• Energy Research
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The integration of residential photovoltaic (PV) systems for self-consumption is expected to unlock a variety of economic, technical and social benefits, such as the creation of local work and the reduction of the price of electricity, CO2 emissions and electrical power losses in the transmission network. In spite of all these advantages, regulatory barriers prevented the development of renewable self-consumption in Spain prior to October 2018, when a new regulation introduced the right to self-consume electrical energy without charges. This work aims to estimate the effect of residential self-consumption on the Iberian electricity market. To achieve this goal, a ceteris paribus approach was adopted, the accumulated scattered PV self-production was turned into a reduction of the aggregate demand in the market and the new clearing point was established. Based on 2017 market data, the results showed that a 1% curtailment of the annual demand due to PV self-consumption could reduce the cost of the market-traded energy by almost 2%. European Commission, Horizonte 2020 SI-1778/12/ 2018

uch of the social housing stock in southern Europe is obsolete in energy terms, with users who also present very specific socio-economic profiles requiring in-depth study. Proposals for this type of housing stock of current energy retrofitting policies, based on standardized user patterns, will only contribute to increasing the ‘performance gap’ between real and estimated consumption. This study evaluates the thermal comfort conditions and energy consumption in the specific case of social housing in southern Spain, under a severe summer climate. This evaluation is based on in-situ data measurements of three housing units in use. This paper aims to test which adaptive comfort models work best in the specific conditions of the case studies and to identify the user behaviours which reduce thermal comfort. Thus, real user patterns were established and measured data were analysed. The results show that the case studies are in discomfort conditions during a high percentage of occupied hours, mainly due to the severe climate and the unsuitable use of passive measures including natural night-time ventilation and solar protection. This situation worsens with limited use of local cooling systems due to financial constraints. National regulations should define different retrofitting targets based on climatic and socio-economic conditions.

An ever more environmentally conscious society demands the use of green, sustainable and high-efficiency renewable energy resources. However, large-scale energy storage remains a challenge for a deep penetration of power produced from renewables into the grid. The Calcium-Looping (CaL) process, based on the reversible carbonation/calcination of CaO, is a promising technology for thermochemical energy storage (TCES) in Concentrated Solar Power (CSP) plants. Natural limestone to be used as CaO precursor is cheap, non-toxic and abundant. Nevertheless, recent works have shown that carbonation of CaO derived limestone at optimum conditions for TCES is limited by pore-plugging, which leads to severe deactivation for large enough particles to be employed in practice. In our work, we have synthesized inexpensive CaO/SiO composites by means of a biotemplate method using rice husk as support. The morphological and compositional features of the biomorphic materials synthesized help improve the CaO multicycle activity under optimum CSP storage conditions and for particles sufficiently large to be managed in practical processes. Peer Reviewed

In the recent years, the integration of heat storage systems inside building components has been applied for heating and cooling purposes. The implementation of the thermal energy storage inside the building is used to manage and smooth the peak demand. An innovative constructive system including heat storage has been designed to reduce the energy consumption of the HVAC systems, during both heating and cooling periods. It consists of a prefabricated concrete slab with macro-encapsulated PCM inside its hollows. An installation of air ducts allows the air to be forced through the inside of the slab and therefore enhancing the heat exchange with the PCM. The operational mode during summer lies in solidifying the PCM during the night time and using the cold stored as a cooling supply during the day. Moreover, a solar air collector is installed for the winter mode, where the heat from the solar radiation is used to melt the PCM and cover part of the heating demand. The objective of this study is to analyse the benefits of this new system and to quantify its potential in reducing the energy consumed both for heating and cooling. The work partially funded by the Spanish government (ENE2011-28269-C03-01 and ULLE10-4E-1305)

Abstract Given that the existing residential buildings are expected to become a huge part of the future stock due to their low replacement rate, retrofitting plans are crucial to meet 2030 and 2050 energy efficiency targets. Notwithstanding, an extensive assessment of the current energy and thermal performance of the stock must be conducted prior to the proposal of energy saving measures in order to properly tackle the retrofit process. Thus, the analysis and characterisation of the existing buildings under real variability conditions through statistical techniques is key to provide useful information at the stock level, instead of the most commonly single-building level approach. In the presented study, a statistical analysis on the most predominant variability ranges of the social housing stock of southern Spain (Andalusia) is carried out. Efforts are focused on the building characterisation of the linear block typology. To do so, an extensive database, which contains information on slightly under 39,500 social dwellings, is analysed. The conclusions reported in this study may be implemented into the construction of real case building archetypes through bottom-up building stock modelling techniques with the objective of assessing the real energy and thermal performance of the existing stock, providing useful information for public stakeholders.

This paper focuses on the combined use of geographical information systems and multi-criteria decision methods when developing a decision support model in order to determine the most favourable sites for the installation of wind turbines on a regional scale. This study differs from others in three ways: (1) it analyses two distinct scenarios (depending on whether major or minor constraints, as defined in the existing literature, are applied); (2) the area under study, Cadiz, already has an extensive network of wind-generating facilities; and (3) this study analyses at length areas where installation is not suitable. The methodology is proven to be a valid and appropriate tool for identifying potential areas for wind-energy facilities on a regional scale for both planners and investors. The model is proved to be useful for planning and evaluating phases: for example, it helps to outline criteria which can be used to define sectors where the number of suitable areas for wind-energy facilities can be increased, as well as locations where repowering might be a suitable alternative.

A comprehensive assessment of indoor environmental conditions is performed on a representative sample of classrooms in schools across southern Spain (Mediterranean climate) to evaluate the thermal comfort level, thermal perception and preference, and the relationship with HVAC systems, with a comparison of seasons and personal clothing. Almost fifty classrooms were studied and around one thousand pool-surveys distributed among their occupants, aged 12 to 17. These measurements were performed during spring, autumn, and winter, considered the most representative periods of use for schools. A new proposed protocol has been developed for the collection and subsequent analysis of data, applying thermal comfort indicators and using the most frequent predictive models, rational (RTC) and adaptive (ATC), for comparison. Cooling is not provided in any of the rooms and natural ventilation is found in most of the spaces during midseasons. Despite the existence of a general heating service in almost all classrooms in the cold period, the use of mechanical ventilation is limited. Heating did not usually provide standard set-point temperatures. However, this did not lead to widespread complaints, as occupants perceive the thermal environment as neutral—varying greatly between users—and show a preference for slightly colder environments. Comparison of these thermal comfort votes and the thermal comfort indicators used showed a better fit of thermal preference over thermal sensation and more reliable results when using regional ATC indicators than the ASHRAE adaptive model. This highlights the significance of inhabitants’ actual thermal perception. These findings provide useful insight for a more accurate design of this type of building, as well as a suitable tool for the improvement of existing spaces, improving the conditions for both comfort and wellbeing in these spaces, as well as providing a better fit of energy use for actual comfort conditions.