English

This paper shows preliminary results of 18 out of 30 inspected ventilation systems in low rise, low energy residential buildings. We propose a method for the assessment of energy efficiency of ventilation systems. The majority of the inspected exhaust systems fulfills the conditions for the demanded air flow rates and energy efficient operation. However, typically the distribution of airflows to the rooms of the supply zone is rather weather dependent due to insufficient airtightness of the buildings and large stack heights.

This paper presents the results of a monitoring programme on a medium sized educational building which has had the external walls re-clad. The objective behind the re-cladding was to improve the durability of the building and to improve the thermal performance. The objectives of this work were to establish the viability of the calculation techniques used to simulate the ventilation, thermal and moisture performance of the re-cladding system. The results have shown that there is a good agreement between the methods currently being used and the actual performance.

The fan and the ductnetwork is designed for 100% ventilation rate. Because the fan energy is the main important energy consumption in systems all over the year it is worthwhile to control the systems correctly. By reducing the air volume rate the pressure drop in the ductnetwork drops nearly with the second power.

The paper presents some selected results of evaluation of improvement effectiveness of thermal insulation and tightness of multifamily dwelling houses located in the region of Silesia. The effect of the modernization work on heat consumption (to heat the buildings) and ventilation performance is discussed. Attention is paid mainly to the sensations of the flat users connected with air flows and change. Prospects of effective implementation of thermorenovation of buildings are evaluated in the conclusions when taking into account predominating role of ventilation.

In recent years plants have increasingly become an integral part of building interior design. Greened office space and large enclosures can provide a better human environment not only because of psychological reasons. Due to photosynthesis, plants interact with the "aerial" environment. Water evaporation aflects room air humidity and temperature. Water uptake rates offive common plants in typical indoor climate conditions have been studied. Water evaporation of these plants can now be predicted in architectural design studies.

The "Passivhaus Darmstadt-Kranichstein" is a 4 unit terrace house with an extremely low total annual energy consumption of less than 32 kWh/m² of living area, thereof about 12 kWh are needed for room heating /Feist 1994/. The determinig factors for the low consumption are the superinsulation, airtightness of the thermal envelope in combination with a highly efficient VAV ventilation system, and an improved window construction. The "Passivhaus" therfore is a typical example of an improved low energy house.

Four classrooms of two secondary schools located around Lyon in France have been monitored. The objectives are to analyse the quality of the indoor air and the thermal comfort and also the behaviour of the occupants towards opening of the windows. This paper briefly describes the context and the nature of the monitoring campaign, and presents the results of the measurements with direct interpretation of the ventilation needs.

After a short description of the physical phenomena involved, unified expressions are worked out describing net airflow and net heat flow through large vertical openings between stratified zones. These formulae are based on those of Cockroft for bidirectional flow, but are more general in the sense that they apply to situations of unidirectional flow as well. The expressions are compatible with a pressure network description for multizone modelling of airflow in buildings. The technique has been incorporated in the flows solver of the ESP-r building and plant energy simulation environment.

In the UK the increased use of natural ventilation in buildings is being encouraged, particularly during hot weather as an alternative to air conditioning or mechanical ventilation. In order to take advantage of this option building designers need to be able to estimate potential air flows. Conventional calculation methods assume windows to be simple openings, however in practice the situation is more complex since during hot weather the opening is likely to be shielded by some form of solar shading device.

In order to demonstrate conformity with the current Building Regulations, many house builders are incorporating sumps beneath the ground floor construction of houses within the designated Radon Affected Areas. These sumps will allow for later depressurisation of the below ground floor construction and thereby prevent radon passage to the internal building environment. There are concerns regarding the costs of these measures and also the potential for these sumps to be used by vermin as nesting sites as well as their effectiveness.