English

In recent years, concerns about global warming and greenhouse gas emissions have motivated designers to reduce building energy consumption through the implementation of passive solutions without compromising users’ thermal comfort. This evidence has stimulated a renewed interest in designers for the exploitation of natural ventilation as means of passive cooling solutions. The adoption of ventilative cooling is particularly suitable for large spaces (non-residential buildings) as a measure to reduce the HVAC system high cooling loads.

Overheating is an unwanted consequence of modern building designs and internal gains that will be aggravated by the effects of climate change on local climates within urban and suburban areas. To minimise the energy cost of limiting overheating several different approaches exist for passive cooling dissipation techniques. Free cooling by ventilation, or Ventilative Cooling, (VC), is a generally accepted effective, energy efficient, mitigation strategy to building overheating. There are many factors that influence the design and selection of suitable VC strategies.

This paper introduces a comparison study of measuring the airtightness of a house sized test chamber using the novel pulse technique and the standard blower door method in a controlled environment. Eight different testing plates have been applied to the improvised envelope of the chamber to establish different leakage characteristics. Each testing plate has a unique opening in the centre of the plate, achieved by obtaining a different combination of shape and thickness of the opening.

Recirculation hoods equipped with carbon and plasma filters are becoming more and more popular. The aim of this study is to determine the effectiveness of recirculation hoods with regard to PM2.5 and NOx removal in a 26 m3 lab kitchen with a gas furnace. With the carbon filter PM2.5 is reduced for about 30%. A fresh carbon filter removed about 60% of the NO2, dropping within a few weeks of cooking to 20%. With the plasma hood NO2 concentrations were above the WHO 1-hour limit and the Dutch health council 15 minutes limit.

Energy renovations seek to improve the airtightness of dwellings and thus require ventilation and heat recovery to maintain or improve energy-efficiency, indoor climate, and durability. These ventilation systems often control the indoor air of an apartment as a single climate zone, which neglects the different demands of individual rooms. Renovations result in greater retention of heat and air inside the building envelope, so rooms become especially sensitive to gains from solar radiation, occupancy, moisture loads and pollutants.

Most natural ventilation (NV) systems used in non-residential buildings are single sided (SS). These systems are easy to integrate in the building layout, since, unlike in cross-ventilation (CV), these systems do not require access to two facades or a central stack. Current knowledge about SS NV flow penetration away from the façade can be found in building regulations and design rules of thumb.

Natural ventilation has the potential to provide cooling and fresh air and cut 40% of the total energy consumption of European office buildings. While in the milder seasons natural ventilation is an obvious low-energy choice, if poorly designed it can cause overheating in summer and poor air quality in winter. In order to promote the use and design of naturally ventilated (NV) buildings, it is therefore important to understand how current NV buildings perform in terms of thermal comfort and indoor air quality.

As UK homes are insulated and draught proofed in an attempt to reduce wintertime heating demand they become more airtight. Any reduction in infiltration could have a detrimental effect on indoor air quality. Controllable background ventilation provided by trickle vents is one method of maintaining indoor air quality.

The lack of indicators assessing ventilative cooling effectiveness in a way to compare it with active cooling technics, makes its acceptance more difficult. Practitioners, norms, standards and guidelines are used to design and evaluate cooling systems in terms of Cooling Power (CP) or Seasonal Energy Efficiency Ratio (SEER). What could be the CP of a passive technique based on a day to night offset of the cooling process? What could be the SEER of mechanical night ventilation for summer cooling?

The polyurethane foam industry is projected to reach a worldwide value of up to $74bn by 2022 and with airtightness of new and retrofitted properties continually increasing, an important question arises: what is the impact of these materials on the indoor air quality (IAQ), occupants’ health and indoor environment?