overheating

The most representative typology of residential buildings of Catalonia has been simulated in TRNSYS to evaluate the impact of both infiltration and natural ventilation. The typology is a block of apartments constructed during 1950-1980. 

The new initiatives and regulations towards nearly zero energy buildings forces designers to exploit the cooling potential of the climate to reduce the overheating occurrence and to improve thermal comfort indoors. Climate analysis is particularly useful at early design stages to support decision making towards cost-effective passive cooling solution e.g. ventilative cooling.

Higher insulation and air tightness levels of buildings, increase the risk on overheating. Ventilative cooling as passive technique can limit overheating and decrease cooling energy consumption. The national energy performance regulations (EPBD) determine whether, how and under which requirements ventilative cooling can assist to reduce cooling demand and overheating. Therefore, those regulations are a key factor in the market uptake of ventilative cooling. Without a realistic and achievable approach, ventilative cooling will marginally be applied in buildings.

A post-occupancy evaluation was carried out in three prefabricated timber housing developments in the UK to identify the potential of summertime overheating. All the case studies selected are recipients of various low-energy or sustainability awards built within the last eight years. Two of the case studies are modern multi-storey apartments blocks (Bridport and Stadthaus) and the third one (Oxley Woods) a housing development with ten different prototypes.

In 2004 the first adaptive thermal comfort guideline was introduced in the Netherlands. Recently a new, upgraded version of this ISSO 74 (ATG) guideline has been developed. The new requirements are hybrid in nature as the 2014 version of the guideline combines elements of traditional non-adaptive comfort standards with elements of adaptive standards. This paper describes the new guideline and explains the rationale behind it. Also changes in comparison with the original 2004 version and issues related to performance verification are discussed.

Climate changes have progressively produced an increase of outdoors temperature resulting in tangible warmer summers even in cold climate regions. An increased interest for passive cooling strategies is rising in order to overcome the newly low energy buildings’ overheating issue. The growing level of air-tightness plays in low-energy buildings a double-acting role: reduction of energy demand and lack of adequate infiltration rate.

The synergistic effects between summertime ventilation behaviour, indoor temperature and air pollutant concentration in relation to energy retrofit and climate change have been under-investigated to date. This paper explores such interactions in a social housing setting. The case study flat is located on a mid-floor of a high-rise council tower block in central London. Dwellings of this type are likely to be occupied by vulnerable individuals (elderly people or people suffering from ill health or mobility impairment).

It is important to understand and model the behaviour of occupants in buildings and how this behaviour impacts energy use and comfort. It is similarly important to understand how a buildings design affects occupant comfort, occupant behaviour and ultimately the energy used in the operation of the building. In this work a behavioural algorithm for window opening developed from field survey data has been implemented in a dynamic simulation tool. The algorithm is in alignment with the proposed CEN standard for adaptive thermal comfort.

There is a growing consensus that the climate is changing faster than at any time in the past millennium. This is likely to have major effects upon many aspects of the built environment. UK Climate Impact Projections 09 indicate significant increases in Summer Mean Temperatures. This may suggest a requirement for cooler buildings during the summer months. In consequence, that would likely lead to an increase in demand for mechanical ventilation and comfort cooling.

As overheating problems in glassy buildings came up more and more, EMPA put a focus on the determination and modelling of the total solar energy transmittance (TSET) of multiple glazing combined with different shading systems within the framework of IEA Task 27 "Performance, durability and sustainability of solar faade components". Experimental data were produced by a calorimetric outdoor test facility near Zurich (Switzerland).