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.
Describes experiments carried out in 4 low energy electrically heated houses incorporating extra thermal insulation and heat recovery mechanical ventilation systems. Airtightness was made an objective so that the ventilation system would provide as much of the required fresh air as possible. Instrumentation was installed during construction to monitor the performance of the houses, with the cooperation of eventual purchasers. The houses were leak tested and sealed where necessary.
Explores the various roles that mathematical models can play in the design of energy efficient ventilation systems. Uses an example (an existing terraced house) to illustrate how models may be used to investigate the energy implications and air distribution patterns of a range of mechanical andnatural ventilation options. Identifies key parameters needed for accurate results, and compares predicted infiltration rates with actual measurements taken in the house. Concludes that models of proven validity are an invaluable aid in ventilation design studies.
Uses the SEGAS "Autovent" constant concentration apparatus to measure the fresh air entering and the local ventilation rate in each cell of amulti-celled dwelling with both natural and mechanical extract ventilation. Measures fresh air entry into each cell using tracer gas constant concentration and decay techniques. Conducts decay tests without artificial mixing, and interprets them by computing the area under the decay curve to obtain local ventilation rates. Compares the 2 measurements, giving the ventilation efficiency of each cell and an idea of air quality in each room of the house.
Gives results from fiel trials of the performance of various mechanical ventilation systems. Carries out measurements in buildings built during the seventies, using the tracer gas decay technique with N2O. Tests 3 cases:< 1. Air supplied only through register above door< 2. Air supplied both through register and the slot under the door< 3. Air supplied only through slot under the door.
Notes initial airtightness requirements in SBN 1980 and discusses various forms of ventilation. Discusses how tightness testing can reveal location and magnitude of leaks. Gives theoretical method of calculating air leakage flow and relates this to practical measurement. Considers different alternatives such as pressurising the building and combining tightness testing with thermography. Discusses 1980 building regulations and what buildings ought to be tested. Lists critical points of a building and measures which can contribute to good airtightness.
Notes job losses in prefabricated timber housing industry in Sweden and Hjaltevad's endeavours to produce a large series popular house with low-energy characteristics. House is on one and a half floors and has an occupied area of 150 sq.m. Heating economy is strongest sales argument with estimated annual consumption of 8000 Kwh. Low energy consumption results from electric boiler and heat pump. The heat pump assumes a mechanical exhaust air system and heat extracted is added to hot water system. Notes strict control of tightness before external cladding is nailed in position.
Examines the possibilities of achieving energy-efficient ventilation systems in naturally ventilated homes (which include the use of intermittent extract fans in individual rooms). Discusses factors affecting energy efficiency. Treats general design requirements for mechanical and natural ventilation systems. Discusses the characteristics of natural ventilation systems, including leakage, weather and window opening. Compares natural and mechanical systems. Provides suggestions for natural ventilation design.
Gives an account of the results of research into ventilation and radiation in buildings, including one-family dwellings and blocks of flats. Investigation includes recording the air change rate, the radon levels, the radium emanation rate and gamma radiation. The object of the investigation is to obtain background material for continued research into limit values for radon and radium emanation levels in dwellings.
Examines the fundamental building heat loss calculations. Points out some anomalies in the traditional view of room thermal behaviour. Treats equations governing room heat loss taking account of the temperature of the walls and the environmental temperature. Justifies the use of the environmental temperature rather then the air temperature. Examines the heat loss due to ventilation. Discusses the use of the temperature ratio.
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