Results 1 - 10 of 123
Results 1 - 10 of 123. Search took: 0.017 seconds
|Sort by: date | relevance|
[en] A long distance energy supply plant has been operated on the basis of geothermal energy in Neubrandenburg since September 1988. At present it is still the largest heat generation plant for the utilisation of low thermal pore storage in Germany. The setup and the function of the plant are explained. After the municipal works of Neubrandenburg took over the plant, it was redesigned in order to give a better guarantee for the supply, to improve the economic efficiency and to minimise the environmental impact. At present long distance energy can be provided at a price of 99,00 DM/Mwh for 2000 utilisation hours per year. (BWI)
[de]In Neubrandenburg wird seit September 1988 eine Fernwaermeversorgungsanlage auf der Basis geothermischer Energie betrieben. Sie ist auch heute noch die gr''osste Waermeerzeugungsanlage zur Nutzung niedrig-thermaler Porenspeicher in Deutschland. Aufbau und Funktionsweise der Anlage werden beschrieben. Nach Uebernahme durch die Stadtwerke Neubrandenburg wurde die Anlage umgestaltet, um die Versorgungssicherheit zu erhoehen, die Wirtschaftlichkeit zu verbessern und die Umweltbelastungen zu minimieren. Derzeit kann Fernwaerme zu einem Preis von 99,00 DM/Mwh bei 2000 Ausnutzungsstunden pro Jahr bereitgestellt werden. (BWI)
[en] Geothermal energy currently provides a stable and environmentally attractive heat source for approximately 20 district heating (DH) systems in the US. The use of this resource eliminates nearly 100% of the conventional fuel consumption (and, hence, the emissions) of the loads served by these systems. As a result, geothermal DH systems can rightfully claim the title of the most fuel-efficient DH systems in operation today. The cost of producing heat from a geothermal resource (including capitalization of the production facility and cost for pumping) amounts to an average of $1.00 per million Btu (0.0034 $/kWh). The major environmental challenge for geothermal systems is proper management of the producing aquifer. Many systems are moving toward injection of the geothermal fluids to ensure long-term production
[en] The City of Boise, Idaho, an Idaho Municipal Corporation, is proposing to construct a well with which to inject spent geothermal water from its hot water heating system back into the geothermal aquifer. Because of a cooperative agreement between the City and the US Department of Energy to design and construct the proposed well, compliance to the National Environmental Policy Act (NEPA) is required. Therefore, this Environmental Assessment (EA) represents the analysis of the proposed project required under NEPA. The intent of this EA is to: (1) briefly describe historical uses of the Boise Geothermal Aquifer; (2) discuss the underlying reason for the proposed action; (3) describe alternatives considered, including the No Action Alternative and the Preferred Alternative; and (4) present potential environmental impacts of the proposed action and the analysis of those impacts as they apply to the respective alternatives
[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] 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] 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 total geothermal resource is much larger than that contained in all the fossil and uranium reserves worldwide. The author explains how the enormous potential of this clean, reliable, energy source is just beginning to be realized with the construction of geothermally powered electrical generating stations, district heating systems, food processing plants and greenhouses throughout the world. (author)
[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] 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.