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In the research project 3for2 Beyond Efficiency, low-exergy distributed cooling and ventilation systems for application in the tropics are designed and tested in a demonstrator building in Singapore. The HVAC system designed consists of passive chilled beams for sensible cooling, fan coil units for latent cooling and dedicated outdoor air handling systems for IAQ control. The design reduces building space requirements due to less ventilation equipment.

Mechanical ventilation is vital in modern homes to insure adequate indoor air quality. However, builders, homeowners and policy makers may perceive best practice as a risk, especially if invoked during peak outdoor thermal conditions which may compromise comfort and energy use. In North America, ASHRAE Standard 62.2- 2016 defines best practice, yet ventilation code specifications vary internationally.

The early design stage of a building is decisive for describing the concept of the HVAC system. Designers and practitioners can adjust and optimize the design during this stage as it provides them with enough resilience to adapt new changes. In practice, a well-defined optimization process is essentially required in order to achieve the project’s goals within a reasonable time span. These goals vary from one project to another, and sometimes they require a comprehensive study to identify the factual and stochastic parameters and their impact on the design.

Night-time ventilation is a natural cooling technology, in which cold ambient air is used to cool indoor spaces. This literature review analyses how recent studies have defined the effectiveness or efficiency of night-time ventilation. Most studies used the similar indicators related to heat removal, energy saving, cooling demand reduction, and thermal comfort. However, there were significant differences between the definitions of performance of night-time ventilation, both in terms of criteria of judgement and methods of analysis.

Design of ventilation systems in Belgium is currently based on the Belgian Standard NBN D 50-001:1991. This regulation is more than 25 years old, and is not anymore suited to new technologies developed in the frame of increasing energy performance of buildings and its associated ventilation systems. This standard defines four classic ventilation systems, going from A (natural ventilation) to D (double-flux ventilation eventually with heat recovery). One of its main shortcomings is that it does not consider demand controlled ventilation (DCV) systems.

Traditionally, occupancy-based ventilation controls have only ventilated when occupants are present – usually based on measurements of CO2 and/or humidity.  These indictors may be fine for pollutants released directly by occupants, such as bioeffluents, or by their activities, such as cooking and cleaning. However, they do not account for pollutants not associated with occupancy, such as formaldehyde from building materials and furnishings.

In order to better address energy and indoor air quality issues, ventilation needs to become smarter. A key smart ventilation concept is to use controls to ventilate more at times it provides either an energy or IAQ advantage (or both) and less when it provides a disadvantage. This would be done in a manner that provides improved home energy and IAQ performance, relative to a “dumb” base case. This paper highlights that a favourable context exists in many countries, with regulations and standards proposing “performance-based approaches”.

It is well known that the olfactory sensitivity changes with exposure time and concentration of odor under continuous exposure to odor in the air. This decrease of odorous sensitivity, the increase of odorous threshold in other words due to continuous exposure to odor is called olfactory adaptation. 

Since the turn of the century, alarming data produced by the Indoor Air Quality Observatory (OQAI) have led to changes in French legislation, including, most notably, the introduction of compulsory labelling for construction products (decree no. 2011-321 of 23 March 2011).

Carbon dioxide included in exhaled breath is often used as a tracer gas when estimation of ventilation aspect in buildings with occupants is performed. Indoor carbon dioxide concentration is also adopted evaluation of ventilation commonly. It is needed for these investigations to grasp occupants’ carbon dioxide production rate accurately.