significant energy savings in this area with optimized kitchen ventilation system and innovative food preparation/storage technologies ( Figure ES.1), but technologies are not yet available (from multiple vendors) to allow us to attain the 50% energy savings goal in all climate zones. If the process loads are removed from Figure ES.1, the energy savings from the building-related components are well beyond the 50% energy saving goal, ranging from 55% in warm climates to 65% in cold climates. i...

End-Use Savings Shapes: Measure Documentation: Add Exhaust Air Heat/Energy Recovery

“…Some building types, such as food service buildings, may be less suitable for adding energy/heat recovery retrofits because most of the building exhaust tends to occur through bathroom and kitchen exhaust hoods. A PNNL technical document for reducing energy usage in quick-service restaurants recommends using runaround energy recovery coil to utilize the large amount of heat available in kitchen exhaust air [12]. However, the study does not discuss the practicality of such a measure given the quality of kitchen exhaust.…”

Advancing Urban Building Energy Modeling: Building Energy Simulations for Three Commercial Building Stocks through Archetype Development

“…As the PE for food sales and services was not calculated due to unavailability of the actual data, we compared the results with the existing literature. The variation was 8% according to Zhang et al [66] for the same climate zone in the US. In addition to calculating the PE, a two-sample Kolmogorov-Smirnov (KS) test was performed to analyze the similarity of distributions of the simulated and actual EUIs.…”

“…Both the PE and KS results demonstrate the validity of the UBEM-simulated results and prove that they can be adopted by Pittsburgh for further energy planning and conservation strategies. The low PEs for both sales and shopping and healthcare facilities were likely because of the experiences of the research team in characterizing archetypes with greater similarity to real-world operation and the availability of representative input parameters, especially found in [66,67]. The errors for both building stocks were almost similar and could mainly be traced to various occupant-related inputs and internal equipment.…”

Restaurant Energy Use Benchmarking Guideline

“…Zones in a building, especially in a food service facility, may have different balance points. The energy used by food service appliances is typically 30%-50% of total building energy (Claar et al 1985;Smith et al 1999;Smith and Fisher 2001;Zhang et al 2010). Some of this energy leaves the building through kitchen exhaust, exfiltration through drive-through windows, and with take-out orders.…”