Identifying Energy Auditing Process and Information Exchange Requirements for the Commercial Building Retrofit Sector

Transcription

1 737 Identifying Energy Auditing Process and Information Exchange Requirements for the Commercial Building Retrofit Sector Tabitha L. SPRAU COULTER 1, Jason HINSEY 2, Robert M. LEICHT 3, Michael G. WHELTON 4 and David R. RILEY 5 1 Pennsylvania State University, Department of Architectural Engineering, 104 Engineering Unit A, University Park, PA 16802; PH (814) ; tls420@psu.edu 2 Pennsylvania State University, Department of Architectural Engineering, 104 Engineering Unit A, University Park, PA 16802; PH (814) ; jwh278@psu.edu 3 Pennsylvania State University, Department of Architectural Engineering, 104 Engineering Unit A, University Park, PA 16802; PH (814) ; rmleicht@engr.psu.edu 4 Pennsylvania State University, Department of Architectural Engineering, 104 Engineering Unit A, University Park, PA 16802; mwhelton@psu.edu 5 Pennsylvania State University, Department of Architectural Engineering, 104 Engineering Unit A, University Park, PA 16802; driley@engr.psu.edu ABSTRACT With an increased emphasis on sustainable buildings, building owners have begun to demand better methods of predicting building system performance, in particular with respect to energy. A variety of energy modeling programs have been developed to meet the growing interest in energy efficient buildings. However, the energy modeling software is typically cumbersome to use and was designed to compare various system options for new construction. The retrofit sector of the building industry lacks a clearly defined energy auditing process and energy modeling tools developed specifically for retrofits. This research develops high level process models and the necessary information exchanges which can be utilized to develop a building typology tool for retrofit buildings. The study defines: (1) the need for a standard and transparent energy auditing process and modeling tools intended specifically for commercial retrofits; (2) typical vs. desired information flows (through an industry workshop) and a high level process model; and (3) initial criteria for a retrofit specific energy analysis methodology by determining which outputs and inputs are needed at the various stages to perform an accurate and useful energy assessment. INTRODUCTION Over the past several years, the building industry has begun to realize the benefits of a sustainable approach to building design and construction. With rating systems such as LEED, government funded incentives, and new tools to help make sustainable building projects run more efficiently; there has been a significant increase in the number of building owners who are opting to pursue sustainable design elements on their project (Tobias, 2009). Building owners are also beginning to recognize the sustainable benefits of investing in upgrading to more efficient

2 738 building systems through building retrofits (Tobias, 2009). The sector is not without challenges. The building renewal market now comprises of a growing and significant segment of the construction building industry. NEEA highlights the top 5 barriers to achieving deep energy renovation in commercial buildings: 1. A lack of localized, relevant financial best practices and tools, coupled with traditional lease structures that fail to monetize energy efficiency. 2. A scarcity of shared knowledge, common vocabulary, clear communication and collaboration to connect deep energy renovation benefits to values that matter to key stakeholders, e.g. sustainability, profitability, comfort, competitive advantage. 3. Complicated, non-standardized measurement and verification (M&V) of energy savings doesn t translate to key decision makers, such as lenders, owners and tenants. 4. Building owners lack motivation to connect building performance to a clear business case for energy efficiency. 5. The region lacks a predictable roadmap for opportunistic, whole-system efficiency measure integration that bundles investment strategies and building types with strategic energy management principles and practices. (NEEA, 2010) Between the increased emphasis on sustainable building designs, and increasing energy costs; building owners have a growing interest in reducing building energy consumption and improving the reliability of the projected energy consumption. Energy simulation tools designed for new construction are limited in their capacity to accurately model existing building conditions.... The programs were mostly developed to simulate new buildings where an absolute result was not expected and only comparative results were expected (Waltz, 2000). With the current energy modeling software and energy auditing processes, it is difficult to model actual energy consumption of the buildings at the system level and to model future building loads based on proposed system improvements. This makes it difficult for designers and building owners to perform effective screening audits. Screening audits are relatively quick energy analysis performed during the preliminary planning phase of a project to determine what building systems upgrades are most worthwhile, and to aid in the development of appropriate design and renovation scopes to maximize the return on investment from building system retrofits. By gaining a better understanding of the current energy auditing process, the research will develop a high level energy assessment (audit) process model and categorical information exchanges related to building systems. The research will also justify the future need to follow the energy auditing process on several retrofit projects to validate the required information and understand the auditing process. PROBLEM STATEMENT As mentioned above, the current energy modeling programs and energy auditing process are very complex and produce unreliable results, especially for retrofit of buildings. While there are energy modeling programs available, there lacks a clear Big Picture understanding of the interrelationships of energy audit information and each energy modeling programs capabilities. And while the benefits

3 739 of integrated project deliver has been confirmed, there lacks an understanding of how the integrated concept should be applied to energy audits. There are industry members performing energy audits, and certifications but there lacks an industry standardized process, procedures, and methods with many firms developing proprietary approaches for performing energy auditing. This is particularly true for the retrofit building sector which lacks a retrofit specific, interoperable, easy to use energy modeling path to aid in the design for retrofit process. The variability of the available modeling tools is demonstrated in Table 1 through the comparison of inputs from energy modeling tools used by two different companies. These tools were benchmarked against the important systems outlined by the certified energy management (CEM) program. The tools are referred to simply as Energy Modeling Tool 1 and Energy Modeling Tool 2 since they are trademarked property of their specific companies. Table 1. Comparison of Energy Modeling Tool s Inputs System Information Included in Energy Modeling Tool Energy Modeling Tool 1 Energy Modeling Tool 2 Inputs for accurate Energy Predictions (as outlined in CEM) Gross Floor Area X X X Number of Floors X X X Year Built X X Location X X X Building Occupancy X X X Weather (Daily Temperatures) X X X Electricity X X X Natural Gas X X Fuel Oil X X X Energy Cost X X X Maintenance X X Control Strategies X X Building Materials X X X HVAC System X X Electrical Supply System X Lighting System X X Boiler & Steam System X Hot Water System domestic X X Compressed Air System X Motors X X Special Purpose Process Equipment X X Water & Sewer System X Without a clear understanding of the impact retrofit upgrades will have on a building, owners are unable to justify making improvements to their existing building or justify financing for the upgrades. The retrofit building industry lacks an initial screening audit tool. A theoretical screening audit tool would need significantly less inputs then a full energy modeling tool such as equest and contain a matrix which would aid owners throughout their initial decision making processes. The development of energy modeling screening tools designed specifically for retrofit buildings which are easier to use and less time consuming, would help building designers and owners understand their buildings energy performance.

4 740 Similarly, a processs model that clearly illustrates what data inputs need to be collected at each point throughout the performance e of an energy audit on retrofit buildings would make the auditing process more transparent and run more efficiently. In particular, the ability to perform not one, but an appropriate series of energy analyses whichh would build and feed appropriate information downstream to the design assessment and retrofit design process in a reliable manner is a critical step, which this process model is intended to facilitate. RESEARCH METHODO OLOGY The intent of this research is to determine more precise data requirements for a retrofit specific energy auditing process and energy modeling tools to make the flow of information from the existing building itself, through the buildings metering tools, to the energy auditing tools more efficient and informative to the assessment and design team(s). Figure 1 shows the ideal flow of energy auditing building data and how this information should be in an open standardd formation, such as Industry Foundation Class (IFC). The current energy modeling software programs were evaluated to demonstration whether or not these programs weree capable of accommodating for the differences between new construction and retrofit projects. Figure 1. Ideal Flow of Information for Energy Audits One observed gap between the current auditing tools and the information requirements necessary to model a potential retrofitt project is there inability to model existing systems which have potentially become more inefficient overtime. After the initial research was completed and the information gaps were identified, Penn State University and the Department of Energy co-hostedd a workshop, Defining the Integrated Process, in the Philadelphiaa Navy Yardd for academic researchers and industry members actively involved with the BIM and sustainable building industries. In an effort to identify whether the current retrofit energy auditing process was perceived by industry members to be sufficient, workshop participants partook in tasks which involved outlining the ideal integrated design, construction, and operation and maintenance process for retrofits; andd identifying information exchanges and key attributes that would help improve the building industry. Table 2 on the following page provides background information on the workshop participants.

5 741 The workshop confirmed that the industry currently lacks an appropriate level of information flow from the building systems to the energy modeling programs. The workshop sessions were also used in confirming the clear lack of integration of energy audit information into the design process. The designers identified challenges in the understanding of when energy audits should be performed, what data should be collected for the energy auditing, how the data should be collected, and how this data would be used to perform design functions. The knowledge gained at the workshops was used in conjunction with the information gained from the initial research, to develop a high level energy auditing process. This data was used to make an initial attempt at comparing what inputs and outputs currently occur at the various stages of an energy audit to those that should be collected during each phase of the process. Table 2. Demographics of Workshop Participants Percentage of total Workshop Participants (47 total participants) Industry Members 36 % GPIC Members (a combination of researchers from industry and academia) 64% Focus Areas Represented HVAC Designer Architect LEED Coordinator Lighting Designer Electrical Designer Energy Specialists Construction Management BIM Specialist Energy Management (Auditors) Process Mapping Researchers LEED Enclosure and Material science Lighting Systems ENERGY AUDITING Energy auditing is a process which... assesses facility systems, observes site conditions, analyzes and evaluates equipment and energy usage, and recommends strategies to reduce energy, water and associated costs to help clients meet established goals. ( Job/Task Analysis..., 2011) ) There is a lot of data that can be collected during an energy audit which includes information from energy bills, data from building metering devices, and information that can be gathered from doing a building walk through. Due to the lack of a transparency and a process map which shows the ideal energy auditing process, particularly for retrofit buildings, each individual or organization performs their energy audits a little differently. While there are a vast variety of processes of performing energy audits, most individuals will agree that there are four phases of an energy auditing (Figure 2): 1. Screening Audit(s) 2. Low Fidelity Modeling and Assessment 3. Detailed Whole Building Audit(s) 4. Design Retrofit Programming & Analysis Full energy audits are time consuming and costly (level 3 on the previous page). Depending on the contractual agreement between the building owner and the individual performing the energy audit, energy audits are often viewed as a sunk cost which is recovered through the fees made on the retrofit.

6 742 Figure 2. High Level Map of Energy Auditing for Retrofit Buildings To prevent an individual or organization from performing time consuming, detailed whole building energy audits that may not lead to the organizationn being rewarded a retrofit job, an energy screening audit followed by an initial energy assessment can be performed. The energy screening audit usess initial energy data to evaluate the current building to determine whether there is potential savings to be achieved warranting performance of a detailed whole building audit. The energy screening audit and initial energy assessment for commercial retrofits should be performed during the discovery phase of design andd construction but there lacks a reliable screening audit tool for retrofit buildings. By improving the reliability of the screening audit feeding initial energy modeling decisions for projecting design options and reducing the effort to perform a screening audit, the cost and reliability of the whole process can be improved. COMPLEXITIES IN THE DESIGN OF RETROFIT BUILDINGS When designing a building s infrastructure,, there are many facets that need to be taken into account. A building design team typically consists of architects, interior designers, structural engineers, and HVAC, electrical and related system engineers. These team members have to work together to produce a building that is both functional and aesthetically pleasing. A building design team must consider the complexities of how all these building system and components work together. Integration and collaboration among the various building stakeholders is especially important for buildings pursuing any level of sustainability (Korkmaz, 2007). Retrofit buildings require the building designers to consider some issues that are not present in traditional new construction building projects: Evaluation and benchmarking of the previous building systems What building updates are necessary to meet new building requirements? Is the building currently occupied? What portion of the building is being renovated?

7 743 ENERGY MODELING SOFTWARE One of the most important aspects of the assessment process is the actual energy modeling process and the software used to predict building performance. Some of the most commonly used energy modeling programs include equest, Energy Plus and Design Builder. These programs serve as a great starting point in terms of energy prediction abilities but there remains room for improvement. (Grondzik, 2010) One of the most notable challenges is that the energy modeling programs currently being used are difficult to operate. They require extensive knowledge of both the software program and of the building system components. A large number of manual input windows increase the possibility of user error. Since the energy modeling programs are so resource intense, the individuals constructing the models tend to continuously compare the same typical systems rather than optimizing the investigation by evaluating additional systems that may be more energy efficient. The current energy modeling programs were created primarily for comparing the energy consumption of various systems in new buildings and while they are good for comparison, they do not accurately predict energy performance (Dahl, 2008). The retrofit building industry needs tools and methodology that enable energy performance evaluation and projections more accurately and reliably. When building owners decide to upgrade their facilities, they are making an investment in their building and they want to know when the upgrades will provide a known, reliable return. If an owner is unaware of the type of energy savings their building upgrades will produce, they cannot justify the upfront renovation costs. DEFININING THE INFORMATION EXCHANGES With evidence that the current retrofit energy auditing process needs significant improvement, it is essential to begin identifying the information needed at each of the stages to improve the flow of information. The initial approach taken is to begin at the energy modeling stage and work backward to determine what data needs to be collected during each phase to obtain the desired outputs (Table 3 and 4). Table 3. Initial Screening Energy Auditing for Retrofits, Inputs and Outputs Initial Screening Energy Auditing for Retrofits Current Energy Audit Process Proposed Energy Auditing Process Inputs Outputs Inputs Outputs Information from the building owner regarding the current building systems and desired systems 1 to 3 previous years energy bills Decision of whether or not to proceed with a retrofit with little concrete data to prove how improvements will alter the buildings energy performance Tools Blower door tests Visual checks of basic building systems Building Size Building Type Building Location Weather Data Basic Building System Information 1 to 3 previous years energy bills Accurate energy profile of current conditions Comparison of building to standard building & systems Comparison of current building to proposed upgrades Metrics that compare retrofit improvements for buildings energy performance Tools Typical system energy profiles and typology of buildings by use and system make-up

8 744 Table 4. Whole Building Energy Auditing for Retrofits, Inputs and Outputs Detailed Energy Audit for Retrofits Current Energy Audit Process Proposed Energy Auditing Process Inputs Outputs Inputs Outputs Building Size Building Type Building Location Basic Building Systems Information Proposed System Improvements Inaccurate energy profile for current building system Tools Energy modeling tools such as equest, Energy Plus and Design Builder Building Size Building Type Building Location Detailed Building Systems Information Proposed Building System Improvements Targeted system monitoring Accurate energy profile of current conditions Comparison of current building to base building Comparison of current building to proposed system upgrades Tools Energy modeling tools that are capable of accounting for the complexities associated with retrofit buildings When developing the tables, focus was placed on the auditing steps because without the proper information being collected during the audits, the initial energy assessment, and the programing and design analysis will be inaccurate. The main finding from the development of the input and output tables is the lack of tools which adequately assess the retrofit feasibility of commercial buildings. RESEARCH LIMITATIONS The research presented has been based on a combination of existing literature, discussions and outcomes from an industry workshop, and studies of companies energy auditing processes. While all of the data collected identifies a need for a retrofit specific energy auditing process, the energy auditing process on several retrofit projects will be followed to further validate the required information and process steps of the high level process model along with the need for better retrofit energy auditing resources. Observing the current energy auditing process on several retrofit buildings, will also allow for the identification of any additional problems with the auditing process that need to be addressed. RESEARCH SUMMARY The data collected verified there are gaps between the capabilities of the current energy auditing tools and what is needed for a retrofit energy auditing tool. The industry lacks an energy auditing tool which is able to produce quick building profile data during the initial screening audit. Similarly, energy audits currently focus on system specific upgrades rather than examining the benefits of a fully integrated retrofit design. The development of a building profiling tool would help building owners and designers make more informed decisions about which buildings offer the best opportunities to upgrade based on the buildings projected energy performance data. The research also verified that the current energy auditing process lacks integration and transparency as retrofit planning transitions into retrofit design, particularly in a manner which support integrated and high performance outcomes. Further validation and development of a detailed process map which clearly indicates

9 745 what information needs to be collected and when that data should be collected would help to significantly improve the auditing process for retrofit buildings. FUTURE RESEARCH Just as it is important to perform an initial screening energy audit, it was important to perform an initial research study to verify the need for a more in-depth analysis of the current retrofit energy auditing process. This report is intended to: Serve as justification for the development of a more detailed and validated energy auditing process model which supports an integrated design process for retrofit projects. Begin to outline the data requirements for each energy auditing phase. Identify the need for more a streamlined flow of information, whichh will likely require new tools designed explicitly for commercial retrofit buildings And, serve as a starting point for a more in-depth retrofit buildings. analysis of the current energy auditing process for commercial Figure 3. Building Profiling Tool Example Once a more in-depth analysis of the energyy auditing process for retrofit buildings has been performed, steps will be taken too develop the methodology and tools to support reliable design for energy efficient retrofit buildings. Data will be collected to develop a building typology data base. This data will be then used to develop a retrofit specific initial screening energy audit building profiling tool. Figure 3 showss data input windows for the retrofit screening audit tool. After an energy auditing process and easy to use screening tool for retrofit buildings has been developed, case studies will be used to test the proposed Building Typology

10 746 Profiling Tool and further improve on the developed energy auditing process. The desired end results is a meaningful building profiling tool which can quickly and easily be used during the initial screening energy audit to show how the building being audited compares to a similar baseline building in terms of energy consumption and how various system retrofit options would impact the buildings overall energy performance. The profiling tool will break down the building s energy usage according to major systems and subsystems so that the areas where improvement is needed can be quickly identified. REFERENCES Dahl, P. (2008). Managing end-user feedback in sustainable project delivery. The Pennsylvania State University: The Graduate School Department of Architectural Engineering. Doctor of Philosophy, A Thesis in Architectural Engineering. Defining the integrated process (2011). Workshops Co-hosted by Penn State University and the Department of Energy. Organized by John Messner, Robert Leicht, and Muscoe Martin, Philadelphia, Pennsylvania: Oct Job/Task analysis for a commercial building energy auditor: public comment draft (2011). U.S. Department of Energy: Energy Efficiency & Renewable Energy. < buildings/commercial _initiative/pdfs/energy_auditor_jta_comment.pdf> (Feb., 2012). Grondzik, W., Kwok, A.G., Stein, B., and Reynolds, J.S. (2010). Mechanical and electrical equipment for buildings. 11 th edition. John Wiley & Sons, Hoboken, New Jersey, Korkmaz, S. (2007). Piloting evaluation metrics for high performance green building project delivery. The Pennsylvania State University: The Graduate School Department of Architectural Engineering. Doctor of Philosophy, A Thesis in Architectural Engineering. Northwest Energy Efficiency Alliance (NEEA) (2010). Existing building renewal: deep energy renovation planning workshop summary report. Portland, Oregon. Tobias, L., and Vavaroutsos, G. (2009). Retrofitting office buildings to be green and energy-efficient. Optimizing building performance, tenant satisfaction and financial return, Urban Land Institute, Washington, DC. Waltz, J. P. (2000). Computerized building energy simulation handbook. Liburn, Georgia.