• Energy Research

The increasing importance of shallow geothermal resources in the decarbonization of heating and cooling systems requires the correct management of all the project stages. One of the fundamental steps in this process is determining the space energy demand, which plays a significant role in the subsequent geothermal design. In the context of Spain, different tools are available for the estimation of the mentioned parameter. For evaluating these procedures, this research applies the principal energy demand calculation tools and uses the outcomes for the later design of the shallow geothermal system. Results show how the Spanish official tools (HULC and CE3X) provide lower energy demand values adjusted to the construction conditions of the building that allow the optimization of the geothermal well field. On the contrary, simpler, and more intuitive applications (regular spreadsheets and GES-CAL) assume higher heating energy demands, which in turn implies an oversizing of the geothermal scheme. Even though all the procedures ensure to cover the energy requirements of the building, the most precise tools manage to reduce the initial investment of the system and its operating costs, in addition to reducing the global CO2 emissions because of the lower power of the associated geothermal heat pump.

A low-cost multi-sensor aerial platform, aerial trike, equipped with visible and thermographic sensors is used for the acquisition of all the data needed for the automatic analysis and classification of roof surfaces regarding their suitability to harbor solar panels. The geometry of a georeferenced 3D point cloud generated from visible images using photogrammetric and computer vision algorithms, and the temperatures measured on thermographic images are decisive to evaluate the areas, tilts, orientations and the existence of obstacles to locate the optimal zones inside each roof surface for the installation of solar panels. This information is complemented with the estimation of the solar irradiation received by each surface. This way, large areas may be efficiently analyzed obtaining as final result the optimal locations for the placement of solar panels as well as the information necessary (location, orientation, tilt, area and solar irradiation) to estimate the productivity of a solar panel from its technical characteristics.

Abstract Very low enthalpy geothermal systems have been traditionally associated to the use of electricity as primary energy heat pumps supply. Gas engine heat pumps (GEHP) have been recently introduced in the current market. In this research, the electric heat pumps (EHP) as well as the GEHPs (considering natural gas and biogas as combustibles) have been analysed. The calculation of the ground source heat pump (GSHP) system has been made for a building placed in three different areas. Results reveal the influence of the heat pump configuration on the whole geothermal design. This research finally considers the European policies whose aim is a sustainable low-carbon economy by 2020. According to the existing Energy Efficiency Directive, energy requirements are defined for new and existing residential and non-residential buildings in the Member States. Based on these standards, the research compares the geothermal heat pump scenarios and a traditional one to determine if they would meet the regulation. Final results show that the Directive is a highly-demanding regulation that can only be respected by using EHP in one of the areas. The rest of geothermal heat pumps scenarios are much closer to meeting the energy standards than the traditional fossil heating sources.

RESUMEN: La enorme aplicabilidad de la técnica termográfica se tiende a particularizar en la llamada termografía cualitativa sin prestar atención a las amplias posibilidades que la termografía aporta cuando se utiliza en combinación con una excitación controlada del material; lo que se conoce como termografía activa. Esta técnica ha tenido un desarrollo importante durante los últimos años, sin embargo ha sido en estos tiempos cuando se ha consolidado como una innovadora, completa y versátil modalidad de ensayo no destructivo (END) que posibilita una rápida obtención de información útil para la evaluación de materiales sin llegar a requerir altas inversiones económicas. En este artículo se pretende plasmar una visión global y aplicada de la técnica siguiendo un triple acercamiento: primero, repasando la investigación teórica de los procesos de captación, extracción y procesamiento de datos; segundo, aportando como resultado del trabajo diferentes clasificaciones de la técnica en base a lo establecido en la investigación teórica; y finalmente, definiendo las distintas aplicaciones dentro de la ingeniería e industria. Palabras clave: Termografía activa, ensayo no destructivo (END), imagen térmica, fuente de excitación, procesamiento de imagen.

The correct design of a low enthalpy geothermal system is a priority to ensure the expansion of this renewable energy in the alarming world energy panorama. In this sense, the present research has analyzed how the estimation of the initial energy demand of a space plays a fundamental role in the corre-sponding geothermal design. Thus, the main tools used in Spain (location of the study case) in the calculation of the energy demand have been used for then de-signing the shallow geothermal system. Results show that the official tools (HULC and CE3X) provide lower energy demand values and adjusted to the construction conditions of the building that allow the optimization of the geo-thermal well field. On the contrary, simpler, and more intuitive applications (regular spreadsheets and GES-CAL software) assume a higher value of heating energy demand, which in turn implies an oversizing of the geothermal scheme. Even though all the procedures ensure to cover the energy requirements of the building, the most precise tools manage to reduce the initial investment of the system and its operating costs, in addition to reducing the global CO2 emissions because of the lower power of the associated geothermal heat pump.

The current energy context demands the use of environmentally friendly solutions that contribute to the displacement of traditional fossil fuels. In this regard, heat pumps have become an important tool in the decarbonization of the heating and cooling energy system. With the aim of providing new information in the field, this research is conducted to analyze the suitability of a Ground Source Heat Pump (GSHP) and an Air Source Heat Pump (ASHP) in two different scenarios. Systems are designed to cover the heating needs of a building placed in a cold climate area, characterized by being in a thermally and geologically favorable formation (Case 1), and in a mild climate location where the geology is not so appropriate for the thermal exchange with the ground (Case 2). Results highlight the need to perform an exhaustive study of the subsoil and the external conditions of the area for a reliable selection. In Case 1, the ASHP option is discarded due to the demanding outdoor air requirements that rocket the operating costs of the system. In Case 2, both solutions are viable, with the geothermal alternative preferred if the initial investment can be assumed, providing economic advantages from the 17th year of the system operation.

Abstract The use of low-impact energy sources is gradually growing with the aim of reducing greenhouse gases emission and air pollution. The alternatives offered by geothermal systems are one of the key solutions for a future renewable development, enabling the electrification of heating systems and the use of biofuels. This research addresses an overview of geothermal heating systems using ground source heat pumps in different European countries. Besides the traditional electrical heat pumps, gas engine heat pumps aided by natural gas or biogas are analysed in three areas. From a previous research, the technical parameters defining the geothermal system are used here to evaluate the most appropriate system in each scenario. The evaluation of different influential factors (operational costs, initial investment, environmental impact, and availability) allows defining the most recommendable systems for each area. Results of this multi-parametric study show that gas engine heat pumps aided by biogas could mean an excellent solution in all countries, also contributing to the management of waste and polluting substances. If biogas systems were not available, the electrical heat pump would be the first option for areas 1 and 3 (Italy and Sweden) but not for area 2 (United Kingdom), where natural gas is preferred.

This work focuses on the automatic identification of forest fire risk areas along high-voltage power lines through the development of a tool and its validation on a real forest area. The tool allows one to automate the whole process, which includes the classification of the point cloud, the computation of the catenary of the wires using different calculation methods, the estimation of the vegetation growth and the identification of the risk areas. To this end, a coarse-to-fine approach is proposed, so that a preliminary analysis is performed with public airborne LiDAR data, and then a more detailed inspection is provided with drone LiDAR data over those areas classified as high risk. The tool and the methodology developed were validated along a high-voltage power line of 53 km in a real forest area. The results show that although the preliminary analysis based on public airborne LiDAR data is more conservative, it is very useful for selecting those areas of higher risk for further analysis with drone LiDAR data.