Vertical temperature

Urban areas have roughness and thermal characteristics different from those of their rural surroundings. Although the increased roughness affects both the vertical wind profile and the vertical temperature profile, the effects due to the thermal features are dominant. The asphalt, concrete,... 

The size and influence of eddies on the vertical expansion of continuous plumes have been related to vertical temperature structure (3). Three ap-... 

Fig. 19-4. Vertical expansion of continuous plumes related to vertical temperature structure, The dashed lines correspond to the dry adiabatic lapse rate for reference.

Aircraft can take vertical temperature soundings and can measure air pollutant and tracer concentrations and turbulence intensity. Airborne lidar can measure plume heights, and integrating nephelometers can determine particle size distributions. 

Vertical temperature gradient The lapse rate (rate of decrease in temperature with increases in height) must be taken into account because it affects the final height to which a buoyant plume rises. 

The vertical temperature gradient (the lapse rate) is usually not monitored by routine meteorological observation, and it, too, must be approximated from estimates of solar insolation, solar angle, and differential heating due to uneven cloud cover. For purposes of diffusion analyses, the lapse rate is usually approximated by a constant. 

Takemasa, Y., S.Togati, and Y. Aral. 1996. Application of an unsteady-state model for predicting vertical temperature distribution to an existing atrium. ASHRAE Transactions, vol. 102, no. 1. 

We now put the cylinder of Example 7.5.4 inside a room with a vertical temperature gradient of 1.5 C/m (see Fig. 7,78). In this case we assume that there are other heat sources in the room. We want to Investigate how this temperature stratification influences the volume flow in the plume above the cylinder, and at what height the plume stops. 

The flow rate of the plume through the zone boundary depends on the plume strength and vertical temperature gradient. In the case of a zoning strategy, the plume flow rate may also depend on the air distribution method and device because of the interaction between the plume and the supply air.-... 

E. Sandbetg, H. Koskela, and T. Hautalampi, Convective flows and vertical temperature gradi ent with the active displacement air distribution, in Roomvent 9H, Stockholm,. Sweden, 1998,... 

A characteristic of many industrial halls is that zones of occupancy take up only a small portion of the room volume and height. In addition, the flows are normally buoyancy dominated. This results in a vertical temperature stratification that can be utilized for room air conditioning design in order to achieve effective climatization along with low energy consumption. 

Vertical temperature and contaminant distribution within the stratification strategy, typical schemes. To is supply air temperature, T is the temperature at the floor level, Tj Is room temperature, Cq and Q are contaminant concentrations in supply and room air above the stratification height, and y, is the stratification height... 

During summer. Fig. S. 6a, there is a need for cooling in the occupied zone (area up to 2 m from the floor level) rhus it is desirable to apply the stratification strategy with vertical temperature and contaminant stratification in the hall in order ro save cooling energy costs. This can be done, for example, by using a low-impulse air supply with the devices at the floor level. 

R V.. Nielsen, Vertical temperature distribution in a space with displacement ventilation. In lEA Annex26 Elnergy Efficient Ventilation of Large Enclosures, Rome 1995. 

Most room models contain only one zone air node, thus assuming perfect mixing of the zone air and a homogenous temperature distribution in the space. Spatial temperature variations, such as vertical temperature gradients, are not considered. For specific applications such as displacement ventilation or atria, models with several zone air nodes in the vertical direction have been developed. ... 

Outside air entering the space through openings near the ground spreads over the floor and absorbs energy from the floor surface. The resulting air temperature increase leads to buoyancy and forces the air up into the upper hall zone. This results in a temperature stratification in the hall. Due to this vertical temperature gradient, the air in the occupied zone does not reach the exhaust air temperature (see Fig. 11.37). 

Figure 12.41 shows the results of three experiments with a similar Archimedes number and different Reynolds numbers. The figure shows vertical temperature profiles in a room ventilated by displacement ventilation. The dimensionless profiles are similar within the flow rates shown in the figure, although the profile may involve areas with a low turbulence level in the middle of the room. A test of this type could indicate that further experiments can be performed independently of the Reynolds numbers. 

II FIGURE 12.41 Vertical temperature profile in the room for three different experiments with identical Archimedes number. 

Height allowance A percentage added to heat loss calculations to compensate for the vertical temperature gradient. 

The major reasons for the beluu ior of vertical temperature in water bodies are the low thermal condnctii ity and the absorption of heat in the first few meters. As tlie surface waters begin to heat, transfer to low er layers is reduced and a stability condition develops. The prediction of thermal behavior in lakes and reser oirs is an important power plant siting consideration and also is a major factor in preienting e.xcessive thermal effects on sensitive ecosystems. Furthermore, the extent of thermal stratification influences the vertical dissolved ox)gen (DO) profiles where reduced DO often results from minimal exchiuige with aerated water. ... 

Condenser horizontal or vertical, temperature of cooling water, water quantity limit... 

The stream population is shown in Figure 16.16 with a vertical temperature scale. The interval temperatures... 

The dispersion coefficients are a function of atmospheric conditions and the distance downwind from the release. The atmospheric conditions are classified according to six different stability classes, shown in Table 5-1. The stability classes depend on wind speed and quantity of sunlight. During the day, increased wind speed results in greater atmospheric stability, whereas at night the reverse is true. This is due to a change in vertical temperature profiles from day to night. 

Owing to the fact that nearly all the heat generated by this type of electrolyser has to be dissipated via the anolyte flow, for the full industrial-scale demonstration electrolyser with an element size 2.5 m2 it was decided to use the bubble jet system [3], which was successfully tested previously with the chlor-alkali method. For FIC1 electrolysis, which from the material side is optimised to an approximate operation temperature of 60°C, an intense vertical temperature-profile flattening is essential to reduce the external flow rates and to allow rather low anode-side inlet temperatures. The intensive vertical mixing with the bubble jet proved to be suitable for this purpose. 

One important experimental parameter is also the furnace which is used in the thermogravimetric apparatus. There always exist pronounced radial and vertical temperature gradients which can be found by calibration runs. As an example, the determination of the vertical temperature distribution by Wiedemann41 may be referred to. Also the amount and shape of the sample can contribute to a temperature gradient. This fact is of special importance for kinetic studies. Considerable temperature differences - up to several °C - can exist at different locations of the sample holder. 

Parameters in the model are listed in Table I. The flow, structural, and boundary conditions are known quantities. The frequency factor and activation energy for coke burning were the values determined by Weisz and Goodwin (1966) from the experiments discussed earlier, and the catalyst diffusivity D was measured directly in the laboratory. The value of a was determined from direct observations of the CO/CO2 ratio in each zone of the operating kiln. The remaining parameters are known quantities. Thus, there are no adjustable parameters available to tune the fitting of predicted values to observed data, for the fraction of coke remaining and for the vertical temperature versus distance from the top of the kiln. 

A meteorological description, including wind speed and direction at each location in the airshed as a function of time, vertical temperature structure, and radiation intensity. 

Technically the thermocline is the depth zone over which the vertical temperature gradient reaches maximal values. This depth zone varies with season, latitude and longitude, and local environmental conditions. The top of the thermocline is defined by... 

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