Most Easy, Efficient and Low Cost Geothermal Systems for Retrofitting Civil and Historical Buildings

Project Information

GEO4CIVHIC

Grant agreement ID: 792355

DOI

10.3030/792355

Project closed

EC signature date 6 April 2018

Start date 1 April 2018

End date 30 November 2023

Funded under

• SOCIETAL CHALLENGES - Secure, clean and efficient energy

Total cost

€ 8 143 120,97

EU contribution

€ 6 841 960,75

Coordinated by

CONSIGLIO NAZIONALE DELLE RICERCHE
Italy

Periodic Reporting for period 3 - GEO4CIVHIC (Most Easy, Efficient and Low Cost Geothermal Systems for Retrofitting Civil and Historical Buildings)

Reporting period: 2020-10-01 to 2023-11-30

Summary of the context and overall objectives of the project

GEO4CIVHIC developed and demonstrated easier to install and more efficient Ground Source Heat Exchangers (GSHEs) and new Heat Pump (HP) solutions. This was done by using an innovative compact drilling machine tailored for the narrow built environment, by developing a compact rotating-vibrating drilling head and by developing several geothermal and dual source HPs. These were designed for building retrofits maintaining high temperature heating systems in most cases. A decision support system (DSS) and other tools support a holistic engineering and controls approach.
GEO4CIVHIC’s target was to accelerate the deployment of shallow geothermal systems for heating and cooling (H&C) in retrofitted buildings, historical buildings in particular. The project addressed new approaches to borehole drilling, high temperature heat pumps efficiency, the use of refrigerants with low global warming potential (GWP) and software assessing the feasibility of shallow geothermal H&C. An expert group of companies and research centres, experts in the entire value chain of shallow geothermal installations, developed these innovative and sustainable solutions.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Constraints and barriers for the application of shallow geothermal energy in urban contexts were analyzed.
The concept of “Drillability”, predicting the most suitable drilling methods for a given underground, was used to develop European and municipal scale maps validated in the different demo sites. Such maps as well as the Application developed for the purpose will help designers in the selection of the most suitable drilling technique in function of the underground.
New technological solutions for each component of a geothermal system, such as drilling machines and equipment, GSHEs and HPs were developed.
A compact, versatile drilling machine (Figs.1,2) able to operate in difficult to access built environment was designed, manufactured and equipped with a novel vibrating-rotating drilling head (Fig.3). The main features of the drilling machine are increased accessibility, reduced noise, lower emissions and space requirements, as well as less drilling time and cost.
GSHEs were designed with better performance to extract more thermal energy per meter from the underground and quicker to install.
Different types of HP (Fig.4) have been developed to overcome the restrictions for historical buildings and reducing the refurbishment costs and their invasiveness. Prototypes were designed to operate at high temperatures with good efficiency avoiding total or partial replacement of radiators. Additionally, dual source HP prototypes were developed to operate with both ground and air energy source, avoiding load unbalances in the underground and/or less GSHEs to install.
Research into low environmental impact refrigerants led to the choice of low GWP refrigerants for the HP prototypes.
Software tools were developed providing a holistic engineering solution to optimize installation and operation of shallow geothermal systems. (a) A DSS, freely available online, assesses the pre-feasibility cost and impact of shallow geothermal solutions. (b) A “Drillability” mobile Application for iOS and Android devices recommends a preliminary drilling solution, length and number of borehole heat exchangers to install. (c) A Building Energy Management System, based on Artificial Intelligence, integrates geothermal energy with other Renewable Energy Sources to minimize energy taken from the grid.
The technological solutions were installed and monitored in 3 pilot sites (Padova, Bilbao, Valencia) and in 6 real sites with different urban contexts, climates and undergrounds [Ferrara, Padova and Udine (Italy)], La Valletta [Malta], Mechelen [Belgium] and Greystones [Ireland].
Furthermore, the solutions were implemented "virtually" in 12 buildings through energy simulations and feasibility studies.
Economic and environmental impact assessment ran over the entire duration of the project, including vibration and noise measurements in the real demonstration sites.
A holistic strategy assessing the potential of the integration of GSHPs in historical buildings has been developed. Solutions were demonstrated to a wide variety of stakeholders, showcasing the methodologies for their successful integration including the drilling and completion of GSHEs as well as the integration of the HP solutions to deliver both H&C with minimal intervention to different building fabrics and types.
An analysis on the cost effectiveness and performance of the solutions from a market point of view was made across a diverse range of scenarios: real and virtual cases, covering both civil and historical buildings, were assessed.
Communication and dissemination activities were running over the development of the project.
A comprehensive training package (user manuals, technical brochures) translated in 6 languages besides English was developed and used in the different training courses and workshops.
The creation of the “European Centers of Excellence (EcoE) for Shallow Geothermal Application in Civil and Historical Buildings” in 4 Universities is worth mentioning among dissemination activities. The ECoE aims to improve the knowledge and expertise in shallow geothermal H&C among geologists, drillers, designers, researchers, by exploiting its resources to help to move the business forward.
The EcoE (https://geo4civhic.eu/european-centers-of-excellence/) will continue even after the end of the project.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

GEO4CIVHIC managed to open new perspectives for the application of geothermal energy in urban contexts.
Shallow geothermal energy is one of the most efficient solutions for the decarbonization of the H&C of civil and historical buildings.
Drillability maps recommend to stakeholders the drilling technology to use.
The versatile drilling machine facilitates access in narrow roads, can be lifted in confined spaces at reasonable costs due to a reduced weight and enables drilling several boreholes in a single area. In addition, a semi-automatic feeder allows safe and fast change of drilling shafts and casings with much less human effort.
The vibro-rotating drilling head demonstrated being a valuable solution in hard and consolidated undergrounds. It allows for a reduction of the drilling time, noise and fuel consumption since it requires much less compressed air flow than state-of-the-art methodologies (e.g. down-the-hole-hammer).
The drilling rig, the semi-automatic feeder and the rotating-vibrating drilling head reached the market.
The novel HPs demonstrated very good performance and reliability. With such HPs, the existing heating system can be preserved, reducing the renovation costs. The dual source HPs allow for the use of the air as a source, reducing the size as well as the cost of the geothermal field. The latter reached already market stage.
GEO4CIVHIC solutions, despite higher initial investment costs, offer substantially higher economic returns over project lives of 25 years compared to traditional retrofits with gas boilers, air-to-air or air-to-water HPs. These results would even see substantial improvement in the scenario of increasing gas prices, driven either by the general economic environment or by policy measures.
Shallow geothermal systems can produce a significant benefit on the health, reduce the urban heat island effect and avoid heavy investments in the electricity grid due to their higher efficiency over air to water HPs.

figure-3-the-rotating-and-vibrating-drill-head-in-operation-in-ireland-1.jpeg

figure-1-the-compact-drill-rig-being-lifted-into-an-enclosed-garden.jpg

figure-4-the-co2-driven-heat-pump-supplying-high-and-low-temperature-terminals-mounted-in-series.jpeg

figure-2-the-semi-automatic-arm-lifting-drilling-shaft-and-the-rig-with-the-rotating-vibrating-head-in-the-background.jpg