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.
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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 FY14, BTO funded PNNL to develop and integrate AFDD methods for both air-side and refrigerant-side fault detection and diagnostics with one of the leading advanced RTU controllers sold in the market today. The work also includes testing and validating the integrated solution in the field. If the results from the field demonstrations show reliable fault diagnostics, it will encourage utilities to provide incentives to pursue the integrated technology because it makes the retrofit controller more cost effective and could make market adoption of the retrofit controller even more attractive to building owners.
Seven AFDD algorithms were developed, deployed and tested on the RTU controller for detecting and diagnosing faults with RTU economizer and ventilation operations using sensors that are commonly installed for advanced control purposes.
This guide covers each major step in procuring a solar photovoltaic (PV) system:
- Conducting technical and financial studies
- Financing a PV system
- Project execution
- Operations and maintenance
- Assessing benefits
The guide provides information on the basic steps, key considerations, and where to go for more information. It is intended to provide an overview and some level of detail, with pointers to highly detailed information and resources.
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.
The commercial real estate mortgage market is enormous, with almost half a trillion dollars in deals originated in 2015. Relative to other energy efficiency financing mechanisms, very little attention has been paid to the potential of commercial mortgages as a channel for promoting energy efficiency investments. The valuation and underwriting elements of the business are largely driven by the “net operating income” (NOI) metric – essentially, rents minus expenses. While NOI ostensibly includes all expenses, energy factors are in several ways given short shrift in the underwriting process. This is particularly interesting when juxtaposed upon a not insignificant body of research revealing that there are in fact tangible benefits (such as higher valuations and lower vacancy and default rates) for energy-efficient and “green” commercial buildings.
This scoping report characterizes the current status and potential interventions to promote greater inclusion of energy factors in the commercial mortgage process. It includes the results of
a literature review and extensive stakeholder discussions with 40 lenders, owners, service providers, advocacy organizations and others.
This fact sheet discusses NREL's production of conceptual microgrid designs—plans for electrical generation and distribution systems capable of autonomous operation—that deliver reliable, economical, and sustainable energy.
The text below includes sample language and potential resources that may be used to complete appraisals of a green or high performance building. It is not intended to serve as a complete or comprehensive list, and should be utilized as a guide aid in the development of the appraisal report. Highlighted sections represent those that require specific attention from appraisers, and should be customized as necessary to reflect the actual resources and information used during the appraisal process.
This guidance walks building owners through five steps to obtaining an appraisal that evaluates the energy efficiency benefits
of high performance buildings. This may help obtain favorable terms with a lending institution.
STEP 1: Gather the information a lender or appraiser will need to analyze your property.
STEP 2: Provide contact information for development or retrofit professionals involved with the property.
STEP 3: Ask questions at the time of your loan application.
STEP 4: Review the completed appraisal closely – and objectively.
STEP 5: Ask follow-up questions regarding the appraisal report.