Annex 31. Energy Storage with Energy Efficient Buildings and Districts: Optimization and Automation

Transcription

1 Annex 31 Energy Storage with Energy Efficient Buildings and Districts: Optimization and Automation Prepared by: Fariborz HAGHIGAT, Ph.D., P. Eng., FASHRAE Concordia Research Chair Energy & Environment Department of Building, Civil and Environmental Engineering Concordia University, Montreal, Quebec, H3G 1M8 - CANADA Fariborz.Haghighati@concordia.ca Page 1

2 1: Background and Justification Evidence from a variety of research suggests that the built environment contributes substantially to global energy consumption and to production of greenhouse gases that impact climate change: buildings use about 40% of the worldwide total energy. This fact highlights the importance of targeting building energy use as a key to decreasing energy consumption. Hence, energy efficient buildings (EEBs) together with building integrated or district generation and cogeneration systems have been suggested as approaches to achieving this goal. Low energy buildings and districts require appropriate combinations of heating, cooling, and electrical services. There are a number of challenges in the design, construction and operation of EEBs and districts. Presently, designers use guidelines developed for passive solar buildings to design EEBs where the focus is on the design of a well-insulated and airtight building envelope populated with energy efficient systems and controls. Then, the building is connected with appropriate sources of renewable energy either directly or through a district energy network. The main drawback of renewable energy sources is the variability and intermittence in their availability; causing significant mismatches between the time of energy demand and energy production. To make these future energy sources and conversion technologies a viable solution, it is necessary to use significant levels of energy storage technologies that enable matching of supply and demand. Energy storage technologies play a crucial role in designing and operating high performance sustainable buildings and districts, and are definitely needed for the efficient use of renewable energy resources by dealing with the intermittency of energy supply and demand. However, there is still a distinct lack of guidance on the effective integration and operation of thermal energy storage at the building or district levels. In regards to electrical storage technologies, the current lack of knowledge, both technical and financial, about integrating these technologies into buildings, has led to inefficiency in operation and high reliance on grid connections as the current norms. In such applications buildings are connected to the utility grid, allowing for any surplus energy to be exported and shortfalls to be imported. These buildings buy back the electricity from the electric grid when renewable energy generation cannot meet their energy requirements. In this way, the electric grid is treated as a virtual energy storage system to overcome the temporal mismatch between energy supply and demand. The large scale electric grid is becoming increasingly powered by renewable sources and increasingly experiencing issues caused by their inherent intermittency, leading to curtailment of renewable generation and associated costs. Installation of smaller scale renewable generation at the district or building level is restricted by the capacity of the local electric grid to accept excess generation. Hence, whilst treating the electric grid as virtual energy storage can be currently Page 2

3 feasible for few buildings, as renewable generation increases this will not be sustainable from the grid point-of-view. Thus, the ability of low energy buildings and districts to act as energy storage nodes to buffer these fluctuations (and potentially gain a financial benefit) is the key to increasing renewable electricity generation at all scales. For EEBs or districts to reach their full potential, the issue of integrating energy storage and optimizing its operation must be properly addressed. It is worth stating that, the essential goal for achieving EEBs and districts is to reach the appropriate combination, integration, and optimization of different distributed energy systems with energy storage. It is not the objective to maximize energy exported to the grids and then disperse it to be used at other places. Thus, to effectively meet the concept of EEBs, whether or not this is achieved by using district energy resources, energy storage has a vital role to play due to the intermittency in energy demand against the transient cost or availability of energy resources. In other words, all types of energy storage technologies, e.g. thermal, chemical, and electrical, must be taken into consideration to find the optimum use of flexible energy supply systems. Further research is needed to develop efficient and reliable design approaches and operating strategies for storage in conjunction with thermal and electrical energy produced on-site in buildings and districts, and to support intermittency in the external grid. Previous annexes have dealt with some issues in this area. ECES Annex 7 evaluated various strategies for energy storage control and operation for industrial and building applications, but focused only on cold storage. ECES Annex 19 dealt with the optimization and improvement of industrial process heat and power generation with thermal energy storage techniques, but focused only on high temperature applications (i.e., TES technologies for applications beyond 120 C). ECES Annex 23 deals with the application of energy storage to various types of EEBs, but focused mainly on the development of simulation tools and not on the integration, and development of control strategies. ECES Annex 24 mainly focused on the development of advanced materials and systems for the compact storage of thermal energy. Solar heating and cooling (SHC) Task 40 and energy conservation in buildings and community systems (ECBCS), Annex 52 - (IEA/ECBCS) dealt with buildings that integrated heating/cooling systems with local power generation and used the electricity grid as buffer storage: This was one approach towards achieving net zero energy solar buildings. 2: Identified Research Gaps Research in the area of design and analysis of EEBs and districts is inherently interdisciplinary. The current research approach to energy efficiency, though multidisciplinary in principle, is hindered by the lack of effective tools, methodologies, and demonstrations that address interdisciplinary aspects of the effective integration of storage in buildings and districts Page 3

4 Over the last decade, extensive research has been carried out on the improvement of energy efficiency in buildings. However, this research has focused on the optimization and improvement of individual sub-system/components (e.g. air-conditioning systems) rather than optimizing the whole system at building, district or grid levels including economic cost/benefits. Current industry practices are compartmentalised and seldom consider the detailed interactions between a building s sub-systems such as mechanical ventilation systems and renewable energy systems, particularly when energy storage systems and local grids are also involved. Thus, optimization of whole system efficiency and effectiveness is rarely achieved. In addition, the concept of energy use and storage integration with renewable energy technologies for buildings and districts requires not only integration and optimization but also accurate forecasting and controls to predict and react to future energy demand as well. For example, weather forecasts and building dynamics can be integrated into the energy management system to improve predictions of renewable energy generation and expected electrical, heating and cooling demands. This allows an appropriate orchestration of energy conversion systems and storage to maximise the overall performance. 3: Scope, Objectives and Limitations 3.1 Annex Scope The Annex is developed within the scope of: combination of energy storage and other components; efficient integration of energy storage into buildings and districts; optimisation of building and district operation. 3.2 Objectives The general objective of this Annex is to address the integration, control, and optimization of energy storage with buildings, districts, and/or local utilities. The focus will be on the development of design methods/tools, optimization, and advanced control strategies for effectively predicting, evaluating, and improving the performance of EEBs and districts when energy storage is available. This objective can be subdivided into five specific objectives: A. To assess the technical potential and total performance of energy storage systems in energy efficient buildings and districts. B. To develop methods and tools to evaluate and optimize the total performance (energy, environmental, and economical) of whole systems. C. To develop efficient and advanced control algorithms and/or strategies for the operation of whole systems, for different climatic conditions and energy markets, Page 4

5 D. To develop and provide design guidelines for integrating energy storage into energy efficient buildings and districts, E. To demonstrate and disseminate the knowledge and experience acquired in this Annex through case studies and validated demonstration projects. 4: Demarcation The Annex will focus on analysis and development of design and control tools for optimization and control of integrated energy efficient buildings and districts with energy storage. 5: Means 5.1 Methodology To address the specific Annex objectives, the research and development work in the Annex will be divided into a number of tasks provided below; 5.2 TASKS TASK A (Modeling): Methodologies and tools for the evaluation of combined various energy storage and energy efficient techniques/components Modeling will be deployed in support of the objectives outlined above: to assess the performance of energy storage systems in EEBs and districts; to underpin tools and methods for optimisation of energy performance; to support development of controls; to inform design guidance; and to be applied, demonstrated and disseminated as a part of the Annex outputs. Modeling will require to be applied at component, building, and district levels. Modeling will support the requirements of the various actors involved in meeting the overall Annex objectives (e.g. component suppliers and developers, building designers, building services engineers, controls developers, district planners etc.). Modeling will support technical and financial operational and life cycle analysis. In order to address this range of requirements it is envisaged that a multi-fidelity modelling strategy will be required supporting different levels of detail within an integrated overall approach. Task A-1 (Component): This task will involve the following steps: a focussed review of component modelling requirements and available methods; definition of the most promising approach(es); application, evaluation and demonstration of the tools and methods; development of documentation including guidance and other dissemination materials. Task A-2 (Building): This task will involve similar steps focussed on the building level: a focussed review of requirements and available methods; definition of the most promising approach(es); Page 5

6 application, evaluation and demonstration of the tools and methods; development of documentation including guidance and other dissemination materials. Task A-3 (District): This task will involve similar steps focussed on the district level: a focussed review of requirements and available methods; definition of the most promising approach(es); application, evaluation and demonstration of the tools and methods which specific focus on the representation and parameterization of energy storage within district energy optimization models; Sensitivity analysis techniques will be used to identify key parameters influencing optimum operation of storage, as well as the quantification of uncertainties in their values under different operational scenarios; development of documentation including guidance and other dissemination materials. Task A-4 (Financial and Lifecycle): This task will focus on financial and lifecycle modeling across the levels: a focussed review of requirements and currently available methods; definition of the most promising approach (es); application, evaluation and demonstration of the tools and methods; development of documentation including guidance and dissemination materials. Task A-5 (Integration): This task will be focussed on integration and interoperability of the modeling tools and methods and their usability across the different application domains. The requirements of the various actors involved in meeting the Annex objectives (Tasks A to D) will be gathered and a solution delivered that meets these requirements. This task will also consider requirements of future users of the Annex outputs and the delivery of useful and useable solutions to them. Similar steps (review, define, demonstrate and disseminate) as for the other tasks will be followed. The output of the proposed multi-fidelity modeling approach will allow system behaviours to be represented in sufficient detail in a computationally effective way. The final Task A outputs will be: 1. A review of the state of the art in modelling to support the integration, optimisation, automation and control of energy storage in low energy buildings and districts. 2. Guidance and recommendations on approaches to modelling of energy storage in low energy buildings and districts (in synergy with other IEA Annexes). These final outputs will be reports. There will also be interim reports giving progress in these two areas, they are expected to form the basis of conference and journal publications. TASK B (Optimization): Methodologies and tools to optimize the total performance (energy, environmental, and economical) of whole systems. Optimization will be developed considering both methodologies and tools. It will be applied at component, building, and district levels. It will help designers, controls developers, district planners to identify the best(s) solution(s) which satisfy the energy needs (heating, cooling, and electricity) considering a multi-criteria and multi-source approach Page 6

7 The task B will be based on results from the previous task concerning physical modelling of component(s), building(s) and district(s) (subtasks A-1 to A-3). Financial and life cycle performance assessment (task A-4) will be accounted for in order to calculate the global performance. The last task A-5 is also a key point to ensure the coupling between tools for dynamic simulation and optimization. Task B results may be applied to optimize the parameters in advanced control systems (task D). Task B-1 (Review): This task will focus on a review of methodologies and tools dedicated to the optimization of the total performance at component, buildings, and districts levels. It will cover different matters like modelling approach related to the design phase, multi-objectives optimization, interoperability between numerical tools, performance assessment, computational time reduction, formulating uncertainty during the whole cycle of the building (robust optimization), and decision aid making. The most promising approaches will be considered in the next three subtasks. Task B-2 (Component): This task will focus on recent developments of optimization methods and tools at the component level. The efforts will be extensively based on the results coming from Task A-1 (modelling) and that also provide valuable feedback to this task. Various fields can be identified like improvements on heat exchangers for thermal storage employing thermochemical or phase change materials in order to optimize the usage of the available storage capacity and increase peak power output. From the electrical point of view, as being a less mature and market-ripe technology, considerable effort on the stability and efficiency at the component level is essential. Task B-3 (Building): This task will focus on recent developments of optimization methods and tools at the building level. Dynamic simulations are necessary to consider storage and interactions between multi-source systems, building envelope, occupant, and external environment. All the system and building envelope configurations will be assessed based on the whole life cycle of the building. A comparison between the standard design methods and multi-objective optimization methods including uncertainty (robust optimization) will be proposed. The computational time reduction and the global optimum convergence will be two key points. The use of surrogate models will be particularly considered to reduce calculation time. Task B-4 (District): This task will focus on recent developments of optimization methods and tools at district level. The participants from U. of Cambridge have recently developed a computer model called Distributed Energy Network Optimization (DENO). This model in its current form is developed for the UK technology-policy context. DENO is a state of the art mixed integer linear programming (MILP) model that is designed to optimise system design, unit dispatch, and energy distribution at hourly intervals. We propose to extend the model as part of the annex activity on the following fronts: (a) Investigate techniques for incorporating thermal storage within the model for both heating and cooling, (b) Compare technologies for seasonal and diurnal storage at the district Page 7

8 scale, and (c) Evaluate optimum scale and scenarios under which energy storage yields economic and environmental benefits. Furthermore, the benefits of storage will be assessed under those contexts where the demand for energy is fast outgrowing centralized generation. For example, energy demand in India is increasing at the rate of 6% per annum, however the generation capacity is not increasing at the same rate, thereby widening the demand supply gap. This is leading to frequent load shedding and forcing the commercial buildings to rely on large UPS and captive generation. These systems are inefficient, need high maintenance, and cause localized noise and air pollution. Using a Distributed Energy Resource System (DERS) that can couple with a District Cooling/Heating system (co-generation) and off-peak energy storage could help in bridging the demand supply gap in an efficient and environmentally friendly way. TASK C (Control): To develop efficient and advanced control algorithms and/or strategies for the operation of whole systems, for different climatic conditions and energy markets Advanced control strategies will be developed to minimize the demand-side required grid power in order to achieve the EEBs and districts objectives. It should be mentioned that the vast majority of existing simulation and optimization studies have focused on design optimization problems, rather than problems related to the operation phase of building or district and its system. The scope of this task is to develop models suitable for the real-time control of an EEB or district. This task requires an accurate model for the thermal response of the EEB or district to predict the required loads, zone temperatures and mechanical system energy consumption and power demand, TES capacity, available energy resources, etc. This model has to be tuned during the operation to ensure the stability and efficiency of control decisions that are made based on its prediction. The complexity of thermal and mass transfer phenomena within a building or district in normal operation is difficult to capture with direct modeling techniques. An extensive search will be carried out to identify the most commonly used control models in this field, and a systematic approach for model evaluation and application will be developed and applied. Task C-1 (Review): This task will focus on a review of the most promising methodologies and techniques available for the control at building and district levels. It will cover different matters like modelling approaches adopted in the design phase, multi-criteria optimization, predictive ability, interoperability between numerical tools, performance assessment, computational time reduction, uncertainty during the whole cycle of the building or district (robust optimization), and decision aid making. The most promising methodologies and techniques will be considered in the next two subtasks Page 8

9 Task C-2 (Building): This task focuses on control strategies for storing/releasing energy in a single building: reviewing the present states of control methods, classification and identification of various operating modes composing control strategies, application of mathematical programming techniques to develop control strategies at the building level, and verification of these techniques by comparison with field measurement. Task C-3 (District): This task focuses on control strategies for storing/releasing energy at the district level: reviewing the present states of control methods for building complex and districts, classification and identification of various operating modes composing control strategies, accounting energy system consequences, application of mathematical programming techniques to develop relevant control strategies at the district level, and verification of these techniques by comparison with field measurement. TASK D: Demonstration/Case Studies This task will involve the data collection of specific information about case studies or experimental demonstration activities related to components or experiences developed at building or district level. The aim of the task is thus to define a common and comprehensive format to get all technical, energy, economic and environmental data in order to analyze, assess and compare available information and carry out a final report of the obtained results. A template will be created for the measurement and display system to be deployed in buildings and districts containing integrated renewable energy sources and energy storage strategies. The first part of the activity will identify the important values/information that have to be measured/acquired in different analyzed contexts. The work plan will be organized on the following items: 1. Definition of a preliminary specific datasheet format for data collection on case studies; The task leader will define a common and comprehensive datasheet format containing all requested information about case studies or demonstration activities; 2. Sharing of the format draft and collection of comments and suggestions; The datasheet format will be sent to subtask leaders in order to collect comments and suggestions useful to obtain a shared structure according to different needs. 3. Definition of the final datasheet format for data collection on case studies; The datasheet final format will be defined in accordance with all subtask leaders. 4. Sharing of a datasheet related to case-study; Page 9

10 A complete datasheet containing all requested information about the Italian case-study will be provided and shared to all participants in order to represent a reference for other countries. 5. Collection of datasheets relating to all case studies, according to the defined format; All datasheets related to case studies or demonstration activities will be collected and checked in order to ensure their completeness; 6. Data analysis; Acquired data will be analyzed with the aim to compare results under technical, economic, energy and environmental points of view, highlighting pros and cons of each project; 7. Final report on analyzed data and information. The task leader with the support of all subtask leaders in the preparation of a final report in order to disseminate the knowledge and experience acquired within the Annex. Management of the Annex The Annex will be managed by the Operating Agent assisted by task leaders and subtask leaders. Operating Agent -The Operating Agent is responsible for the overall performance and the time schedule of the Annex, for reporting, and for information dissemination activities. The Operating Agent is Canada, Fariborz Haghighat. Task Leaders: A: Task Leader Dr. Paul Tuohy, UK B: Task Leader Dr. Gilles Fraisse, France C: Task Leader Dr. Ryozo Ooka, Japan D: Task Leader Dr. Niccolo Aste, Italy Deliverables and Target Audience The main focus of the proposed research is to advance the design of an integrated EEBs technology and systems in term of enhancing its efficiency, reliability, economics and environmental impact. The target audiences are the construction industry, utility companies, building operators and policy makers. The Annex deliverables will be: Reference book providing detailed information for the integration of energy storage and renewable energy sources with energy efficient buildings, and communities. Develop advance optimization tools for designers, A review of the state of the art in modelling to support the integration, optimisation, automation and control of energy storage in low energy buildings and districts Page 10

11 Guidance and recommendations on approaches to modelling of energy storage in low energy buildings and districts (in synergy with other IEA Annexes). Report on control strategies maximising flexibility while maintaining comfort Recommendations for control systems for implementation in buildings/communities Report the outcomes of laboratory and field measurement, Recommendations for future work on the application of energy storage with building/communities. Dissemination The aim of the Annex is to develop the basis for incorporation of the flexibility of buildings in the future Smart Energy systems and thereby facilitate energy systems based entirely on renewable energy sources. The obtained knowledge is also important when trying to develop business cases that will promote the utilization of building flexibility in the future energy systems. Dissemination of the results of the annex to the parties responsible for the future energy systems is, therefore, outmost important. The dissemination of the Annex will consist of: International dissemination: Organizing seminar/workshop at each meeting, homepage, newsletters, special workshop and session at national/international meetings, presenting papers at international conferences and publishing articles in the international journals. National dissemination to utility companies, governmental decision makers and the building industry will be done via presentations at meetings and submission of articles to the national journals. Time Schedule A preparation phase of one year from June 2013 to May A four-year project period from June 2014 to June 2018 (including reporting phase) Page 11