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Under-estimating the ventilation flow rate results in increased sanitary risks and damage to the existing building structure. Over-estimating ventilation flow leads to energy waste. In this context, a number of approaches have been designed to determine indoor air quality indicators. The aim of these is to compare comfort and sanitary quality in different atmospheres. This document presents four air quality indicators developed by three French teams and one Danish team.We examine the strengths and weaknesses of each design, plus their specific areas of use.

A new ventilation and cooling system called OKOMAIR has been developed and investigated. The main idea is to separate carrying off cooling loads and providing fresh air to the occupants without mixing it with the return air. Return air is cooled by fan coil devices. The undiluted outside air is provided directly to the working zone and cooled by a cold waterstorage. This storage is charged by cool outside air during night. Use of the new system leads to high comfort for the occupants and reduces cooling energy.

Mechanical ventilation with heat recovery (MVHR) and passive stack ventilation (PSV) systems are both proposed as methods of ensuring satisfactory ventilation rates in UK housing. MVHR provides controlled ventilation in all rooms together with heat recovery, while the cheaper PSV system offers lower running costs, but without heat recovery and without a controlled air supply to all rooms. The relative energy consumption of the two systems depends on a number of factors that are difficult to predict.

Dynamic insulation stands for an insulation through which an air flow flows. The air flow is usually the normal ventilation flow. The air can flow in the same or in the opposite direction of the normal heat flow. The dynamic insulation can be arranged as single where only inlet or exhaust air passes the insulation, or as combined where inlet and exhaust air pass one half of the insulation each. Dynamic insulation using exhaust air might result in condensation problems in cold climates.

An even distribution of room air can improve indoor air quality, lower energy costs, and create thermally comfortable environments. This paper investigates the influence of the design of plaque diffusers on the efficiency of supply air. For better comfort and more accurate observations, the isothermal flow investigation was made in a small scale chamber with the air supply and exhaust on opposite walls. The supply air was spread radially and symmetrically over the vertical inlet wall. Plaques of different sizes, both solid and perforated were tested.

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.

In conjunction with IEA Annex 18, DCV-systems, a test on an auditorium in a school in Tyreso south of Stockholm has been carried out. The auditorium has 450 seats on a slightly sloped floor and a ventilation system with low impulse air supply devices placed at the lower (front) part of the auditorium. The system is intended to act as a displacement ventilation system during operation with heat load from people. The flow rate is governed by a CO2 sensor in the exhaust air device. In non-operational state, and if heating is necessary, the system operated with recirculation of air.

Within the framework of demonstration and industrial pilot projects in the energy sector supported by the Commission of the European Economic Communities, an important experiment has been dedicated to the HYGRO-ADJUSTABLE NATURAL VENTILATION (Contrat EE/166/87/FR). The experiment took place on three sites: Les ULIS (France), NAMUR (Belgium) and SCHIEDAM (the Netherlands).

For several years the technology of chilled ceilings has been a favourite issue among HVAC technicians and underwent a boom in the past few years. According to the survey of a German technical journal, on March the first 1993, a total of 308,490 m² of chilled ceilings had been installed in German buildings, out of which 69 per cent had been installed in new buildings and 31 per cent in modernized projects. Cooling ceiling systems are the ideal.application where high demands are placed on comfort requirements and where the energy loads are very high compared to material loads.

High quality is a prerequisite for industry to sell its products. To secure an optimized production and at the same time assure a minimum of wastage, it is often required that the production takes place in an environment where control is exerted on the particle concentration in the air and also on thermal conditions. Medical production is subjected to requirements from the authorities to comply with definite requirements of purity, according to the pharmaceutical in question.