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Energy-Conscious Planning and Zoning . |
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3.4 Wind
as Influence on Energy-Conscious Planning
Like all meteorological parameters, the influencing factor of wind is not independent of solar radiation. Since the wind is able to exert mechanical forces of destructive magnitude and since its effects include, among others, the blowing, mixing, and transport of foreign substances in the air, this factor is of particular importance for urban development and the energy industry. This also pertains to various forms of wind energy usage, both traditional uses and those that have been perfected for today’s world. In connection with energy-conscious planning and building in the sense of this booklet, however, the topic at hand is not that of wind energy usage, but rather the characteristic ability of the wind to significantly influence the heating requirements of interior spaces through the transfer and transport of heat. The wind also defines the air exchange rate of interior spaces via joints and leakages in exterior building components. In the interests of a comfortable setting, potentially undesirable airflows can often only be balanced out by the respective users of an interior space through excessive counter heating, which is why the ENEV (2007) limits the allowable gaps in and permeability of doors and windows (i.e. limitation of heat loss). In DIN 4701 (Rules
for Calculating the Heating Requirements of Buildings), the wind
factor is taken into account through the parameters "location"
(normal or open), "area" (strong or weak winds), and
"type of building" (stand-alone or row building).
The average wind velocities in Germany range
from 2 m/s to 7 m/s, which has a drastic effect on heating
energy usage. According to OHLWEIN (1979) and LOESCHCKE (1988),
it can be shown that every 1 m/s increase in average wind
velocity prompts an increase in heating energy usage of 4% to
9%. The following sections are intended to
communicate the information necessary to evaluate a location
with respect to its wind conditions. In the interest of
energy-conserving planning, the goal is a location with as
little wind and turbulence as possible. It must be noted, however, that this aspect
often competes with the interests of air pollution control and
with the urban climatic question of optimal aeration. Even in
the low-wind region of southwestern Germany, the argument for
overcoming by means of sufficiently ventilated land surfaces the
disadvantages of low air exchange such as air pollution,
humidity, and frequent fog has great importance. Special attention should therefore be given in the consideration of the energy-related wind factor to the avoidance of extremely unfavorable (i.e. especially windy) locations and overly wind-susceptible building forms. Through the evaluation of planning alternatives it should then be possible to reach compromises with other planning factors when necessary. |
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| Fig. 3/22b: Wind measurements: Measured according to standard in 10 m height | |||
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