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Towards optimised performance, design and comfort in hybridGEOTABS buildings hybridGEOTABS presented a 1.5hr workshop on Tuesday 28th May on the second day of CLIMA2019, concluding the REHVA-organised afternoon sessions. The workshop was chaired by Lieve Helsen (KU Leuven). The attendees had the possibility to learn the advantages of radiant heating and cooling systems from an energy and comfort perspective and how these are designed in the context of the overall optimisation of hybridGEOTABS systems, being introduced as well to innovative design procedures for these systems.   The CLIMA hybridGEOTABS workshop presentations:   Introduction to hybridGEOTABS - Eline Himpe, UGent Indoor Environment Quality benefits of Radiant Systems - Ongun B. Kazanci, DTU TABS in hybridGEOTABS - Qian Qang, Uponor PCM ceiling panels as a renovation solution in hybridGEOTABS buildings - Ongun B. Kazanci, DTU Innovative Procedures for the Optimised Design of hybridGEOTABS buildings - Wim Boydens, Boydens Engineering hybridGEOTABS Design Method - Jelle Laverge, UGent  

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How to design hybridGEOTABS buildings’ components This was the first training course provided by the hybridGEOTABS consortium partners.  The course was well-attended and feedback was positive on the training provided. The aim is to provide the Training material in the form of a Guidebook which will be available to buy from the REHVA eshop. hybridGEOTABS refers to the efficient integration of the combination of GEOTABS (GEOthermal heat pumps in combination with Thermally Activated Building Systems (TABS)) and secondary heating and cooling systems in a building. Teachers Lieve Helsen from KU Leuven, Qian Wang from UPONOR, Pieter Brepoels from Viessman and Hector Cano Esteban from GEOTER illustrated the key aspects of borehole design, heat pump requirements, distribution systems related to TABS and the potential of MPC in this new approach. The aim was to introduce to the attendees the design and optimization of the borefield from an economical and security of thermal supply point of view, the construction and system integration of TABS, the advantages of TABS and its suitable application in the respective building type and energy systems. And how a MPC approach works, which benefits it can create and why it has especially advantages when applied in hybridGEOTABS buildings.

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"How to express hybridGEOTABS in the ALDREN Evaluation Scheme?" The joint workshop was held on March 27, 2019 at the Technical University of Denmark (DTU), Kongens Lyngby. During the morning, a working session was held between ALDREN and hybridGEOTABS to exchange experiences and knowledge amongst the partners in order to explore potential working practices between both projects. Discussions led to the potential of applying the ALDREN methodology in at least one of the pilots of the hybridGEOTABS' project. During the afternoon the workshop was open to the public attended by about 65 people (approximately 40 in person and 25 via webinar).   The full video of the workshop can be viewed here   Summary of the presentations and links   The ALDREN procedure presentations:   Introduction to ALDREN – Mathieu Rivallain, CSTB EVCS ratings - Jana Bendžalová, ENBEE Energy Performance Verification - Robert Cohen, Verco Indoor Environmental Quality (IEQ), Productivity and Health - Pawel Wargocki, DTU Financial Performance - Yona Kamelgarn, Certivea ALDREN Building Renovation Passport & Renovation Strategies - Marta Maria Sesana, PoliMI   hybridGEOTABS - Radiant Heating & Cooling, IEQ, Health Productivity and Comfort presentations:   The history of TABS and its worldwide applications - Bjarne W. Olesen, DTU How to design a hybridGEOTABS building? (state-of-the-art) - Wim Boydens & Jelle Laverge, UGent Innovative controls in hybridGEOTABS: MPC concept and first results - Jiri Cigler, Energoklastr Indoor Environmental Quality Productivity and Health – Pawel Wargocki, DTU Innovations in radiant heating and cooling systems: use of PCM - Ongun B. Kazanci, DTU   The session ended with a live poll among attendees from both research and industry. You can read the results from the polls here: ALDREN poll and hybridGEOTABS poll   A Questions and Answers session followed the end of the workshop, providing some more insight into both projects:   ALDREN Q&As   Is there a definition of the  Nearly or Net-Zero Energy Building  (NZEB) at the EU level or only at the National levels? Jana Bendžalová: ALDREN has its definition of Nearly Zero Energy building (NZEB) in class A. The value is not necessarily fully in line with the national definition commissioned by member states because of many differences in calculation methodologies, indicators (e.g. total or non-renewable primary energy), floor area, primary energy factors, export of produced energy from RES etc.  The definition is tested on model buildings with the national input values for thermal envelope and systems properties.  The definition of ALDREN NZEB for office buildings in term of non-renewable primary energy use is close to the Commission recommendation (EU) 2016/1318 on guidelines for the promotion of nearly zero-energy buildings and best practices. Robert Cohen: Just a quick comment that the European Green Building Councils are also defining zero-energy buildings for the World Green Building Council, so there are national definitions being developed at the moment.  The Dutch Green Building Council has come up with a definition called the Paris Proof concepts, which is really interesting.   Should the renovation passport use or integrate BIM? Marta Maria Sesana: For sure within the ALDREN procedure we are going to investigate this aspect.  One module of the ALDREN BuildLog is title and structured to collect Documentation and BIM.  It's definitely another big issue to investigate, and the desire of ALDREN is to go on that path.   It was presented that the building passport should be taken with the building for it's lifetime.  How do you envisage who will manage this - who are the actors during this process, and what are their roles? Marta Maria Sesana: When we started to structure the data model of the ALDREN Building Renovation Passport in detail, we were aware on the need to keep in mind that along the path there are different 'actors' and their knowledge, background and expertise are not the same. For that reason we have structured it with different Level of Information (LoI) or let’s say Level of Detail (LoD) to not lose data quality, but at the same time to reach different target people. People trained by the ALDREN approach should fill in the ALDREN BRP and for them we are preparing dedicated training material and the pilots will be the first real application of the approach. LoD will support a better comprehension for different actors. For that reason we are also looking at a lightversion, I mean a more friendly version, with few but comprehensible indicators or clear rating even for the building owner or user. Some building passport initiatives already exist, but they are focused on residential buildings, so ALDREN will be the reply for the non-residential ones. In all LoI, the different actors need to understand what exact data they are referring to; which indicators or which energy they should consider, which renovation strategy, and when they should apply it and so on.  The importance of a common language and the data quality will be the key to have a user friendly and comprehensible tool to trigger renovation. Along the ALDREN approach, users can give feedback for example, but they wouldn't be the person who updates the passport/logs. Mathieu Rivallain: We can also slightly reposition this question in line with what we do with EPCs. This passport is not the only item of building documentation that is supposed to be revised over time and performed, for example, every 10-years because it has a certain validity.  In line with EPCs, we could figure out that EPC assessors could be responsible for updating the building information and building documentation, at least with respect to some topics. Related to energy ratings, this is quite direct. The inclusion of health and wellbeing parameters, depending on how far we go, could also be introduced in this vision. The question of meeting the targets between predicted and actual performance is maybe to be dealt slightly differently, because this issue is to be considered when we renovate the building. If we just exploit the building without a renovation programme or plan, maybe the strategy could be slightly different. Some companies offer their services to perform this analysis along with the deep renovation process. Depending on the topic, perhaps the professionals to be involved can be different, but not yet totally conclusive. Robert Cohen: I was at a very large meeting of financial investors who are interested in the building passport, not really for understanding the energy situation in a building, but to understand the investment potential for the property.  If they have this data digitally they can play this financially, and that is also why there is a lot of interest in the building passport.   hybridGEOTABS Q&As   How do you deal with the fresh air and ventilation in hybridGEOTABS? (There is a system that uses the slab to condition fresh air, is that considered?) Bjarne W. Olesen: We don't use that, but there's always a ventilation system, and often when building with TABS this is used as a secondary system to provide some cooling or heating, and if you need dehumidification. In that case it works as the secondary heating/cooling system. In othercases there may be another secondary heating system, but often it's the air system, which you have for the ventilation that's being used. But to use air to heat or cool the slabs - we know it was first introduced in Sweden many years ago, and there is a company promoting it in the UK. The difference here is energy is still carried in the air, but we want to carry so much of the energy as possible in the water, because it is more energy efficient.  Plus, there has also been discussion about how clean the channels in the concrete are, and what are the risks for bad air quality and so on. Wim Boydens: Air activated TABS are used in practice here and there, e.g. in Luxembourg, but to our opinion are especially reserved for buildings where a balance between fresh air demand and thermal demand is found, as well as the installed volume flows needed for these purposes, taken in to account the time shift that can be integrated for the thermal demand. The outdoor temperature profiles ( day-night ), as well as the building envelope and the internal loads are determining the suitability as well. As such, this concept could find cases where the advantages of night cooling and free cooling could be strong deciding factors. For example, the concept has been elaborated and proposed by our boydens engineering office in a competition for a large technical school, with passive building envelope, high occupation density, and high glazing factor for daylight purposes. In this case, the air flow was continued and controlled at night time to cool down the concrete for the next day. During day time the radiant/convective effect of the slab added to the cooled down ventilation supply by the cool core of the slab. In winter period the core was preheating the ventilation air in daytime. The fast reacting secondary system provided the additional needed heat depending on the internal loads. The concept looked promising, however challenging for the control that should obviously be predictive. But, as in so many cases, the architecture was by far the determining factor of the jury, even if they had put forward a high weight to the sustainable energy concept. Maybe the concept, even if it was rather simple, was not very well understood. Sometimes human limitations are decisive, our should we say all times?   I was very interested by the phase-changing materials being connected to Photovoltaics, especially in the night? Ongun B. Kazanci: The main idea is that we have the PCM panels in the room, removing heat from the room, so you need to get rid of that heat somehow. The photovoltaic and thermal panels (PVT) are on the roof, and normally you would install for electricity, and if you have the 'T' (thermal) you can also get some heat out if it, but you can also use them for cooling if you circulate water through them, radiating heat to the sky. We have some storage tanks in between, so they are not connected directly to the PCM panels.   Are the phase-change material panels already commercialised or not? Ongun B. Kazanci: The ones we showed are the ones we are testing are the only panels that exist, and not commercialised. So we took what was existing, tried to combine them, but found they weren't optimal for our purposes, so took a lot of time and testing. Bjarne W. Olesen: There are some other panels on the market; the first one we used was a commercial product that was able to buffer humidity.   What about using gypsum panels? Bjarne W. Olesen: But, is there piping in them? We are only talking about those that you can activate with piping. The problem with PCM is that you can use them as passive, and maybe use night air cooling to generate or make them solid again, but the heat conductivity is so bad, you need to have a very good connection where you want to remove / supply heat.   The only point was that there are gypsum panels already available and whether it is simple to just integrate some pipes? Bjarne W. Olesen: We did look at that because we took one of those gypsum boards and just had a standard suspended metal radiant panel. We thought the easy way is to take existing products. So we took 1.5-2cm gypsum panels, and made a good contact with the metal surface of the radiant panel, but it didn't work that well because of the heat conductivity. So the best way is to have the pipes within the panel. Ongun B. Kazanci: We want something that we can control, within a panel as it's not just increasing thermal inertia/mass in the room, but have something that we can do more with. There have also been some ideas to increase conductivity by using graphite in the construction, but the prices just go up, and it becomes very expensive.   Who is going to sell the MPC solution that you are developing and how it will be packaged, and by which partner? How will you do this market uptake after the project? Jiri Cigler: Energoklastr or the new start-up company set up by KU Leuven - TACO are partners who intend to take this up. One possible business plan would be, in the case of new buildings, to design and build the building by one company who also develops the model that can also be used for the validation of the design. Then this model can be used directly for MPC.  This makes sense compared to current practice, there are big savings in this development in cost and commissioning, as it no longer takes 2 years to commission a TABS system, but 1-2 months to set up all communications and then it should work. Filip Jorissen: Another possible business plan is to have existing control companies implement MPC as a substitute for RBC. Eline Himpe: We are working on a business plan within the project and there will be more outcome during the coming year.   What do you know about the cost effectiveness of MPC and PCM, depending on the current state of the building, if it is already an energy efficient building? These savings are very well evaluated using heating degree base data and so on, but in this case there is no benefit of MPC for example on the heat pump efficiency.  With GEOTABS buildings, the lower the peak load, the better the COP, would increase the potential of MPC much higher than the 23% improvement.  There have been comparison between RBC and MPC in the case of hybridGEOTABS buildings and the savings have been higher than 50%. Bjarne W. Olesen: For some of the bigger markets, they would implement it. Also for the need for continuous maintenance of a system, which you can combine with MPC. So I certainly think there is a market for it. Filip Jorissen: Depending on the implementation, the cost effectiveness does not rely only on energy savings, i.e. we hope to show using the demonstrations that MPC has improved robustness and that MPC requires less implementation time and less commissioning. Furthermore, variable electricity prices and improved fault detection and fault handling can be integrated, and besides cost savings substantial sustainability gains can be realised by e.g. increasing the share of renewable and residual energy sources (R2ES), long-term sustainable use of the underground, use of low-exergy systems … if ‘the polluter pays principle’ is appropriately implemented, this evidently also results in cost savings. Wim Boydens: If you compare the MPC solution with continuous commissioning, it is clear who scores best in the whole investment and operation cost. Continuous commissioning is always present in a way, even if it is done in a non exemplary or only corrective way by just reacting when problems occur. The (loan) cost of these interventions are huge, but hidden in maintenance costs for bigger buildings.  

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Key Modules and Optimisation Approach for hybridGEOTABS Buildings: Background and state‑of‑the‑art Our consortium partners, Héctor Cano Esteban, Qian Wang, Jan Hoogmartens and Ongun Berk Kazanci introduce hybrid MPC GEOTABS and its key modules, and their optimisation in the REHVA Journal's February 2019 edition.   As the first article of a serial of project disseminations, this paper introduces the working principle of hybrid GEOTABS, as well as their main components/modules. The optimization approach of key modules in common practice is also discussed. This article aims at providing a basic knowledge of the concept as a preparation for the up-coming optimization development and integration of the involved key modules. Subjects wthin the article focus on: Hydronic radiant heating and cooling systems : TABS and its optimization approach Heat pump and secondary system module and its optimization Geothermal and renewable supply module optimization Read the full article here  

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Our workshop at WSED2019 - World Sustainable Energy Days, was held on 28th February at the European Energy Efficiency Conference, in Wels, Austria.   Wim Boydens introduced the workshop as Chair and addressed both the state of the art of hybridGEOTABS technology and the future potentials in terms of results' exploitation. Presentations included topics on Heat pump design and markets, model predictive control, geothermal applications, design and value of hybridGEOTABS buildings. Our total number of attendees reached 11 external stakeholders, as well as the six speakers presenting the project, 17 total. This encouraged a lively and discursive open debate following the talks, based on: “Challenges for market deployment and policy support”   The questions and answers have been added as FAQs providing more information on hybridGEOTABS buildings and the motivations of the project. Q&As I'm interested in the MPC controller process and how nowadays it can be effective on the outputs of the hybrid technologies? Lukas Ferkl (Energoklastr): The optimisations produced by MPC do not depend on the starting point of characterisation but, as Anke Uytterhoeven (KU Leuven) added, the important goal is to take into account the most amount of predictions and anticipations that are involved in the technology development process.   Do MPC predictions take into account inhabitants' behaviour as an indicator? Lukas Ferkl: This is not a needed indicator, but if it is taken as a parameter it will for sure improve the quality of the predictions because the more information is gathered, the best outcomes are reached when it comes to behavioral anticipations.   Are family households taken into consideration for this project and how many individuals are keen to provide behavioral data? Lukas Ferkl: Considering family households lots of data are needed, so, at the moment, public buildings such as school and offices are more predictable in terms of energy behaviours because we already know what are the daily activities involved and how they are interconnected to the building itself.   Is the problem about individual's behavioural data collection related to the involvement of volunteers that are able to participate on predictions? Anke Uytterhoeven: The development of an MPC controller has got better potential rather than giving to individual's freedom to react to the behaviour of the system.   Do saving costs on energy efficiency have to take into account the individual's issues as well? Lukas Ferkl: There are already examples where the electricity network can save costs making households pay just for the energy consumed from the city grid and not pay for the one produced locally. SEB attendee: Sadly, in Austria this is still not possible.   How could the building envelope energy storage combine the thermal comfort using a MPC controller to have a temperature adjustment not just reacting in the present, but also predicting a future adjustment? Wim Boydens: The envelope has a system of pipes that is being heated while the MPC can predict the temperature overnight or during the day for the next 6-8 hours.   Is it possible with the hybridGEOTABS system to have different comfort levels in different rooms of the building? Wim Boydens: TABS controls set a profile-controlled temperature that does not change among different zones.   For the combined heat pumps systems, and the new technologies related to them, it is needed a high level of expertise and, at the same time, we need companies that are able to provide specific technologies. So, how is hybridGEOTABS going to assure a good quality of these outcomes? Gert Dewandeleer (Nathan): The key point is to train the installers to a high level of expertise. Wim Boydens added that on the control side as well there is still lots of work to do and it constitutes a big challenge. SEB attendee agreed that on the heat pump installation side, the training is a very important issue and in her company there is already a program developed for trainings/installations.   In my company we are also dealing with TABS buildings, but they do not constitute a scalable technology if there are no experienced people that can fill the gap between the novelty and the technology itself. Anne Caminade (Lemon Consult): Usually a tendering document is based on a collection of data that is used to develop the project, letting the installers be aware on how to work with the systems involved. Also, students can be included in training programmes as well, and in any case there is always a quality assurance assessment for every project launched. Wim Boydens noted there is also the plan to start a training body that is not focused just on the heating pumps installation, but on their integrations with other systems. Gert Dewandeleer added that from the manufacturers side there is already the possibility for the installer to actually visit the installation site checking whether or not the heat pump was installed correctly.   Who are the potential customers of the project? Wim Boydens: At the moment the project outputs are being tested on 4No. case study buildings where elderly houses and schools are included.   How could a designer quantify the value of the flexibility of the system 20 years from now? (Wim Boydens) SEB attendee: Company customers are willing to follow a new approach but then, on a practical side, we can see that there is a lack of courage when it comes for example to public buildings (using an example about a public building in Austria that could have been a good starting point to invest in new energy systems, but it then resulted in a weak designed construction). Another example in Salzburg, was how inhabitants are slowly moving outside the city, in the suburbs, to build single family houses and the key problem is that construction companies still don’t know that they can already use new technologies. In addition to this, the company already has a team working on building services, and the Austrian regulation schemes require different indicators combinations not only focused on energy efficiency, but also on primary energy consumption.   Another issue is that the technology focuses on single buildings, while it should be focused on a district. Lukas Ferkl: An example related to a district in Netherlands shows good results and it is working fine even if the starting investment was high.  Plus there is also another call within the H2020 projects to be exploited concerning energy districts.   Does hybridGEOTABS also considers the retrofit of existing houses? Wim Boydens: There are already tests on the ceiling effects and the face-change materials. Anne Caminade then gave a short introduction to face-change materials.   Regarding the installation of heat pumps, in Salzburg there are many cases where there is no possibility for the installers to drill (geodetic local regulations issues). Wim Boydens: This also happens in Luxembourg, where there is no possibility to drill as there is an underground layer of drinkable water.  In countries where there are no rules on geodetic regulations it is better to not rush the technology.   The discussion ended with Wim Boydens addressing the potentials of hybridGEOTABS and how nowadays people are of course attracted by new technology advantages, but in order to have a market uptake it also needed a life-cycle analysis otherwise, and SEBs agreed, companies will not invest on them. The feedback about the whole WSED event was excellent – more than 660 experts from 60 countries participated in the 3 conference days of the World Sustainable Energy Days.

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Testbed building up-and-running Our partners from Energoklastr, have been monitoring this small-scale testbed building, located in Prague (CZ), at the University Centre for Energy Efficient Buildings (UCEEB). It is now running the last of its tests, with the aim of evaluating various cost functions and validation of simplified models for Model Predictive Control (MPC). The tests are performed in our hybridGEOTABS Work Package 3 – "Development of an MPC Toolchain for the hybrid MPC-GEOTABS concepts". This is a scaled-down building with a TABS ceiling, which enables us to perform simplified tests to evaluate various hypotheses concerning the MPC. The actual “computer”, where all MPC calculations happen, is tiny. Despite the complexity of the calculations, the power of today’s computers enables implementation of MPC into such tiny devices, making them suitable for retrofitting and tight installations.

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