Civil works began on December 3rd, 2020 at the Perugia Pilot. At that time, partner IDSGEORADAR performed a ground-penetrating radar measurements survey. Meanwhile, partner R2M operated UAV flights with and without a thermal camera. And all throughout the drilling phase, partner UNIPG completed the Structural Health Monitoring (SHM).
After one week, the works completed the shallow excavations of up to 2.5 meters deep. This meant the area was ready for the 50 centimeters of the sand bed that increases the conductivity on the ground.
Later, on January 11th, the company in charge of the fieldwork started the installation of the slinky GHEXs that go 2 meters deep. It considers 5 parallel trenches, with 1.35 m of mutual distance, 24 meters of average trench length, and 53 rings for each trench.
After the GHEXs installation, on January 18th, GROENHOLLAND came to the Perugia Pilot to install the fiber optic cable (FOC) monitoring. This technology has a particular approach that allows remote checking of the new system’s performance while matting underground temperature.
To increase the innovative aspects and the scientific relevance, UNIPG installed on the first two trenches, two parallel tubes of a drip plant that allows experimental evaluations and comparisons that consider different boundary conditions and configurations, such as with varying ground hydration content.
Finally, civil works were completed on January 28th as soon as all the excavated area was backfilled with an additional 50 cm of sand. Also, the ground excavated material was reused on-site.
Furthermore, all the heating/cooling system components: heat pumps, boilers, tanks, are available on-site. And today, FAHRENHEIT’s chiller also arrived at Perugia!
Presently, UNIPG is working to complete the whole installation by the end of March and to move forward with the commissioning of the system.
The GEOFIT consortium successfully held our 6th General Assembly (GA) on November 4th and 5th, 2020, hosted remotely by R2M Solution. Important progress has been carried concerning the design of the GEOFIT systems to be installed in each of our five pilots. And although we are facing some delays during this installation phase due to the COVID-19 sanitary situation, the geothermal field in the school of Sant Cugat has been completed during the summer and installation at other pilots is planned to start before the end of the year.
Drilling and civil works for the horizontal connection to the plant room in Sant Cugat pilot (AJSC)
During the two-day meeting, we discussed the progress of our work and individual Work Packages, putting special focus on the pilots’ progress. The project moves in the right direction and the work is getting more advanced.
Among the progress included in the partners’ presentations, overviews on the last decisions made regarding the Bordeaux and Galway pilots were shown by NUI GALWAY and NOBATEK, progress on the engineering design tool for ground heat exchangers was shown by GROENHOLLAND, as well as how the GeoBIM platform is being implemented by IDP in the more advanced demo-sites, Sant Cugat and Perugia.
Two workshops were also organized during the GA, the first one to discuss the life cycle approach within the project context, led by EURECAT, and the second one to start analyzing the pilot business cases and discuss why Geothermal is an appealing technology for building retrofitting, led by R2M.
The meeting closed by setting up the next steps and plans for the upcoming six months.
On the 6th of October, IDS GeoRadar was at the pilot in Perugia to perform a Ground Penetrating Radar (GPR) survey over the area where excavation works will be executed.
Nowadays, GPR is commonly used to detect both metallic and nonmetallic underground objects, as well as providing 3D location, reporting depth, and “X,Y” location.
However, this technology has some drawbacks. Mainly, that it requires an expert, typically a trained geophysicist, to interpret the scans. In GEOFIT this issue was addressed and an algorithm, capable of detecting most of the buried utilities, has been developed.
At Perugia, IDS GeoRadar used a recently developed compact GPR array solution designed to provide a 3D mapping of underground utilities. This is called STREAM C and uses a massive antenna array with two polarizations that provide a huge amount of data, thus dramatically increasing the detection performance and the level of accuracy of the survey.
The analysis of the collected data will therefore allow avoiding damages to the buried infrastructures when performing the excavation for the heat-exchanger installation.
We have finished the geothermal catchment field in Pins del Vallès School in Sant Cugat, one of our five Geofit pilots. It consists of twelve 120 m deep vertical boreholes and one horizontal directional drilling.
Works carried out during the month of August include, on the one hand, drilling, installation of geothermal heat exchangers and pressure tests, and on the other hand, all civil and installation works related to the horizontal connection between wells and the plant room where the ground-source heat pump will be installed.
The next steps to be taken in our Spanish pilot include the installation of the passive cooling in the administrative building designed by Uponor and the installation of the new electrically-driven heat pump provided by Ochsner and currently under tests at AIT Austrian Institute of Technology GmbH laboratory.
From 27th to 31st July, SIART and IDSGEORADAR were at Sant Cugat pilot for structural monitoring, during the same week drilling works started. The goal was to perform structural monitoring before and during drilling, and see any impact in the school buildings.
IDSGEORADAR installed a Hydra-G system which monitored real-time measurements of sub-millimetric displacements in the administrative building and in the primary school. This system provides the high-accuracy and resolution radar technology. The system was accompanied by an optical and infrared HD camera providing real- time visual inspection of monitored area, draping radar data on a 3D model of the scene created using the radar system.
On the other hand, SIART installed several accelerometers in both buildings, administrative and primary school, to monitor vibrations before and during the first drilling carried out on 31st July. The goal of monitoring before drilling works is to know the building frequency, and see, once the drilling starts, if it has changed due to the vibrations propagation throughout the terrain. Once data has been captured, SIART will analyze them and present some results.
On 31st July, Catalana De Perforacions (CDP) started the drilling works at the Sant Cugat demo site. The design of the geothermal field consists of 12 boreholes up to 120m deep and one Horizontal Directional Drilling (HDD).
Image 1: location of the 12 boreholes.
While drilling the first well, some problems with the ground material, mainly clays, and the groundwater level at depths beyond around 60 meters were faced. The borehole heat exchangers are double U PERC 100 SDR 11 PN16, with a diameter of 32mm.
On the other hand, on 3rd of August, the works related to the horizontal connection between the collection chamber and the plant room where the Ground Source Heat Pump (GSHP) will be installed, also started.
These works, including the geothermal field and the horizontal connection between the chamber and the plant room, should be completed on 31st August according to schedule.
Image 2: the second borehole drilled
Image 3: excavation of the collection chamber of the pipes coming from the 12 boreholes
The stakeholders in a building retrofit project often are unfamiliar with shallow geothermal energy (SGE) technology and potentially have conflicting requirements [MUSE, 2019]. The following table shows the influence and interest of (in)directly involved stakeholders of typical SGE for building retrofit projects, in the framework of suggested management principles.
Building upon results of ‘sister projects’ such as the aforementioned MUSE, as well as GEO4CIVHIC and GRETA among others, GEOFIT takes a close look at the wide spectrum of SGE stakeholders in order to develop commercial-ready solutions. In order to gage SGE for building retrofit viability in Europe from a commercial standpoint, the typology of existing building stock is a critical factor. Therefore, one of the key images for this purpose comes from the Buildings Performance Institute Europe , shown below:
Another focus of GEOFIT Market Analysis is the sizing of market opportunities, defined by the specific technologies or ‘markets’ that together make up the full GEOFIT solution set. Initially investigated ‘markets’ include ground source heat pumps, heat exchangers, structural health monitoring, geographic information systems, building information modelling, building energy management systems, architecture, engineering, and construction, horizontal directional drilling, project management software and services, heating, ventilation, and air-conditioning, and drones.
Bienvenue a Bordeaux! The most elegant city in France! Last week we were at the Geofit4th 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!
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.
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.
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.
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.
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.
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.
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.
This project has received funding from the European Union’s H2020 programme under Grant Agreement No. 792210.