Radiant heating and cooling, including building component embedded systems, have become a common heating and/or cooling technology in the recent few years. Some currently available building simulation programs have the ability to model these systems. Some others do not, but users have developed their way of modeling by using the program’s limited possibilities. A systematic and complete validation with enough diagnostic power for this type of problem was missing to date. This was developed in the frame of IEA Task 22 'Building Energy Analysis Tools'.
Four areas in Texas have been designated by the United States Environmental Protection Agency (EPA) as non-attainment areas because ozone levels exceed the NAAQS1 maximum allowable limits. These areas face severe sanctions if attainment is not reached by 2007. Four additional areas in the state are also approaching national ozone limits (i.e., affected areas)2. In 2001, the Texas State Legislature formulated and passed Senate Bill 5 to reduce ozone levels by encouraging the reduction of emissions of NOx by sources that are currently not regulated by the state3.
The international building physics toolbox (IBPT) is a software library specially constructed for HAM system analysis in building physics. The toolbox is constructed as a modular structure of the standard building elements using the graphical programming language Simulink. Two research groups have participated in this project. In order to enable the development of the toolbox, a common modelling platform was defined: a set of unique communication signals, material database and documentation protocol. The IBPT is open source and publicly available on the Internet.
A preliminary investigation is made into the global variation in irradiance under the Clear, the Intermediate (partly cloudy) and the Overcast sky conditions (Nakamura et. al., 1986, 1987). A formula for global irradiance is proposed as a function of solar altitude and geographical altitude (height above the sea level) under each of the conditions based on measured data. These formulae can be used to estimate the cumulative global e over a year for any location given the daily sky conditions.
It is necessary for fire safety that in case of a flash-over situation, the windows in the outer skin would break very fast and before the windows in the inner façade would break, so that the model of Law is valid in which case the NEN 6068 could be applied. The wind blows towards the building for a worst- case situation. Computational Fluid Dynamics (2D) is used for calculating convective heat transfers assuming a specific heat source for the fire. WINFIRE is used for the predicting of radiation.
In this study, formulae for predicting projected area factors and view factors of individual body parts of standing and sedentary humans for detailed radiation analysis were developed. For this purpose, detailed geometry models of the human body were generated representing an average subject with a height of 1.75 m and a DuBois’ area of 1.83 m2. Thermal analysis software incorporating advanced, voxel-based ray tracing techniques and regression analysis were deployed to model the local projected area factors of humans exposed to direct and diffuse solar radiation.
The evaluation of shading devices is generally carried out using a sequence of shadow pattern images showing the progression of solar penetration for particular times of the day or year. This approach can reveal when solar penetration may occur, say at the summer solstice, but it cannot give a quantitative measure of the degree and likelihood of solar penetration over a representative period of a full year. This paper describes a new image-based technique to quantify the effectiveness of shading devices.
This paper describes a performance-based evolution model using GA as the evolution algorithm and CFD as the evaluation mechanism. The advantages of such an evolutionary performance-based design approach is that diverse instances of the state space can be investigated in relation to specific goal requirements that will enhance the possibility of discovering a variety of potential solutions.
Experimental studies in building energy usage and environmental analysis are very time consuming and expensive, and require sophisticated sensors and instrumentation techniques. So, there has been great interest in developing Computational Fluid Dynamics (CFD) computer codes to improve building design and HVAC systems. The majority of these CFD programs are based on the solution of Navier-Stokes equations, the energy equation, the mass and concentration equations as well as the transport equations for turbulent velocity and its scale.
A study by Reinhart and Herkel showed term predictions of daylight availability in architectural spaces should take the conditions of all individual time steps into account. However, most contemporary simulation tool algorithms require such long computation times that it is impractical or even unrealistic to simulation of the daylight penetration for each time step. This paper discusses two adaptations of a known algorithm, radiosity, that bring down the required computation time for an annual prediction from the order of days to the order of seconds.
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