PR2004

In the scope of the EU supported project RESHYVENT, the possible integration of Renewable Energy Solutions (RES) into hybrid ventilation systems has been analysed. The focus has been on solar and wind applications to substitute the use of fossil fuel. The feasibility of the investigated options depends on the ventilation concept the RES is integrated into, the location of the building geographically, placement of the RES in the building and on the urban environment.

The aim of the project is to study, develop, build (prototype system) and evaluate an energy efficient demand controlled hybrid ventilation system for dwellings in a cold climate. Hybrid ventilation in a cold climate means a ventilation system with low pressure drops, which result in a minimisation of the mechanical energy for ventilation, and that natural driving forces can play an important role.

The aim of this paper is to investigate the effect of improved air distribution on symptoms and self-evaluated productivity in a landscape office in which the air was distributed with ventilated cooled beams. The intervention consisted of the improvement of evenness of the air distribution by installing an extra whirl diffuser at the end of every second cooled beam. As a consequence, the draught risk quantified by the draught rating model DR, was reduced to some extend.

Major ventilation developments covering systems, measurements and design methods have taken place over the last 25 years. Our understanding about the impact of ventilation on the indoor environment and energy use has also evolved. This paper outlines these developments. Many future challenges are considered including minimum ventilation rates, energy efficient cooling, cost effective heat recovery and the development of calculation techniques.

For retrofitting of existing dwellings MVHR is seldom applied, despite the potential in energy saving and improving thermal comfort and indoor air quality. Major barriers and limitations for application are lack of space, especially for the supply ducts and the MVHR units as well as the complexity of execution. Also initial costs are an important barrier. Limiting supply ducts could be beneficial for application in single family dwellings. In a study some configurations with simplified air supply with MVHR in single family dwellings have been investigated.

One of the major sources of problems in dwellings -if not the main source- is moisture, especially due to surface and interstitial condensation on walls and roofs. For this reason, it seems important to evaluate the current standardisation and reference documents dealing with moisture and eventually to develop new assessment methods. This is the goal of the Belgian project "Moisture problems in roofs", carried out by BBRI, KUL, RUG and W&K. The first step is to collect a large number of indoor climate measurements in recently built dwellings built.

The Sint-Pieterschurch in the city of Ghent is one of the largest churches of the city. It was built in the 17th century. The city council wants to use the church not only for its religious functions, but also for cultural activities as concerts and exhibitions. To be able to do this the thermal comfort of the visitors has to be guaranteed. At this moment the church has no central heating system. Gas heaters are used during services. Installing a central heating system will influence the humidity and moisture behaviour of the church.

Approximatly over 90 percent of buildings in Poland are ventilated in a natural manner. Thescale of problems in the functioning of ventilation in our opinion is serious.In about 3 million apartments inhabitants use gas water heaters, burning fuel in an openchamber. Therefore in these types of apartments the use of mechanical exhaust ventilation isforbidden.Experiences in using mechanical ventilation is not always positive (frequent complaints aboutthe excessive noise of the installation and the high consumption of energy by the fans).

Research has shown that highly efficient solar powered ceiling fans improve thermal comfort and potentially provide health benefits when air conditioning or conventional ceiling fans are not available, such as during the 2003 summer heat waves in Europe, and in many undeveloped areas of the world. Ceiling fans can improve the spatial effectiveness of heating, ventilation and air conditioning (HVAC) systems. They can reduce air conditioning energy use if occupants increase thermostat set-points and reduce frequency of operation, and if waste heat from the fan motor is minimized.

Local control of ventilation in large buildings is considered to be a main issue in energy savings regarding the huge energy losses that are usually induced by such large volumes. An efficient ventilation system and the development of local control ventilation strategies could prevent large buildings from having an unsuited or overvalued ventilation and reduce significantly the energy consumption.