The HVAC Systems have a big impact on the quality of life and it is one of the prime contributors for the energy consumption of the conditioned space. Because it is a significant investment, choosing a HVAC system involves careful planning so as to ensure that the occupants are comfortable all year round.  

This article highlights how different mechanical systems can be easily compared using cove.tool in the early stages of design where even the geometry of the project is still being discussed. The article includes a Large Office building prototype provided by Pacific Northwest National Laboratory (PNNL) which is located in Denver, CO (ASHRAE Climate Zone 5B) for analyzing the impact of different mechanical systems. Following table contains some key inputs used to create the Large Office model:

The HVAC systems chosen for the analysis are:

  1. VAV/Air Cooled Chiller/Gas Boiler
  2. Packaged Unit/Gas Furnace
  3. Fan Coil System/Water Cooled Chiller/Electric Boiler
  4. VRF System/Air Cooled

Various performance parameters of the systems mentioned above are indicated in the table below: 

The details about the performance curves of various chillers supported by cove.tool can be found in this article

To see the impact of the different mechanical systems on the project, create the copies of the project and select the systems for the analysis from the 'System Type' dropdown from 'Building System' tab on 'Baseline Energy' page. The Energy Usage Intensity (EUI) breakdown for the selected systems can be seen below:

  1. VAV/Air Cooled Chiller/Gas Boiler

     2. Packaged Unit/Gas Furnace

       3. Fan Coil System/Water Cooled Chiller/Electric Boiler

      4. VRF System/Air Cooled

For a side-by-side comparison of the projects with different systems, the users can utilize the 'compare feature' of cove.tool. The following images shows the comparison for the 4 systems selected for analysis:

This feature is exceptionally useful when analyzing the impact of different systems on the heating and cooling energy of the conditioned space. This can be achieved by selecting the chosen parameters from the legends below the breakdown diagram. 

Heating Energy Comparison for the systems can be found in the image below:

Cooling Energy Comparison for the systems can be found in the image below:

In conclusion, the HVAC system selection is a crucial decision for any project because it directly contributes to the energy consumption and comfort of the occupants. Cove.tool can make the selection process a lot easier and help to find the right fit in the early stages of design where a lot of system types are being considered for the project.


Related Articles:

Did this answer your question?