| Title | H?savթk Energy թ՞ Multiple use of geothermal energy. |
|---|---|
| Authors | Hreinn Hjartarson, Run??lfur Maack and Sig???r J??hannesson |
| Year | 2003 |
| Conference | Iceland Geothermal Conference |
| Keywords | geothermal, multiple use, effective use, efficiency, flexibility, sustainability. |
| Abstract | H?savթk town is located on the coast of SkjԹգlfandaflթi in the northern part ofIceland. Twenty 20 km south of H?savթk is the Hveravellir geothermal area.Geothermal fluid from three boreholes that were drilled there in 1974 թ՞ 1998 ranges in temperature from 115? to 130?C. Close by are several natural hot springs and pools that discharge about 100?C hot water. H?savթk Energy started utilisation of geothermal hot water from Hveravellir as early as 1970. Until the year 2000 the Hveravellir fluid was flashed to 100?C at the wellhead and the hot water fed under gravity to the town through a 20 km long buried asbestos cement pipeline. There it was used for space heating, drying and also to heat greenhouses and farmhouses inthe district. Temperature drop along the route was up to 15?C and significant thermal energy was also lost in the flashing process. In the nineties it became clear that the old pipeline needed a thorough overhaul. In H?savթk new markets for 80?C to 120?C hot water were being developed both for heating and industrial use. This prompted the idea of expanding the foreseen refurbishment of the existing system to include diverse cascaded uses. In connection with renewal of the pipeline it was decided tochange operation of the whole system. The main goals were: թ՜to secure energy supply to the consumers in the future. թ՜to increase diverse use of geothermal energy.թ՜to utilise the geothermal energy and large quantity of cold fresh water to attract new industrial utilities into the area and strengthen economy in general.թ՜to extract more energy from the geothermal fluid.To achieve these goals 124?C geothermal fluid from the production wells is in the new system transported under pressure to the Energy Centre located in the town. The Energy Centre building houses Kalina Binary Electric Power Plant, heat exchangers and control equipment. The net output of the electrical plant is 1.7 MW, which suffices to meet about three-quarters of the townթ՟s current electricity demand. In the electric power plant the water is utilised down to 80?C which is proper water temperature for the district heating system and various other applications. From the Energy Centre water of resp. 120?C and 80?C in temperature is piped to the diverseindustrial users in H?savթk and to the townթ՟s district heating system. Furthermore, the geothermal water is used for fish farming, greenhouses, health centres and bathing facilities. Such an integrated system renders vastly improved efficiency in the utilisation of the geothermal energy. The paper describes reconstruction of the geothermal system in H?savթk, the process design and the system facilities. |