Use of geothermal energy for heating and sanitary hot water production geothermal water to be exploited from a sandy shallow reservoir by means of a doublet.
Four vertical wells (two by Morgo island and two by Grado district to heating) will give geothermal water at 30 to 40 deg. C. Geothermal fluid will be conveyed from Morgo island, to the district heating system through a pre-insulated undersee pipeline, water temperature will be upgraded to 85 deg. C using a gas driven heat pump. District network to be built will ensure heat distribution. This is one of the first user of very low enthalpy resources although geothermal fluid has to be transported to a long distance.
The geothermal energy extracted from the deposists located in the lagoon of Grado, will be employed for the heating of public and private building in the town of Grado and the production of warm water for sanitary purposes.
The project will be produced 2520 Thermal TOE/year and 2154 Electric MWh/year, by using 480.000 cu m/year of geothermal water and 2204 TOE/year of methane gas.
This new output will substitute 3863 TOE/year of the oil which is at present used for heating, and 538 TOE/year used to generate electric power, for a total energy saving of 2197 TOE/year.
The installation is composed of the following sub-systems :
a) GEOTHERMAL SUB-SYSTEM : consists of wells up to 200 m in depth and of other components such as : endothermic motor-pumps fit to recover the heat of cooling and of exhaust gases; pre-insulated pipes for the under-water conveyance of warm water; surface heat exchangers; reinjection pumps; filters, etc..
b) HEATING INSTALLATION SUB-SYSTEM : consists of endothermic internal combustion engines, powered by methane or by fuel oil, operating cooling screw compressors, fitted into thermo-dynamic "heat pump" circuits. The main innovation of these circuits is their capacity to adjust the volume of compression to variations in thermal load, maintaining a constant C.O.P. value. The installation also includes appropriate boilers and other conventional apparatuses to consent the normal running of the system.
c) DISTRIBUTION SUB-SYSTEM : is a network of pre-insulated steel pipes, fit for warm water conveyance. The pipes are provided with valves and other interception and regulation devices, heat exchangers and individual cost metering.