| Title | Estimating Low-Enthalpy Geothermal Energy Potential in Four Cities of Southern Chile: A Battle Against Particulate Material Pollution |
|---|---|
| Authors | Diego ARAVENA, Mauricio MUÑOZ, Pablo VALDENEGRO, Linda DANIELE, Diego MORATA |
| Year | 2020 |
| Conference | World Geothermal Congress |
| Keywords | geotermal heat pump, chile, hydro-geology, exploration, patagonia |
| Abstract | The majority of cities located in central and southern Chile are highly polluted with particulate material. This problem is originated by the use of firewood as a heating source. Without the necessary ventilation, large and medium cities such as Santiago, Talca, Temuco and Osorno reach high PM10-PM2.5 concentrations, well above any national or international norm. In order to reduce the emission of PM within the next decade, we propose the use of geothermal heat pumps (GHPs) as an environmentally friendly alternative. This work aims to compare the available energy for closed and open loop systems in four cities of central-southern Chile. We discuss the possibilities for implementing scalable prototypes in these cities and their possible impact in PM emissions. An hydrogeological analysis was performed in each city including i) data gathered from the national water agency (Dirección General de Aguas; DGA) and ii) data measured in shallow wells (water temperature, static level and electrical conductivity). The data was then used to calculate available energy for open systems. Thermal properties of soils (thermal conductivity, thermal diffusivity and specific heat) were measured in each city and the data was used to calculate available energy for closed systems. Available data was analyzed in a Geographic Information System (GIS). The comparison of available energy for open and close loops was then analyzed in the light of each city's urban configuration (available space, energy demand, etc.). Static levels in Santiago range between 2.5 and 165 m depth. In Talca, Temuco and Osorno static level varies from 3 to 45 m depth. Hydraulic transmissivities are similar in Santiago and Talca, ranging between 10 and 7000 m2/day with temperatures ranging from 15 to 19 ºC. Temuco and Osorno on the other hand, show a wider spectrum of transmissivities ranging from 1 to 1000 m2/day with temperatures ranging from 13 to 14 ºC. Given the high hydraulic gradient and groundwater recharge present in south-central Chile, there is great potential for the use of this resource implementing geothermal heat pump systems. Although variability exists in some parameters, the values measured in this study suggest that GHP could help mitigate air pollution in all the prospected areas. |