| Title | Multiple integrated applications for low to medium temperature geothermal resources |
|---|---|
| Authors | Elíasson, Einar Tjörvi, Björnsson, Oddur B. |
| Year | 2003 |
| Conference | European Geothermal Conference |
| Keywords | |
| Abstract | The world’s population calls for greater and faster energy development to help improve its lot through more employment and better living conditions. Conscious of the apparent deterioration of the environment as manifest in deforestation, despoiling of lakes and rivers not to mention greenhouse effects, it is, however, not prepared to sacrifice too much of the natural environment. This puts pressure on scientists, engineers and developers to find ways and means to meet this new challenge of sustainable energy development. The new focus is therefore on sustainability and alternative renewable energy resource development. Sustainability may be achieved in a number of ways; the way most likely to achieve rapid increase in energy output without consequent deleterious environmental impact is the revamping and integration of what we already have. This paper attempts to address sustainability as it applies to geothermal energy development. It outlines concept of multiple integrated use of geothermal energy whilst pointing out tenable benefits attainable through applying this concept, such as improved reservoir life and sustainability, lower specific environmental impact, and greater marketing flexibility and profitability. The paper point out the paramount importance of striving at maximum effective temperature drop across the application. This is commensurate minimum flow rate, optimal pumping requirements and minimal fluid extraction from the geothermal reservoir. In geothermal house heating systems this requires the adoption of: • Large and effective radiators. • Double pipe heating system. • Thermostatic control on each radiator. Where modification of existing house heating systems, e.g. conversion from a single pipe to a double pipe system or installation of larger radiators is not feasible, cascaded flow of the geothermal fluid through a combination of heating systems of different temperature levels presents a solution. Economic criteria favour direct use of the geothermal water where its chemical quality is suitable. Otherwise heat exchangers of resistant materials are necessary to isolate the geothermal fluid from the heating fluid where corrosion or scaling of the piping and radiator system is to be expected. Such heat exchangers must be designed for maximum temperature drop of the geothermal fluid. The paper describes heating system configurations and characteristics of geothermal heating systems, their automatic control systems and recommended geothermal field management and monitoring systems. A few actual project examples demonstrate what has been done and what can be done; and ideas are put forward for new developments and innovations to make geothermal energy more generally attractive and useful worldwide. |