ventilation

Ventilation and healthy classes are a recurring problem. Continuously increasing the air flow rate improves the living environment, but is unacceptable in terms of higher costs and energy loss, which is why a different approach is needed. The research question asked in this study is : Is a central ventilation system operating at low power, but combined with a decentralised ventilation system with heat recovery, more economical and energy efficient and at the same time does it provide the premises with a constant and good air quality?

This paper presents results from a project on the assessment of the indoor air quality (IAQ) benefits that might accrue from the use of a balanced energy recovery ventilation system. The study compared the whole-building pressure, IAQ and ventilation performance of a balanced energy recovery ventilation (ERV) system with that of an exhaust-only ventilation system (continuous exhaust from master bathroom).

Ventilation is critical in interpreting indoor air quality (IAQ), yet few IAQ assessments report ventilation rates; even when they do, the measurement method is often not fully described. Most ventilation assessments use a tracer gas test (TGT) to measure total air change rate. In a TGT, the indoor air is marked with an easily identifiable gas (tracer) so that the air exchange rate can be inferred by monitoring the tracer’s injection rate and concentration.

The proposed Annex should bring researchers and industry together to investigate the possible energy benefits by using gas phase air cleaners (partial substitute for ventilation) and establish procedures for improving indoor air quality or reduced amount of ventilation by gas phase air cleaning. The project shall also establish a test method for air cleaners that considers the influence on the perceived air quality and substances in the indoor air.

Product connectivity makes products and systems remotely controllable and possibly interoperable with other devices in the house. 
The most common way to achieve this interoperability is to connect these devices locally. On the other hand, products may also be cloud-connected, which allows an easier and seamless interoperability between devices. Hence, data are collected and stored in the cloud. As soon as the measured data is sent to the cloud, large set of data are available and can be anonymously retrieved and statistically analyzed. 

Indoor carbon dioxide (CO2) concentrations have been used for decades to purportedly evaluate indoor air quality (IAQ) and ventilation. However, many applications of CO2 as a metric have reflected a lack of understanding of the connection between indoor CO2 levels, ventilation and IAQ. In many cases, an indoor concentration of 1800 mg/m3 (1000 ppmv) has been used as a metric of IAQ and ventilation without understanding its basis or significance.

Many studies reported that there were insufficient ventilation and excessive CO2 concentration in air-conditioned residential buildings, but few solutions were provided. This study first investigated the performance of three possible ventilation strategies of air-conditioned residential buildings, including overnight natural ventilation, short-term natural ventilation, and short-term mechanical ventilation.

By the end of 2020 all newly constructed buildings have to be nearly zero energy buildings (nZEB). In school and office buildings the ventilation system has a large contribution to the total energy use. A smart control strategy that adjusts the operation of the ventilation to the actual demand can significantly reduce this energy use. Consequently, control systems are becoming an important part of the ventilation system in these nZEB buildings.

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.

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.