HVAC Diagramming Approach

To allow for industry standard HVAC system representation, a collaborative process was established through which a team of engineers and architects continuously provided practitioner  input for the HVAC interface layout, component shapes and icons used for screen representation, the workflow for cross referencing loops as well as labeling and data visualization formats. Through this process, several methods were identified to reduce HVAC system generation time, allow effective manipulation of system configuration at a component level, and let users establish, edit and view HVAC controls in more intuitive ways. Some advanced visualization features include automated demand side creation, zone HVAC group composition and library assignment capabilities, system level priority tables for controls and a separate layer for HVAC controls that can be turned on and off to reduce visual clutter.

HVAC Diagramming

Visualization of the HVAC Diagramming approach is implemented within Simergy at different levels ranging from the overall system level to aspects of different loop designs down to the individual component level.  At the highest level the user can draw or view the air, hot water, chilled water, condenser water and mixed water loops associated with the design.  In addition the user can incorporate sensors and controls into the design on a separate layer that allows the user to view them integrated into the loop design or turn them off, so that a more simplified view of the loop is shown.  The two dimensional representations are set up to be familiar to design engineers with the intent that they will be more accessible and intuitive to users and serve as a guide to the additional capabilities that Simergy provides.  

HVAC system templates

Each of the HVAC system templates contains the inputs and component shapes for the complete system design, so that simulations can be run just by selecting these templates.  By selecting an HVAC system template the user can visualize any or all of the air, water and condenser loops overlaid with the sensor and controls layout.  Another item related to the overall loop type definition is the system level controls, which are incorporated into each loop.  Depending on the loop type the types of system level controls provided will vary.  The user can easily see and reference what system level controls are set up for the loop by looking at the control scheme priority tables located on the lower portion of the HVAC diagramming canvas.  

Zone HVAC Group

At the next level down portions of the loop designs can be automatically created and/or set up as templates by the user.  The demand side creation of the air loop design can be visualized by the user after a few input selections have been made, and then edited from there.  A key part of the demand side, the Zone HVAC group, can also be set up as a template so that the user can easily incorporate different equipment types into the Demand Side of the Air Loop.  The Zone HVAC Group allows the user to set up and visualize the components for the sensor types, incorporate different types of zone equipment and establish priorities for the zone equipment.   In addition, the user can establish groups for different types of components, which also can save time in set up and simply the view of the system design as well. 

Object Component Shape

At the most basic level of the approach is the object in EnergyPlus.  In Simergy we refer to an object as a component shape.  Each relevant object within EnergyPlus has a component shape created for it within Simergy.  Approximately 200+ object shapes are available to the user distributed across multiple stencils within the user interface, so that they are grouped in an intuitive and accessible way.  The component shape is the visual queue provided to the user to assist set-up and understanding of the system design.

 

While typical engineering design drawings layout and explain the design, they don’t always show all the relevant detail and they are not required to be fully integrated across the drawing set for every aspect of the design.  For HVAC diagramming to function successfully within Simergy, the HVAC system design must be fully integrated and the user must be able to track how the energy model is being configured and when viewing results effectively investigate the potential causes.   For Simergy the capability to visualize and track starts with the component shapes, which provides the glue that ties all the different levels mentioned above together.  

 

Example:  Consider a zone group that includes VAV boxes with a reheat coil that is connected to the hot water (HW) loop.  The VAV component shape will contain four ports, two air ports and two hot water ports.  If the user is looking at the air loop they will see the VAV box preceding the zone group with the air path moving through it.  The hot water ports will show off page references that provide a unique identifier that matches the VAV object shape within the hot water loop.  The user can go to the hot water loop and look for the VAV object shape that is showing the off page references for the air ports that matches the identifier number from the shape on the air loop.  This is especially helpful to the user as the loop design representations get more complex and when multiple users are working on a project and/or if a colleague is asked to review an energy model.  

 

Simergy also incorporates extensive validation rules related to different aspects of the HVAC system design; however the ability for the user to track performance at the component level in addition to the validation rules is a very useful combination, especially as users are trying to make sense of the simulation results.

 

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