I am using E+ outputs such as fans power consumption, cooling coils, baseboard heaters power consumption and adding them to generate HVAC power consumption. When I compare the aggregated HVAC power consumption with the HVAC output power variable generated by E+ I observe that E+ HVAC output is showing spikes as shown in the attached picture (x-axis is just the time, y-axis is the power). The outputs are from the same tool but why are they different. What is E+ adding to the HVAC output variable that is causing spikes.
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A chiller for example will turn off if the partload ratio drops under 20%. This kind of behavior is possibly true for other kinds of equipment in your system (like your DX units). A good design will add components and or controls to handle the spikes. Checkout the minimum cycle time of the DX units. What do the room air temperatures do? Make sure the space is heating up and cooling down realistically. A small space with perfect insulation, no infiltration and no internal mass may have very fast temperature changes.
On 13 Apr 2016 7:40 pm, "Fakeha Sehar
fakeha_s@xxxxxxxxx [EnergyPlus_Support]" <
EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
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I have a building with each zone supplied by a packaged unit (DX coil and gas furnace) and baseboard heater. The HVAC power consumption output shown by E+ has a lot of spikes but when I simply add the pumps, fans, cooling and electric reheat coils and baseboard heaters power consumption I do not see any spikes. Picture attached showing the HVAC power consumption output by E+ and then one generated by adding all HVAC components' power for a single summer day. Why is E+ showing spikes in the HVAC output?