energy consumption

In this demonstration project the energy consumption, temperature and humidity curves, and occupancy behaviour are measured, registered and evaluated in 8flats with air infiltration and ventilation as stated in VDI 2088 in thecentre of a block. These are compared with the other 16 flats in the block. Results of the first tests are presented.

Various ventilation systems have been examined in unoccupied test houses under natural climatic conditions. Two identical test houses were used to enable comparison of the effects of different ventilating systems on the air change rate and heat consumption. The systems examined were natural ventilating devices placed in the window area and centralized and decentralized mechanical systems. With the decentralized systems, draughts were generally unavoidable. Heat recovery from exhaust air at an air change rate of 1.0 h-1 gave a measured heat consumption saving of about 16 per cent.

Errors resulting from treating a house as an enclosure surrounding a single, well-mixed volume of air are explored in detail for a ranch house with abasement. A fairly typical ventilation pattern is assumed and three quantities, the air exchange rate, the indoor pollutant concentration from a given emission, and the energy required to heat infiltrating air, are calculated and compared using both the one and two zone models for this house.In general, the errors were around 10-20% if the basement was included in the one zone models and 30-40% if the basement was neglected.

Ventilation heat losses have been investigated in an experimental low energy house with active and passive solar energy use and an auxiliary heater. A measuring method was developed and tested which gave the possibility of dispensing with long-duration tests in occupied dwellings. The heat losses are dependent on characteristic data of the room and the diminution of the room temperature with time. Measuring error is less than 10%.

In newly built well insulated houses, a wind of 4 m/s will produce an air change rate of almost 0.3 h-1. However it is considered necessary to obtain air change rates of 0.7 h-1. 

The theoretical and experimental study of heat losses and energy consumption and its influence on the air quality in buildings has been undertaken by the Silesian Technical University since 1980. The heat consumption of buildings isinfluenced by the thermal insulation of buildings components, airtightness of these components and the types of ventilation systems. Simultaneously, the thermal comfort and also air quality is influenced by the modern building material and different types of buildings.

The total energy consumption for five detached houses with air change rates of around 3 per hour right after construction, was measured and compared with estimated values, over a three-year period. Air change in the bedrooms was also measured. It was found that the recommended value was only obtained in very tight houses. If two windows are open, the ventilation system is partly short-circuited. A modified exhaust air ventilation system was designed to provide a sufficient air change in the bedroom with a reduced total air changein the house as a whole.

Aerodynamic phenomena affecting the ventilation process, such as aerodynamic mixing, generation of secondary and slightly turbulent flows, roof contours, infiltration and convection and their connection with geometric parameters of the object and energy expenditure for ventilation are analysed.

Air infiltration in two well-insulated houses is being investigated to determine its effect on energy use and indoor air quality. The first paper of this series provides a general perspective on the design. This paper reports on the effect on conservation measures taken, including the installation of an air-to-air heat exchanger, on air exchange and energy use. A third paper presents pollutant measurements and modelling results.

In 1981 Norwegian building regulations introduced quantitative requirements to air leakages in different types of buildings. The requirements were formed as maximum allowed air changes per hour at 50 Pa pressure difference according to the pressurization method. To evaluate the consequences of these new requirementsimposed to Norwegian building industry a model proposed by the Nordic Committee for Building Regulations (NKB) was used. The average air leakages of residential buildings , built before the new requirements,are known through a research project performed i n 1979.