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Various studies demonstrate a significant impact of ductwork leakage on the fan power consumption of ventilation systems. They have shown that the total energy used by fans can be reduced by 30-50% by improving the airtightness of the ductwork system. However, most of those studies focused on non-residential and multi-family buildings. This study focuses on single-family dwellings; specifically houses.  

Over the last few decades, there is a clear target for reducing energy needs in the building sector. The above objective can be achieved both by renovating the existing building stock and/or by constructing new buildings that will meet the characteristics of zero or nearly zero energy buildings. In order to construct or renovate a building into a zero or almost zero energy building, different passive, active and hybrid systems can be used. One such system is a solar air heater collector.

Situated 1º North of the equator, Singapore has a year-round hot and humid climate with temperatures in the range of 25 and 32º C and relative humidity around 70%.  In view of these environmental conditions, there is really no need for “Heating (or simply “H”) in the traditional Heating, Ventilating and Air-Conditioning (HVAC) terminology.  Consequently, the term Air-Conditioning and Mechanical Ventilation (ACMV) is used in the local industry.

An accurate temperature gradient calculation is essential for displacement ventilation (DV) system design, since it directly relates to the calculation of the required supply air flow rate. Inaccurate temperature prediction can cause the poor thermal comfort and w sizing of the ventilation and cooling systems.

This paper presents a comparative study based on CFD simulation between the performance of Impinging Jet Ventilation (IJV) and Mixing Ventilation (MV) systems in providing indoor air quality and thermal comfort for a mechanically ventilated occupied large open plan office (floor-to-ceiling height > 5m). Large spaces differ from spaces with standard heights because of the significant upward stratification.

In recent years, many multi-type package air conditioning systems for buildings have become widespread in office buildings in Japan, and there are many cases where one air conditioning space is shared by using several indoor air conditioning units. The advantages of multi-type package air conditioning system are that it is possible to operate and control individually for each indoor unit, and that the user can arbitrarily change the temperature setting of the indoor unit.

Ventilation systems play an important role in providing a good indoor air quality in dwellings. Mechanical exhaust ventilation systems implement natural vents, also called trickle vents, to supply outdoor air to the dwelling. The airflow through these natural supply vents depends on the natural driving forces, i.e. wind and the stack effect, which vary in time.  

Japan will have to further reduce CO2 emissions to meet its obligations under the Paris Agreement negotiated at the 2015 United Nations Climate Change Conference. Society is increasingly demanding higher energy-efficiency standards and zero-energy buildings because general commercial buildings have high energy costs, especially for air conditioning.

Health Canada’s cross-Canada residential radon survey report from 2012 demonstrated that roughly 7% of Canadian homes contain radon levels above the Canadian guideline of 200 Bq/m3. The research outlined in this paper evaluates the effect of ventilation rates on radon levels in two homes located in Ontario, Canada. The first case study consisted of short-term (2 day) radon monitoring in a home using three ventilation strategies; one heat recovery ventilator (HRV) running, two HRVs running, and both HRVs turned off.

Radon gas is a well-known building´s pollutant which can affect negatively people´s health (WHO, 2009). Radon´s source is the soil underneath buildings. Radon moves from the soil to the buildings by advection through cracks and joints, and diffusion through porous materials. Once radon enters buildings it can accumulate in lower areas due to lack of ventilation. Ventilation is one of the main ways to prevent radon from accumulating in enclosed spaces in the case of moderate radon concentrations up to 600 Bq/m3 (Collignan, 2008).