Town thermal island characteristic prediction technique and system based on digital image analysis

Abstract

The invention provides a prediction method and a system for protecting a town heat island characteristics which are based on the digital image analysis, and relates to the field of environmental engineering. A town digital elevation model DEM is established according to a town planning map; a flow region network model is established by taking the flow region of buildings as a 'node' and taking the flow opening as a 'branch'; the mass conservation equation, the loop pressure equation, the flow relation equation and the heat balance equation are established according to the flow region network model; the air mass flux, the pressure difference and the air temperature between the town buildings are calculated, and the flow region in which each pixel is positioned is identified; the direct solar radiation, the diffuse solar radiation, the long-wave radiation and the reflected radiation energy distribution of an analysis surface are calculated; the specific heat, the density and the thermal coefficient of each pixel in an underlying surface image are obtained; therefore the temperatures of the underlying surface and each wall surface are calculated, and the town heat island characteristics are predicted. The invention uses the digital image processing technology, and thus the problem of dynamic boundary in a town outdoor heat environment is successfully solved; the purpose of optimizing the town heat environment is realized.

Description

technical field [0001] The invention relates to the field of environmental engineering, in particular to a prediction method for solving urban heat island change laws, and develops a corresponding prediction system. Background technique [0002] Urban heat island is a characteristic of urban climate and a typical feature of the influence of cities on air temperature. In urban areas with high population density and industrial concentration, the combined effect of a large amount of heat emitted by human activities and other human conditions causes the temperature in the urban area to be higher than that in the surrounding suburbs, and the high-temperature city is surrounded by low-temperature suburbs. This phenomenon This is called the "urban heat island" phenomenon. A large number of research results at home and abroad have shown that all cities in the world, regardless of their size and latitude, have urban heat island effects. Computer simulation technology is one of the ...

AI Technical Summary

Problems solved by technology

[0005] (1) At present, most calculation grids (ground and air) use the same grid size, which takes a long time to calculate. Assume that the wall temperature is used as the boundary condition of CFD calculation, and the wall temperature is not calculated, but only a single solution to the CFD equation. The calculated results have a large deviation

[0006] (2) The simulated boundary conditions lack reliability. If the test values ​​are used as the boundary conditions, many measuring points are required, and it is unrealistic to measure the boundary conditions of each simulation process.

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