computer

The computer-aided ventilation system design requires the programming of a large number of empirical tables and observations on the use of mathematical expressions which describe numerous ventilation parameters. In order to use computers with efficiency and to reduce programming inessentials, a set of numerical approximations are developed. These expressions are divided intotwo categories: 1) external variables and 2) system variables. The external variables are basically the duct resistance calcultions.

A computer analysis of stack effects in a large multi- storey building was performed, comparing the air flow (and consequent hypothetical smoke concentrations at higher floors) with and without a smoke shaft. Additionally, tests were performed on one building using one of two stairwells as a smoke shaft. Results indicate that a smoke shaft can be effective in limiting smoke movement to upper stories, as long as the fire floor is not open to outside air (such as by a broken window), or the smoke shaft is not open to a floor higher than the fire floor.

The effect of ventilation in the space between a main wall and an exterior siding is examined with respect to reducing the building's cooling load. The buoyant force of the air in the space is considered as the motive force of air flow and the effect is treated as a problem of simultaneous heat and mass-transfer. A simulation program of heat and air flows in a wall has been developed using laminar flow theory, and its validity is examined by thecomparison of the simulation results with a weather exposed full-scale model test.

A comprehensive computer program for the prediction of air flow and smoke migration in the building was applied to the 11 story administration building of the National Bureau of Standards. Natural air leakage rates under various climatic conditions for several ventilation system operations were obtained. The computed results were compared with measured air leakage rate by using the sulphur hexafluoride tracer gas technique. Smoke migration was simulated for the selected pressurization conditions.

A control program for a natural ventilation system for agricultural buildings is described which calculates a required ventilation rate, then adjusts vent openings to achieve this ventilation rate with equally distributed flows. 

Describes a new procedure for predicting the thermal comfort of people in naturally ventilated buildings. The procedure starts by obtaining, for each important wind direction, velocity ratios between points of interest inside the proposed bu

Defines "sick buildings" and describes sensory symptoms reported. Both laboratory research and field trials have been carried out, using a mobile environment chamber, gas dosing equipment, an air analysis laboratory and computer systems. Pattern analysis of indoor air samples indicate importance of interrelationship between a large number of chemical substances and several different sensory perceptions. Lists current research.

Describes a program which enables a hand-held computer to perform the energy audit calculations used in Building Practice Note No.20 "Estimating energy savings from reinsulating houses". The computer prompts the user for information, and provides a fast and versatile way of performing energy audit calculations.

Carries out a review and evaluation of residential building energy analysis programs in 6 steps - 1. Survey of the experience and needs of electric and gas utilities in residential building energy analysis 2. Identification of currently available programs for residential energy use analysis 3. Examination and summary of intended capabilities of 10 programs 4. In depth analysis of the engineering bases of 5 programs (DOE 2.1, ENCORE-CANADA, HEAP, REAP and TRYNSIS) 5. Tests of these 5 programs 6.

In the calculation of natural ventilation systems there is a lot of data which is not dependent on the ambient weather conditions. Data calculated by project engineers include geometrical size of the building; effective vertical distance between inlets and outlets; indoor loads/heat, moisture, fouling gases; interior climate requirements, relative humidity, density of air etc.Some of these factors are not changeable after the completion of the building, but there are some which could or need to be changed.