This paper addresses the topic of site characterization for the design of Shallow Geothermal Energy (SGE) systems, namely of thermoactive geostructures, which are geotechnical structures, such as piles, retaining walls and tunnel linings, also used as heat exchangers as part of closed-loop SGE systems. Such solutions, being increasingly adopted for buildings’ and infrastructures’ heating and/or cooling, are considered sustainable and cost effective. For the design of the primary circuit of the SGE system, which is embedded within the superficial soil layers, a comprehensive knowledge of the ground condition at the site is mandatory. This includes the evaluation of the energy features and whether the system can provide the required energy needs during the operational period, as well as the verification of the structural and geotechnical safety and functionality requirements. The site characterization for SGE systems involves different stages, from desk studies to detailed characterization, including in-situ trials, laboratory testing of undisturbed soil samples and the study of possible interferences. The specific aspects that will be addressed are: (i) the assessment of the site undisturbed ground temperature and its hydrogeological features; (ii) the thermal and thermomechanical characterization of the different soil layers; (iii) the investigation of the ground-heat exchanger thermal resistance; (iv) the collection of information related to the environmental constraints and to potential interferences among multiple users, which are related to the service life of the structure. The overall aim is to ensure a proper design of the SGE system for guaranteeing its sustainability in the long term.

Climate change is already being felt in Europe, unequivocally affecting the regions’ geo-structures. Concern over this is rising, as reflected in the increasing number of studies on the subject. However, the majority of these studies focused only on slopes and on a limited geographical scope. In this paper, we attempted to provide a broader picture of potential climate change impacts on the geo-structures in Europe by gathering the collective view of geo-engineers and geo-scientists in several countries, and by considering different geo-structure types. We also investigated how geo-structural concerns are being addressed in national adaptation plans. We found that specific provisions for geo-structural adaptation are generally lacking and mainly come in the form of strategies for specific problems. In this regard, two common strategies are hazard/risk assessment and monitoring, which are mainly implemented in relation to slope stability. We recommend that in future steps, other geo-structures are likewise given attention, particularly those assessed as also potentially significantly affected by climate change. Countries considered in this study are mainly the member countries of the European Large Geotechnical Institutes Platform (ELGIP).

Energy geostructures are an innovative and sustainable renewable energy technology that has been demonstrated to be a successful solution for heating and cooling of buildings while contributing to CO2 emissions reductions. Therefore, the advantages of the technology together with the existing successful implementation examples has led to an increase trend of implementation of these structures. Different types of structures and foundations have started to be used for energy equipping. The paper presents the preliminary considerations of a real project implementation of energy geostructures at the New Unit of an Emergency Hospital in Romania. A specific type of energy foundation system was implemented for structural and economic reasons, represented by isolated foundations on energy piles. Compared to the classical pile foundation with general raft on top, this system presents several differences and challenges in term of both energy and mechanical aspects. The purpose of the paper is to highlight the particularities of such energy foundation, focusing especially on the thermo-mechanical behavior of the piles.

Development of innovative technologies for alternative energy sources represents an important challenge of the twenty-first century. It is a given fact that sustainability and energy efficiency started to be in the past years two of the requirements that are more and more present in all sectors of development. Energy geostructures represent an innovative technology in the construction sector that has significant contribution to its development by providing sustainable energy efficiency and CO2 emissions reduction. The concept behind this technology refers to the use of structural concrete elements of a building and give them a second role, that of energy exchanger between the building and the soil. This chapter represents an introduction into the concepts of this technology. Aspects related to the advantages of the system, principles, design and implementation considerations aspects are presented in the frame of thermal and thermo-mechanical behavior of the interacting soil and of the energy geostructures.

Following the Directive 2010/31/EU on energy performance of buildings, EU state members have developed national plans for increasing the number of nearly zero energy buildings through measures that facilitate the implementation of renewable energy technologies. Due to this policies changes and also due to their incontestable advantages, energy geostructures are showing an increasing trend in number of implementations all across Europe. However, it is important that besides “good statistics”, the quality and efficiency of what is implemented to be ensured so that a real change is generated in terms of renewable energy exploitation and CO2 emissions reduction. The paper refers to challenges that are encountered in the process of implementation of energy geostructures especially on emerging markets for this technology, such as Eastern Europe, with emphasis on several case studies and evidence from Romania.

Performance and success of energy geostructures systems are already facts proven by research and practice. The number of implementations is in constant grow and due to their advantages, such systems have started to be implemented in a variety of structural elements. Among the various types, energy piles are the most common type of energy geostructures. However, most of the existing research, experimental sites and case studies refer to energy piles as a foundation element. This paper presents the concept and implementation steps of a different type of energy piles system which is a retaining wall of piles built in Cluj-Napoca, Romania. The paper is based on a real project case study, where large diameter piles are used as retaining wall for an urban excavation on a steep slope with high slope failure potential. The piles from the retaining system have been energy equipped in order to be used as an energy exchange element with the ground for heating and cooling demand of 3 new residential buildings from the same site. The paper will present the concept of an urban energy retaining wall and implementation stages of the project.

As the role that the society plays in energy and use of resources is of importance, what is vital is early education, as it is one of the pillars significantly influencing the planning of a "cleaner future" energy wise, especially through utilizing energy-specific education techniques. Up to this point, it has been suggested that younger students tend to describe Renewable Energy Sources (RES) as 'Clean' rather than 'Green', while their selection in the color that best describes them is Yellow or White rather than Green. On the subject of redefining RES, a total of 2217 face-to-face interviews are conducted in schools in three countries in the Baltics and Eastern Europe countries, i.e. Latvia, Lithuania, and Romania, in order to further contribute to the discussion of which term-'Clean Energy' or 'Green Energy'- is the term of choice for students of younger age with no or less formal education and experience on the subject of best naming RES. As far as the color to best represent RES is concerned, younger students tend to choose Yellow or White instead of Green, a choice that shifts to Green in higher grades. The results, with the exception of Lithuania where older students chose the term 'Clean Energy' as well, confirm those of previous studies in Greece and Bulgaria, enhancing the importance of the elicitation of such preferences in order for energy issues to become part of the educational system of all levels. As Clean and Yellow or White are the terms of choice for naming and describing RES according to young students, it is imperative that the scientific community reconsiders and adjusts said preferences in education and research, for the better -future- implementation of renewable energy practices and use of resources. (C) 2018 Elsevier Ltd. All rights reserved.

Increasing use of the ground as a thermal reservoir is expected in the near future. Shallow geothermal energy (SGE) systems have proved to be sustainable alternative solutions for buildings and infrastructure conditioning in many areas across the globe in the past decades. Recently novel solutions, including energy geostructures, where SGE systems are coupled with foundation heat exchangers, have also been developed. The performance of these systems is dependent on a series of factors, among which the thermal properties of the soil play a major role. The purpose of this paper is to present, in an integrated manner, the main methods and procedures to assess ground thermal properties for SGE systems and to carry out a critical review of the methods. In particular, laboratory testing through either steady-state or transient methods are discussed and a new synthesis comparing results for different techniques is presented. In situ testing including all variations of the thermal response test is presented in detail, including a first comparison between new and traditional approaches. The issue of different scales between laboratory and in situ measurements is then analysed in detail. Finally, the thermo-hydro-mechanical behaviour of soil is introduced and discussed. These coupled processes are important for confirming the structural integrity of energy geostructures, but routine methods for parameter determination are still lacking.