Studies the techniques and issues related to evaluating the airtightness of homes. The first section discusses the physics of air infiltration and the techniques used to measure infiltration rates. Also discusses pressurization testing and its relation to infiltration. The second section presents experimental work aimed at several questions raised in the first section. A long term experiment involving weekly pressurization testing of a home reveal the short-term reproducibility of the test results and the seasonal variation in a home's tightness.
States that in a tight house with a vapour barrier, an air management system is needed to provide fresh air and remove the build-up of moisture generated by the occupants. Briefly describes a typical air management system,incorporating an air-to-air heat exchanger, and discusses the need to provide an acceptable ventilation rate, which controls pollutant level but minimizes heat losses.
Examines and tests a number of commercial air-to-air heat exchangers to determine their performance as installed in each house. Results show that although some heat exchangers indicate a high performance level, there are many installation and operational faults. A number of recommendations are made on the selection, installation and operation of air-to-air heat exchangers in houses.
Tests a room-size, residential air-to-air heat exchanger for effectiveness of heat recovery. Conducts experiments in a small wood frame building, the Test Chamber, on the roof of the lab building. Determines heat recovery efficiency by comparing actual heat loss to that expected due to mechanically induced ventilation. The heat exchanger recovers almost 50% of the heat contained in the outgoing air flow. Additional experiments quantify effects of fan power consumption and heat conduction through the case of the device.
Residential energy consumption can be decreased if air infiltration is reduced. However, reduced air infiltration can lead to problems with indoor air quality (eg excess humidity and high levels of indoor-generated air contaminants.). One sol
Investigates excessive energy consumption in a house mechanical ventilation and heat exchanger. Explains why the house consumes so much energy. Analyses the ventilation system and defines a "coefficient of performance". Such a factor could characterise the energy requirement of a ventilation system. Emphasizes that the ventilation system is to be regarded as an entire system and that a certificate for the exchanger does not guarantee that the totalsystem will perform satisfactorily.
Describes a series of experiments to determine the ventilation performance of 2 different models of wall or window mounted heat exchangers. Determines their nominal efficiency by the measurement of tracer gas decay rates at several indoor locations. Notes significantly higher local ventilation efficiencies in rooms where heat exchangers are operating. Some preliminary tests indicate that internal leakage between the air streams contribute significantly to the ventilation inefficiency of these systems.
Briefly reviews different types of air-to-air heat exchangers, and their relative efficiency. Discusses their effectiveness in removing indoor pollutants such as radon and formaldehyde from tight houses.
Presents the operating principles for four basic types of air-to-air heat exchangers suited for small scale use: rotary, coil-loop, heat pipe and plate. Discusses individual advantages and disadvantages. Describes test program initiated to evaluate the performance of a few commercial units as well as several units designed and/or built at the University of Alaska. Presents preliminary results from several of these tests along with a critique on theirdesign. Gives a short list of manufacturers of air-to-air heat exchangers in the appendix.
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