computer

Describes a computer program written in 1900 fortran which is suitable for computing natural ventilation rates in multi-storey buildings. Lists the assumptions made, the data requirements and output available. Gives a print-out of the program.

Describes a method of analysing the stack effect on a multi-storey building. The building is divided into zones and a computer programme calculates air-flow and pressure for each zone. Analysis is given for an example hypothetical building under different temperature, wind and air leakage conditions. Shows that the method can be used to evaluate the difficulty in opening doors due to pressure differentials and the noise resulting from air flowing through cracks around doors.

Measurements of the dynamic heat transfer in a four-bedroom townhouse were made under controlled conditions in a large environmental chamber to explore the viability of a computer program developed at N.B.S. labelled NBSLD for predicting heating and cooling loads and inside temperatures. Test house was factory-produced, of modular design and lightweight (wood) construction. Tests were performed with simulated outside summer, winter and autumn diurnal temperature cycles. Inside temperature was maintained at 75 f and the activities of a six-member family were simulated.

Reports a theoretical study of natural ventilation made jointly by HVRA (UK) and Institute for Public Health Engineering TNO (Netherlands). Uses analogue and digital computers, and results so derived were used to produce a design method suitable for rapid assessment of the natural ventilation of projected buildings. Shows this method to be quicker, cheaper, and more accurate than the crack method (measured leakage at windows and doors) or the air change method.

Derives mathematical relationships for the connection between pressure loss and volume flowrate using simple crack models and applying known laws of similarity for flow in pipes or gaps. Demonstrates how these relationships permit more exact determination of the permeability of cracks in normal building structural components than has been possible hitherto with the use of a few approximate average values for crack permeability coefficients and pressure exponents.

Describes experimental method of determining air leakage characteristics of exterior walls of a building. Method involves pressurising the building with the supply air system and measuring flow rates of outside supply air and resultant pressure differentials across building enclosure. Uses results to obtain flow coefficient and exponent for exterior walls. Checks method by results of computer simulation of a building, finding good agreement.

Describes experimental method used and results obtained in a series of experiments to investigate characteristics of air flow through cracks in dwellings, including the straight-through, l-shaped and multi-cornered forms found in the construction of a dwelling. Aim is to supply accurate knowledge for computer simulation of ventilation effects in a room.

Points out that difficulty in calculating fortuitous ventilation in buildings caused by infiltration means that energy demand of a building contributed by it is scarcely ever known. Provides equations describing infiltration due to pressure differences, which in turn are caused by wind conditions, inside/ outdoor temperature differences and possible influence of mechanical ventilation systems. Describes computer program developed in Finland to calculate air infiltration. Demonstrates infiltration rates in houses.

Points out that ventilation heat loss can account for 50% of total loss in a well-ventilated house. Presents analysis of mechanics of natural ventilation. Describes computer-based model developed by British Gas Corporation for predicting ventilation patterns in houses. Uses calculations applying the method to illustrate basic reasons why natural ventilation is likely to cause problems in heating well-insulated dwellings. Discusses these problems in detail. Treats how ventilation could affect sizing of appliances and indoor thermal environment.