VC

It is well known, that energy consumed by the HVAC systems in buildings represents an important part of the global energy consumed in Europe (Directive 2010/31/EU). Latent heat storage has been widely studied (Cabeza et al. 2011, Zhou et al. 2012) for its potential in many applications for building energy management (Lim et al. 2014). Passive implementation of phase change materials (PCM) in buildings has demonstrated significant energy reduction of HVAC systems, but with some limitations (Castell et al. 2010). For this reason, active implementation of PCM in buildings has high potential.

The aim of this study is to analyse the behaviour of natural ventilation techniques in low-rise commercial buildings in terms of Indoor Air Quality (IAQ).

Nowadays, important efforts are deployed to reduce energy consumption in the field of residential buildings. Concerning new constructions, low-energy consumption buildings such as “passive” houses constitute a suitable solution to decrease the environmental impacts.In this kind of building, air tightness is improved and heating needs are reduced compared to traditional constructions. In order to ensure a good indoor air quality, controlled mechanical ventilation is required.

Controlling indoor humidity is important in homes, because high indoor humidity is associated with occupant health and building durability issues. Ventilation is often used to avoid peaks of moisture in homes, such as in kitchens and bathrooms. However, in hot-humid climates, outdoor air can have higher humidity than indoors, and continuous whole house ventilation can lead to increases in indoor humidity levels.

In determining ventilation rates, it is often necessary to combine naturally-driven ventilation, such as infiltration, with mechanical systems. Modern calculation methods are sufficiently powerful that this can be done from first principles with time varying flows, but for some purposes simplified methods of combining the mechanical and natural ventilation are required—we call this “superposition”. An example of superposition would be ventilation standards that may pre-calculate some quantities within the body of the standard.

The effect of Phase Change Materials (PCMs) to optimize indoor thermal comfort conditions and reduce cooling energy requirement when included in envelope components and materials is demonstrated by an extensive scientific literature (Zhou et al., 2012. Orò et al., 2012). In this view, this research consists of the development and prototyping of an innovative passive cooling polyurethane based membrane with PCMs inclusion for roofing applications (Pisello et al., 2015).

The framework in which the SINHOR project takes place is the "Service Contract R + D + i Relating to Competence Scope of the Ministry of Public Works and Housing" with the research project entitled "Analysis of the energy performance of closures concrete based on maximizing the benefits derived from the thermal inertia". Meeting the "20-20-20" targets for reduction of CO2 emissions necessarily involves a drastic reduction of energy consumption in buildings. SINHOR project is oriented to promote the use of concrete solutions in buildings based on maximizing the benefits of its thermal inerti

For zero and low energy buildings, high-energy efficiency ventilation is very often confused with a complex mechanical ventilation system with heat recovery. In school gymnasiums, where large volumes have to be ventilated, and where intermittent occupation is very usual, demand controlled natural ventilation has several advantages, making this technique very attractive. High stack height makes natural ventilation very efficient, limiting the necessary number and dimensions of windows.

In response to the European Energy Performance Buildings Directive 2010/31/EU and the Energy Efficiency Directive 2012/27/EU, buildings have increasingly become more insulated in order to reduce the heating losses to a minimum. However, this could also lead to the problem of indoor high temperatures during warm and transition seasons. Furthermore, the Intergovernmental Panel on Climate Change (IPCC) warns about increases in temperature of more than 4 ºC by the end of the century.

Because of the customer need of best possible comfort condition and satisfaction, shopping centers are conditioned by means of basic HVAC systems, often without considering the potential of natural ventilation to contribute to air change rate, and to reduce the cooling demand. Mechanical ventilation systems are also preferred to natural ventilation because more controllable and reliable since they are not affected by the uncertainty of natural forces.