English

Indoor environmental quality (IEQ) is generally taken to encompass four main factors: indoor air quality (IAQ), thermal conditions, visual quality, and acoustical quality. Although there is an implicit concern for safety, the predominant metrics all four in standards for design of buildings are based on perceived quality or comfort.

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.

In this study the performance of a residential demand controlled (DC) extract ventilation system with an air-to-water heat pump was analysed via dynamic simulations. A real life test case was setup to validate results. The ventilation system controls automatically the extract air in functional as well as habitable rooms, ensuring indoor air quality (IAQ). The total extract rate is mixed with outdoor air as heat source of the air-to-water heat pump (2.5 kW at standard reference conditions). Domestic hot water (DHW) as well as space heating (SH) can be alternatively supplied.

Demand controlled ventilation (DCV) can reduce the energy use significantly compared to a constant air volume (CAV) system. However, there is still a large uncertainty about the real energy savings and the ventilation efficiency. Furthermore, control and operation of the system are more complex. To formulate answers to these questions, measurements on a DCV system in a university building in Ghent, Belgium provide insight in the system operation and performance and the air distribution in the classrooms. Monitoring is carried out in March and May 2015.

Indoor carbon dioxide (CO2) concentrations have played a role in discussions of ventilation and indoor air quality (IAQ) since the 18th century. Those discussions have evolved over the years to focus on the impacts of CO2 concentrations on building occupants, how these concentrations relate to occupant perception of bioeffluents, the use of indoor CO2 concentrations to estimate ventilation rates, and CO2–based demand control ventilation. This paper reviews how indoor CO2 has been dealt with in ventilation and IAQ standards in the context of these issues.

It is estimated that people spend 60-90% of their life in indoor environments. Therefore, it is obvious that indoor air quality (IAQ) and thermal comfort are of highly importance for the health and wellbeing of the population. Consequently, buildings should be designed to ensure proper indoor conditions. Furthermore, the need to mitigate climate change and to reduce energy import dependency, provides additional challenges for the design and operation of buildings and requires a dramatic reduction in their energy consumption and emissions.