6.2.3. Processes

6.2.3.1. Maintenance of Temperature and Start-up

still to be written.

6.2.3.2. Incoming flows

still to be written.

6.2.3.3. Outgoing flows

still to be written.

6.2.3.4. Process Schedules

For each process its running time may be defined by either a small set of parameters that define the amount of time per day day and the number of days per year, or in a much more detailed fashion. The detailed schedule offers the definition of running times per week day and these weekly profiles may again be choosen for freely choosen spans within the year.

To define a schedule for a process it first must be selected from the Process list on tab Process data in the Process data section of EINSTEIN.

With only four parameters it is possible to define the times of activity of a process. The effective hours of operation per day, the number of cycles per day, the duration of each cycle and the days of operation per year ar these parameters. As the first three are actually redundant, it is enough to enter two of them.

../_images/screenshot_simple_schedules.png

If this simple modelling is not enough, you can choose the Detailed schedule checkbox and define a detailed schedule instead.

If you are interested how simple schedules of processes are converted into schedules that can be compared with the detailed schedules and how the parameters of a simple schedule are calculated from a detailed one, please read the chapter Process Model in the Technical manual.

A detailed schedule of operation is based on intervals of daily process running times that are assigned to a selection of weekdays to form weekly profiles. The weekly profiles are then assigned to different calendar date periods of a year. The result is a profile of process utilization as a percentage of nominal load for every hour of a year.

The scaling of the nominal load does not change process temperatures but scales flow rates and energy demands linearly. The scaling may exceed 100%.

6.2.3.4.1. Weekly Profiles

Weekly profiles are defined on the tab Profile in the Process data section of EINSTEIN. There are basically four steps to form a weekly profile:

  1. Add daily time intervals with a scale factor to a daily profile
  2. Select the weekdays for the daily profile
  3. Enter a descriptive name for the weekly profile
  4. Add the new profile to the list of available weekly profiles
../_images/screenshot_profiles.png

To change existing intervals and weekly profiles or use them as a starting point for new ones click on the respective list entry to load their settings into the control elements. After your changes click Add to add a new entry or Change to modify the currently selected entry. Click Remove to delete the currently selected list entry.

6.2.3.4.2. Period Schedules

The weekly profiles are assigned to calendar date periods on the tab Schedule in the Process data section of EINSTEIN. A standard year starting and ending on Monday is assumed, so only the months and days of a period are taken into account. There are basically three steps to form the resulting yearly profile for a process:

  1. Select the starting and stopping dates for a calendar period. Also a scale factor for the period and an additional one for the times defined as holidays may be specified during this period.
  2. Select the weekly profiles for the specified calendar period. Multiple weekly profiles may be selected at once by holding the Ctrl-key when clicking.
  3. Add the period schedule to the yearly profile of the process.
../_images/screenshot_schedules.png

To change existing periods or use them as a starting point for new ones click on the respective list entry to load their seetings into the control elements. After your changes click Add to add a new entry or Change to modify the currently selected entry. Click Remove to delete the currently selected list entry.

You should not create two periods with overlapping times of activity or use several weekly profiles with overlapping times of activity in the creation of a period.

Once you add a new calendar period or select one from the list the weekly running profile of the process for the complete first week during this period is plotted as a graph of process load by hour of week.

Any time not covered by a period is considered to have a process activity of zero.

Basicly the load of a process is its nominal energy demands times the product of the daily scale and the period scale times the holiday scale if it applies. The precise calculations behind the scheduling are documented in the Technical manual.

6.2.3.4.3. Process Schedule Parameters

Additional global parameters for process scheduling are specified on the tab Schedule in the Process data section of EINSTEIN. There are four global parameters for the schedule of a process:

  1. Startup time specifies the duration of the process startup phase.
  2. Inflow time specifies the duration of the process charging phase.
  3. Outflow time specifies the duration of the process discharging phase.
  4. Holiday scaling specifies the scale factor to the process load during the holiday periods entered on the tab Period of operation in section General Data of EINSTEIN.
Phase \Delta t Process type
batch continuous
Operation [t_0,T]
Startup [t_0,t_0+\Delta t]
Inflow [t_0,t_0+\Delta t] n.a.
Outflow [T,T+\Delta t] n.a.
../_images/process-times.png