English

Enhancing the energy efficiency of buildings imposed by global warming and by the perspective of fossil fuel dwindling requires new technical solutions, more efficient. The race for efficiency directly affects ventilation and air tightness of buildings, the main potential causes of heat loss in homes. If heat recovery is emerging as an effective solution to meet energy performance and indoor air quality in climates with harsh winters, some other solutions appear to be very efficient in moderate climates.

The thrust of airtightness specification and testing is derived from energy considerations. The application to healthcare buildings and specialist laboratory facilities embodies the same principles but derives the appropriateness of the criteria with reference to [a] producing controlled and controllable cascading pressure zones and [b] specifying or quantifying the potential exposure in the event of failure of mechanical ventilation.

During the recent decades, energy consumption of buildings, together with the costs for operation, has gained increasing concern. HVAC systems stand for a significant share of the total energy consumption in buildings. Demand-controlled ventilation (DCV) has proved to be an efficient system that gives opportunity to strongly reduce energy consumption, especially when contamination loads or temperature load vary during the operating hours. 30-60% energy reduction can be expected by applying proper DCV.

Large buildings can not always be tested as a single pressure zone. In Europe, different approaches have been proposed concerning the choice of representative parts of the building (sampling method) and the compliance check in situations, when several parts of the building have to be tested separately. The preliminary Czech standard TNI 73 0330 defines a sampling method, as well as subsequent treatment of results and compliance check procedures for multifamily residential buildings. This contribution reports the results of a trial test of TNI 73 0330 method.

The improvement of energy efficiency is the key issue after the energy performance of buildings directive came into the force in European Union countries. The city of Kuopio in Finland participate a project, in which different tools will be used and tested to improve the energy efficiency of public buildings. In this project there were pilot buildings e.g. schools. The other pilot school consumed much more heating energy than the other same type of school. Air tightness was measured using the own ventilation system of the building and by remote control from the central operation room.

Normally, the design of a ventilation system in a dwelling is based on national regulations, related design rules, building tradition and general knowledge about healthy indoor air quality, ventilation and air handling units. In practice, the actual performance of ventilation systems is determined by ventilation components, building properties, outdoor environment and occupant behavior. Unspecified items in the design rules and uncontrollable items in the design stage will bring uncertainties which may cause the actual performance deviating from the designed performance.

The paper presents the whole year simulation of humidity based demand controlled hybrid ventilation in multiapartment building. The simulation was performed for NAPE (National Energy Conservation Agency) multifamily residential reference building. This allowed the authors to compare obtained results with earlier investigated behaviour of the NAPE building with passive stack ventilation and mechanical exhaust ventilation.

As part of a project aiming at assessing ventilation in low energy buildings, this study analyses the performance of innovative ventilation systems used in a single-family building. Five ventilation systems are investigated by simulation using SIMBAD Building and HVAC Toolbox. The results then show better performance in terms of energy demand and indoor air quality (IAQ) for balanced ventilation systems, either permanent or intermittent management.

Wind is a potential dominant factor regarding the air infiltration through building envelopes. Due to its dynamic characteristics, quite complex aerodynamic phenomena arise around a structure or through cracks and openings. Energy perfomance is influenced by the climate conditions and thus it should be much more researched. Despite the fact that steady state measurements of infiltration rates offer a simple and easy way of estimating an enclosure’s airtightness level, a supplement to those methods might be imposed.

Most European standards and national regulations about ventilation rates are based on indoor air quality assumptions in terms of contamination. On the other hand, indoor air humidity is important for human health as well. In case of high flow rates during the heating seasons in cold climates, the indoor air humidity tends to low values.