This handbook describes the use of tracer-gas techniques for measurement of airflow in ducts. Initial measurements were carried out in the laboratory to examine the accuracy of these techniques. The mixing of tracer gases (eg, sulphur hexafluoride, SF6) in ducts of various shapes and sizes was examined using different types of tracer injector. Airflow estimated using tracer-gas techniques (eg, constant-injection, pulse-injection) was compared with measurements made with traditional instrumentation such as pitot-tubes and hot-wire anemometers.
In view of the rapid expansion of the heat pump market in Japan, a rough calculation has been made to determine the expected impact of the increased use of heat pump air conditioners on the environment. It was found that, through the use of heat pumps, the emission rate of substances into the environment can be reduced in comparison to the use of fuel oil. To make efficient use of this characteristic, measures to prevent the release of refrigerant from heat pumps are required.
Computer-based control systems have been widely used for controlling air-conditioning systems in commercial buildings. Computer-based control technology can increase control accuracy and can implement various sophisticated control strategies so that building energy consumption can be reduced. The problem is not how to implement a control strategy, but which control strategy should be used to control air-conditioning systems in commercial buildings.
New research shows that replacing low efficiency window air conditioners with high-efficiency units can produce measurable savings and can be cost-effective in homes with high air conditioning electricity consumption.
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