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EnergyPlus™ is a whole building energy simulation program that engineers, architects, and researchers use to model both energy consumption and water use in buildings.
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Plant Operation Scheme Documentation #5053

Open kbenne opened 9 years ago

kbenne commented 9 years ago

In 01b-InputOutputReference.md, Group – Plant-Condenser Control, ### Operation Schemes (Plant and Condenser)

The documentation is out of date and appears to disagree with code.

Plants and condenser loops must have some mechanism for controlling the operation of the loop and which equipment is available under what conditions. Since there may be multiple control schemes that are assigned various priorities associated with each loop, an overall operation scheme must be defined. The overall scheme consists of the object name, an identifying name that is referenced in the main plant or condenser loop statement, and a list of operation schemes. Each operation scheme must have the type of operation scheme, its identifying name, and the schedule that defines its availability. Note that the order in which the individual operation schemes appear in this list defines its priority versus the others with the same scheduled availability. The first scheme appearing in the list is given the highest priority, the second scheme has second highest priority, etc. In other words, if according to its schedule, the first operation scheme is available, then it is used by the simulation to define how the plant or condenser loop operates. If it is not available, the second operation scheme in the list is checked to see if it is available until the highest priority scheme that is also available is found.  To allow for simultaneous heating and cooling, there is one configuration where multiple operation schemes are available at a given timestep.  This is allowed if a user inputs both a heating range based operation and a cooling range based operation with overlapping schedules.  The simulation will look at the current loop demand to determine if the cooling scheme should be used or the heating scheme.  In other cases, if two schemes overlap (are available at the same time), a fatal error will be encountered.

It seems that the beginning of that paragraph contradicts the very last sentence.

Note that the order in which the individual operation schemes appear in this list defines its priority versus the others with the same scheduled availability. The first scheme appearing in the list is given the highest priority, the second scheme has second highest priority, etc.

vs

In other cases, if two schemes overlap (are available at the same time), a fatal error will be encountered.

Consider revising documentation to ensure it is accurate with current code.

It seems even the development team might be unclear about the intended behavior.

kbenne commented 9 years ago

I uploaded a defect file to demonstrate that when a component is on two operation schemes at the same time, it is actually the last operation scheme in the list that is applied. Not an error like the last sentence of the documentation suggests, nor is it the first scheme listed that is applied. This is more a documentation issue, although the code's behavior seems a little counter intuitive. Wouldn't the first scheme in the list as the documentation describes make more sense?