Learn HVAC Tutorial: Analysis

Once the simulation in done running, you can view the results in the Analysis tab. You should see your simulation run listed in the Simulation Data panel in the L1 tab, much like in Figure 4-1
Figure 4-1 Analysis Window
Figure 4-2 Analysis Tabs
Analysis sub tabs

The first thing you should note about the Analysis tab are the two major sub-tabs: Core Data and Meter Data. From the Core Data tab, you can display results from both your Short-Term Simulation Runs, and your Long-Term Simulation runs. The Meter Data Tab only shows energy use by category based on the Long-Term Simulation.

Let's first look at the Core Data Tab

Core Data

Figure 4-3 Long-Term Simulation Data
Simulation Data

The tabs in the Simulation Data panel show you results from each Simulation Run. For both the Short-Term and the Long-Term Simulations, you specified whether to store the results in Run 1 or Run 2. These now correspond to L1, L2 and S1, S2.

If you did not run a simulation in one of those variables, for example, L2, then the data is blank. For L1, we did run a Long-Term Simulation and thus, we see results.

The Period, highlighted in yellow, tells you how long the simulation ran. For L1 it was a full year.

The Inputs simply list the value that were used/entered for the simulation.

The Outputs is what we are concerned with. Click the arrow next to the building icon to expand the list.

Figure 4-4 Output Variables
Outputs Outputs Expanded Outputs Enlarged

Now you are presented with a long list of variables. You should grab ahold of sliding icon highlighted in Figure 4-4 and collapse the Inputs menu. This will allow you to have a better view of the Outputs.

At the top of the list are your three floors. Each floor is divided into 5-zones and each zone has a set of variables that can be graphed.

Figure 4-5 Output Floors
Output Floor
Below the list of floors are a wide range of other variables which have to do with the HVAC system plant components, energy and resource use, and pollutant production. Simply grab and drag a variable from the list onto one of the chart to display it. Each graph can handle up to two variables.
Figure 4-6 Output Graphs

In Figure 4-7, both graphs are graphing Floor 1>Zone 1> Perimter-1-North: Zone Zone/Sys Sensible Heating Rate and Mean Air Temperature. The difference is that the top graph is Time-Series graph and the bottom graph is an X-Y plot. By hovering your cursor over the data, a pop-up will appear telling you the value for that data-point. The Time Series graph, selected with the TS button on the Graph, displays your selected data on the Y-axis and the Date/Time on the X-Axis. This allows you to see how the variables change over time. The X-Y plot, selected with the XY button, graphs the first variable you select on the X-axis and the second on the Y-axis. This allows you to see trends on how the first variable affects the second variable.

In the case of the Time-Series plot, notice how the Mean indoor temperature varies with the season. Similarly, the Sensible Heating Rate decreases in the Summer and Increase in the Winter. This trend might be slightly obscured by the Air temperature plot, so often it is good with a Time-Series to just view on variable at a time. With the X-Y plot, notice how the Heating Rate does not initially affect the temperature in the space; it is constant, but as the heating rate goes up, the temperature decreases. To clear the data from the graphs and graph different data, hit the Clear button on the graph.

Analysis of the Short-Term Simulation

The Short-Term Simulation data is very similar. Click on S1 and look at the data from your Short-Term Simulation.

Figure 4-7 Short-Term Simulation Analysis
Short-Term Analysis

Here, the outputs are grouped by system component. Open up the Heating Coil and add the Stuck Heating Coil Valve to the first graph. Then add the Heating Coil Leaving Air Temperature to both graphs and the Cooling Coil Leaving Air Temperature to the second graph. Notice the effect the stuck heating coil has on the air temperature and how that in turn affects the air temperature after it leaves the cooling coil.

Meter Data

Finally, look at the Meter Data Tab and take a look at the Energy used by the building during the Long-Term Simulation Run.

Figure 4-8 Meter Data Analysis
Meter Data

This Time Series plot shows you the energy consumption of each HVAC component in the system. You can turn pieces on and off by clicking the colored box next to their name and then hitting Refresh Chart.

Figure 4-9 Meter Data Analysis: Systems Off