For the calculation of velocities in air-jets behind the ventilating outlets, the constants of ventilating outlets must be known. These constants are specified for each type of ventilating outlets experimentally. They can be usually defined from measured behaviours of axis velocities in the main area of jet, which demands to measure velocity profiles in cross flow section, in several distances from the outlet. The constants of ventilating outlets can be also defined from the air-jet extension in the main jet area behind the ventilating outlet.
When designing the outlets for the ventilation or hot-air heating of particular spaces, we meet usually the problems to specify a form and reach of the air jet and a distribution of velocities and temperatures in the space followed. In practice the calculations of nonisothermal air jets are made using a number of calculation relations to be found e.g. in lit. (1) and other. But when applying the analogical relations derived by different authors we can find out considerable differences in results.
Calculation of design cooling loads is of critical concern to designers of HVAC systems. The work reported here has been carried out under a joint ASHRAE-CIBSE research project to compare design cooling calculation methods. Peak cooling loads predicted by the ASHRAE heat balance method are compared with these predicted by a number of implementations of the admittance method using different window models. The results presented show the general trends in overprediction or underpredictiori of peak load. Particular attention is given to different window modelling practices.
Visual DOE is a Windows interface version of the DOE2 simulation program. Its purpose is to help save time in writing BDL input for the simulation. As its calculation engine is the same as DOE2 in the DOS version, DOE should result in the same output as the DOS version. However, difficulties arise in identifying the building's configurations, materials and construction and systems in the two input versions. While modeling a simple one-story Hpassive H building, it was difficult to get a good match in the simulation results in the two versions.
This short paper demonstrates the existence of an error in instantaneous heat loss calculations due to errors inherent in the input data. By implication, these errors will also be present in thermal simulation programs.
Describes a method for determining the air change rate in a room or a building by continuous monotoring of the CO concentration in both supply and exhaust air. By using a mass balance equation, the indoor concentration of CO can be numerically calculated for various air change rates. The value of the air change rate used in the equation that gives the best correlation between measured concentration and calculated concentration provides an estimate of the air change rate for the volume studied.
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