Impact of airtightness on the heat demand of passive houses in central European climate

Excessive air leakage through the building envelope increases the infiltration heat loss and therefore lowers the energy efficiency. Therefore, very good airtightness is required in case of well insulated buildings equipped with a mechanical ventilation system with heat recovery (e.g. n50 < 0.6 h-1 for passive houses). Although the building industry has progressively adopted strategies to comply with such strict limits, it is still important to study how and how much the airtightness influences the energy efficiency of different types of buildings in different climatic conditions.

Bulk airflow measurements in a large naturally ventilated atrium in a mild climate

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.

Design and performance of ventilative cooling: a review of principals, strategies and components from International case studies

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.

A comparison study of the blower door and novel pulse technique on measuring enclosure airtightness in a controlled environment

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.

Efficiency of recirculation hoods

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.

A novel algorithm for demand-control of a single-room ventilation unit with a rotary heat exchanger

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.

Experimental evidence of effective single sided natural ventilation beyond 20ft or 2.5 floor to ceiling heights in open plan office spaces

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.

A longitudinal field study of thermal comfort and air quality in naturally ventilated office buildings in UK

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.

The effect of refurbishment and trickle vents on airtightness: the case of a 1930s semi-detached house

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.

Energy Performance Indicators for Ventilative Cooling

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?

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