English

For residential forced air heating and cooling systems conventional thinking is that air supply registers should be located under exterior windows. There were good reasons for this in the past (primarily to counteract the cold downdraught from the window) but new construction standards (well-insulated walls, better glazing and air tight wall/window interface) mean that there is now less downdraught. Positioning the supply air register away from a window could have a large impact for new construction as duct lengths could be shortened (saving materials and construction time).

The scope of the research described in this paper is to develop, evaluate and propose a new empirical index, the so-called Index of Workplace Comfort (IWC), which quantifies the overall comfort sensation of a user in an office building. The proposed Index of Workplace Comfort is calculated on the basis of both environmental and psychological properly weighted sensation votes of workplace occupants.

The provision of good IAQ in schools is important both for the health of students and in maximising educational achievement. It is, however, common for school classrooms to be significantly under-ventilated and this can lead to high levels of CO2 and other pollutants. Natural ventilation offers the potential to improve IAQ within schools whilst, at the same time reducing running and maintenance costs. Accordingly, this article examines a natural ventilation strategy based on the use of a roof mounted split-duct Windcatcher ventilator. Here, 16 U.K.

The removal efficiency of high efficiency air filters against microbe-carrying particles (MCPs) in the air supply of occupied rooms, such as cleanrooms, was determined. Knowing the size distribution of MCPs in the air to be filtered, and the removal efficiency of a filter against individual particle diameters, the overall removal efficiency was ascertained.

It is widely recognised that the carbon dioxide (CO2) concentration level inside a building is a reflection of the indoor air quality in that building. In most buildings, occupants are a major source of CO2 through exhalation. It is generally accepted that the concentration of CO2 varies with location (horizontal and vertical) within an enclosed space and this can impact on the variation of indoor air quality within the space. Hence, measurement errors related to CO2 sampling strategies in a space are important as they can lead to uncertainties in the mean concentration for the space.

Increasing demand for energy efficiency places new requirements on energy use in historic buildings. Efficient energy use is essential if a historic building is to be used and preserved, especially buildings with conventional uses such as residential buildings and offices. This paper presents results which combine energy auditing with building energy simulation and an indoor environment survey among the occupants of the building. Both when comparing simulations with measurements as well as with survey results good agreement was found.

The air distribution characteristics formed by an "air curtain" ventilation approach are investigated in detail. The airflow visualization and full-scale experimental results of air distribution in an occupied zone are reported in this paper. The Coanda effect of air curtain ventilation and the spreading airflow over the floor in a room are demonstrated. Additionally, the "air lake" or "air pool" phenomenon created by air curtain ventilation resembles displaced air movement to some extent.

The potential application of Passive and Hybrid Downdraught Cooling to residential buildings is explored using an experimental facility constructed and tested in Seville, Spain. The experiment was devised as a prototype of the downdraught evaporative cooling system for the Nottingham University entry to the 2010 Solar Decathlon Europe competition.

Among policy makers in many countries there is seemingly an almost unstoppable demand to require homes, schools and offices to be hermetically sealed and mechanically ventilated. The reasoning is one of control. As the thermal insulation properties of buildings improve, ventilation accounts for an ever-increasing proportion of the total thermal energy loss. Current thinking suggests that, by incorporating mechanical systems, a substantial amount of ventilation losses can be recovered through heat recovery.

Although the power law has been broadly accepted in measurement and air infiltration standards, and in many air infiltration calculation methods, the assumption that the power law is true over the range of pressures that a building envelope experiences has not been well documented. In this paper, we examine the validity of the power law through theoretical analysis, laboratory measurements of crack flow and detailed field tests of building envelopes.