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hybridGEOTABS project - MPC for controlling the power of the ground by integration Our introductory article, part of a series in the REHVA Journal explaining Hybrid GEO-TABS and ongoing results, is now available in June's publication. Future articles will focus on the Case Study Buildings, dedicating each article to one building: Solarwind, Ter Potterie Care Home, Elementary School Libeznice, Infrax (Dilbeek) and Haus M The article is also available to preview/download from our technology page, where other articles and factsheets are also available.

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hybridGEOTABS May 2018 Newsletter is now available to read, with news on our Madrid Symposium, REHVA-ATIC Conference Talks, Dates for next Symposium and more...  

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KU Leuven, SYSI, Boydens and IWT hosted the Boydens Academy in Dilbeek, with guest speaker: Professor Ian Beausoleil Morrison “Building performance simulation, ready, set… let’s educate to get ready” His seminar was entitled, “PROVIDING HIGH FRACTIONS FOR SPACE AND WATER HEATING IN COLD CLIMATES THROUGH SEASONAL STORAGE” Presentation abstract: Heating, cooling, and ventilating the places we live in, and providing the hot water, lighting, and appliance services we need, consumes tremendous amounts of energy; this contributes significantly to environmental and energy security issues.  For example, housing accounts for 30% of all electricity and 26% of all natural gas consumed in Canada, and produces 13.5% of the country's greenhouse gas emissions.  Although these figures vary from region to region, a similar situation exists in most OECD countries, including Belgium. In most cool and cold climates, space and water heating account for the majority of the energy demand in housing, and therefore offer the greatest potential for savings.  This seminar will describe ongoing research at Carleton University (Ottawa, Canada) aimed at devising and evaluating methods for providing the majority of space and water heating needs (>90%) through solar energy.  It will first provide some context by explaining the Canadian energy situation and current housing construction practices.  A simulation-based analysis of a solar thermal system employing seasonal storage will then be presented, followed by a description of the design, construction, and commissioning of a full-scale research house.  Finally, preliminary results from the first annual experiment conducted at the facility on the seasonal storage of solar thermal energy will be provided.   Meet Prof. Ian Beausoleil-Morrison: Ian Beausoleil-Morrison is Professor in the Faculty of Engineering and Design at Carleton University in Ottawa, where he holds the Canada Research Chair in Innovative Energy Systems for Residential Buildings.  He is co-founder and has been Co-Editor of the Journal of Building Performance Simulation since its establishment in 2008.  He has been a Director of the International Building Performance Simulation Association (IBPSA) since 2004, and was Vice-President of that organization from 2006 to 2010, and President from 2010 to 2015. In 2015 he was awarded the grade of Fellow of IBPSA. His research interests include solar housing, seasonal thermal storage, micro-cogeneration, and understanding and controlling for occupant behaviour. Currently he is the Lead Investigator of the Urbandale Centre for Home Energy Research, a research house situated on the Carleton University campus that is dedicated to the long-term study of solar-thermal and other innovative energy systems for radically reducing the dependence of housing on fossil fuels and the electrical grid.

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Our new animation is now live...have a look at the explanatory video about hybridGEOTABS, along with links to follow the development of the project. https://youtu.be/sEboWPqFlFU

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Project Progress Development of a Dedicated hybrid MPC-GEOTABS Design Strategy A major project objective is the development of a design strategy for hybrid GEOTABS buildings that integrates the sizing of primary GEOTABS and secondary fast reacting systems, and an MPC based control strategy. The design strategy will allow an estimation of the system size and performance in early design phase in order to assess the feasibility of efficiently implementing a GEOTABS system. The design strategy needs to be straight forward, avoiding complex and expensive engineering studies. One of the subtasks comprises an analysis of the relevant European building stock for assessing the feasibility of efficiently implementing a GEOTABS system by sizing its main system components, that is the Ground Source Heat Exchanger (GSHX) and the Heat Pump (HP). In 2017, the partners from Ghent University developed the methodology for doing a building stock analysis. The inputs to the process are the overall geometrical properties of a large amount of buildings of the relevant typologies (multi-family residential buildings, offices, schools and care houses) throughout Europe, and energy-efficiency related parameters. The output of the process are simulated load duration curves, that will allow the sizing of the main GEOTABS components. During the process, Building Information Modelling and Building Energy Simulation models are used in order to perform detailed energy simulations starting from limited and general building data. Development of an MPC Toolchain for the hybrid MPC-GEOTABS Concepts Rule Based Control (RBC) strategies are traditionally used to control heating/cooling when using a combined GEOTABS – secondary system. However, RBC strategies are not able to harvest the full potential of the combined system because  they act on fixed rules. They are based on static building models. The time delay of the system response is accounted for by heuristic rules, requiring a lot of trial-and-error to tune the control parameters. They are applicable to a specific and space-limited area, there is no optimisation on the level of the whole building.  This is caused by extreme complexity of the respective RBCs and the fact that it is practically impossible to generalise their rules for the building level. This problem becomes even more severe in view of the rising complexity of building automation system tasks in modern office buildings. RBC therefore asks for important case by case efforts to tune the control parameter during the commissioning phase, resulting in high commissioning costs. To improve the overall efficiency, so called Model Predictive Control (MPC) strategies could be used. Current approaches to MPC, however, need extensive measurements on the building as training data before the MPC is operational (black box or grey box approach) and is therefore only implemented some time after delivery of the building. Moreover, using the grey box approach setting up the MPC requires substantial modelling and identification work. The sizing however is done based on assumptions of a typical RBC approach. Post hoc tests and simulations have demonstrated that, due to its specific ability to take maximal advantage of the buffering effect, optimal component sizing in an MPC GEOTABS building can be up to 50 % smaller than that under RBC assumptions. MPC strategies are already tested since some years in experimental set-ups and real buildings and proof to be more effective since they use predictions of the variations in both the sources and demands and satisfy demand at minimal primary energy use (or other optimisation criteria) while exploiting the energy storage capacity whenever beneficial. However, though improving the energy efficiency and lowering the operational cost, it is currently economically not feasible to implement MPC at scale due to the high engineering, monitoring and commissioning cost to set up the MPC. The white box MPC Toolchain developed in the hybridGEOTABS project attempts to automate the controller design process as much as possible in order to reduce these costs. Application of MPC Toolchain to Solarwind A simulation model of Solarwind has been developed using the Modelica language. The model includes the building envelope, HVAC (heating, ventilation and air conditioning) models and the Rule Based Controller (RBC) model. The model simulates the energy flows in detail, including pressure-dependent fan and pump electrical power uses and temperature-dependent coefficients of performance for the heat pumps. This model serves as a benchmark for a second model, which is used in an MPC. This second (MPC) model is a modified version of the simulation model and is quite detailed compared to models used in other research. However, due to the efficient implementation of the used toolchain, computation time is acceptable. The large level of detail enables the MPC to modulate fans and pumps by lowering the supply pressures, which significantly reduces their electrical power use. Moreover, the MPC is able to coordinate various heating and cooling loads within the building. This way residual heat from zones with a lot of internal heat gains are used to heat colder zones, or equivalently: cold from cool zones is used to cool otherwise overheating zones. This leads to very high system efficiencies since heat and cold demand neutralise each other. Moreover, the MPC is better able to predict the required heat loads than the RBC, which often heats the building too much using the concrete core activation. This excess heat then must be cooled away by the air handling units, which leads to additional electrical energy use. Concept and Impact Validation Appropriate performance indicators and reference baselines are defined for performance assessment. The impact of specific environmental conditions in TABS buildings on the comfort, productivity and health of the end-users will be investigated in case study buildings. Specific performance indicators, including energy performance, cost functions, indoor environment quality, environmental/resource intensity performance for TABS environments, will be drafted and performance impact will be assessed with respect to baselines/benchmarks (non-GEOTABS and RBC GEOTABS). RBC strategies and parameters will be surveyed in the case study buildings and from previous (research) projects. Emulator models for these case study buildings, created and validated using advanced building energy simulations, will be used to define a reference control strategy with its associated performance levels as the RBC GEOTABS benchmark. The emulator models also play a key role in the development of the new hybrid GEOTABS design and control approaches. 

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Our first Stakeholders Engagement Board (SEB) Meeting progressed well today. With Jelle and Eline (UGent), Wim (Boydens) and Lieve Helsen (KUL) presenting and introducing the H2020 Project to our SEB. Following the presentations, there was an active and productive open table discussion, about collaboration moving forward with the porject over the next few years. Thanks to those who attended and to REHVA for hosting our meeting and New Year Cocktails! #geothermal #heatingandcooling #thermalcomfort #cleanenergyEU #renewables #hybridgeotabs

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