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Thermal energy systems’ resilience is especially important for extreme climates, such as arctic or tropical environments. While metrics and requirements for availability, reliability, and quality of power systems have been established (DOD 2020), similar metrics and requirements for thermal energy systems are not well understood. In one of the first attempts to address this deficiency, a study was conducted to better understand the level of reliability required for energy supply systems that will be capable of supporting environmental conditions required for the facility’s mission, the comfort of people, and sustainment of a building in arctic environments under predominant threat scenarios. This paper is split into two parts. The purpose of Part I is to present the methodology and results of a unique temperature decay test conducted during the winter, along with blower door tests on five representative military buildings in Alaska. In Part II, the modeling analysis is compared and calibrated to the experimental data collection for the thermal decay test (TDT). A reliable building model allows us to predict the maximum time available to repair the heat supply system before the building needs to be evacuated, when damage is done to equipment or facilities critical to the building operations, or when damage is done to the building itself. This will provide guidance to building managers on evacuation and sustainment procedures for buildings in arctic climates that are affected by fuel or electrical disruptions. [ABSTRACT FROM AUTHOR]

Numerous pilot projects conducted all over the world have demonstrated that energy use in commercial and public buildings can been reduced by more than 50% after renovation. In fact, some renovated building shavemet the Passive House Institute energy efficiency standard or have even achieved a net zero energy state (Zhivov et al. 2015). Research (IEA 2009;ASHRAE 2015) has identified more than 400 energy efficiency measures that can be used when buildings are retrofitted. Such measures include those related to the building envelope, mechanical and lighting systems, energy generation and distribution, and internal processes. Implementation of some individual measures (such as building envelope insulation, improved airtightness, andcogeneration)cansignificantlyreducebuilding heatingand cooling loads or minimize energy waste, but require significant investments with long paybacks. However, when a limited number of core technologies are implemented together ("bundled"), they can significantly reduce energy use for a smaller investment and thereby provide a faster payback. Characteristics of some of these core technology measures depend on the technologies available on an individual nation's market, on the minimum requirements of national standards, and on economics (as determined by a life cycle cost [LCC] analysis). In addition to these measures, requirements related to building envelope-related technologies (e.g., insulation levels, windows, vapor and water barriers, and requirements for building airtightness) depend on specific climate conditions. National teams associated with the International Energy Agency Energy Conservation in Buildings and Communities Program (IEA EBC) Annex 61, Business and Technical Concepts for Deep Energy Retrofit of Public Buildings (EBC 2015), have studied such conditions by computer simulation (Case et al. 2016; Rose et al. 2016; Riel et al. 2016; Yao et al. 2016). This paper summarizes the results of these studies, which will be used in an IEA Energy in Buildings and Communities (EBC) Programme Annex 61, Deep Energy Retrofit--Case Studies (IEA 2015). The key to making a deep energy retrofit(DER)cost effective is to time the retrofit as part of a major building renovation that already has allocated funds, including those required to meet minimum energy requirements. Since there is an overlap between the funds allocated for the retrofit and those required for the DER, achieving the DER requires only an incremental cost because the DER is evaluated based on a bundle of core technologies, not on individual energy efficiency measures. To evaluate the cost effectiveness of DER project using bundles of core technologies, compared to a typical major building renovation based on minimum energy requirements, this paper proposes the use of net present value (NPV) of the differences in energy savings, maintenance, and insurance costs and other operational costs and revenues to estimate the budget increase limit, which makes the DER project LCC effective. Since most of parameters required for an LCC analysis differ not only by the individual country but also within the country (first costs and labor rates, energy rates, life of the project, and inflation and discount rates), the concept of scalar Ratio (McBride 1995) is used to calculate limitations in renovation budget increase. [ABSTRACT FROM AUTHOR]

The increasing world-wide emphasis on net zero (NZ) or low-energy communities (LECs) has brought with it a concomitant requirement for high quality technical analysis and optimization to support planners. The authors' experience in energy planning for military installations has identified best practice processes as well as common analysis tasks performed by LEC planners. Requirements for data collection, modeling, optimization, and organization of inputs and results are significant, leading to higher cost, long study times, and limits on the number of alternative scenarios that can feasibly be considered. In addition, changes in data or scope can lead to considerable rework, leading to further delay and potential for the introduction of errors. This paper describes a computational framework and reference implementation for LEC analysis and optimization designed to automate many of the repetitive and time-consuming organizational, modeling, and optimization tasks involved in LEC planning. The framework incorporates whole building simulation, community-wide optimization of distribution and supply, geospatial data, and an overall approach to data organization that permits implementers to use their choice of modeling software. A reference implementation of the framework, the NZ planner was developed and tested at four Department of Defense installations. Results show decreased time to set up studies and to conduct simulations and optimization. This paper provides examples and discusses trade-offs between process steps that should be automated and those that are more appropriate for human judgment and experience. [ABSTRACT FROM AUTHOR]

The Army is required by law (EPACT 2005, EISA 2007) to eliminate fossil fuel use in new and renovated facilities by 2030 and to reduce overall facility energy usage by 30% by 2015. Army policy is to achieve eight net zero energy pilot installations by 2020, 25 net zero energy installations by 2031, and for all installations to achieve net zero energy status by 2058. Achieving Net Zero Energy (NZE) will only be possible if an optimum mix of demand reduction and renewable sources are put in place at a community (installation) or building cluster scale. The Army operates what are essentially small campuses, or clusters of buildings on its installations. The US Department of Energy (DOE) is focused on the national grid scale or on individual buildings, while the commercial focus is on retrofits to individual buildings. There are only few case studies worldwide that address dynamics of energy systems at the community scale, and to date, there is a lack of tools to perform that task. The building stock at most US Army installations is complex and includes a mix of high and low energy use buildings. Energy use in these buildings varies due to the different military mission and requirements for each building, installation growth and expansion, and soldier deployment. Achieving net zero energy economically at such installations will require a seamless blend of energy conservation in individual buildings and building systems automation, utility management and control, and power delivery systems that have the capability to offer integration of on-site power generation (including renewable energy sources). This paper describes the Net Zero fossil fuel based energy optimization process and illustrates it with an example based on the results of study conducted for a cluster of buildings at Fort Irwin, CA. The integrated optimization process is being developed under the Army research and development project "Modeling Net Zero Installations - Energy (NZI-E)" and the International Energy Agency (IEA) Energy Conservation in Buildings and Community Systems (ECBCS) Annex 51. The process is stepped, beginning with the optimization of each building to achieve the most cost effective energy efficient optimization of building envelope and energy using systems. Then energy saving measures affecting the total building cluster are optimized taking advantages of the diversification between energy intensities, scheduling, and waste energy streams utilization. The energy demands of the resulting energy-use optimized cluster will require the minimum sized renewable energy system needed to make the building cluster Net Zero fossil fuel energy. [ABSTRACT FROM AUTHOR]

Community-scale energy planning represents a multidiscipline problem involving the competition of many economic, environmental, energy security, and logistical requirements. This complex problem is routinely faced by U.S. military installations, both domestic and abroad, and can result in unnecessary financial and personnel costs if a suboptimal solution is chosen. In response to this problem, the U.S. Army Corps of Engineers (USACE) has developed a community-scale, mixed-integer linear programming (MILP) based model to assist in the selection of energy supply and distribution equipment and to determine optimal schedules of operation. The model was developed to minimize the total annual equivalent cost of providing thermal and electric power to clusters of buildings by selecting from existing or potential equipment using a fully centralized, fully decentralized, or hybrid approach, while meeting all other required constraints. This paper describes the model (with an emphasis on its unique elements in relation to similar existing models), its limitations, and considerations for future work. [ABSTRACT FROM AUTHOR]

Thermal energy systems’ resilience is especially important in extreme climates such as arctic or tropical environments. While metrics and requirements for availability, reliability, and quality of power systems have been established (DOD 2020), similar metrics and requirements for thermal energy systems are not well understood. In one of the first attempts to address this deficiency, a study was conducted to better understand the level of reliability required for energy supply systems that will be capable of supporting environmental conditions required for the facility’s mission, the comfort of people, and sustainment of a building in arctic environments under predominant threat scenarios. This paper is split into two parts. The purpose of Part I is to present the methodology and results of a novel temperature decay test conducted during the winter, along with blower door tests on five representative military buildings in Alaska. In Part II, a building modeling analysis is compared and calibrated to the experimental data collection for the thermal decay test (TDT) and a reliable building model that allows prediction of the maximum time available to repair the heat supply system before the building needs to be evacuated when damage is done to equipment or facilities is described. The results from the field tests described in Part 1 indicate that the rate of decay is dependent on the time of day (i.e., amount of sunlight) and building features, and will vary within the building relative to wind direction. This study, combined with the modeling analysis addressed in Part II, will provide guidance to building managers on evacuation and sustainment procedures for buildings in arctic climates that are affected by thermal energy supply systems, HVAC systems, fuel, or electrical disruptions. [ABSTRACT FROM AUTHOR]

Resilience is contextual. The concept of design basis threat can be used to capture a contextual scenario to measure the resilience of district energy systems against. Design basis threats are low-probability, high-impact events such as hurricanes, flooding, earthquakes, etc. We present a computer-based simulation program to assess the resilience of community-scale district energy systems to various design basis threats. This program simulates both building and districtlevel energy systems consisting of an interconnected network of components. Multiple flows of energy can be modeled: notably, both thermal (heating/cooling) and electrical flows and their interactions. This network of components is made subject to various scenarios which represent one or more ideal cases (i.e., "blue-sky") as well as design basis threats. Each scenario has a probability of occurrence and zero or more intensities associated with it such as wind speed, vibration, water inundation level, etc. Fragility curves are used to relate a scenario's damage intensities (e.g., wind speed) with a component's chance of failure. Performance of the network is assessed while taking into account the possibility of failure due to routine reliability as well as various threats. In so doing, various resilience metrics such as maximum contiguous downtime, energy availability, and load-not-served can be calculated. [ABSTRACT FROM AUTHOR]