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

Periodic Reporting for period 2 - GEO4CIVHIC (Most Easy, Efficient and Low Cost Geothermal Systems for Retrofitting Civil and Historical Buildings)

Okres sprawozdawczy: 2019-10-01 do 2020-09-30

GEO4CIVHIC (Most Easy, Efficient and Low Cost Geothermal Systems for Retrofitting Civil and Historical Buildings) develops and demonstrates easier to install and more efficient Ground Source Heat Exchangers. This is done by using innovative compact drilling machines tailored for the built environment and by developing or adapting Heat Pumps for retrofits in combination with other Renewable Energy Sources through a holistic engineering and controls approach.
GEO4CIVHIC’s target is to accelerate the deployment of shallow geothermal systems for heating and cooling in retrofitted existing and historical buildings. It is based on innovative solutions developed by an international expert group of companies and research centres, experts in the complete value chain of shallow geothermal installations.
The different barriers in urban environment (technical, social, cultural, economic and legislative) for shallow geothermal heating and cooling in the renovation of existing civil and historical buildings were identified.
The concept of “Drillability”, predicting the most suitable drilling methods for a given underground, was utilized to develop maps at European (Fig. 1a,b) and at municipal scale for the different real sites.
Such maps will help designers in the selection of the most suitable drilling technique in function of the underground.
The drilling methods, Borehole Heat Exchangers (BHE) and grout developments take into account the constraints of drilling in built environment. A compact, versatile drilling machine (Fig. 2) able to operate in built environment was designed and manufactured and coupled with a novel vibrating-rotating drilling head, increasing accessibility, reducing mud, noise, space requirements as well as drilling time and cost.
Tests with the new machine and its components were performed in a quarries in Italy, in Germany and at the premises of partner Hydra in Molinella. The roto-vibrating drill head of ThyssenKruppInfrastructures confirmed its performance in basalt rock. The learnings from the tests were extremely useful adjust the drilling tools, to re-design the heat exchanger joints and to organize the drilling in the demonstration sites.
The drilling operations at the pilot site of the CNR in Padova lead to redesigns of the heat exchanger joints and the drill bit to lose of the Hydra-Red drilling methodology. The patent on this methodology, requested during the Cheap-GSHPs project, has meanwhile been granted in Italy.
A survey of the very shallow and horizontal geothermal systems was made. The simulations and monitoring of one particularly interesting system, the Steinhauser system, demonstrated very positive results.
Refrigerants with low global warming potential (GPW) were simulated, tested and selected for the heat pump prototypes (Fig 3). Five different heat pumps are developed. Plug and play heat pumps was tested in laboratory and installed in the pilot sites in Padova and in Bilbao. A monitoring system with novel temperature sensors and in house made thermal energy meters to study of the refrigeration cycle in situ was built. The hybrid low temperature heat pump for Malta is in laboratory testing whilst the high temperature prototype for the Dublin site is under construction. The special prototype to supply simultaneously the combination of medium and low temperature systems for Mechelen passed the laboratory testing. The high temperature hybrid heat pump for the historical building in Ferrara also passed laboratory tests successfully.
At the CNR pilot, the well points, converted into co-axial heat exchangers, have been installed, sealed with the special grout and pressure tested. In addition, one of the co-axial heat exchangers was installed.
Several optimization applications and tools are under development (DSS for rapid feasibility assessment, applications to support designers on the drilling and end-users in management of energy, management system integrating GSHPs with other renewables).
Almost all design and preparatory work for the installations at the four demonstration sites has been completed. Effective installation has been delayed due to the COVID-19 pandemic. GEO4CIVHIC technologies will also be applied to 13 virtual sites.
A legislative and regulatory analysis and an Environmental Impact Analysis (EIA) for the case study sites was completed. A Life Cycle Analysis compares the project technologies with other heating and cooling solutions. The EIA demonstrated reduced environmental impacts at the construction phase. A risk assessment based tool to support decision makers at the initial stages of retrofit project implementation has been developed for the DSS. A separate tool to support policy makers in the planning and management of shallow geothermal resources in urban environments was developed. Detailed recommendations to national standard bodies and to the CEN technical committee have facilitated new EN standards on BHEs.
A first draft of the key exploitable results (KERs) and the Intellectual Property (IPR) was compiled
The Training, Education, Dissemination (TED) plan is being implemented by all partners with presentations in remore conferences, participations in fairs and publication of scientific articles. The setup of the Centers of Excellence continued with the underwriting of a Collaborative Agreement between partners and with the definition of the training modules, their content and the respective responsibles.
Progress towards cost efficient installation of shallow geothermal systems in retrofitted buildings in urban environment is encouraging
Drillability maps at European and municipal scale recommend to stakeholders the drilling technology to use. Several elements of the piling methodology were improved, tested and redesigned bringing the technology closer to market and reducing further the costs. The methodology requires low torque and small amounts of water in unconsolidated soils, reducing machine size and nuisance. This facilitates the use in built environment.
The newly developed roto-vibrating drill head was mounted on a small drilling machine with a dismountable power pack and a telescopic support of the mast. Such a machine facilitates access in narrow roads or can be lifted in confined spaces at reasonable costs due to a reduced weight. The telescopic mast support permits to drill several boreholes, also inclined, without having to displace the machine. Finally, the machine is equipped with a diesel engine of the latest generation, the first in kind from the engine supplier achieving very low emission levels.
The new plug and play geothermal heat pumps of small size allow the replacement of the heating and cooling systems in individual apartments of condominiums with minimum installation costs. Connecting such pumps to a shared set of borehole heat exchangers allows apartment owners to maintain their independent heating and cooling plants while taking advantage of a common geothermal energy source. The high temperature heat pumps for historical buildings permit to preserve all or part of the heating terminals, thereby reducing the renovation costs with renewable energy sources.
Figure 3 - Heat Pump prototype
Fig. 1b - Preferred drilling methods according to the underground geology (100 m depth)
Fig. 2 - Drilling machine at Padova- CNR (Italy) demo site
Fig. 1a - Dublin thermal conductivity weighed on 100 m depth