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Building hygrothermal performance, indoor air quality and energy consumption depend heavily on envelope airtightness. Over the last three decades, single-family dwellings have been amply studied in this respect by researchers in North Europe, the United States and Canada. However, very few studies have been conducted on airtightness in multi-family housing in warm climates such as Mediterranean Europe. This paper aims to enhance the understanding of building airtightness in early twenty-first-century multi-family buildings in southern Spain. Blower Door tests were conducted in 45 units in seven such buildings. The main airtightness parameter values found are reported and compared to the data for other buildings in southern Europe. The paper includes a statistical analysis of the findings, characterises building types and describes the protocol used to identify and quantify air leakage pathways. The conclusion drawn is that although a rough predictive model can be developed, the results are widely scattered due to the impact of the random component of manual construction, even in buildings with identical construction characteristics and types. The values recorded are nonetheless consistent with the findings for other European surveys. [ABSTRACT FROM AUTHOR]

The Spanish residential building stock built between 1940 and 1980 period presents a high energy saving potential as it represents a significant percentage of the total housing stock and it was built without any regulation regarding energy efficiency. Accordingly, the first aim of this paper was to quantify the energy saving potential and the related reduction in CO 2 emissions of the housing stock in those years. The work focuses on the Mediterranean climate of the Comunitat Valenciana Region, therefore the energy efficiency strategies proposed are passive and deal with the envelope of buildings. On the basis of the results obtained, several scenarios with intervention periods of 10, 20 and 30 years were calculated. The conclusion was that with the current rate of annual building renovation, it will be nearly impossible to reach the goals established by the EPBD. Only a deep transformation of the building fabric within this sector could help in achieving them. Finally, it should be noted that the proposed methodology can be applied to other areas with different climates, particularly in Spain. [ABSTRACT FROM AUTHOR]

The paper shows the results of measurements of carbon dioxide concentrations conducted in the school buildings located in two different climates: Białystok (Poland) and Belmez/Córdoba (Spain). CO 2 concentration in first 45 min met requirements of regulations, but with medium occupation of places in classrooms, then the recommended values were excided. We developed a model for CO 2 level estimation. This model allowed us to simulated the CO 2 concentration for full occupation of classrooms in both countries. In these cases CO 2 concentration would exceed maximum value (1000 ppm) during the first hour. Furthermore required air change rates were calculated: for actual occupation they should be in a range 2.5–5 h −1 to maintain IDA2 and carbon dioxide concentration below 1000 ppm, while in case of full occupation even 6–9 h −1 . Finally, surveys of student satisfaction were performed in situ during the measurements of CO 2 level to obtain the dependence of student comfort perception on this concentration. [ABSTRACT FROM AUTHOR]

The total energy demand of data centres has experienced an important increase in the last years. This is why data centres industry and researchers are working on implementing energy efficiency measures in data centre portfolio. The cooling system of these unique infrastructures can account for 40% of the total energy consumption. Therefore, air management plays an important role to reduce operating costs and to increase overall cooling system efficiency. In order to improve and optimize the energy consumption and thermal management in data centres, appropriate metrics are imperative to evaluate their efficiency and performance. The present paper examines the air management of a real data centre by the use of the most promising air metrics. Noticeable air recirculation and hot spots were observed in the facility. Dynamic modelling was used to evaluate the benefit of air inefficiency mitigation. The combination of air management improvement with increasing the supply air temperature and reducing the air flow rate would allow important energy reduction in the cooling system. [ABSTRACT FROM AUTHOR]

• Effects of multi-zone heating systems in residential buildings are assessed. • Data obtained from 336 scenarios in Mediterranean climates are evaluated. • Results are evaluated under economic and energy criteria. This paper explores the effects of multi-zone heating systems in residential buildings in different Mediterranean climates. The aim is to evaluate their potential in residential sectors to provide a general basis from the results (from the energy and economic point of view). In addition, if feasible, a further detailed evaluation of this management strategy for optimising the energy use in residential buildings would also be carried out. To do so, the effects of two different zoning controls in different types of apartment, occupancy patterns, building characteristics and locations in Spain, have been assessed. Different combinations of these parameters have resulted in 336 different scenarios that have been dynamically simulated using Design Builder software. The obtained energy results have been analysed in detail. Moreover, an economic analysis of these results has also been carried out to evaluate the economic feasibility of these systems in residential buildings located in temperate climates. This has been calculated by evaluating the maximum investment that can be assumed in each scenario to achieve different payback periods (namely 10 and 20 years). The results obtained show that these systems could be a cost-effective strategy aimed at reducing the energy consumption in residential buildings, not only in cold climates, such as is shown in the literature (the majority of the studies found are located in the UK and northern countries), but also in more temperate climates, such as that of Spain. Savings of around 20% were obtained in the most usual scenarios in Spain (coherent with results obtained in previous studies in the UK found in the literature), showing that in several cases, the initial investment in zone-controlled systems could be paid off in less than ten years, especially in large apartments and the coldest weather conditions. [ABSTRACT FROM AUTHOR]