Forth Assembly in Bordeaux

Bienvenue a Bordeaux! The most elegant city in France! Last week we were at the Geofit 4th General Assembly where we had the chance to share all the advances achieved since the last meeting.

We managed to get into intense planning and discussing agenda, mostly related to very important issues regarding the implementation of the pilots and how the technical solutions and legal issues could be approached. 

We found out, for example, of an interesting opportunity involving the different types of soils in the five different pilot sites. Drilling on different soils are options that can be explored and harnessed for the project interests.

The assembly also dealt with technical issues that will affect the activities scheduled for the next six months.

 

 

We also visited the demo site in Talence, in the very same building where we carried out the meeting. Our host (SAED) kindly showed the space where the future Geofit installation will be placed. It was almost as being on a living lab! Technical discussions and problem solving for the heat pump installation were part of the second day too.

 

 

 

 

The weather wasn’t very inspiring but we managed to get a very clear path for the next six months and everyone left with a positive feeling facing the new work roadmap. Merci la France!

 

 

 

Low temperature heating and high temperature cooling

Article by  Henrikki Pieskä (KTH) and Qian Wang (Uponor)

A heat emission system is an integral part of a building’s HVAC-system. Heat emission system is the interface between the heat source and the building user, so a proper design is essential both for energy efficiency and user comfort.

Example of a low temperature heating system combined with a heat pump (Hesaraki and Holmberg, 2014)

 

The objective of studying heat emission systems in GEOFIT is to present designs for innovative low temperature heating (LTH) and high temperature cooling (HTC) systems for the studied pilot buildings. There are many types of LTH and HTC systems, but common to all of them is that in comparison with conventional heat emission systems they require smaller temperature difference between the heat source and the conditioned space to operate the system.

LTH and HTC have therefore potential for increasing the efficiency of ground source heat pumps, because the smaller temperature difference means the heat pump has to do less work to cover that difference. In temperate climates it is in some cases even possible to use passive cooling, where a HTC system is directly coupled with a ground heat exchanger, thus bypassing the heat pump completely.

Ceiling cooling absorbs heat through both radiation and convection
© Center for the Built Environment at UC Berkeley, ©Caroline Karmann, CC-BY-SA-3.0

RADAR TECHNOLOGIES FOR MANAGING THE RISK RELATED TO THE DRILLING/DIGGING IN GEOFIT

By IDS GeoRadar

Geothermal based building retrofitting involve complex operations, such as drilling and digging, which must be considered as risky activities both for the excavation crews and the buildings close to the work area; managing these risks is one of the key objectives for GEOFIT.

In fact, digging up an area without having reliable information on existing utilities and the local geology, can be problematic, even dangerous. For example, it’s worth noting that, in Europe, during new installations, about 90,000 incidences of third party damage to gas pipelines are reported every year and 100,000 in USA. There is little doubt that these instances of damage would be reduced by the use of reliable location techniques.

A typical tangle of buried assets

In this respect, the Ground Penetrating Radar (GPR) technique is very attractive because, amongst the various state-of-the-art methods available, it is the only one capable of accurately locating both metallic and non-metallic buried objects, without prior knowledge of their position.

Historically, the location of underground plant and equipment has been based on record information held by utility companies. This information, even if it exists (and much of it does not) is often inaccurate, incomplete or out of date.

Radar is well-known for its ability to detect aircraft, ships, vehicles, birds, rainstorms and other above-ground objects. It relies for its operation on the transmission of electro-magnetic energy, usually in the form of a pulse, and the detection of the small amount of energy that is reflected from the target. The round-trip transit time of the pulse and its reflection provide range information on the target.

Buried objects can also be detected by ground penetrating radar (GPR) and there are details of such work dating back to 1910, with the first pulsed experiments reported in 1926 when the depths of rock strata were determined by time-of-flight methods. The technique has since been used extensively in geophysical and geological investigation with the emphasis usually on deep penetration. Deep penetration requires operation at frequencies of a few MHz or tens of MHz, requiring large antennas and the accompanying consequence of low resolution of the objects detected.

The detection of buried utilities’ plant imposes a particular set of constraints on the effective use of a GPR. The majority of buried plant is within 1.5m of the ground surface, but it may have a wide variation in its size, may be metallic or non-metallic, may be in close proximity to other plant and may be buried in a wide range of soil types with implications for large differences in both the absorption and the velocity of propagation of electro-magnetic waves.

Rapid GPR data collection (IDS GeoRadar Stream C system)

In addition, a further limitation of the technique concerns the interpretation of GPR data, which is not trivial in many situations; in this respect, the latest developments in GPR are oriented towards the design of equipment featuring real-time 3D high resolution images of surveyed areas.

However, this visualisation improvement cannot fully solve that limitation; for this reason, in GEOFIT  workpackage 2 novel and effective automatic processing tools will be developed. These tools are intended to aid operators to analyse the large amounts of information (tens of Gigabytes) as quickly and efficiently as possible, so that an exhaustive collection of underground information will be possible.

3D presentation of buried assets in a CAD.

Moreover, drilling and digging may in principle interfere with the stability of buildings close to the work area; as a matter of fact, ground in the vicinity of the buildings under renovation may be subjected to movement or even collapse when drilling/digging and this can compromise the stability of that building.

The solution being implemented in GEOFIT is based on the GBInSAR (Ground Based Interferometric Synthetic Aperture Radar) technology. GBInSAR equipment are nowadays used to remotely monitoring millimetre displacements  at large distance (up to several kilometres).  Typical applications concern the slope stability monitoring in mining plants, landslide monitoring in risk areas close to civil buildings, bridge load testing and stability monitoring.

Unfortunately, available technology use signals with a main frequency around 16 GHz and this does not permit to achieve a very high resolution and neither to measure the displacement of the building in 3-D.

Monitoring a dam with a high definition GBInSAR

IDS GeoRadar has recently designed a radar that uses a millimeter wave technology (W band) and this is theoretically able to provide both range and angular measurements with a very high accuracy  (< 0.1 millimiters). This technology is therefore candidate for being exploited in the monitoring the stability of a building in 3-D.

In this sense, in some pilot sites of GEOFIT a real-time stability monitoring session will be executed with the radar installed in the area interested by the retrofitting process.  The system will therefore provide real-time information about the displacement of the building surface and warn the operators if a displacement of the buildings is measured.

Possible output during building monitoring, the measured displacement is visualized as heat map

 

GEOBIM: Geographical and Building information creating Integrated Environments

By Sergio Velásquez – IDP

GEOFIT project represents a challenge and an opportunity for a geothermal based retrofitting of existing buildings. It covers several disciplines in terms of the processes developed and the data provisions at architectural, physical, geographical, technological, contractual, economical and life cycle levels.

In general terms, physical and energetic assessment is required to start a correlated retrofitting strategy aimed to improve the energy efficiency of an existing building. At the same time, the participation of different actors and disciplines are based on technical appreciations and judgements following a segmented timeline which provides a planning strategy to be considered complex in terms of the diversity involved. The strategy must be quite clear because different actors are playing to get the objectives from different expert disciplines and an integrative standardized methodology must be implemented because the sources of information are also diverse.

Expert disciplines:

      • Architecture
      • Geology
      • Geothermal analysis
      • Drilling
      • GIS
      • Heat exchange
      • HVAC
      • Mechanical, electrical and piping
      • Heat distribution
      • Control and monitoring
      • Economical
      • Contractual/legal
      • Construction/installation
      • Commissioning

Information sources:

      • Building owner
      • Geographical data provider
      • Geological data provider including drilling information (boreholes)
      • Geothermal systems design
      • Geothermal heat exchange design
      • Energy analysis, simulations and optimization (building)
      • Heat exchange and distribution design
      • Regulatory framework and permits

These two paths have been integrated with a common Integrated Design and Delivery Solution methodology (IDDS) that has made possible to define the BIM execution plan. The execution plan brings together actors and disciplines and states the information exchange requirements aimed to facilitate the integration within a GEOBIM platform by using open standards and Industrial Foundation Classes (IFC-4).

 

Onsite execution, delivery solutions and GEOBIM environment for GEOFIT project

 

GEOBIM concept is an integrated environment where architect (defined in terms of BIM -Building Information Modelling) and geographical information covering the geothermal conditions of the building site, come together. It is expected that BIM data coming from different CAD formats and translated into IFC-4 can be reused in geographical applications – BIM to GIS solutions. This is another challenge to be solved by GEOFIT project because there are many differences between BIM and Geo data formats. With respect to geographical information, CityGML and LandInfraGML are the most common standards and BIM is defined in IFC format within GEOFIT project. The main outcome is two geometrically model of identical objects, adding attributes (metadata) and level of detail to the objects in both development environments and use compatible open standards.

GEOBIM concept is an integrated environment where architect (defined in terms of BIM -Building Information Modelling) and geographical information covering the geothermal conditions of the building site, come together. It is expected that BIM data coming from different CAD formats and translated into IFC-4 can be reused in geographical applications – BIM to GIS solutions.

GEOBIM integration has been thought as a solution for the GEOFIT demo sites management covering the multidimensional concept of BIM, nevertheless, to import BIM data into geographical information systems is not a trivial task. The seven dimensions are: Geographical location, vector information (planes, drawings and available documentation), three-dimensional rendering of the buildings, duration and timing analysis – scheduling, cost analysis, sustainability assessment, lifecycle, and facility management and control beyond building occupancy. IDP supports the GEOFIT partnership to create this integrated environment providing a right decision making tool among all of the potential solutions along the geothermal facility lifespan of the project.

 

Development of a ground source hybrid heat pump with cooling function

By Fahrenheit

In the field of adsorption heat pumps, there are currently few studies on the combination with compression heat pumps and gas condensing boilers. Compared to conventional compression heat pumps, this concept offers a better EER and COP and makes it possible to use the optimum ratio between electrical and thermal energy depending on the operating conditions.

Part of the Geofit project is therefore the new development of a ground source hybrid heat pump consisting of a zeolite-based adsorption unit, driven by a gas condensing boiler, and an electrically driven compression unit. In this way, the electrical energy consumption of the heat pump is reduced and the system is able to work with less environmental energy, which also allows the realisation with less powerful earth sources. Due to the desired modular design, the concept will later be flexible and suitable for new installations, but also for retrofitting applications.

The heat pump developed by Fahrenheit GmbH will be tested in the laboratory of CNR ITAE under various boundary conditions and optimised for control before validation under real conditions in the demonstration buildings in Italy and France.

The focus of the development is on a simple connection of the gas condensing boiler and the ground collector to the hybrid heat pump and the optimisation of the control of the system.

Drilling bit materials for an improved performance

by Montse Vilaseca, EURECAT

Drilling is a key technology enabling heat exchangers installation and plays an important role in the building industry, both in sedimentary as well as in rock drilling. Tools employed in drilling are known as drill bits, and are the responsible for mechanically penetrating and crushing the rock underneath them. The wear of drilling tools has always been a predominant factor for the costs of geotechnical engineering measures and hard rock excavation. This fact is not only related to material and personnel costs arising from drill bit maintenance and replacement but also because of the direct and negative impact of wear on the drilling performance of a worn drill bit. Improper selection of a bit results in lower penetration rates, fast wearing of the teeth and frequent bit changes, which results in higher drilling costs overall.

Drilling is a key technology enabling heat exchangers installation and plays an important role in the building industry… Improper selection of a bit results in lower penetration rates, fast wearing of the teeth and frequent bit changes, which results in higher drilling costs overall.

During the first year of GEOFIT project representative tools from vertical and horizontal drilling operations (needed in the different pilots of the project) have been selected and provided by CDP after their end life. For vertical drilling, down to the hole hammer and drag bits have been studied. For horizontal drilling, tricones (crushers) have been selected. Drill bit materials and main damaging mechanisms have been characterized and identified in Eurecat aiming to select alternative materials and solutions in order to:

    • reduce drilling times
    • improve rate of penetration (ROP)
    • improve abrasion and chipping/spalling resistance of drill bits

 

Figure 1. Analysed drill bit.

 

Drill bit inserts are commonly made with cemented carbides (also named hardmetal, cermets or cemented carbides), which are sintered composite materials consisting of two phases called hard phase (WC) and binder phase (Co). This combination of hardness and toughness makes WC-Co a successful material in drill bit inserts. However, the mechanical properties of the material are strongly dependent on composition and structure. A high Co content gives a tough material and high WC content gives a hard but brittle material. In addition, WC grain size and carbon content affect the properties.

Cemented carbide buttons are inserted and/or soldered into holes of a steel tool body. Taking into account the main damage mechanisms identified in hard metal buttons of drill bits for GEOFIT project and looking into recent publications and developments, advanced alternative hard metal grades have been selected to improve their tribo-mechanical properties based on (i) varying the grain size of the hard phase and the binder content, named Dual properties (DP) and (ii) macro gradients of Co-migration. In the same manner alternative steels with high strength, high wear resistance, good toughness and good dimension stability specially designed for drilling applications have been selected. These alternative hard metal and steel grades are being systematically tested in Eurecat laboratory in order to obtain a classification of their tribological behavior (friction and wear resistance).

Wear tests have been designed in order to reproduce the same damaging mechanisms observed in drilling tools. Cemented carbide discs are slid against quartz and other abrasives used as counter parts. Quartz content of rock is one of the main geomechanical parameters influencing wear of drill bits. Test conditions (pressure, speed and time) have been adjusted until the same wear mechanisms have been obtained. Figure 2 compares surface of drill bit button from a tool and of a wear scar obtained in the lab, in both cases surface cracks, carbides deformation and adhesion of ore material are identified.

Figure 2. Scanning electron microscopy images (10,000 X magnification) of surfaces from a) worn drill bit button and b) wear scar from laboratory test.

 

Taking into account the main damage mechanisms identified in hard metal buttons of drill bits for GEOFIT project, advanced alternative hard metal and alternative steels grades have been selected to improve their tribo-mechanical properties and are being systematically tested in Eurecat laboratory in order to obtain a classification of their tribological behavior (friction and wear resistance).

Main results obtained in laboratory wear tests are:

    • Coefficient of friction: describes the interaction between drill bit material and rock material.
    • Wear rate: which is the worn drill bit material volume per sliding distance and applied force. Is obtained measuring wear scars (see Figure 3).

These are valuable parameters which are used to feed tool wear models that will predict tool live, models under development by LTU in the framework of GEOFIT project.

Figure 3. Wear scar topographic images corresponding to different grades of hard metal after wear tests under the same conditions (applied force, speed and time): G3 presents higher volume loss.

Third General Assembly in Vienna

From the 7th to the 9th of May the GEOFIT consortium gathered in Vienna to hold their third general assembly. The meeting was organised by AIT (Austrian Institute of Technology) in their premises located in Giefinggasse, which also put together a traditional Austrian dinner in the city centre for all partners to enjoy the food and carry on discussing emerging ideas.

Significant progress were made regarding the core hardware technology to be installed on the pilot sites during this three-day meeting. Very important decisions were made on the coordination of work packages. 

Highlights included the management of data gathering and analyses from the pilots’ hardware implementation, and reviewing the advances made regarding the advances on the overall system and building integration for efficient management.

AIT also organised a visit to their impressive lab premises where all partners could see by themselves the prospective advances that can be reached in geothermal energy development. The building itself had implemented energy efficient tools that help reduce energy consumption.

On top of the general assembly a very interesting stakeholder workshop was held on the 8th May with participation from AIT -that was also the organiser- GROEN, CDP and Uponor were all partners participated. 

The consortium closed the meeting  having established clear goals for the next 6 months and looking forward to the work ahead.

Implementation of the pre-retrofit data monitoring

By Adriaan Brebels, i.LECO NV, Belgium

For the different demo sites in the Geofit project a one-year pre-retrofit data-monitoring plan has been implemented. The data to be collected comes from different instruments and different sources.

Fig 1: Current model of energy usage. The current energy usage of heat and electricity is to take it from the net when you need it.

Locally, we measure the internal and external climate parameters (temperature, humidity, CO2, wind speed…) and energy consumption (heat and electricity) for the different participating buildings. Specific for the parts of the building that will be covered for heat by the heat pump, the additional installation of a heat meter will provide the time series for the heating profiles.

The local conditions are measured by weather stations as by IoT devices from Netatmo, or from weather stations and internal sensors that were already in place. The data from the different energy meters and internal sensors are collected by the local Building Management Systems or directly from the energy meters by a gateway.

Beside the local data, also the data from the weather forecast for the sites are synchronized into the IoT platform ‘EcoSCADA’ (Ecology/Economy Supervisory Control and Data Acquisition) of I.LECO. This makes it possible to have online dashboards and reporting besides the possibility to retrieve the data by a fast API.

Fig 2: Functionalities of the IoT platform EcoSCADA

Based on all this collected data the best dimensioning of the heat pumps can be defined and additional investments can be advised for local production (as solar panels) and local storage (as chemical batteries or hot water)

This time-series provide insight into consumption anomalies (for instance because the building uses too much energy during nights, weekends and holidays) what can result in energy savings after the retrofit.

Additionally – also due to the heat pumps – there will be more time flexibility for the load in the energy sources (for instance by pre-heating or lowering ventilation when the CO2 is still low enough).

All this will prepare a control strategy for the multi-component energy system. This control system needs to optimize the energy flow between the different components. This is done using forecast technology (for local consumption and local production) and markets’ knowledge (as the price of electricity). Other consumers out of the energy community can use the electricity. Energy providers can base the billing on blockchain technology instead of the classing billing.

Fig.3 : Multi-component energy system. The optimization of the usage of the different sub-components can avoid peaks and can contribute to the net stabilization.

 

Progress on demonstration activities

by Gisela Soley, from COMSA

The enhanced geothermal systems that are being developed under the GEOFIT project will be installed in 5 pilots located in 4 different countries covering the following scenarios: urban retrofitting, rock drilling and seismic retrofitting.

Since the start of the project, demo sites’ owners have been providing information to the technical partners in order to start the development of the most appropriate designs in terms of energy efficiency and integration within the existing building. Good understanding of the current situation is mandatory and following the IDDS (Integrated Design and Delivery Solutions) methodology through workshops with local stakeholders and partners involved and monthly calls has allowed determining the type of drilling (vertical, horizontal or excavation) and ground heat exchangers, and type of heat pump (electrically-driven developed by OCHSNER or hybrid developed by FAHRENHEIT) to be installed, as well as proposing innovative heating and cooling distributions systems for the different scenarios.

Below are detailed some of the technologies that have already been agreed in three of the pilots and also explained the constraints encountered up to now in the other two.

Pins del Vallès School in Sant Cugat (ES). The power needed is about 100 kW, so it has been estimated that 19 boreholes of 120 m deep are required. Besides improved vertical drilling, Horizontal Directional Drilling (HDD) will be performed (several alternatives have been analysed by CDP as shown in the picture below). The heat pump is being developed by OCHSNER and technical specifications and tests are being carried out in AIT labs. In principle, the heat pump will be used for heating 3 buildings (administrative, primary school and sports pavilion) and passive cooling has been proposed for the administrative one.

Sant’Appollinare offices in Perugia (IT). The office building for demonstration activities is placed in the Sant’Appollinare Medieval Fortress and its heating and cooling demand are about 16kW and 6kW respectively. As the loads are not very high it has been considered a good pilot to install horizontal ground heat exchangers and optionally, coiled slinky ones, and a hybrid configuration for the heat pump that is being developed by FAHRENHEIT and tested in CNR ITAE labs. This building has floor heating as heating distribution system and it has been proposed to refrigerate the offices by free-cooling.

Kingfisher swimming pool in Galway (IE). In this building there is CHP and two gas boilers. The two gas boilers cover the heating demand during the night; so apparently, the best solution will be to replace these two boilers by the ground source heat pump. This pilot is still under decision with regards to number of boreholes needed and capacity of the heat pump, but it has been agreed that improved vertical drilling will be performed and that OCHSNER will manufacture an electrically-driven heat pump as heating demand is quite high.

University building in Bordeaux (FR). In the last weeks, a new building on the ENSAM campus in Talence has been proposed after facing some technical and administrative constraints with the initial Nobatek office building demo site. The new building is being under study by the partners involved to see if it is suitable for shallow heat exchangers and for a hybrid heat pump system. The Consortium expects to have a clear picture of this pilot in the next general assembly taking place in May.

Residential building in Aran Islands (IE). After the visit in Aran last January, where eight different houses were surveyed, the Consortium has to come to a decision concerning which house(s) will be selected for demonstration activities according to the heating systems installed, emitters, existing passive measures if any, drilling space, accessibility and internet connection. CFO is in contact with the householders in order to get their approval. What it is clear is that retrofitting measures (external insulation and low temperature heating system) must be considered in order to improve the thermal comfort as well as to ensure the efficiency of the geothermal system to be installed. In addition, it is being analyzed that the final retrofitting and geothermal system proposed have the broadest range of applicability in the Aran Islands.

In parallel, monitoring plan for each demo building is being elaborated in order to establish the baseline which will allow comparing and assessing the performance of the building before and after renovation. While weather stations are now operational in Sant Cugat in order to monitor indoor/outdoor conditions, we are pending of their installation in Galway and Perugia. Next step is to install heat and electricity meters so that the 1-year pre-intervention monitoring period can start in these three pilots. Once Bordeaux and Aran pilots are clearly determined, the team will proceed with the monitoring tasks.

 

Thermally driven heat pump development and testing

By CNR – ITAE

Within GEOFIT project, a novel heat pump will be developed, able to efficiently exploit geothermal energy to provide heat under several climates and conditions. To this aim, a hybrid configuration for a reversible heat pump is being developed: it consists in the coupling of a gas-driven adsorption cycle with a vapour compression cycle. In this way, the temperature lift on the vapour compression cycle that is commonly employed is reduced and the energy consumption of the component is lower. The proposed solution, that is modular and based on commercial components, is suitable for both new installations and retrofitting applications, allowing a high flexibility.

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