Technical Support Document to Facilitate Adoption of ASHRAE Standard 90.1 Performance Rating Method (PRM)
Maria Karpman, Karpman Consulting; Christina LaPerle, Karpman Consulting; Michael Rosenberg, Pacific Northwest National Laboratory [for U.S. Department of Energy November 2023]
This report describes solutions to the common PRM adoption challenges, including calculating energy savings by fuel type and electricity demand savings relative to current code and avoiding “fuel switching” when reporting savings of the proposed design relative to the current code. The calculations described in this technical support document are automated in the ASHRAE Standard 90.1 Performance Based Compliance Form and the Compliance Form Companion Tool described above.
National BEM Certification Scoping Study
Maria Karpman, Karpman Consulting; Christina LaPerle, Karpman Consulting; [for .S. Department of Energy (DOE) and the USA chapter of the International Building Performance Simulation Association (IBPSA-USA), September 2023]
This report investigates the feasibility of forming a national certifying body that will establish and oversee the quality assurance and quality control (QA/QC) framework for code and beyond-code programs that use building energy modeling. The primary goal of such a certifying body would be to help improve consistency, market acceptance and penetration of compliance modeling.
The research involved surveying 5 jurisdictions and 15 beyond-code programs to understand their project volume, modeling requirements, building energy modeling (BEM) tools acceptance practices, modeler and reviewer qualification requirements and quality control and quality assurance process. In addition, three national certification programs were reviewed including ASHRAE BEMP for energy modelers, IRS Section 179D for simulation tools, and Residential Energy Services Network (RESNET ®) Home Energy Rating System (HERS) for simulation tools, modelers, reviewers, training providers and projects.
The report discussed lessons learned from past certification efforts, and identifies opportunities to follow RESNET’s successful approaches in the residential sector and apply them to the commercial sector. The report also presents a roadmap for establishing market-based BEM software, modeler and reviewer certifications for commercial and multifamily buildings.
All Hands On Deck: Raising the Bar on Whole Building PerformanceBased Code Compliance and Above-Code Programs
Maria Karpman, Karpman Consulting; Michael Rosenberg, Pacific Northwest National Laboratory; Bing Liu, Northwest Energy Efficiency Alliance; Jeremiah Williams, U.S. Department of Energy [for 2020 ACEEE Summer Study August 17-21, 2020]
ABSTRACT: In 2019 a large-scale national effort was launched with support from U.S. Department of Energy, Pacific Northwest National Laboratory (PNNL) and Northwest Energy Efficiency Alliance (NEEA). The project aimed to develop a long-term vision and a roadmap for achieving a practical application of whole building performance-based code and above code program compliance in commercial buildings. The work was aided by engaging over 70 stakeholders across the country representing jurisdictions, above-code programs such as LEED and ENERGY STAR Multifamily Program, members of ASHRAE Standard 90.1 and other Standard committees, IBPSA and developers of all major energy simulation tools. The performance path requires whole building energy modeling and is gaining momentum. Many see it as the future of the commercial energy codes and the main pathway for achieving zero energy buildings. The paper describes the findings from a stakeholder survey on the current state of performance-based path, its market penetration, trends, implementation practices and adoption challenges. It discusses the patterns revealed by experience of the states with decades-long history of performance-based compliance such as Florida and California and opportunities for taking advantage of the synergies between code and above-code programs. In addition, the paper provides an overview of the tools and resources developed as part of the effort including the compliance form for ASHRAE Standard 90.1 Section 11 and Appendix G, modeling submittal review manual, and modeler and reviewer qualification requirements. The tools and resources would help remove market barriers, deliver immediate benefits to jurisdictions and rating authorities, and achieve energy efficiency through whole-building performance path.
Quality Assurance and Quality Control of Building Energy Modelling for Program Administrators
Maria Karpman, Karpman Consulting & Michael Rosenberg, Pacific Northwest National Laboratory [for Northwest Energy Efficiency Alliance (NEEA) January 2020]
ABSTRACT: Building energy modelling (BEM) is increasingly used to certify green buildings, establish incentives for utility programs, document compliance with energy codes, optimize the design of new buildings, and inform project retrofits. It is viewed as an essential tool for achieving carbon-neutral and net zero designs. The majority of projects that use BEM complete it as part of their participation in a BEM program, such as Leadership in Energy and Environmental Design (LEED), utility incentive programs for new and existing buildings, and energy code compliance. Thus, technical policies of these programs shape the marketplace’s understanding of the applications and value of energy modelling and set the standard practice for BEM services.
Buildings are complex systems composed of numerous interacting components that are influenced by external factors such as weather and occupant behaviour. BEM tools use physics-based equations to calculate building energy use at hourly or subhourly timesteps.
Program administrators use a variety of tools and practices to mitigate these challenges. They develop the supplemental modelling requirements and standardized compliance forms, and establish methodologies for verifying achieved performance and reviewing submittals. However, these quality assurance (QA) and quality control (QC) frameworks are created for specific BEM programs, with little cross-pollination between program administrators and no consistent methodology for evaluating outcomes. A new standard that takes a holistic approach to mitigating the implementation challenges of BEM programs would improve the quality and consistency of modelling outcomes and increase the BEM programs’ administration effectiveness.
Building Energy Modeling Has Its Place
Maria Karpman, Karpman Consulting; Michael Rosenburg, PNNL [for electroindustry, Vol. 24 No. 4, July/August 2019]
ABSTRACT: Buildings are complex systems composed of numerous interacting components that are influenced by external factors such as weather and occupant behavior. Building energy modeling (BEM) tools use physics-based equations to calculate building energy use at hourly or sub-hourly timesteps. Typical applications of energy modeling include optimizing building designs, documenting compliance with energy codes, demonstrating above-code performance for programs such as LEED, and evaluating the cost-effectiveness of building retrofits. Millions of dollars in utility program incentives are awarded to projects based on their modeled performance. The American Institute of Architects (AIA) emphasizes the role of energy modeling for achieving carbon-neutral buildings: “Our numbers continue to demonstrate that energy modeling is an essential component of success” (AIA’s 2030 by the Numbers—2016 summary).
Building System Efficiency Modeling— Improving the Accuracy of Building Energy Modeling
Maria Karpman, Karpman Consulting; Contributions made by: Chris Balbach, Performance Systems Development; Michael Patterson, Trane; Caitlin Bohnert, Trane'; Delia Estrada, Trane [for 2018 National Electrical Manufacturers Association, NEMA BE P1-2018]
ABSTRACT: Building energy modeling (BEM) tools are used to document compliance with energy codes, in green building certification, for incentive programs, to help optimize new designs, and to inform project retrofits. Organizations like ASHRAE and AIA advocate for the wider use of energy modeling, viewing it as essential for achieving low-energy and net-zero energy buildings. However, discrepancies between modeled and actual building performance have been widely reported, reducing credibility and bringing into question the feasibility of relying on energy models for decision-making.
This paper explores reasons for disagreements between the actual and modeled energy use for several building systems, including lighting, motors, and controls. It highlights substantial uncertainty in the impactful modeling inputs for these systems related to occupant behavior, building operation, and actual versus ideal performance. It also reviews the selected capabilities of the simulation tools, including eQUEST, Trane TRACE, IESVE, EnergyPlus, and OpenStudio based on the input from tool vendors, developers, and users.
ASHRAE Standard 90.1 Performance Rating Method, PHIUS+, and PHI Comparative Evaluation Study
Maria Karpman, Karpman Consulting; Shelley Beaulieu, TRC Energy Services; [2017 ASHRAE Building Performance Analysis Conference, Atlanta, GA, September 27-29, 2017]
ABSTRACT: NYSERDA legacy multifamily new construction program required projects to meet or exceed the requirements of EPA Energy Star Multifamily High Rise Program (EPA MFHR), an approach which requires whole building energy modeling based on ASHRAE Standard 90.1 Performance Rating Method (PRM). The approach advocated by the Passive House community to design and construct high performance multifamily housing aligns with broader efforts associated with NYSERDA Clean Energy Fund. The comparative analysis was initiated with the goal to allow any one of these alternative protocols to establish eligibility for a given building design to receive the financial support available through NYSERDA Multifamily New Construction Program, as well as other New York State and New York City housing agencies, irrespective of the protocol followed. This comparative study was completed with significant support from the Passive House community, including representatives from both PHIUS & PHI.
The energy modeling was based on the DOE / PNNL High-rise Apartment Prototype modified to reflect several variations of high performance multifamily designs typical for New York. All configurations were modeled in each protocol by independent teams with expert knowledge of Appendix G, PHIUS+, and PHI protocols and simulation tools. All models were shared between the teams to enable peer review.
The results produced by the three protocols for each modeled configuration highlighted significant differences between the methods, with App G predicting the highest energy use for all cases, and PHI resulting in the lowest prediction of energy use. The more optimistic assumptions for occupant behavior and energy used by systems and equipment that are not inherent in building design, such as consumer electronics and in-unit lighting, compared to those prescribed in the EPA MFHR Simulation Guidelines, was the key contributor to the trend. Difference in the modeling rules was another important factor. For example, the Passive House protocols allow credit for the manual controls, such as lowering the window blinds to reduce solar radiation, or opening windows to provide free cooling, whereas only automatic controls that are inherent in design can contribute toward savings following the App G method. Capabilities of the simulation tools used by each protocol were compared based on the software requirements of ASHRAE Standard 90.1 Section G2.2.1. The impact of the units used to express building performance was also examined. The study results and methodology may be used to establish equitably stringent performance thresholds for the three protocols.
Feasibility Study to Investigate Translational Capacity of the Selected Whole Building Rating Systems
Bing Liu, PE, PNNL; Michael Rosenberg, PNNL; Gail Hampsmire, Green Business Certification Inc; Maria Karpman, Karpman Consulting; [IBPSA Building Simulation 2017 Conference, San Francisco, CA, August 7-9, 2017]
ABSTRACT: The report describes comparative testing of the whole building asset rating systems including ASHRAE Standard 90.1 2016 Performance Rating Method, Building Energy Asset Score, and ASHRAE Building EQ As-Designed, and operational rating systems including ASHRAE Building EQ In-operation and EPA Portfolio Manager. The work was completed in the framework of the National Labeling Group (NLG) facilitated by NYSERDA, that included stakeholders representing states, municipalities, organizations and technical experts involved in the building ratings and benchmarking. The overarching goal of the NBLG was to inform the benchmarking laws, and explore feasibility of a generic building label that may be used in conjunction with the different rating systems, and express the building performance metrics in a uniform way independent of the rating system used. It was envisioned that this approach would eliminate the market confusion from the difference in scoring used by the individual rating systems, while giving adopters the flexibility to choose which rating system(s) can be used in conjunction with the generic label in the given program or jurisdiction.
Feasibility of the concept depends on whether it is possible to map the native scores or grades produced by the rating systems to the generic efficiency descriptor(s). The study focused on establishing the general agreement between the rating systems, and exploring the possible mapping.
Research and Development of the Energy Point System
Maria Karpman, Karpman Consulting [for New York State Energy Research and Development Authority, October 12, 2012]
ABSTRACT: The report outlines the concept and development methodology of the Energy Point System (EPS) intended for consideration as an alternative path of compliance with the Energy Conservation Construction Code of New York State (ECCC NYS) for retrofit projects. The EPS allows performance trade-offs between systems included in the scope of the retrofit while avoiding the expense of energy modeling, which is often not justified for smaller retrofit projects.