The possibilities of using geothermal energy are slowly expanding to all areas of energy consumption, so the assessment of geothermal potential has become the backbone of energy policies in countries ...that have the potential. Countries and companies that have experience in the oil and gas industry are increasingly exploring the possibilities of first using the acquired knowledge, and then using the existing oil and gas infrastructure for the use of geothermal energy. For this reason, it is necessary to analyse the possibilities of using the existing infrastructure with all its limitations to maximise the energy potential of geothermal energy. The existing oil infrastructure, especially the wells, is in many cases not suitable for the production of brine and it is necessary to analyse the maximum impact of each well for the production of geothermal energy, with particular attention to the equipment installed in the well and the thickness of the geothermal reservoir in the oil and gas fields that would be suitable for the production of brine.
One of the important sources of renewable energy is geothermal heat. Its special feature of being independent 24/7 ensures the stability and security of the system, either for electricity or heat ...production. Geothermal energy has a local character and is limited by the geological characteristics of each state. In the Republic of Croatia, the development of geothermal energy is closely related to the development of the oil industry, as geothermal deposits were discovered during oil and gas exploration. Considering the established temperature gradients in Croatia, there is a greater possibility of using geothermal energy, and for this, it is necessary to evaluate its full potential and possibilities of use. The aim of this research is to determine the heat potential of the Croatian part of the Pannonian Basin System (CPBS), a part of Croatia with exceptional geothermal potential, based on the analysis of a large amount of well data with confirmed water inflow. In order to estimate the heat in place, the available data on the presence of inflow, temperature, and porosity, as well as permeability and volume for each well/reservoir included in the assessment, were considered. In geothermal reservoirs, one of the most important pieces of data besides petrophysical and thermodynamic data is the potential of the well, i.e., the maximum flow under certain permeability and porosity conditions. To define this, the productivity index was made dependent on the permeability of each well, and the inflow in each well was risked using Monte Carlo for three main geological phases in CPBS, which subsequently influenced inflow and spacing between production and injection wells. The beta-PERT distribution for permeability is used in Monte Carlo simulation to determine the most likely values and produce a distribution that resembles the real probability distribution. As a result, geothermal potential was mapped according to the obtained values of heat in place for part of the CPBS covered with analysed wells.
In the last decade, due to climate change concerns and new environmental regulations in the EU, there was a tremendous rise in installed heat pump systems in new homes and buildings. The majority of ...these installed units are related to air-source heat pumps, as they offer a good trade-off between capital and operating expenses. However, when analysing heating and cooling heat pump systems from the primary energy consumption and ecological aspects, groundwater and shallow geothermal heat pump systems offer superior efficiency, compared to all market-available thermo-technical systems today. In the last decade, ground-source systems have seen some technological improvement by employing new borehole heat exchanger designs, such as piping with internal fins and a wider diameter (so called Turbocollector) to enhance the heat transfer between fluid and rock, as well as to reduce the pressure drop in the system. Furthermore, the process of drilling deeper offers higher ground temperatures and consequently higher seasonal performance factors in the heating cycle, due to the effect of the geothermal gradient. Nevertheless, although deeper boreholes provide better heat extraction rates per meter during the heat pump heating cycle, at the same time, it reduces heat rejection rates during the heat pump cooling cycle. The objective of this paper is to analyse and evaluate benefits and downsides of a new approach in the heat pump system design with deeper borehole heat exchangers of up to 300 m, comparing it to the traditional design of double-loop exchangers with 100 m depth. The geothermal borehole grid design simulation model, along with heat extraction and rejection, is performed on a yearly basis. The results are showing that the benefits of shallow geothermal boreholes, from the hydraulic and thermodynamic point of view, still dominate over deeper solutions.
The term resilience, which has been present in science for almost half a century, stands for the capacity of some system needed to overcome an amount of disturbance from the environment in order to ...avoid a change to another stable state. In medicine, the concept of resilience means the ability to deal with daily stress and disturbance to our homeostasis with the intention of protecting it from disturbance. With aging, the organism becomes more sensitive to environmental impacts and more susceptible to changes. Mental disturbances and a decline in psychological resilience in older people are potentiated with many social and environmental factors along with a subjective perception of decreasing health. Distinct from findings in younger age groups, mental and physical medical conditions in older people are closely associated with each other, sharing common mechanisms and potentiating each other’s development. Increased inflammation and oxidative stress have been recognized as the main driving mechanisms in the development of aging diseases. This paper aims to reveal, through a translational approach, physiological and molecular mechanisms of emotional distress and low psychological resilience in older individuals as driving mechanisms for the accelerated development of chronic aging diseases, and to systematize the available information sources on strategies for mitigation of low resilience in order to prevent chronic diseases.
Aging is associated with many personal, social, and environmental challenges that increase the risk of loneliness. Loneliness is a painful emotional experience associated with a perceived lack of ...connection and intimacy. Loneliness accelerates health deterioration, but the presence of chronic health conditions (comorbidities) in older individuals may potentiate the feeling of loneliness. The relationships between health status and loneliness in older individuals have not been assessed in an integrated manner, although it is necessary for planning efficient interventions. The aim of this study was to fill in this knowledge gap, by attempting to create an integrated model of loneliness in older individuals.
The sample consisted of 189 (58% F) older individuals (> 60 years) (mean ± SD, 78.47 ± 6.65), attendees in Primary Health Care. Different factors associated with loneliness in the older population were assessed, and classified as demographic, environmental, physical (health-related), and psychological, in addition to functional abilities. A set of standard questionnaires was used to assess psychological factors and functional abilities. The hierarchical regression model assessed the effect of particular blocks of factors on status loneliness. The second aim was to analyze how psychological factors mediate associations between health status (comorbidity level) and loneliness.
Indicated that increasing comorbidity, anxiety, lack of positive moods, not having hobbies/activities, low perception of social support, impaired cognitive function, and suppression of emotion expression, are significant predictors of loneliness. Mediation analysis informed us of how to help patients with comorbidities feel less lonely. Interventions that were suggested were those that can reduce anxiety and depression, improve cognitive abilities and emotional regulation control, and enhance social support.
Results can help understand the pathophysiology loops linking poor health status (comorbidity level) of older individuals and loneliness, and have significant potentials from the translational perspectives, as a decision-support tool.
The theory of Thermal Response Testing (TRT) is a well-known part of the sizing process of the geothermal exchange system. Multiple parameters influence the accuracy of effective ground thermal ...conductivity measurement; like testing time, variable power, climate interferences, groundwater effect, etc. To improve the accuracy of the TRT, we introduced a procedure to additionally analyze falloff temperature decline after the power test. The method is based on a premise of analogy between TRT and petroleum well testing, since the origin of both procedures lies in the diffusivity equation with solutions for heat conduction or pressure analysis during radial flow. Applying pressure build-up test interpretation techniques to borehole heat exchanger testing, greater accuracy could be achieved since ground conductivity could be obtained from this period. Analysis was conducted on a coaxial exchanger with five different power steps, and with both direct and reverse flow regimes. Each test was set with 96 h of classical TRT, followed by 96 h of temperature decline, making for almost 2000 h of cumulative borehole testing. Results showed that the ground conductivity value could vary by as much as 25%, depending on test time, seasonal period and power fluctuations, while the thermal conductivity obtained from the falloff period provided more stable values, with only a 10% value variation.
When considering implementation of shallow geothermal energy as a renewable source for heating and cooling of buildings, special care should be taken in the hydraulic design of the borehole heat ...exchanger system. Laminar flow can occur in pipes due to the usage of glycol mixtures at low temperature or inadequate flow rates. This can lead to lower heat extraction and rejection rates of the exchanger because of higher thermal resistance. Furthermore, by increasing the flow rate to achieve turbulent flow and satisfactory heat transfer rate can lead to an increase in the pressure drop of the system and oversizing of the circulation pump which leads to impairment of the seasonal coefficient of performance at the heat pump. The most frequently used borehole heat exchanger system in Europe is a double-loop pipe system with a smooth inner wall. Lately, development is focused on the implementation of a different configuration as well as with ribbed inner walls which ensures turbulent flow in the system, even at lower flow rates. At a location in Zagreb, standard and extended thermal response tests were conducted on three different heat exchanger configurations in the same geological environment. With a standard TRT test, thermogeological properties of the ground and thermal resistance of the borehole were determined for each smooth or turbulator pipe configuration. On the other hand, extended Steady-State Thermal Response Step Test (TRST) incorporates a series of power steps to determine borehole extraction rates at the defined steady-state heat transfer conditions of 0/−3 °C. When comparing most common exchanger, 2U-loop D32 smooth pipe, with novel 1U-loop D45 ribbed pipe, an increase in heat extraction of 6.5% can be observed. Also, when the same comparison is made with novel 2U-loop D32 ribbed pipe, an increase of 18.7% is achieved. Overall results show that heat exchangers with ribbed inner pipe wall have advantages over classic double-loop smooth pipe designs, in terms of greater steady-state heat extraction rate and more favorable hydraulic conditions.
Classic and extended step thermal response test were conducted on three different locations in Zagreb. Measurements with the classical thermal response test were used to determine thermogeological ...properties of the ground and thermal resistance of the borehole for each location. Different values of thermal conductivity are the result of differences in the geological profile and depth of the sites. In addition, experimental research of the steady-state thermal response step test (SSTRST) was carried out to determine heat rejection rates for passive and active cooling in a steady state regime. Results showed that the heat rejection rate is only between 8-11 W/m, which indicates that the coaxial system is not suitable for passive cooling demands. Furthermore, the heat pump in passive cooling mode uses an additional plate heat exchanger which causes heat losses and additional temperature rise of the working fluid by approximately 1.5 °C. Therefore, the steady-state rejection rate for passive cooling is even lower for a real case project. The coaxial heat exchanger should always be designed for an active cooling regime with an operation of a heat pump compressor in a classical vapour compression refrigeration cycle.
Chronic diseases, such as type 2 diabetes (T2D), are difficult to manage because they demand continuous therapeutic review and monitoring. Beyond achieving the target HbA1c, new guidelines for the ...therapy of T2D have been introduced with the new groups of antidiabetics, glucagon-like peptide-1 receptor agonists (GLP-1ra) and sodium-glucose cotransporter-2 inhibitors (SGLT2-in). Despite new guidelines, clinical inertia, which can be caused by physicians, patients or the healthcare system, results in T2D not being effectively managed. This opinion paper explores the shift in T2D treatment, challenging assumptions and evidence-based recommendations, particularly for family physicians, considering the patient's overall situation in decision-making. We looked for the possible reasons for clinical inertia and the poor application of guidelines in the management of T2D. Guidelines for antidiabetic drugs should be more precise, providing case studies and clinical examples to define clinical contexts and contraindications. Knowledge communication can improve confidence and should include clear statements on areas of decision-making not supported by evidence. Precision medicine initiatives in diabetes aim to identify subcategories of T2D patients (including frail patients) using clustering techniques from data science applications, focusing on CV and poor treatment outcomes. Clear, unconditional recommendations for personalized T2D management may encourage drug prescription, especially for family physicians dealing with diverse patient contexts and clinical settings.
Kindergarten Grdelin in the city of Buzet, Istria, Croatia, was chosen to undergo a deep retrofit of the current thermotechnical system, as a part of the HORIZON 2020 HAPPEN project1. The existing ...shallow spiral heat exchanger field is insufficient to cover heating loads of the building. Therefore, additional BHEs were drilled and completed to determine optimal borehole heat exchanger type within the same geological environment. Four BHEs, either single U (1U) or double U (2U), with different geometrical setting and depth were tested: BHE-1 (50 m, 2U DN32 ribbed), BHE-2 (75 m, 2U DN40 ribbed), BHE-3 (100 m, 2U DN32 smooth) and BHE-4 (150 m, 1U DN45 ribbed). A thermal response test (TRT) was performed to obtain the ground thermal properties. Furthermore, synthetic TRT curves were calculated to describe temperature response in the case of different heat pulses. This was done to determine heat extraction rates and the capacity of each BHE type, according to EN14511 norm. It was established that the BHE-4 is the optimal design for heating and cooling purposes on the selected site due to positive impact of the geothermal gradient, higher initial borehole temperature and a positive effect of the ribbed inner wall.
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