English

The IEA EBC Annex 68 project on “Indoor Air Quality Design and Control in Low Energy Residential Buildings” has been recently completed. The project considered indoor air pollution loads in dwellings, particularly how such pollutants are emitted in dependency of the hygrothermal conditions: temperature, moisture and air flows. Thus, a proper understanding of the mutual interactions between hygrothermal conditions and pollutants was needed to obtain optimal paradigms for demand-controlled ventilation.

The overall objective of the “Annex 68” Project, which belongs to the International Energy Agency’s “Energy in Buildings and Communities” Implementing Agreement, has been to develop the fundamental basis for optimal design and control strategies for good Indoor Air Quality (IAQ) in highly energy efficient residential buildings, and to disseminate this information in a practically applicable guide. The strategies shall facilitate the possibility to design and operate residential buildings with minimal energy use, while ensuring impeccable indoor climates.

In order to evaluate the impacts of volatile organic compounds (VOCs) emissions from building materials on the indoor pollution load and indoor air quality beyond the standard chamber test conditions and test period, mechanistic emission source models have been developed in the past. However, very limited data are available for the required model parameters including the initial concentration (Cm0), in-material diffusion coefficient (Dm), partition coefficient (Kma), and convective mass transfer coefficient (km).

IEA-EBC Annex 68 “Indoor Air Quality Design and Control in Low Energy Residential Buildings” is an international collaborative project to provide new insight into methods and strategies for ensuring high indoor air quality in dwellings during both design and operation phase of their life cycle. Within the Annex 68 work, we defined a common exercise, which focusses on model-to-model comparison of different simulation tools to assess their modelling abilities with respect to combined heat, moisture and pollution transfer.

To achieve stringent energy objectives, new dwellings are subject to energy conservation measures including low air permeability and high levels of insulation. Mechanical Ventilation with Heat Recovery (MVHR) can be used to control the balance between energy efficiency and Indoor Air Quality (IAQ) in these buildings. This paper evaluates the effectiveness of the design and operational strategies adopted in a new development comprising two apartment blocks in East London.

In order to achieve nearly net zero energy use, both new and energy refurbished existing buildings will in the future need to be still more efficient and optimized. Since such buildings can be expected to be already well insulated, airtight, and have heat recovery systems installed, one of the next focal points to limiting energy consumption for thermally conditioning the indoor environment will be to possibly reducing the ventilation rate, or making it in a new way demand controlled. However, this must be done such that it does not have adverse effects on indoor air quality (IAQ).

Both new and renovated existing buildings will in the future need to be optimized in such a way that can achieve to have nearly no energy use while still providing impeccable indoor climates. Since such buildings can already be assumed to be very well insulated, airtight, and to be equipped with heat recovery systems, one of the next focal points to limiting energy consumption for thermally conditioning the indoor environment will be to possibly reducing the ventilation rate, or to make it in a new way demand controlled.

This paper presents the initial reflections in the frame of Subtask 1 – Setting the Metrics of the IEA EBC Annex 68 – Indoor Air Quality Design and Control in Low Energy Residential Buildings. The first step of IEA Annex 68 aims at summarizing the current knowledge on target pollutants for residential buildings and at evaluating indoor air quality (IAQ), i.e. how to define indices that provide useful information allowing to achieve low risks for health in indoor spaces, and how to enable the comparison of solutions for achieving high IAQ taking into account energy efficiency.

AIVC's Ventilation Information Paper #44: Residential Cooker Hoods,  summarizes current knowledge on cooking contaminant emissions, its effects on IAQ, and identifies standards for assessing the efficacy of cooker hood (also known as a range hood) performance.

AIVC Technical Note 68 (TN 68) "Residential Ventilation and Health” is one of the outcomes of the work performed under the framework of AIVC’s project “Ventilation & Health” and benefited from contributions by several authors and many structured discussions held during specific sessions at AIVC events. TN 68 summarised studies that prioritise pollutants in the indoor environment and presented a