English

Local climate change and in particular, the urban heat island, is the more documented phenomenon of climate change. It deals with the development of higher ambient temperatures in the dense areas of cities suffering from high anthropogenic heat release, compared to the temperature of the surrounding suburban or rural areas. Actually, there are available measurements for about 400 cities around the world. Heat island exists at any latitude and may be present during the day or night period, depending on the local thermal balance.

This paper presents a comparison of Indoor Air Quality in several buildings constructed prior to the implementation of the new Spanish regulation on thermal installations (RITE, 2007 modified on 2013) and some new ones that fully accomplish the requirements of this new regulation.

Choosing the right baseline level of ventilation has a big impact in the calculated energy needs of buildings.

The north of the Iberian Peninsula is characterized by a high level of humidity during the summer.

Recently research at the Eduardo Torroja Institute for construction sciences proposes a new wording for the IAQ regulations for dwellings included in the Spanish Building Code.
The main goal of the earlier research was to adapt required ventilation rates to real needs to achieve a reduction of ventilation rates and energy demand with no negative impact on indoor air quality.

The Spanish Building Code (BC) regulates indoor air quality (IAQ) requirements in dwellings by establishing threshold continuous flow rates according to the occupancy, use of the rooms and their usable area. The implementation of this threshold flow allow adequate IAQ.
A revised IAQ requirement have been proposed. These new requirement quantifies the IAQ as a function of CO2 concentration which means an non continuous flow rates ventilation systems will be able to be used.

For zero and low energy buildings, high-energy efficiency ventilation is very often confused with a complex mechanical ventilation system with heat recovery. In school gymnasiums, where large volumes have to be ventilated, and where intermittent occupation is very usual, demand controlled natural ventilation has several advantages, making this technique very attractive. High stack height makes natural ventilation very efficient, limiting the necessary number and dimensions of windows.

Ventilation in low energy refurbished buildings is the cause of a big part of energy losses. In order to reduce this impact, some energy regulations prescribe a solution (such as the Swiss energy Law, prescribing heat recovery) and others prescribe a system global performance (such as the EU delegated regulations No 1254 and 1253 /  2004 determining a global energy performance label of the ventilation system).

In response to the European Energy Performance Buildings Directive 2010/31/EU and the Energy Efficiency Directive 2012/27/EU, buildings have increasingly become more insulated in order to reduce the heating losses to a minimum. However, this could also lead to the problem of indoor high temperatures during warm and transition seasons. Furthermore, the Intergovernmental Panel on Climate Change (IPCC) warns about increases in temperature of more than 4 ºC by the end of the century.

Because of the customer need of best possible comfort condition and satisfaction, shopping centers are conditioned by means of basic HVAC systems, often without considering the potential of natural ventilation to contribute to air change rate, and to reduce the cooling demand. Mechanical ventilation systems are also preferred to natural ventilation because more controllable and reliable since they are not affected by the uncertainty of natural forces.