Case study describing how adidas implemented a best practice of a planned replacement program for its rooftop units (RTUs), which resulted in significant cost and energy savings. The case study outlines the planning process, implementation, results, and the future plans of their RTU replacement program.
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This document lists a set of resources that can help small business owners make informed decisions about their energy use and identify opportunities for long-term financial savings from energy efficiency improvements. These resources include case studies, energy savings and investment calculators, technical guides and information on state and federal incentives programs.
Argonne’s Energy Efficiency Decision Support Calculator is a simple tool that small business owners can use to quickly analyze the high-level economic impact of investments in energy efficient products, retrofits or capital improvements. This tool requires minimal input data and is accessible to anyone, regardless of their experience with energy issues. It is intended to complement many of the more involved, technology specific calculators that are referenced in Argonne’s “Resources for Informed Small Business Energy Efficiency Decision Making.”
Regency Centers is a national owner, operator, and developer of neighborhood and community shopping centers with over 300 properties throughout the United States. Regency Centers recently upgraded the parking lot lighting at Rona Plaza in Santa Ana, California. Rona Plaza is a grocery-anchored shopping center with 52,000 square-feet of gross lettable area and 250 parking spaces across 77,000 square feet of parking area. Regency Centers retrofitted the existing parking lot and exterior wall mounted fixtures, which were high-intensity discharge (HID) fixtures, with high efficiency LED fixtures coupled with a wireless dimming system. The retrofit resulted in energy savings of nearly 88% compared to pre-existing conditions and was recognized by the Lighting Energy Efficiency in Parking (LEEP) Campaign with the Highest Percentage Energy Savings in a Retrofit at a Single Parking Area award.
The second largest gaming company in the world by revenue, MGM Resorts International (MGM) has recently installed energy efficient parking area lighting and controls at 65% of its U.S. facilities. With 20 U.S. facilities in NV, MI, and MS, MGM lighting projects have covered more than 8 million square feet of parking area. By replacing more than 4,400 existing metal halide and high-pressure sodium light fixtures in the parking facilities with a mixture of LED and induction fixtures, MGM saved 4.5 million kWh per year across their portfolio.
Most impressively, at the MGM Grand Detroit Casino–a 401-room hotel and gaming facility— the company achieved 4 million kWh of annual energy savings by replacing medium-wattage metal halide fixtures in a 2.6 million square foot parking structure with high efficiency, low- wattage LED fixtures.
This case study details the very successful Walgreens proactive RTU replacement program that has resulted in 50% efficiency improvements. The streamlined process allows Walgreens to reduce installed cooling capacity, increase RTU efficiency, provide improved service, and reduce overall costs compared to emergency replacements.
JCPenney saved over 47 million kWh and $5 million with variable frequency drive retrofits of rooftop units across 131 stores. The case study describes the decision process and results of this successful program.
The case study details how the U.S. Navy saved over 100 MWh annually with five year payback by installing advanced RTU control retrofit packages at Pearl Harbor, Hawaii.
In 2011, the U.S. Department of Energy’s Building Technology Office (DOE’s BTO), with help from the Better Buildings Alliance (BBA) members, developed a specification (RTU Challenge) for high performance rooftop air-conditioning units with capacity ranges between 10 and 20 tons (DOE 2013). In April 2013, Carrier’s 10-ton WeatherExpert unit model was recognized by DOE to have met the RTU Challenge specifications. Carrier also committed to have its entire line of WeatherExpert models for commercial buildings compliant with integrated energy efficiency ratio (IEER) meeting the RTU Challenge requirement. This report documents the development of part-load performance curves and their use with the EnergyPlus simulation tool to estimate the potential savings from the use of WeatherExpert units compared to other standard options.
A detailed EnergyPlus model was developed for a prototypical big-box retail store. The model used the performance curves from the new model along with detailed energy management control code to estimate the energy consumption of the prototypical big-box retail store in three locations. The energy consumption by the big-box store was then compared to a store that used three different reference units. The first reference unit (Reference 1) represents existing rooftop units (RTUs) in the field, so it can be considered the baseline to estimate potential energy savings from other RTU replacement options. The second reference unit (Reference 2) represents RTUs in the market that just meet the current (2015) Federal regulations for commercial equipment standards, so it can be used as the baseline to estimate the potential for energy savings from WeatherExpert units in comparison with new RTUs that meet the minimum efficiency requirements. The third reference unit (Reference 3) represents units that meet ASHRAE 90.1-2010 requirements. For RTUs with cooling capacity greater than 11,000 Btu/h, ASHRAE 90.1-2010 (ASHRAE 2010) requires two-speed fan control or variable-speed fan control.
The following conclusion can be drawn about the comparison of energy cost for WeatherExpert unit compared to the three reference units:
• Using Reference 1 as the baseline, WeatherExpert units result in about 45% lower heating, ventilation and air conditioning (HVAC) energy cost in Houston, 55% lower cost in Los Angeles, and 35% lower cost in Chicago. The percentage savings of electricity cost is more than 50% for all three locations.
• Using Reference 2 as the baseline, WeatherExpert units result in about 39% lower HVAC energy cost in Houston, 52% lower cost in Los Angeles, and 32% lower cost in Chicago. The percentage savings of electricity cost is 44%, 55%, and 57%, respectively for the three locations.
• Using Reference 3 as the baseline, WeatherExpert units result in about 25% lower HVAC energy cost in Houston, 35% lower cost in Los Angeles, and 18% lower cost in Chicago. The percentage savings of electricity cost is 29%, 38%, and 37%, respectively.
Based on the simulation results, the WeatherExpert RTU Challenge unit, if widely adopted, could lead to significant energy, cost and emission reductions. Because the cost of these units was not available and because the costs would be specific to a given installation, no attempt was made to estimate the potential payback periods associated with any of the three reference scenarios. However, if the incremental cost relative to any of the three reference cases is known, one can easily estimate a simple payback period.
Dollars saved through energy efficiency can directly impact your bottom line. Whether you are planning for a major renovation or upgrading individual pieces of building equipment, these improvements can help reduce operating costs, save on utility bills, and boost profits. This fact sheet provides a guide for small businesses to find the resources to increase the energy efficiency of their buildings.