The flow will be countercurrent.Click Next and run the simulation.Condenser Design Procedure SDSM&T4/9Here are the results from the shortcut calculations. Set the specification to 0.0 so that the steam will leave the exchanger as saturated water. (Note* you may want to run a simulation using the Heater block as was done in the previous examples, this step will be skipped in this manual)Now at the Setup page for the heat exchanger (shown at left), run a shortcut calculation based on the Hot stream outlet vapor fraction. (See reference one or two for help) After the flowsheet is complete (shown above), give Aspen the other required information: title, property methods, and the stream data given in the problem statement. Generally, a system of equations from energy balances has to be solved and possible iterations are needed.Condenser Design Procedure SDSM&T3/9Start by creating a flowsheet of a block from the HeatX icons. On the other hand, the hand calculations can become very tedious. (See reference two) Hand calculations will be needed again since Aspen has difficulty estimating condensation heat transfer coefficients accurately. Design on Aspen is very similar to that of boiling design. Physically, the steam will flow from top to bottom inside the tubes while the Ethylene glycol will move countercurrently in the shell area. (See recommended readings) This example will use a vertical condenser with the condensation inside the tubes. Each setup requires different considerations as well as different heat transfer correlations. The condensation can occur on the outside or inside of the tubes. Physically, condensers are very similar to normal shell-and-tube heat exchangers. An example of a condenser can be seen in Coulson and Richardson. Just as in boiling design, the condensation heat transfer coefficients are on the scale of 103 W/ m K. From this aspect, design of condensers is usually done with the assumption of film condensation as was done with this example. The latter gives higher heat transfer coefficients however, generally you need surface coatings to achieve the dropwise mechanism. There are two forms of condensation: film and dropwise condensation. 263 through 266 General Design considerations When a surface temperature of a solid is lower than the saturation temperature of a gas, condensation occurs. 5-20 through 5-22 and 11-11 through 11-12 Incropera and DeWitt pg. Recommended readings: Perrys 7th edition pg. Before beginning the actual design on Aspen, make sure to read the following selections to become familiar with the mechanisms of condensation. steam 64 kmol/hr Ti = 374 K Pi = 1 atmEthylene Glycol To = 365 KEthylene Glycol 657 kmol/hr Ti = 340 K Pi = 1 atm Condensed steam To = TsatCondenser Design Procedure SDSM&T2/9Once again, hand calculations will be needed for the condenser design. The plant manager recommends using a vertical countercurrent heat exchanger with the steam in the tubes. Once again, Ethylene Glycol is available at 340 K and 1 atm. The following example will be used.Problem statement : Saturated steam at 1atm and 101 C needs to be condensed so that it may be used as a stripping fluid in a column downstream. If you are HVAC designer, these equations are important for you to understand how the calculation programs work.Condenser Design on Aspen-Plus Software(Heat Exchanger design with a phase change) Author: Jim Lang (SDSM&T, 2000) This is a continued look into the process of condensation and condenser design on AspenPlus. Domestic Hot Water Recirculation Pump/Supply SizingÄownload All HVAC Calculations Formulas PDF - Rules of ThumbĪll these HVAC calculation formula pdf are needed for the design of central air conditioning ststems.Steam and Steam Condensate Pipe Sizing Equations.Pump Net Positive Suction Head (NPSH) Calculations.HVAC calculation formula pdf includes the following:
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