Air-Heating Equipment

Many different methods of heating the air for industrial ventilation purposes are possible. 

In all warm-air design applications, consideration must be given to the effects of stratification in tall buildings. Stratification increases the roof and high-wall fabric losses and the air change rate by the stack effect, and hence the ventilation loss. These effects may increase the heat loss by 25% over that of a radiant heating system. 

In many cases, warm-air heating is the cheapest heating system to install from the initial-cost point of view the running costs, however, will be higher than for a radiant heating system to provide the same conditions. 

The ventilation system can be used to full advantage during the summer months with the heater off to provide outside air and assist in removing the heat gains. 

The selection of equipment to meet the above needs depends on many factors options include these  

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Air conditioning and warm air heating equipment and oommercial and industrial refrigeration equipment... 

Air Drying Equipment. Tunnel kiln dryers (70) are long furnaces comprised of several zones of different temperature, humidity, and air flow through which the ware travels on a moving car or belt. These kilns afford continuous processing. Periodic kiln cross-circulation dryers (70) are box furnaces in which ware is stacked on permanent racks or on a car that can be shuttled in and out of the furnace. Fans or jets are used to circulate heat uniformly through the ware. The process is not continuous, but production rates can be enhanced by shuttling multiple cars. 

This chapter describes the room air conditioning process, including the interaction of different flow elements room air distribution, heating and cooling methods, process sources, and disturbances. Air handling equipment, including toom air heaters, is discussed in the form of black boxes as far as possible. 

Free convection currents generated by air heating or cooling by surfaces (process equipment, external walls)... 

If air conditioning systems are designed for buildings housing electrical equipment, the heat generated by the electrical equipment must be considered when sizing the air conditioning equipment. Artificial heat is seldom required in all but the coldest of climates. 

The most advantageous application of the heat pump in the UK at the present time is where air cooling is required in the summer and air heating from the same piece of equipment in the winter. The alternatives will be electric resistance heating, with a higher fuel cost, or the provision of a hot water coil, at extra capital cost. 

Passive heat exchanger equipment for air heat exchange is described in Section 26.4 and shown in Figure 26.5. This can only be used where the ducts are adjacent. Other methods are ... 

Appliance Air-handling equipment Air-conditioning housings Flame retardance, hollow Heat distortion, cost... 

Before a final decision is made, an economic evaluation of the various possibilities should be run. Until this is done it will be assumed the water will come from the water balhs (D-501. D-509) together with the condensed steam from the air heat exchanger and the styrene heat exchanger. This will require using aluminum or plastic lines and extra collection equipment. 

Heat detectors should be spaced to ensure prompt detection of heat given off by incipient fire conditions. Spacing considerations should include the degree of hazard, type of detector used, geometry of the protected area, effects of air handling equipment if it is indoors, or environmental factors (wind, temperature, etc.) if it is outdoors. See NFPA 72 for more information on spacing and installation requirements. 

The critical technology development areas are advanced materials, manufacturing techniques, and other advancements that will lower costs, increase durability, and improve reliability and performance for all fuel cell systems and applications. These activities need to address not only core fuel cell stack issues but also balance of plant (BOP) subsystems such as fuel processors hydrogen production, delivery, and storage power electronics sensors and controls air handling equipment and heat exchangers. Research and development areas include ... 

Heating, ventilation, and air conditioning equipment should be regularly inspected and maintained. Filters on environmental control equipment should be inspected on a regular basis and changed as needed. 

The mobile unit consisting of the thermal oxidizer, air heating unit, blowers, and other equipment is used in conjunction with the portable 25-yd container provided by Hmbetz (personal communication Michael Hmbetz, Hrubetz Environmental Services, Inc., December 1996). 

For air-cooled equipment, the tube spacing is normally determined by the relative values of the inside heat-transfer coefficient and the air-side heat-transfer coefficient. For inside coefficients much greater than the air-side coefficient, tubes spaced on 2.5-in (0.064-m) centers are normally justified. For low values of the inside coefficient, tubes spaced on 2.375-in (0.060-m) centers are normally justified. In the present case, because water is being cooled, the inside coefficient is indeed likely to be much greater, so specify the use of tubes on 2.5-in centers. 

Heating equipment, except electric and warm air furnaces... 

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