In most Dutch classrooms draught results in insufficient ventilation and poor air quality during the heating season, adversely affecting the well being and performance of pupils. Also a considerable part of the year the risk of overheating is high due to the high internal heat load. New analyses show that over 85% of time the heat load and not minimum indoor air quality is the determining factor for the required amount of ventilation. That is if passive cooling is to be preferred above mechanical cooling, with regard to energy conservation.
Due to increasing interest in indoor air quality and demand controlled ventilation in buildings aiming at energy and cost saving, as well as health and comfort aspects, the objective of our work has been the development of a reliable, low cost tool for demand ventilation control. Based on a single microelectromechanical (MEMS) metal oxide semiconductor (MOS) gas sensor VOC detection as close as possible to perceived air quality and additionally, a good correlation with measured CO2 concentrations due to implementation of an empirical data evaluation algorithm has been achieved.
Since the 2002/91/CE EPBD was published, all European countries should making efforts in harmonizing local standards, imposing the assessment of building energy and environmental impact through a common certification procedure. Generally speaking, as a matter of fact, beside the main problem of different methods and tools adopted for evaluating the building energy balance, ventilation is still one of the controversial issues, since each country refers to different local requirements regarding the air-change rate values to be used when performing the calculation.
The dependence of the ventilation on the indoor particulate pollution is highlighted by numerousstudies. The aim of the present study is to examine the influence of the ventilation on the levels of theparticulate concentrations found in dining halls where a large number of students are accommodated. Indoor particulate sources were also quantified.Measurements were conducted in four University dining halls, which are located in different parts ofthe city of Athens.
It is well known that appropriate ventilation represents one of the prerequisites for achieving goodindoor comfort, and we try to ensure a continuous and sufficient intake of fresh air into a building. But,ventilation losses are also one of the most important components of a building thermal balance, andwe try to reduce them as much as possible. In theory, these two seemingly contradictive facts can betechnically adequately solved in various ways.
A questionnaire presented to designers demonstrates the difficulty to explain the specific status, thestratification and the correlation of parameters, features, concepts, principles and requirements.
Renovation of existing buildings, in order to reduce energy consumption, represents a big market inEurope. As the first efforts often concentrate in improving insulation and airtightness of the buildingenvelope, important insufficiencies of ventilation can appear, generating health risks for the occupants and a degradation of the frame. Taking into account the difficulties to insert ductworks in existing buildings, it can be easier to use distributed ventilation systems for room-by-room ventilation instead of centralised systems.
On the way to the solution of our energy-problems, the conditioning of buildings is the most importantsector. We have to create new buildings, that produce more energy than they need in the course of ayear, so called plus-energy buildings and we have to perform large-scale retrofitting of existing buildings. Priority must be given to increasing energy-efficiency. Having fulfilled this, the implementation of renewable energy has to be undertaken.
One of the topics studied in the European IEE-ASIEPI project (www.asiepi.eu) is the way envelopeairtightness is dealt with in the EPB-regulations of the Member States. To this end, a number of surveyshave been made among the participating countries. Also a quantitative comparison on a samplebuilding has been performed. The results of this study are used in the development of an instrumentto compare the energy performance requirement levels among the Member States.
Thermal bridges increase the building energy demand for heating and cooling. For well insulatedenvelopes and buildings with increased energy efficiency, the influence of thermal bridging on theenergy consumption is of major importance. Here the ratio between the thermal bridging effect and the overall thermal losses increases compared to low or medium insulated buildings and it is possible that the effect of thermal bridges on the energy demand compensates or even overtakes, for instance, the energy gain provided by thermal solar collectors for domestic hot water.
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