Making process improvements as a result of applying variable speed drives in other configurations can reduce operating costs significantly.
Q: Which of the following configurations lend themselves to becoming potentially viable applications of variable speed drives?
Installing a variable speed drive to operate one pump that feeds one user (Answer A) allows the variable speed drive to manipulate that flow as part of a feedback control loop. This configuration lends itself to being viable when the energy savings associated with operating with the variable speed drive sufficiently offsets the cost of the installation. Similarly, using two operating parallel pumps (Answer C) can be viable, although two variable speed drives will likely be required to operate the system.
Installing a variable speed drive to operate one pump that feeds multiple users (Answer B) allows the variable speed drive to manipulate the header pressure. This configuration may lend itself to being viable when header pressure reductions (as compared to the existing header pressure) result in energy savings that offset the cost of the installation. Similarly, using two operating parallel pumps (Answer D) can be viable while two variable speed drives will likely be required to operate the system.
These configurations generally focus on energy savings. Making process improvements as a result of applying variable speed drives in other configurations can reduce operating costs significantly.