Heat transfer specification sheet

Heat transfer specification sheet. Courtesy of Heat Transfer Division of American Standard. 

It is assumed that process conditions and physical properties are known and the following are known or specified tube outside diameter D, tube geometrical arrangement (unit cell), shell inside diameter D shell outer tube limit baffle cut 4, baffle spacing and number of sealing strips N,. The effective tube length between tube sheets L may be either specified or calculated after the heat-transfer coefficient has been determined. If additional specific information (e.g., tube-baffle clearance) is available, the exact values (instead of estimates) of certain parameters may be used in the calculation with some improvement in accuracy. To complete the rating, it is necessary to know also the tube material and wall thickness or inside diameter. 

There are also two notable research institutes offering information that may assist the engineer in making out the specification sheets. One of these is the Heat Transfer Research Institute (HTRI). Its staff performs tests to optimize the design of heat-transfer equipment. This information is then encoded in computer programs, which are distributed to the companies that support the research. This means that the engineer s company must purchase a membership to obtain these data. The Fractionation Research Institute (FRI) is a similar institution that deals with the separation processes. 

Tq is the initial sheet temperature at the beginning of the considered phase Ts is the steam temperature U is the overall heat transfer coefficient Mg is the amount of dry solids per unit sheet area Cs is the specific heat of dry fiber Cl is the specific heat of moisture X is the dry basis moisture content... 

The CHX is installed in an air loop to obtain its thermal conductance. Figure 7 shows a flow sheet of the air test loop. A compressor transfers low temperature air into the CHX. After that, it is heated up to the maximum 120°C in an electric heater and flows back to the CHX. The heat is transferred from high to low temperature air in the CHX. An exhausted air from the CHX is released to the atmosphere. Four K-type thennocouples are installed at each inlet and outlet nozzle of the CHX, and the flow rate of air is measured by a vortex flowmeter. As a result, the thermal conductance is calculated by an inlet and outlet temperatures, flow rate and specific heat of air. 

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