Compressor Costing Method
Costing Method Parameters
The following parameters are constructed for the unit on the FlowsheetCostingBlock (e.g., m.fs.costing.compressor) when applying the cost_compressor costing method in the watertap_costing_package:
Description |
Symbol |
Parameter Name |
Default Value |
Units |
|---|---|---|---|---|
Compressor unit cost |
\(C_{comp}\) |
|
7364 |
\(\text{USD}_{2001}\) |
Compressor cost exponent |
\(e\) |
|
0.7 |
\(\text{dimensionless}\) |
Costing Method Variables
The following variables are used on the unit block (e.g., m.fs.unit.costing) when applying the cost_compressor costing method in the watertap_costing_package:
Description |
Symbol |
Variable Name |
Index |
Units |
|---|---|---|---|---|
Vapor flow rate |
\(\dot{m}_{\text{Vap, H2O}}\) |
|
[t] |
\(\text{kg/s}\) |
Pressure ratio |
\(PR\) |
|
None |
\(\text{dimensionless}\) |
Capital Cost Calculations
The capital cost is dependent on the flow rate of water vapor, \(\dot{m}_{\text{Vap, H2O}}\), and the pressure ratio, \(PR\), as shown in the equation below.
\[C_{cap, tot} = C_{comp} \dot{m}_{\text{Vap, H2O}} PR \left( \frac{\eta}{1 - \eta} \right)^e\]
where \(\eta\) is the compressor efficiency
Operating Cost Calculations
Electricity \(C_{elec}\) is a variable operating cost based on the energy intensity \(E\) of the unit process (mechanical work for the compressor), electricity price \(P\), electricity flow \(Q\), and the plant utilization factor \(f_{util}\). The annual electricity costs are calculated as:
\[C_{op, tot} = C_{elec} = E Q f_{util} P\]
Code Documentation
References
El-Sayed, Y. M. (2001). Designing desalination systems for higher productivity. Desalination, 134, 129–58.