1、Shanti Pless is a senior research engineer and Paul Torcellini is the group manager in the commercial building group at the National Renewable Energy Laboratory, Golden, CO. David Shelton is Senior Vice President for DesignSense Incorporated, Olathe, Kansas. Using an Energy Performance Based Design-
2、Build Process to Procure a Large Scale Replicable Zero Energy Building Shanti Pless Paul Torcellini, PhD, PE Dave SheltonASHRAE Member ASHRAE Member DBIA Member ABSTRACT This paper will review a novel procurement, acquisition, and contract process of a large-scale replicable net zero energy (ZEB) of
3、fice building. The owners (who are also commercial building energy efficiency researchers) developed and implemented an energy performance based design-build process to procure a 220,000 ft2 office building with contractual requirements to meet demand side energy and LEED goals. We will outline the
4、key procurement steps needed to ensure achievement of our energy efficiency and ZEB goals using a replicable delivery process. The development of a clear and comprehensive Request for Proposal (RFP) that includes specific and measurable energy use intensity goals is critical to ensure energy goals a
5、re met in a cost effective manner. The RFP includes a contractual requirement to meet an absolute demand side energy use requirement of 25 kBtu/ft2, with specific calculation methods on what loads are included, how to normalize the energy goal based on increased space efficiency and data center allo
6、cation, specific plug loads and schedules, and calculation details on how to account for energy used from the campus hot and chilled water supply. The RFP also provides for stretch goals, such as reaching net zero energy. Additional advantages of integrating energy requirements into this procurement
7、 process include leveraging the voluntary incentive program, which is a financial incentive based on how well the owner feels the design-build team is meeting the RFP goals. We will also discuss how the RFP substantiation requirements that are required throughout the process are critical to ensure t
8、hat what is actually being built matches the energy model inputs. INTRODUCTION The National Renewable Energy Laboratorys (NREL) mission is to advance the U.S. Department of Energys (DOE) and the nations goals in the areas of energy security, environmental quality, and economic vitality. Today, build
9、ings use roughly 39% of total U.S. energy consumption (22% residential, 18% non-residential), with energy consumption in this sector projected to grow by almost 30% in the next two decades. While energy efficiency and renewable energy integration in buildings are increasing over time, new buildings
10、are being built and energy use in existing buildings is increasing at a high enough rate to outweigh the replacement of the building stock over time. In response to this need, the Federal LV-11-C045 2011 ASHRAE 3732011. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.
11、(www.ashrae.org). Published in ASHRAE Transactions, Volume 117, Part 1. For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAES prior written permission.government is beginning to increase the requirements for fed
12、eral high performance buildings. In an October 5, 2009, executive order, President Obama instructed the Federal government to “implement high performance sustainable Federal building design, construction, operation and management, maintenance, and deconstruction by, beginning in 2020 and thereafter,
13、 ensuring that all new Federal buildings that enter the planning process are designed to achieve zero-net-energy by 2030.” (Obama, 2009) Achieving these goals cost competitively will require new tools and strategies as well as refinements of existing design, construction, operations, and maintenance
14、 practices. A new DOE owned office building project has been recently completed at NREL that demonstrates a path to meeting the Federal high performance buildings executive order. The purpose of this paper is to delve into the details of how implement energy use performance requirements as part of a
15、 performance based design build process. We will document this process in a case study of the procurement, design, and construction process of DOEs recently completed Research Support Facility (RSF), a large-scale and replicable net-zero energy office building with contractually required energy perf
16、ormance goals. From the beginning, it was recognized that DOEs new RSF represented a unique opportunity to demonstrate the state of the art in terms of efficient, cost-effective, commercial office design and operation. The RSF will demonstrate that significant gains in energy efficiency can be reali
17、zed in non-residential buildings today with existing technologies in a cost-competitive manner if careful attention is paid to project energy goals, building procurement, and integrative building design. DESIGN AND CONSTRUCTION PROJECT DELIVERY METHODS To understanding the full potential of integrat
18、ed design to deliver cost effective and high efficiency projects, we must first evaluate the various project acquisition and delivery methods to better understand how to deliver cost completive energy efficient projects. Design-Bid-Build In a traditional design-bid-build scenario, the owner enters i
19、nto a contract with a designer to develop plans and specifications for a building. The owner and designer determine the projects scope, including the type of construction and the budget. The designer estimates building costs based on past experience and input from engineers and other consultants. Wh
20、en the design is complete, the owner puts the job out for bid (often with the help of the designer). This process can take weeks or even months for a complex project. During the bid phase, the owner receives and evaluates bids (again, often with the help of the designer) from a number of contractors
21、 competing for the job. The owner then enters into a contract with the successful bidder and warrants that the plans and specifications for the building are complete and correct. The contractor agrees to build the project according to the plans and specifications developed by the designer, and the p
22、arties agree on a price and schedule. The designer and contractor often have no contact or relationship with each other until after the contract is awarded limiting the potential of integrated design concepts to provide the most cost effective energy efficiency strategies. If the bids come in higher
23、 than the designers estimates, the owner and designer must decide how to bring costs back within the budget. This process takes time, and can result in the elimination of energy efficiency and other non-aesthetic building components and strategies. Typical strategies eliminated are energy efficiency
24、 strategies that are not well integrated with the building architecture or envelope, as these can be easily replaced with less efficient alternatives. Because the design and construction contracts are separate, this method offers some checks and balances for the owner (Molenaar, 2009). However, the
25、owner pays a price in scheduling and fully integrated efficiency solutions. This method is also the most time-consuming of the three noted hereand has the potential for adversarial relationships. The resulting value engineering process, disputes, cost overruns, and construction delays cause less-tha
26、n optimal performance, headaches (and often litigation), and increase project costs. Construction Manager at Risk An owner can also retain a designer to furnish design services and a construction manager to build the project who 374 ASHRAE Transactionsguarantees the cost and schedule. In this constr
27、uction manager at risk delivery method, the owner authorizes the construction manager to handle many of the project details, but the owner is responsible for the design. The construction manager is involved from an early stage of the process, and becomes a collaborative member of the project team (M
28、olenaar, 2009). As such, he or she brings construction experience to bear during cost estimating, scheduling, and other preconstruction activities. Design-Build In design-build, the building owner contracts with a single legal entitythe design-builderto provide a completed building based on the owne
29、rs design criteria. Unlike design-bid-build and construction manager at risk, in design-build, the design-builder controls both the design and the construction process. The owner develops a clear, comprehensive request for proposals (RFP) that outlines the expectations for the project, and the desig
30、n-builderlike their master builder forebearsassumes complete responsibility for delivering the project as specified in the RFP, on time and on budget. In prescriptive-based design-build, at least partand sometimes mostof the design solution is included in the owners RFP. Also called bridging, in thi
31、s scenario the owner prescribes the solution in the RFP with plans and specifications. Because the owner developed the solution, the design-builder cannot be held accountable for it. Performance-Based Design-Build In performance-based design-build, the owner does not rely on plans and specifications
32、 to describe the scope of the project. Instead, the owner focuses on the problem(s) to be solved, and leaves the solutions to the design-builder to work out. This delivery method allocates control and accountability differently, in that the owner sets a firm price for the project, develops program d
33、ocuments, and prioritizes performance expectations in a request for proposals (RFP), and then invites design-builders to propose solutions that best meet the performance expectation. The owner then selects a design-builder to complete the project for a fixed price. The successful design-builder is r
34、esponsible and accountable for designing, building, and delivering the project to meet the contractual performance requirements on schedule and for the fixed price (Design Sense Inc., 2008). RESEARCH SUPPORT FACILITY PROJECT OVERVIEW The research, development, demonstration, and deployment of cost e
35、ffective and energy efficient technologies and design processes are part of DOEs and NRELs mission. As such, DOE/NREL felt a sense of urgency about maximizing the energy efficiency of the buildings on the NREL campus. At the beginning of 2007, DOE invested the funding needed to design and build the
36、RSF. The vision was for the RSF to be a showcase of sustainable high-performance design to demonstrate the integration of high performance building design and practices, showcase technology advances, and capture the publics imagination for renewable and energy efficient technologies. The final desig
37、n for the RSF utilizes a wide variety of well integrated off-the-shelf energy efficiency measures to reduce energy consumption by 50% over ASHRAE standard 90.1-2004. Combined with PV mounted on the roof and parking lot, the RSF is designed to offset all its energy use with on-site renewables. The 22
38、0,000-ft2Class A office building will house 822 employees on NRELs Golden, Colorado, campus. NREL is currently leasing office space in a nearby office complex, and the RSF will enable many staff to move to a central location on campus. A review of the energy efficiency strategies utilized is availab
39、le at www.nrel.gov/rsf and Pless (2010). While the RSF incorporates a range of readily available energy efficiency strategies combined in innovative ways, the DOE/NREL teams real breakthrough was rethinking the procurement process. It was decided early in the procurement process that in order to del
40、iver the RSF, with its challenging performance requirements, on time and on budget, a traditional design-bid-build procurement process would not suffice. Rather than designing the building and then putting it out to bid in the traditional way, the team opted for a performance-based design-build proc
41、urement process. The goal to achieve significant energy savings couldnt override a focus on cost effectiveness and ensuring DOE obtained the best value, as DOE provided a firm fixed price of $64 million to design and build the RSF. DOE budgeted the RSFs construction costs (259/ft2) to be competitive
42、 with todays less energy efficient institutional and commercial buildings. To reach this level of 2011 ASHRAE 375performance for the available budget, DOE and NREL felt that a different a different project delivery approach was required in selection of the project team and the design/construction pr
43、ocess. Traditionally, DOE used a design-bid-build approach to project acquisition, selecting separate design and construction contractors. While this process typically provided the best price for the project, it limited the design teams creativity in developing the most cost effective integrated ene
44、rgy efficiency solution. In addition, as learned on past NREL projects, this design-bid-build process limited the design teams full integration with the builder, cost estimators, and subcontractors - resulting in a longer, more costly delivery process with less value. DEVELOPING AN ENERGY PERFORMANC
45、E BASED-DESIGN BUILD PROCESS DOE and NREL selected a performance-based “Best Value Design-Build/Fixed Price with Award Fee” delivery approach (DBIA) in order to: Encourage innovation of the design and build private sector Reduce owners risk Speed construction and delivery Control costs Make optimal
46、use of team members expertise Establish measurable success criteria To familiarize DOE/NREL staff with the finer points of the design-build process, DOE/NREL commissioned the Design-Build Institute of America (DBIA) to conduct a week-long seminar on design-build acquisition strategy. NREL also hoste
47、d a national design charrette to identify and fully define the project and its potential challenges. In addition, DOE/NREL hired a third-party owners representative with design-build experience to help shape the key performance objectives and performance substantiation criteria. Project Objectives I
48、nstead of specifying technical standards such as building size, configuration, conceptual drawings, and other attributes, DOE and NREL specified prioritized key performance parameters as “Mission Critical”, “Highly Desirable”, and “If Possible”. Competing design-build teams were judged based on thei
49、r ability to meet as many of the performance objectives below as possible while meeting the overall budget constraint: 1. Mission Critical a. Attain Safe Work Performance and Safe Design Practices b. LEED Platinum Designation c. Energy Star Appliances, unless other system outperforms 2. Highly Desirable a. 800 Staff Capacity (later adjusted to 822) b. 25 kBtu/ft2including NRELs datacenter c. Architectural Integrity d. Honor “Future” staff needs e. Measurable 50% plus energy savings versus ASHRAE 90.1-2004 f. Support culture and amenities g
