PR1982

Natural and forced ventilation are directly and indirectly influenced by the pressure distribution around a building. Results of full-scale pressure measurements on a typical Swedish timber house are presented. The rate of air infiltration has been calculated by employing the values obtained from full-scale pressure distribution, air leakage characteristics and temperature differences. The results are compared with the actual ventilation obtained from tracer gas measurements.

The investigation was divided into several parts: 1, measurements of a mechanical ventilation system, 2, calculation model for this system, 3, measurements of the air leakage of the facades of a flat and 4, calculation model for this flat.

The purpose of the project has been to determine the saving in energy obtained in the practical operation of an FTX-system -that is, a fan-controlled supply and exhaust ventilation system with heat recovery - compared to an F-system, which is solely a fancontrolled exhaust system. The investigation, carried out in a terrace-house district in Skellefteg, showed the following savings for the FTX-systems in comparison with the F-systems: in 1-storey houses (81 m², airtightness approx. 1): appr. 1000 kWh/year in 2-storey houses (99.5 m², airtightness approx. 3) : appr. 1250 kWk/year.

The aim of the present study is to measure the possible health effects among tenants after certain characteristic energy conservation measures had been taken in their dwellings. Changes in comfort are also included. It is part of a number of projects on subjects such as indoor pollutant source control and changes in house dust mite populations related to moisture changes in retrofitted dwellings.

Describes experiments carried out in 4 low energy electrically heated houses incorporating extra thermal insulation and heat recovery mechanical ventilation systems. Airtightness was made an objective so that the ventilation system would provide as much of the required fresh air as possible. Instrumentation was installed during construction to monitor the performance of the houses, with the cooperation of eventual purchasers. The houses were leak tested and sealed where necessary.

Explores the various roles that mathematical models can play in the design of energy efficient ventilation systems. Uses an example (an existing terraced house) to illustrate how models may be used to investigate the energy implications and air distribution patterns of a range of mechanical andnatural ventilation options. Identifies key parameters needed for accurate results, and compares predicted infiltration rates with actual measurements taken in the house. Concludes that models of proven validity are an invaluable aid in ventilation design studies.

Uses the SEGAS "Autovent" constant concentration apparatus to measure the fresh air entering and the local ventilation rate in each cell of amulti-celled dwelling with both natural and mechanical extract ventilation. Measures fresh air entry into each cell using tracer gas constant concentration and decay techniques. Conducts decay tests without artificial mixing, and interprets them by computing the area under the decay curve to obtain local ventilation rates. Compares the 2 measurements, giving the ventilation efficiency of each cell and an idea of air quality in each room of the house.

Gives results from fiel trials of the performance of various mechanical ventilation systems. Carries out measurements in buildings built during the seventies, using the tracer gas decay technique with N2O. Tests 3 cases:< 1. Air supplied only through register above door< 2. Air supplied both through register and the slot under the door< 3. Air supplied only through slot under the door.

Reports the results of an experimental assessment of the effect of a chimney on the air leakage characteristic of an unoccupied two-storey detached house heated by either gas or electric furnace. Measurements were taken of air tightness values and air infiltration rates with the chimney capped anduncapped.

Uses mathematical models for formaldehyde concentrations in 3 normal rooms in a single family house to estimate ventilation rates needed to maintain the formaldehyde concentration below the Danish recommended indoor standard (0.15 mg/m*3). It appears that in an initial period after the house is finished, a ventilation rate more than 10 times the recommended Scandinavian value (0.5air changes/hr) is needed to keep the concentration below the indoor standard.