Briefly describes the need for air tight houses as an energy conservation measure, and for preventing moisture damage. Shows that very tight houses (0.5 ach/h) with mechanical ventilation function better than houses which have just fulfilled Swedish building requirements, or which have unsuitable ventilation systems. In some cases, condensation has formed on the inside of windows, and individual rooms sometimes receive insufficient ventilation. States that only in sufficiently airtight houses can ventilation be regulated to the required level and efficient heat recovery can function.
Reviews current methods of ventilation measurement in occupied buildings including tracer methods, pressurisation, and thermography. Gives criteria for good ventilation rate measurement techniques. Also explores new methods of measuring ventilation rates in occupied buildings. These include:< 1. Use of non-toxic tracers, including negative ions, CO2 and odour levels< 2. AC pressurisation< 3. The quantification of thermography< 4. Small-scale detection of local air velocities using hot-wire anemometry.
Describes a predictive model for air infiltration in residential structures. Uses wind speed and outdoor temperature data, along with selected building and site parameters to predict average infiltration. Presents long-term field validation results obtained in a portable test structure, together with long-term data from 3 unoccupied test houses at the Owens-Corning Technical Centre. Finds that the ratio between predicted and measured infiltration peaks near one in all comparisons. The estimated standard deviation of the ratios decreases with longer averaging times.
Gives a brief overview of energy-estimating procedures for energy conservation in buildings. States that most of these procedures are either too simplistic to provide the desired level of accuracy and comprehensiveness or they are too complex to gain widespread usage. Reports on the development of a comprehensive modified bin method for estimating building energy usage, created by the ASHRAE Technical Committee (TC) 4.7 for Energy Calculations. This procedure can lend itself for manual calculations and can be easily programmed into microcomputers.
Investigates the accuracy of the TWOZONE computer auditing program (used in analyzing the energy performances of residences) when used with home-owner supplied data. Compares actual energy consumption data collected from houses in New Mexico with estimates obtained from the TWOZONE model using input data from occupant questionnaires. Finds a high degree of variability between predicted and observed values, and concludes that much of the error introduced into the prediction is attributable to the qualitative nature of the data supplied by the respondents.
Reports on seminar at University of Lund, Sweden and the factors affecting U-value: radiation, thermal capacity, moisture in materials, evaporation of precipitation moisture, convection, air movement, quality of work, cold bridges, ageing, air gaps.
Provides a brief summary of Swedish energy policy. Covers current knowledge and research in Sweden concerning low-energy buildings and building services, energy supply, the built environment and heat pumps.
Describes an investigation to see what energy saving can be achieved by the regulation of mechanical ventilation systems in high rise buildings. Measures air leakage in a block of flats, and uses a calculation model to predict the amount of energy lost due to ventilation in various situations. Concludes that the reduction of ventilation has no disadvantageous consequences for the operation of the system, and that the extracted air flow is affected more by incorrect adjustment of extractor vents then by opening windows, regardless of the setting of the ventilator.
Describes results from wind-tunnel tests on models of the Building Research Establishment's experimental building at Aylesbury. The use of several scale models of this building in uniform and in simulated atmospheric boundary-layer flows together with the results from the full-scale experiments allow an assessment of the effect of variations in the ratio of the longitudinal- turbulence integral length scale to body dimension.
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