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[en] Water reuse involves the concept of the exploitation of a previously used water, for a new, beneficial purpose. Actually, in Uruguay, thermal water is just utilised for balneological purposes, in this paper is proposed the water reuse taking the excess of used swimming pool water, and using it for heating and greenhouse irrigation, and australian lobster breeding. An important aspect of sustainable thermal water management is the protection of the exploted thermal water resources, so water reuse plays an important role in water resource, and ecosystem management, because it reduces the volume discharged and also reduces the risk of thermal pollution
[es]El reuso del agua involucra el concepto de explotacion de un agua usada previamente, para un nuevo y benefico proposito. En la actualidad, en Uruguay, el agua termal es solamente utilizada para fines balneologicos; en este trabajo se propone el reuso del agua termal, tomando el exceso de agua usada en las piscinas, para fines de riego y calefaccion de invernaculos y para la cria de langostas australianas. Un aspecto importante de la gestion sustentable del agua termal es la proteccion de su explotacion, por lo tanto el reuso juega un papel muy importante en la gestion del recurso hidrico y de los ecosistemas, ya que reduce el volumen descargado al sistema y tambien el riesgo de contaminacion termal
[en] The Caldes de Boí geothermal waters show important differences in pH (6.5–9.6) and temperature (15.9ºC–52ºC) despite they have a common origin and a very simple circuit at depth (4km below the recharge area level). Thes differences are the result of secondary processes such as conductive cooling, mixing with colder shallower waters, and input of external CO2, which affect each spring to a different extent in the terminal part of the thermal circuit. In this paper, the secondary processes that control the geochemical evolution of this system have been addressed using a geochemical dataset spanning over 20 years and combining different approaches: classical geochemical calculations and geochemical modelling. Mixing between a cold and a thermal end-member, cooling and CO2 exchange are the processes affecting the spring waters with different intensity over time. These differences in the intensity of the secondary processes could be controlled by the effect of climate and indirectly by the geomorphological and hydrogeological setting of the different springs. Infiltration recharging the shallow aquifer is dominant during the rainy seasons and the extent of the mixing process is greater, at least in some springs.Moreover, significant rainfall can produce a decrease in the ground temperature favouring the conductive cooling. Finally, the geomorphological settings of the springs determine the thickness and the hydraulic properties of the saturated layer below them and, therefore, they affect the extent of the mixing process between the deep thermal waters and the shallower cold waters. The understanding of the compositional changes in the thermal waters and the main factors that could affect them is a key issue to plan the future management of the geothermal resources of the Caldes de Boí system. Here, we propose to use a simple methodology to assess the effect of those factors, which could affect the quality of the thermal waters for balneotherapy at long-term scale. Furthermore, the methodology used in this study can be applied to other geothermal systems.
[en] Because fossil fuels still cover a large share of energy demand, a transition is needed towards low-emission sources of heat, such as geothermal energy, biomass, solar power and use of residual heat. Heat storage has a key contribution to make as it provides the flexibility required to manage variations in heat demand and supply. Underground storage can absorb far larger quantities of heat than surface storage, potentially lowering the costs of storing large amounts of heat and reducing the land areas required. HeatStore is one of the nine projects conducted under the European Eranet Geothermica programme, which is working to accelerate geothermal energy deployment. The main goals of the HeatStore project are to reduce costs and risks, improve the performance of high-temperature underground heat storage technology and optimise the management of demand from heat distribution networks. The project partners have set a target reduction in heat production costs of at least 20%. As an expert organisation in the fields of geothermal energy and underground storage, the BRGM is contributing to the HeatStore project in several ways: Participation in benchmarking of the different numerical codes developed by the project partners against data acquired through the demonstrators. Application of probabilistic and possibilistic approaches in handling uncertainties in the development and operation of underground thermal energy storage (UTES) facilities. A study of underground heat storage potential on the scale of a region, by cross-analysing geological data, modelling results produced during the project and existing data on surface terrain (e.g. development of heat distribution networks).
[en] The temperature of the water returning from the network affects greatly the efficiency of a geothermal district-heating system (GDHS). The temperature of the returning water depends on whether there is a heat exchanger between network flow and indoor circulation. The return temperature also depends on outdoor temperature and logic of the indoor temperature control system. In this paper, four control logics are defined depending on whether indoor circulation is separated from network circulation or not. Return temperature and circulation rate of network flow are calculated for these control logics. The results show that the flow rate of the network flow and annual consumption of the geothermal fluid could be decreased about 10% or over by using optimum control logic in district heating systems
[en] Highlights: ► ANN has been modeled for predicting exergy efficiency a GDHS thought exergy analysis. ► The network yields a maximum correlation coefficient with minimum coefficient of variance and root mean square values. ► The ANN modeling can provide high accuracy and reliability for predicting the exergy efficiency of GDHSs. ► Thus, online monitoring system and the performance of GDHS can be implemented. - Abstract: This paper deals with an artificial neural network (ANN) modeling to predict the exergy efficiency of geothermal district heating system under a broad range of operating conditions. As a case study, the Afyonkarahisar geothermal district heating system (AGDHS) in Turkey is considered. The average daily actual thermal data acquired from the AGDHS in the 2009–2010 heating season are collected and employed for exergy analysis. An ANN modeling is developed based on backpropagation learning algorithm for predicting the exergy efficiency of the system according to parameters of the system, namely the ambient temperature, flow rate and well head temperature. Then, the recorded and calculated data conducted in the AGDHS at different dates are used for training the network. The results showed that the network yields a maximum correlation coefficient with minimum coefficient of variance and root mean square values. The results confirmed that the ANN modeling can be applied successfully and can provide high accuracy and reliability for predicting the exergy performance of geothermal district heating systems.
[en] Highlights: • We monitor the Gonen geothermal district heating system for a one-year period. • Six different operating cases are proved to exist in the system. • Energy and exergy analysis is carried out for each case. • Case-based analyses are used to show the annual system performance. - Abstract: In this paper, the effects of different operating conditions of the Gonen geothermal district heating system (GDHS) on its annual energy and exergy performance are investigated. The system parameters such as temperature, pressure and flow rate are monitored by using fixed and portable measuring instruments over a one-year period. Thus the main differences in the annual system operation are detected. The measurements show that the Gonen GDHS has six different operating cases depending on the outside temperature throughout the year. The energy and exergy analysis of the system is carried out for each case using the actual system parameters at the corresponding reference temperatures, which are 3.86, 7.1, 8.88, 11.83, 15.26 and 20.4 °C. The highest and lowest energy (57.32%, 35.64%) and exergy (55.76%, 41.42%) efficiencies of the overall system are calculated at the reference temperatures of 15.26 °C and 3.86 °C, respectively. Besides, taking the six case-based energy and exergy analyses into account, the annual average energy and exergy efficiencies are determined to be 45.24% and 47.33%, respectively
[en] Highlights: • Economic evaluation of GDHS using advanced exergoeconomic analysis for the first time. • The results obtained for two different GDHSs are compared under same condition. • Each component of the Sarayköy GDHS is to operate more economically. • The usefulness of this analysis was clearly demonstrated comparing both the systems. - Abstract: This paper refers to an economic comparison and evaluation of two geothermal district heating systems (GDHSs) under same reference state condition and mechanic/economic parameters by using an advanced exergoeconomic analysis. In this analysis, costs of investment and exergy destruction of each component for the thermal systems such as the Afyon and Sarayköy GDHSs were split into endogenous/exogenous and unavoidable/avoidable parts, and were also compared with each other for the first time. The results obtained show that the advanced exergoeconomic analysis makes the information more accurate and useful, and supplies additional information that cannot be provided by the conversional analysis. Furthermore, the Afyon GDHS can be made more cost effectiveness, removing the system components’ irreversibilities, technical-economic limitations, and poorly chosen manufacturing methods, according to the Sarayköy GDHS. The majority of the components in the Sarayköy GDHS are to operate more economically than those in the Afyon GDHS. As a result, the usefulness of this method was clearly demonstrated comparing both the systems
[en] The article reviews briefly a pioneer project for a construction area of 200000 m''2 with residences, business complexes, a hotel and conference centre and a commercial college in Oslo. The energy conservation potential is estimated to be about 60-70 % compared to direct heating with oil, gas or electricity as sources. There will also be substantial reduction in environmentally damaging emissions. The proposed energy central combines geothermal energy sources with heat pump technology, utilises water as energy carrier and uses terrestrial wells for energy storage. A cost approximation is presented
[en] Natural gas is the largest source for home heating in Canada. However, natural gas prices are sensitive to falling continental supplies, and the increased penetration of natural gas-fired electricity generation in areas of North America is placing additional pressure on continental sources and prices. This feasibility study examined the use of urban geo-exchange projects and community power developers (CPD) to increase the number of geo-exchange units installed by reducing high upfront costs while improving market infrastructure and consumer awareness and confidence. The CPD will provide community building and resource development services in order to facilitate cooperatively owned organization's to manage shared geothermal assets. An urban block in Toronto was used as a case study of a potential redevelopment site. The study showed that a shared geo-exchange system will increase the per residence installation costs. It was concluded that CPDs will play an important role in increasing geo-exchange penetration by addressing the lack of public awareness in renewable energy systems. 3 tabs., 5 figs.
[en] European balneologists have extensively studied the therapeutic value of mineral water. Mineral springs with different mineral contents are recommended for various therapeutic uses. People have been using geothermal water for bathing and good health for many thousands of years A mineral hot spring has greater than 1000 mg/L (ppm) of naturally dissolved solids. Hot mineral spring water contains elements like calcium, magnesium, sodium, potassium as sulphates, bi- carbonates and chlorides, which are used externally to cure many diseases. Manghopir spring contain 38-84 mg/L calcium, 29-56 mg/L magnesium, 388-555 mg/L sodium, 411-599 mg/L chloride, 186-442 mg/L sulphate, 10-25 mg/L potassium, and 1509-2188 mg/L total dissolved solids while the pH was in the range of 7.2-7.8. The temperature of Manghopir Euthermal hot spring remains constant ranging between 40 to 47 degree C. (author)