energy losses

The requirement for better methods of predicting infiltration and natural ventilation rates has been reinforced by the incentive to reduce energy consumption in buildings. Natural ventilation is basically dependent on the effects of wind and temperature difference and on the resistance to airflow through the building. Discusses in detail these factors and highlights areas requiring further study. Briefly illustrates energy savings available by controlling natural ventilation.

Discusses heat losses from buildings. Calculates proportion of heat loss due to ventilation under simplifying assumptions. Discusses factors influencing air change rates. Calculates energy that could be saved in the republic of Germany by reduction of ventilation under three different assumptions of energy price increases.

Describes a model for calculating the energy losses caused by ventilation and uncontrolled leakage of air in buildings. Discusses leakage characteristics of building envelope and duct system, the effects of wind and stack effects. Gives general picture of the calculation model.

Recommends method for determination of extra heat and moisture load of a cold room resulting from leakages through chinks, cracks and porosity. Recommends clause on maximum leakage in delivery conditions. Treats internal and outdoor influences on air exchange, leakage detection and leakage measuring methods.

Notes dangers of incomplete theoretical models distorting technical progress. Cites as example determination of U-value in estimating energy losses through building envelope. Concentrates on considerable energy loss caused by air infiltration, in addition to heat transmission. A step towards a better understanding of total energy flow through building envelope is a method of calculating air leakage. Describes calculation results for a house which show that air tightness is an important property of the building envelope which cannot be neglected.

Reports study of indoor climate-primarily air quality-and energy consumption in a number of detached houses in a group housing area. All the houses were pressure-tested over three years; 1977-1980 and a relatively larger increase in air leakage was measured after the houses had been occupied for approximately one year. Suggests this is due to the drying out of timber, producing cracks. Two types of houses, a and b were investigated when studying indoor climate. both were mechanically ventilated.

Gives preliminary report of a study of natural ventilation and energy consumption in low-cost housing. The study includes the measurement of infiltration rates using tracer gas, pressure differences across outside walls, indoor and outdoor temperatures, air tightness of external walls and the position of windows and doors. Outlines future studies and gives preliminary conclusion that making houses more air tight can save energy.

Reports measurements made in six blocks of flats of energy consumption and wind speed. Gives graphs of results. Concludes that a moderate wind (of 30m/s) increases energy consumption by12% and a strong wind (60m/s) by 25%. Suggests heat loss can be reduced by tightening windows and controlling ventilation.

States that much of the heat loss in American houses can be traced to generic faulty details in design and construction. Discusses style of housebuilding in the United States. Notes vast majority of American houses were built of wood. gives a broad classification of typical houses into seven types. Notes variation in energy performance with climatic region. States intention to undertake case studies to assess the energy performance of each type.

Treats methods of determining energy losses in a building given in 1975 swedish building regulations. Presents findings of a number of measurements using pressure method and thermography carried out during 1977 and winter of 1978. The apparatus and methods have been developed for field work. Presents results which depict different grades of airtightness in different types of building. Discusses use of thermography, which has been extensively used in recent years in Sweden in particular for new buildings. States method has been developed to become subject of a swedish standard.