Normalized heat loss

Taking the amount of heat required for bridging the temperature gap (Tequ - To) for the endothermic mixture as a reference, the normalized heat loss is given by the following expression ... 

Fig. 1.3. The effect of heat exchanger performance, NTU, and heat capacity ratio, h, on the normalized heat loss for heat-integrated processes in (a) countercurrent and (b) counter-cocurrent flow configuration.

During hot functional testing, the transient performance of the pressurizer is checked by determining its normal heat losses and maximum depressurization rate. This information is used in setting the pressure controllers. 

That these reductions are so small suggests what experienced operators already know. An internal cooler may not be necessary because normal heat losses from the unit will suffice to remove an adequate amount of heat from the rinse sump. 

Actual system heat loss (or gain) will normally exceed calculated values because of projertions, axial and longitudinal seams, expansion-contraction openings, moisture, workers skill, and physical abuse. 

The twenty curves shown in Figure 24 are graphs of (0) versus (v) together with the integral of (0) versus (v) for different values of (Ca) and (( )). They are all normalized to the same peak height. The curves include the practical range of heat loss factors that might be expected from an heat of adsorption detector cell. 

Air Temperamre Design temperature for equipment and outdoor transformers shall be 98°F. Design Temperature for the Installation of Service Equipment - Maximum Temperamre 100°F - Minimum Temperamre 60°F Design Temperamre for Calculation of the Heat Loss - Normal Daily Average 79°F. The maximum mean relative humidity is 97%. Mean relative humidity -82%... 

Under certain conditions, such as hyperbaria,airway heat losses can account for a considerable percentage of total body heat production (in some cases > 100%). Normally these threats are ameliorated by rapid moderation of inspired air temperature and humidity by exchanging heat and water vapor between the mucus and airstream in the upper airway. Recovering much of the heat and water vapor contained in expired air minimizes heat and water losses to the ambient environment and aids in whole-body thermoregulation. 

The selection is dictated by economics governing the initial plant cost versus higher turbine output. Usually, the turbine exhaust steam is designed to be slightly superheated, which is desirable, as it allows for heat loss from the steam with minimum condensate losses. At low loads from the turbine, the degree of superheat can rise sharply, well in excess of the normal design conditions, and for this purpose, desuperheaters are often employed to trim the steam temperature at exhaust. 

The normal procedure in estimating the heat loss from any building is as follows ... 

In an operating column the effective reflux ratio will be increased by vapour condensed within the column due to heat leakage through the walls. With a well-lagged column the heat loss will be small and no allowance is normally made for this increased flow in design calculations. If a column is poorly insulated, changes in the internal reflux due to sudden changes in the external conditions, such as a sudden rain storm, can have a noticeable effect on the column operation and control. 

Heat losses from the heater casing are normally between 1.5 to 2.5 per cent of the heat input. 

The split between the radiant and convection section heat varies according to the design. Casing losses are usually between 1 and 3% of the heat release from combustion. The heat loss from the stack is constrained by the desire to avoid any condensation of water vapor in the convection section. If there is any sulfur present in the fuel, then the condensate will be corrosive. The temperature at which the flue gas starts to condense is the acid dew point. For sulfurbearing fuels, the temperature of the flue gas is normally... 

As noted previously, the normal maximum pressure for distribution is around 40 bar. Heat losses in the distribution system might be typically 10% of the fuel fired in the boilers, but can be higher. 

When combustion air preheat is used, the air preheat unit may replace the boiler feed water coil. Flue gas exits this unit at about 300 degrees F. This provides a typical heat loss of 3% of the overall reformer efficiency. Steam is also made in a process steam generator which extracts heat from the reformer outlet process gas. The heat recovery unit and process steam generator normally have a common steam drum. 

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