Airflow window units are a combination of energy efficient fenestration and adjustable shading device, consisting of a double-glazed outer sash and a single-glazed inner sash, with venetian or louvered blinds in between. Space air is admitted
Tests and evaluates the air infiltration control methods employed in buildings. Concentrates especially on silicone sealant applied in situ to opening joints of external windows. Carries out tests both in the laboratory on window samples and in the field on a test building. Checks the effect of the method on air permeability through single windows and on energy loss due to air infiltration through the building envelope.
Reviews the mechanism of air infiltration as a background for introducing a procedure that yields more reliable estimates of average infiltration rates through a window unit than do methods currently employed.The procedure is applied to estimating the average winter heat losses through windows in low-rise residential buildings variously located through out the US. Concludes that, regardless of climate, the heat loss attributable to infiltration through the window unit is small compared with that incurred as a result of direct transmission of heat through the window.
States that comparison of different methods of calculating the volumes of outdoor air entering a building through the window shows that the chief deficiency of the standardised method of calculation is neglect of the importance of the relation between building dimensions, the wind profile andthe resulting pressure distribution at the building. Proposes an approximation method which significantly improves the accuracy of the calculation and also permits the calculation of flow through buildings for each possible combination of the factors determining the flow.
States that draughtproofing offers the shortest payback period of any form of energy conservation. Describes sources of draughts in industrial buildings, including entrance doors, and how heat losses through these can be minimized. Discusses recent developments in the domestic market which have encouraged weatherstripping. Briefly reviews different types of weatherstrip materials and how they should be applied.
A supplement to an earlier aricle. Notes that the trend to airtight windows has altered the order of importance of the factors which influence air flow in buildings. Treats the calculation of the air flow in a building and the constituent factors - pressure loss, differential pressures with air supply, thermal buoyancy, wind, fans. Sets out the calculation procedure and applies it to two worked examples. Illustrates the effect on a building of the pressure drop, thermal buoyancy etc. in diagrams.
States that windows and doors are the biggest source of energy loss in a house. This happens by air infiltration, conduction and radiation. Covers ways of cutting these energy losses to a minimum, including weatherstripping, installing storm doors and incorporating an air lock into the entrance door design.
Sets out the design and construction of pressure test rigs for use in studying leakage rates of windows and doorways in the Arts building of Sheffield University. Tests 7 doors (including fire doors) and selected windows, categorized according to deterioration of sealants. Finds that window leakage is far in excess of the suggested leakage from the CIBS guide (results of infiltration coefficients range from 0.911-6.097). Shows that 56% of the airflow across a doorway is due to the gap between the door bottom and the floor, and that weatherstripping the door reduces the flow by approx. 50%.
Double-glazed windows are poor insulators, with regard to both thermal and acoustic properties. Reports on study of insulated shutters for windows, sponsored by the SCBR and the National Swedish Board for Technical Development. Estimates that the energy loss through such shutters combined with a double-glazed window is about 0.7 w/m2K (compared to 3 to 4 for the window alone) and noise transmission can be cut by 15 to 20 db. Calculates that each square metre of shutter area could save an average of about 300 KWh per year in Sweden.
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