Sensible heat ratio

Total heat Sensible heat Latent heat Sensible heat ratio... 

The steam is generated in a pan of water by electric elements. High-temperature hot water or steam coils could also be used. About 30 per cent of the input appears as waste sensible heat, giving a sensible heat ratio of 0.3. 

The blending of cold and warm air will be thermostatically controlled, so that the humidity in each zone must be allowed to float, being lowest in the zones with the highest sensible heat ratio. 

Such units may use chilled water or direct-expansion refrigerant, and will have the air filter at the top. It may not be possible to introduce outside air through it, so the room will have a pressurized fresh air supply, which will be filtered to remove fine dusts which may affect the computers. Computer room units work with a very high sensible heat ratio of 0.95 or more, so they have large coils to keep the ADP up near the dew point of the room air. Most will have an inbuilt steam humidifier to replace any moisture which is removed on the coil. 

In assessing the ability of an HVAC system to maintain acceptable humidity levels in the building, the more important performance parameter is the sensible heat ratio (SHR) of the equipment. The SHR is defined as the ratio of the sensible cooling load to the total cooling load. Improved latent performance is characterized by a lower SHR. Defining the relationships between SHR and other dehumidification indices is also convenient. In particular, the latent heat ratio (LHR) can be defined as the latent cooling load fraction, and the latent to sensible ratio (LSR) can be defined as the ratio of latent load to sensible load. These ratios appear as... 

The relationships among the psychrometric states, loads, and sensible heat ratio are shown graphically in Fig. 3. For a given pair of entering and leaving air states, sensible, latent, and total loads are proportional to the differences in temperature, humidity ratio, and enthalpy, respectively, as shown in the figure. The SHR is defined by the slope of the line connecting the two points. 

Fig. 3 Coil loads and sensible heat ratio on psychrometric chart.

SHR Sensible heat ratio DB Dry bulb temperature DP Dew point temperature MCWB Mean eoineideni wet bulb MCDB Mean coincident dry bulb... 

Sensible Heat Factor. The ratio of the change in sensible (constant moisture content) cooling enthalpy to the change in total cooling enthalpy. 

The term e/(e — 1), which appears in equations 1 and 2, was first developed to account for the sensible heat transferred by the diffusing vapor (1). The quantity S represents the group ratio of total transported energy to convective heat transfer. Thus it may be thought of as the fractional... 

Zh Ratio of sensible heat removed from vapor to total heat transferred Dimensionless Dimensionless... 

Where the pan is in the air stream the condition downstream of the pan has increased moisture content (kg/kg) found from the airflow and moisture input. On a psychrometric chart, this will lie on a line of sensible-to-total heat ratio of 0.3. Thus, the psychrometric plot shows a steep rise in moisture content with a small rise in dry bulb temperature. The latter is a disadvantage when cooling is... 

A further complication arises with the application to temperate conditions of room air-conditioners which have heen designed primarily for tropical markets. These units typically work with a sensible/total heat ratio of 0.7. Plotting this process line on the psychrometric chart (see Figure 35.3) shows that the ADP will he about 9°C. 

AHs/AHt) = the ratio of the change in sensible heat to the total enthalpy change, (dr/dHt) = slope of the temperature-enthalpy curve, x = vapour quality, mass fraction of vapour,... 

Z Ratio of change in sensible heat of gas stream to change in total heat of ... 

By far the most common way of heat storage is as sensible heat. As Figure 100 shows, heat transferred to the storage medium leads to a temperature increase of the storage medium. The ratio of stored heat to temperature rise is the heat capacity of the storage medium. 

Mixing status in the tank has large affection on outlet response for the ice storage tank with out agitation. If the ice packing factor is small, thermal characteristics of the tank resembles to a stratified water tank. Since the ratio of sensible heat to latent heat is relatively large, conditions should be set to maintain stratification as much as possible. Therefore, large temperature difference in the inlet is preferable. 

The Jakob number (Ja) is the ratio of the sensible heat carried by a liquid to the latent heat of a bubble with the same volume,... 

The air product gas ratio was 0.73, and energy recovery reached about 70 percent (or just over 80 percent If the sensible heat of the gas Is Included). The heat values recorded by the calorimeter are about 8 percent higher than those computed from gas compositions and showing peaks not detected by the gas chromatograph. 

The tray temperatures in our preflash tower, shown in Fig. 4.4, drop as the gas flows up the tower. Most of the reduced sensible-heat content of the flowing gas is converted to latent heat of evaporation of the downflowing reflux. This means that the liquid flow, or internal reflux rate, decreases as the liquid flows down the column. The greater the temperature drop per tray, the greater the evaporation of internal reflux. It is not unusual for 80 to 90 percent of the reflux to evaporate between the top and bottom trays in the absorption section of many towers. We say that the lower trays, in the absorption section of such a tower, are drying out. The separation efficiency of trays operating with extremely low liquid flows over their weirs will be very low. This problem is commonly encountered for towers with low reflux ratios, and a multicomponent overhead product composition. 

The Peclet number, DGC/k = GC/(k/D) and its modification, the Graetz number wC/kL, are ratios of sensible heat change of the flowing fluid to the rate of heat conduction through a film of thickness D or L. 

Index Describes ratio of reaction heat sensible heat —... 

High excess air ratio will result in increasing sensible heat loss in the flue gas, while insufficient air supply means low combustion efficiency. To gain high heat efficiency, a rational excess air ratio needs to be specified. Figure... 

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