Improvements to ventilation systems for the purpose of saving energy may also affect the provision of good air quality. Measurement of ventilation effectiveness may be used to determine whether or not good fresh air distribution and satisfactory contaminant removal has been achieved in a specific case. However, for such measurements to be useful, it is necessary to establish recommended values of the parameters and to check the reliability of the measurement procedures. This paper is concerned with the second of these problems.
It has been shown that thermal imaging can give an indication of air flow rates through small cracks. Using a finite difference analysis package it is possible to determine the surface temperature of an air transfer grille when subjected to airflow rates at higher temperatures than the grille surface. This paper will address this technique by presenting the results of the finite difference analysis package for a specific grille.
Cooling ceilings are more and more proposed, in order to eliminate excess heat in office buildings without consuming much energy in air transport. On the other hand, piston ventilation is proposed to efficiently eliminate contaminants. These two systems may however interact and experiments were planned to look at these interactions. Measurements of the age of air and air change efficiency were performed, together with more classical temperature and air velocity measurements, on various ventilation systems installed in the test chamber of Sulzer Infra, in Winterthur.
Ventilation of buildings is necessary, both to insure adequate indoor air quality and to protect the building itself against condensation and mould growth. On the other hand, ventilation rates must not lead to excessive energy consumption. French regulation doesn't appreciate directly the indoor air quality but fixes requirements for the value of exhaust stale air in service rooms ; furthermore heat losses related to cross ventilation due to wind effects are also taken into account.
The number of smokers differs mainly with age, sex, education, profession, and cultural background. The change in habits from the 2nd World War till today in form of increasing number of female smokers and decreasing number of male smokers is significant. The smoking of tobacco causes pollutants in the form of volatile organic compounds, particles, and carbon monoxide. Many of the pollutants are carcinogenic. In some cases the concentration of specific tobacco smoke related pollutants in room air may be higher than the maximum allowable concentration.
Several demonstration buildings were constructed in order to find technical solutions to energy saving and better indoor air quality in the 1980's in Fiand. Warm air heating systems were installed in two multi-storey residential buildings and in several single family homes. Heat recovery units were installed in many buildings. During renovation, mechanical supply air and heat recovery units were installed in two multi-storey residential buildings. Studies on energy consumption and performance of air conditioning systems were carried out in the demonstration buildings.
The continual reduction of the transmission heat losses of residential buildings causes an increasing importance of the ventilation heat losses. Energy saving can be achieved by using a mechanical ventilation system with heat recovery. A great improvement is the combination of heating and ventilation in one system. In this project such a combined system was developed to reduce the energy consumption of the fans, the operating expenses and also the investment costs in comparison to existing systems. In future a high market acceptance is expected for combined heating and ventilation systems.
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