Maria Karpman, Karpman Consulting; Michael Rosenburg, PNNL [for electroindustry, Vol. 24 No. 4, July/August 219]

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).

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.