eq. (A.316)
This operation models the decrease in temperature of a continuous flow or batch stream. The cooling is achieved using electricity.
The energy balance is represented by the following equation:
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eq. (A.316) |
where:
● P is the electric power (kW),
● m is the mass flowrate of the stream (kg/h),
● cp is the specific heat capacity of the stream (kcal/kg-°C),
● ΔT is the temperature change of the stream (°C), and
● η is the coefficient of performance (COP) (the ratio of cooling load to electricity consumption).
In either Design Mode or Rating Mode, the user specifies the COP. Note that the COP corresponding to 1 “ton” of refrigeration (12,000 Btu/h) per unit of horse power is approximately 4.7. In Design Mode, the user also specifies the desired exit temperature (which is equivalent to specifying the value of ΔT) and the above equation is used to calculate the required electric power, P. If the calculated value of P exceeds the Max Power, the program assumes multiple units operating in parallel. In Rating Mode, the user specifies the value of P and the above equation is solved for ΔT to calculate the exit temperature.
The interface of this operation has the following tabs:
● Oper. Cond’s, see Electric Cooling: Oper. Conds Tab
● Labor, etc, see Operations Dialog: Labor etc. Tab
● Description, see Operations Dialog: Description Tab
● Batch Sheet, see Operations Dialog: Batch Sheet Tab
● Scheduling, see Operations Dialog: Scheduling Tab