Environmental assessment of the CIESOL solar building after two years operation.

Life cycle assessment is applied to assess the environmental benefits and trade-offs of a solar-assisted heating, ventilating, and air-conditioning (HVAC) system installed in the CIESOL building in Almeria (southeastern Spain). The environmental performance of this system is compared to that of a conventional HVAC system using a heat pump. The study evaluates these systems from cradle to grave, and the impact assessment includes, in addition to the CML2001 method, an impact category dealing with impacts on freshwater resources. The results show that the solar-assisted HVAC involves lower impacts in many impact categories, achieving, as an example, a reduction of 80% in greenhouse-gas emissions. On the other hand, key weak points of this system are the production of capital goods, but specially water use for cooling, due to its high impact on freshwater resources. Minimization of water requirements should be a priority for further development of this promising technology.