Still air conditions

Clothing insulation The resistance of a uniform layer of clothing covering the entire body that has the same effect as the actual clothing worn on the sensible heat flow under still-air conditions, /j., in Clo m2 C W-b... 

This is the rate of heat transfer from a surface to the surrounding air (or fluid) due to conduction convection and radiation. It is generally used only in still-air conditions and when the temperature difference between surface and ambient is of the order of 30 K. It is obtained by dividing the thermal transmission per unit area in watts per square meter by the temperature difference between the surface and the surrounding air. It is expressed as W/nf K. 

Heat emission from bare horizontal pipes with ambient temperature between 10°C and 21°C and still air conditions. 

Many of the earlier studies of mass transfer involved measuring the rate of vaporisation of liquids by passing a turbulent air stream over a liquid surface. In addition, some investigations have been carried out in the absence of air flow, under what have been termed still air conditions. Most of these experiments have been carried out in some form of wind tunnel where the rate of flow of air and its temperature and humidity could be controlled and measured. In these experiments it was found to be important to keep the surface of the liquid level with the rim of the pan in order to avoid the generation of eddies at the leading edge. 

The CIB tests consisted of compartments with heights ranging from 0.5, 1.0 and 1.5 m with dimension ratios of D/H, W/H, H/H coded as data sets 211, 121, 221 and 441. A total of 321 experiments were conducted in still air conditions. The wood crib fuel loading ranged from 10 to 40 kg/m2 with stick spacing to stick thickness ratios of 1 and 3. The data are plotted in Figures 11.17 and 11.19. The compartment surface area, A, excludes the floor area in the plot variables. 

Combined convection and radiation heat transfer coefficient hi at the inner surface of a vertical glass under still air conditions... 

Heal transfer through a window is also affected by the convection and radiation heat transfer coefficients between the glass surfaces and sunound-ings. The effects of convection and radiation on the inner and outer surfaces of glazings are usually combined into the combined convection and radiation heat transfer coefficients /i,- and h , respectively. Under still air conditions, the combined heat transfer coefficient at the inner surface of a vertical window can be determined from... 

Acid cleaners based on sulfamic acid are used in a large variety of appHcations, eg, air-conditioning systems marine equipment, including salt water stills wells (water, oil, and gas) household equipment, eg, copper-ware, steam irons, humidifiers, dishwashers, toilet bowls, and brick and other masonry tartar removal of false teeth (50) dairy equipment, eg, pasteurizers, evaporators, preheaters, and storage tanks industrial boilers, condensers, heat exchangers, and preheaters food-processing equipment brewery equipment (see Beer) sugar evaporators and paper-mill equipment (see also Evaporation Metal surface treati nts Pulp). 

Conditions that are warmer than the applicable still-air comfort zone of Fig. 5.7b can often be made comfortable by increasing the air speed. If the conditions are 1 to 6 °C warmer than the still-air comfort zone of Fig. 5.7b, the necessary air speed v) to restore thermal balance and comfort can be estimated from Fig. 5.8, where Tis the temperature difference between the environment and the still-air comfort temperature. Though the increased air speed will bring the whole-body thermal sensation to the comfort level, air motions above 0.8 m/s or so may cause other kinds of discomfort frojn... 

Particle aerodynamic diameter The diameter of a sphere of density 1 g cm that has the same terminal velocity due to gravitational force in still air at set conditions of temperature, pressure, and relative humidity as the particle in question. 

In this example we selected a final outlet temperature of 100°F, This would be sufficiently low if the gas were only going to be compressed and dehydrated. For our case, we must also treat the gas for H2S and COt removal (Chapter 7). If we chose an amine unit, which we will in all likelihood, the heat of the reaction could heat the gas more than 10° to 20 T. making the next step, glycol dehydration, difficult (Chapter 8). In such a case, it may be better to cool the gas initially to a lower temperature so that it is still below 110°F at the glycol dehydrator. Often this is not possible, since cooling water is not available and ambient air conditions are in the 95°F to 1()0°F range. If this is so, it may be necessary to use an aerial cooler to cool the gas before treating, and another one to cool it before dehydration. 

In examining the tower performance it is not the air temperature that sets the capacity, but the heat content or enthalpy of the air. Although the air temperature and wet bulbs at inlet may be different for two different inlet air conditions, it is still possible for the air to have the same enthalpy. Therefore, two different air streams of different conditions can produce the same effect on totver performance. The heat content or enthalpy of all air with the same wet bulb is the same, therefore it is clear that the wet bulb temperature is important and sets the performance. 

Small refrigerators were developed by several companies and some were even installed in hotel rooms in Chicago. Borg-Wamer and other companies produced many compact systems for laboratory uses (23). Air-Industry in France built an air conditioning system for a passenger railway coach that was still in daily use after 10 years of operations without a single thermoelectric failure (24). 

All of these cases considered have not been short term efforts. Market development requires at times infinite patience and understanding. The Goldline Camper from concept to commercial reality took just over one year. By comparison this is a very short time. The application of foamed ABS to the furniture industry is still in the process of commercial development. It has been in this process now for more than two years and will probably require one to two years more before it can be considered a commercial success. The study of electroplating on plastics has been under development for a period of at least seven years. It can now be considered to be a truly commercial product. Purafil, however, was discovered about ten years ago. It was first marketed by our Ingersoll Products Division as part of a line of hospital supplies. The next effort was an exclusive marketing arrangement by York Division as a filter for air condition-... 

Chlorofluorocarbons (CFCs) are widely used in refrigeration and air conditioning, insulation, and plastic foams. Although nontoxic and nonflammable, they are believed to deplete the ozone layer in the atmosphere which shields the earth from the sun s ultraviolet radiation. While action to control the production and use of CFCs was still being debated, McDonalds s Corporation announced it would no longer use foam food containers produced with the aid of CFC in its fast food outlets. 

Figure i. Records taken from a cat chronically prepared with electrodes to record the eye movements (EOG), the electroencephalogram from both sides of the skull (EEG), and the activity of the neck muscles (NMG). The animal was kept in an air-conditioned, sound-attenuated room supplied with a oneway mirror for observation. The records were taken while the animal was awake and active (top left), awake and resting (top right—note alpha waves), just dropped off to sleep (middle left —note "spindles"), in deeper sleep (middle right—note slow waves in EEG) in still sounder sleep (bottom left—note very slow waves), and in paradoxical sleep (bottom right—arousal pattern in EEG). (Note eye movements in awake animal and in paradoxical sleep). Note also reduced electrical muscle activity in paradoxical sleep. Calibrations vertical line at top middle = 100 microvolts (or o.oooi volt), horizontal line = l second. Original from author s laboratory. 

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