Advances in hardware, software and communications have been pointed out as promising tools for building a Smart City. These advances have made possible to face an increasingly complex functionality in different processes that can be found in any city. Applications called "smart" (smart building, smart water, smart energy, smart grid, smart city, smart transport, etc.), start to emerge around the planet. These smart applications are supported by ICT technologies and they connect the physical world and its digital representation. Where novel algorithms and knowledge representation provide with information which can be used to support decision making for users, local authorities, and so on. This paper presents a smart building approach with multiple sensors and the use of a low enthalpy geothermal system to maintain indoor comfort. We decided to go a step ahead and go from smart building to a smart city model of a real location. A smart city model is build and environment is simulated where semantic web technologies and linked open data play a key role.Current work was partially funded by Research Grants: MICINN-INNOVA-INNPACTO IPT_2011_1164_920000 and MICINN-INNOVA-INNPACTO_IPT_2011_1584_920000 by the Spanish Government. First author thanks to the Alternative Energies Research and Development Foundation (FIDEAS) for a pre-doctoral grant and also CONACYT-CIATEQ for additional grant and economic support.