Hopper: Equipment Tab

Variable Definitions, Ranges and Default Values

The following table shows the meaning of the variables appearing in this tab, as well as their default values and their generally acceptable range. Note that due to the manner by which the variables are used by the sizing and costing equations, the range of acceptable values may be further reduced.

Variable	Default Value	Range

◙ Volume The total vessel volume.	0.0 L	Positive
◙ Max Volume The maximum volume that a unit of this type is available for purchase in the market.	10,000.0 L	Positive
○ Max Allowable Working/Vessel Volume The maximum ratio of working (liquid) volume of material to total vessel volume allowed.	90%	(0,100]
○ Equipment Heat Capacity The product of total mass times the specific heat capacity of the vessel.	0 kcal/°C	Positive.

Symbol Key: ○ User-specified value (always input); ● Calculated value (always output); ◙ Sometimes input, sometimes output

Sizing: Design Mode

In design mode, the user specifies the max volume, and the program calculates the number of units and vessel volume based on the volume demand that is specified by the operation carried out as part of the unit procedure hosted by the equipment resource. If that volume exceeds the maximum volume specification then the software will assume multiple number of identical units, each with a volume that does not exceed the max volume specification, so that the total volume is equal to the demand.

To calculate the demand on vessel volume by the operation, the demand on liquid volume by the operation is divided by the operation’s working to vessel volume ratio. The equipment’s max allowable working to vessel volume ratio acts as a constraints on the operation’s working to vessel volume ratio (i.e., the operation’s working to vessel volume ratio must not exceed the equipment’s max working to vessel volume ratio).

For more information on the sizing of a hopper, see Cont. Storage (for Bulk Solids in a Hopper): Modeling Calculations.

Sizing: Rating Mode

In rating mode, the volume of the vessel and the number of units are provided by the user. The program calculates exactly as in the design mode case the demand on vessel volume by the operation carried out as part of the unit procedure hosted by the equipment resource, and if the operation’s vessel volume demand of exceeds the actual vessel volume, it generates a warning.

Costing

Equipment purchase cost is based on total bin volume and material of construction. It is supplied by the built-in model assuming as material of construction CS.

Other Variables

● Equipment Heat Capacity; the product of equipment mass times its specific heat capacity. It is used by operations that are executed in the vessel and involve heating and/or cooling. If part of the heat exchange is directed to the vessel, then this variable is used to estimate heating/cooling losses.

For more information on this equipment, see Hopper.

For information on the left-hand side variables and options, see Equipment Data Dialog: Equipment tab.