Heater/Chiller Costing Method
Costing Method Parameters
The following parameters are constructed for the unit on the FlowsheetCostingBlock (e.g., m.fs.costing.heater_chiller) when applying the cost_heater_chiller costing method in the watertap_costing_package:
Description |
Symbol |
Parameter Name |
Default Value |
Units |
|---|---|---|---|---|
Electric Heater |
||||
Heater unit cost |
\(C_{heater}\) |
|
0.066 |
\(\text{USD}_{2018}\text{/W}\) |
Heat generation efficiency |
\(HE\) |
|
0.99 |
\(\text{dimensionless}\) |
Chiller |
||||
Chiller unit cost |
\(C_{chiller}\) |
|
0.2 |
\(\text{USD}_{2018}\text{/W}\) |
Coefficient of performance |
\(COP\) |
|
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_heater_chiller costing method in the watertap_costing_package:
Description |
Symbol |
Variable Name |
Index |
Units |
|---|---|---|---|---|
Heat duty |
\(E\) |
|
[t] |
\(\text{W}\) |
Capital Cost Calculations
For the Electric Heater:
The capital cost is dependent on the heat duty, \(E\), and the heat generation efficiency, \(HE\), as shown in the equation below.
\[C_{cap, tot} = C_{heater} \cdot \frac{E}{HE}\]
For the Chiller:
The capital cost is dependent on the effective heat duty, \(E\), and the coefficient of performance, \(COP\), as shown in the equation below.
\[C_{cap, tot} = C_{chiller} \cdot \frac{E}{COP}\]
Operating Cost Calculations
Electricity \(C_{elec}\) is a variable operating cost based on the energy intensity \(E\) of the unit process (heat duty for the heater or the chiller), electricity price \(P\), electricity flow \(Q\), and the plant utilization factor \(f_{util}\). The annual electricity costs are calculated as:
\[C_{op, tot} = C_{elec} = E Q f_{util} P\]