Follow these best practices when setting up your model for systems analysis.
System Requirements
Verify each of the following conditions to help improve the likelihood of a successful simulation.
- A hot water loop must have at least one coil that has a load attached to it.
- A condenser loop must have one piece of equipment that has a load attached to it.
- A chilled water loop must have one piece of equipment that has a load attached to it.
- An air system must have at least one piece of zone equipment that has a load attached to it.
- A zone equipment item must serve a conditioned zone, otherwise there is no load to which the equipment can respond.
System Configuration
There are a variety of system configurations that can cause an error in the simulation or which may not behave as expected. Follow the rules below to avoid those issues.
- A space should not be to a Zone Equipment type of Unconditioned and another Zone Equipment type, such as PTAC. The image below represents an example of an incorrect configuration in the System Browser.
- A space should not be present in a piece of zone equipment with a behavior of Group Spaces on Equipment and a piece of zone equipment with a behavior of One per Space if the grouped definition contains more than one space. Using System-Zone Outlines (SZO), it would look like the image below.
- The SZO labeled 1 is attached to zone equipment that has a One per Space behavior.
- The SZO labeled 2 corresponds to zone equipment with a Group Spaces on Equipment behavior.
- If two Zone Equipment exhibit the Group Spaces on Equipment behavior, then the spaces they serve can only overlap (be attached to both Zone Equipment) if all spaces are overlapping.
- An invalid configuration is shown below. Analytical Space 1 and Analytical Space 2 are present in the VAV Zone Equipment, but Analytical Space 2 is not present in the PTAC.
- A valid configuration with both spaces present in each piece of zone equipment is shown in the image below.
- An invalid configuration is shown below. Analytical Space 1 and Analytical Space 2 are present in the VAV Zone Equipment, but Analytical Space 2 is not present in the PTAC.
The space named Analytical Space 1 is in both a Zone Equipment of type Unconditioned and of type PTAC, which is not valid.
Additional Notes
While it is not a requirement, it is a best practice to only group spaces that are spatially co-located. In the simulation, grouped spaces are assumed to have a perfectly mixed air volume, which isn't realistic if spaces aren't adjacent.