Validation Framework

A comprehensive assignment and validation framework was created for implementation in Simergy to support the transformation from the drawing model to the SimModel to enabling simulation using EnergyPlus. This framework includes the creation of assignment and validation rules in a spreadsheet based format. The spreadsheet rules are then converted to XML and applied during run time using functions that help traverse and check loop topology for engineering accuracy, completeness and consistency.

The validation rules serve two purposes:

1. Checking the connections between components to confirm that the inlet and outlet ports are connected for the same fluid type (e.g. air to air, not air to water)

2. Ensures that the air and water loops that the user has created comply with the constraints on HVAC loop topology in EnergyPlus and with EnergyPlus requirements regarding the number and location of critical components.

These rules are a combination of engineering requirements that are enforced by EnergyPlus and limitations on the possible configurations required to make the numerical solution more tractable.

Simergy conducts two types of validation checks:

1)      Pre-Validate Checks - Local checks performed as the HVAC diagramming progresses.  Some examples include:

1. On import and/or each time a new component is added (EnergyPlus specific checks for allowable components)

2. After each connection is made (port compatibility)

2)      Validate for EnergyPlus – which is typically to be selected prior to simulation.

When a user requests validation of the air loop, or a validation event is launched before simulation, any errors encountered are delivered as either 'warnings', 'severe errors' or 'fatal errors' with each level determining what the outcome of the validation function is.

-          Warnings - the engine will continue processing and provide a complete list at the end of a validation run.

-          Severe Errors - the engine will continue processing and provide a complete list at the end of a validation run.

-          Fatal error - the validation engine will stop at that point until the user corrects the particular error.

The Validation Rules Framework is composed of the sections

Zone HVAC Group Validation Rules

Component Counts (Templates)

• Check that Zone HVAC Group only contains one air terminal
• Check that Zone HVAC Group contains no more than four sensors
• Check that Zone HVAC Group contains at least one air terminal or one zone equipment
• Check that Zone HVAC Group contains no more than five zone equipment components
• Check that Zone HVAC Group contains no more than ten components

Component Counts (Project)

• Check that Zone HVAC Group only contains one air terminal
• Check that Zone HVAC Group contains no more than four sensors
• Check that Zone HVAC Group contains at least one air terminal or one zone equipment
• Check that Zone HVAC Group contains no more than five zone equipment components
• Check that Zone HVAC Group contains no more than ten components

Loop Cross Reference Check

• Check that components that have cross loop reference tags have connections assigned to other loops

Class/Type/Sub Type Check

• Check that the class, type and sub type combinations are valid

Air Loop Assignment and Validation Rules

Components required for EnergyPlus

• Check that air loop supply sub-system has at least one flow mover
• Check that air loop demand sub-system has at least one Zone HVAC Group
• Check that air loop demand sub-system has at least one Air Terminal Group

Supply Side: Identify economizer and check/assign outside air subsystem (if present)

• Check that air loop has only one outdoor air damper
• Check that air loop has only one outdoor recirculation damper
• Check that air loop has only one outdoor exhaust damper
• Check that air loop that contains an outdoor air damper also contains a recirculation damper
• Check that air loop that contains an recirculation damper also contains an outdoor air  damper
• Check that air loop that contains an exhaust air damper contains both an outdoor air damper and a recirculation damper
• Check that air loop has only one outdoor air louver
• Check that air loop has only one exhaust air louver
• Check that air loop that contains an outdoor air louver also contains an exhaust air louver
• Check that air loop that contains an exhaust air louver also contains an outdoor air louver
• Check that recirculation damper has a mixer downstream in the economizer (Air Mixer)
• Check that recirculation damper has a splitter upstream in the economizer (Air Mixer)
• Check that only the outside air and recirculation streams are the inlets to the economizer mixer
• Check that only the exhaust air and recirculation streams originate from the splitter upstream of an economizer
• Check that an outside air path starts with an outside air louver
• Check that an outside air path ends with an exhaust air louver

Supply Side: Splitter and Mixer validation across Supply-Demand boundary

• Check that only one splitter has been added to the supply side of the air loop
• Check that only one mixer has been added to the supply side of the air loop

Supply Side: Identify and assign sub-systems and supply side branches

• Check that only one splitter has been added to the supply side of the air loop
• Check that only one mixer has been added to the supply side of the air loop
• Check that no more than three outlet connections are included from a single component in the supply side of the air loop
• Check that a mixer is upstream of a splitter in the supply side of the air loop
• Check that only one splitter is included in the air loop economizer

Supply Side: Check consistency between Air Terminal Types and Loop Duct Types

• Check that a triple duct air terminal is not included in a single or dual duct system
• Check that a dual duct air terminal is not included in a single  duct system

Assign demand-side Supply Air and Return Air path

• Check that a maximum of two supply plena are included on the demand side
• Check that only supply plena or air terminals are included on the demand side upstream of the Zone HVAC Group
• Check that a maximum of two return plena are included on the demand side
• Check that only return plena are included on the demand side downstream of the Zone HVAC Group
• Check that only supply plena, splitters or air terminals are included in the demand side upstream of the Zone HVAC Groups
• Check that only return plena or mixers are included in the demand side downstream of the Zone HVAC Groups

Controls

• Check that each fan has an availability schedule assigned to it
• Check that each coil component has an availability schedule assigned to it
• Check that each evaporative cooler has an availability schedule assigned to it
• Check that each dehumidifier has an availability schedule assigned to it
• Check that each air terminal component has an availability schedule assigned to it
• Check that each unitary HVAC component has an availability schedule assigned to it
• Check that each zone baseboard component has an availability schedule assigned to it
• Check that the economizer component has an economizer controller assigned to it
• Check that the economizer component has an availability manager assigned to it
• Check that supply air temperature controller is assigned to coils
• Check that zone air temperature controller is assigned to a zone HVAC group

Loop Cross Reference Check

• Check that components that have cross loop reference tags have connections assigned to other loops

Connectivity

• Check that a thermal zone is downstream of an air terminal

Class/Type/Sub Type Check

• Check that the class, type and sub type combinations are valid

Air Loop Controls

The validation rules for the following components vary in the number of steps but they are a combination of validating component IDs for the components and associated components, sensor placement validation and different connection tests.

Supply Air Temperature Controller

• Check that heating and cooling coils are connected to the supply air temperature controller
• Check that a temperature sensor is located at the outlet node of the last component on the supply side.
• Check that the outdoor air temperature controller is connected to the supply air temperature controller

Single Zone Temperature Controller

• Check that each Zone HVAC Group in the air loop is connected to a zone air temperature controller
• Check that a temperature or humidity sensor placed in the Zone HVAC Group that specifies the control node for the controller is connected to the controller
• Check that only temperature sensors are used for zone air temperature control and humidity sensors are used for zone air humidity control
• Check that each of the zone air temperature controllers is connected to the supply air temperature controller

Supply Air Humidity Controller (Multi-Zone)

• Check that heating and cooling coils are connected to the supply air humidity controller
• Check that a humidity sensor that specifies the control node for the supply air humidity controller is connected to the controller and placed at the outlet node of the last component on the supply side of the air loop

Single Zone Relative Humidity Controller

• Check that a humidity sensor is placed in the Zone HVAC Group that specifies the control node for the controller is connected to the controller

Outdoor Air Controller

• Check that the outdoor air controller is connected to the recirculation air damper
• Check that the outdoor air controller is connected to the outdoor air damper
• Check that the outdoor air controller is connected to the exhaust air damper
• Check that the supply air temperature controller is connected to the outdoor air controller

Outdoor Air Pre-conditioning Controller

• Check that an air temperature sensor is connected to the outlet node of the last component in the outdoor air stream
• Check that the outdoor air preconditioning controller is connected to at least one heating or cooling coil in the outdoor air system

Ventilation Controller

• Check that the ventilation controller is connected to a CO2 Sensor in the Zone Group

Daylighting Controller

• Check that the daylighting controller is connected to an illuminance sensor in the zone group

Water Loop Assignment and Validation Rules

The different sections and associated validation checks of Air Loop Controls includes:

Components required for EnergyPlus

• At least one pump required in the water loop
• At least one chilled water demand group or component required (CHW loop)
• At least one demand component or group required (CW loop)
• At least one hot water demand group or component required (HW loop)
• At least one chilled/hot water demand group or component required (MxW loop)

Identify and assign branches in Supply Loop

• Non-Return Valves and Common Pipes
• • Check for number of common pipes on supply side
  • Check for valve type in common pipe branch
  • Check that only the non-return valve is located in common pipe branch
  • Check for Common pipe connection to the point where the supply and demand sub-loops connect
• Ice Tank
• • Check Ice tanks are in chilled water or mixed water loops
  • Check that only one ice tank is on a loop
  • Check that pump is not located on ice tank parallel branch
  • Check that only one ice tank is on a parallel branch
  • Check that parallel ice tank branch is connected to point where supply and demand sub-loops meet
• Water Tank
• • Check that only one water tank is on a loop
  • Check that pump is not located on water tank parallel branch
  • Check that pump is not located on water tank parallel branch
  • Check that only one water tank is on a parallel branch
  • Check that parallel water tank branch is connected to point where supply and demand sub-loops meet
• Pumps (SimFlowMover:Pump; SimFlowMover:PumpSet)
• • Check that supply side inlet branch forms whole supply sub-loop or terminates at a splitter for parallel branches
  • Check for connections and components on supply side outlet branch downstream of primary supply side energy transfer equipment.
  • Check that only one pump is located on each branch
• Tempering Valve
• • Check that only two parallel branches are allowed with a tempering valve
  • Check that branch pumps are not included with tempering valve.
  • Check that only one tempering valve is included on demand side
  • Check that tempering valve is the first object in demand sub loop
  • Check that only tempering valve is included in common pipe branch
• Splitters
• • Check that only one splitter is allowed on supply side of plant loop (in addition to common pipe)
• Demand Side Inlet Branch
• • Check that demand side inlet branch forms the whole demand sub-loop or terminates at a splitter for parallel branches.

Classify Loop Typology and Validate Splitters and Mixers

• Condenser Loops
• • Check no common pipes located in condenser loops
  • Check that tempering recirculation is not included in condenser loops
  • Common Pipes - Check that tempering recirculation only included in primary-secondary loops
  • Thermal Energy Storage - Check that only one thermal energy storage tank is included in water supply sub-loop
  • Ice Thermal Storage - check that no ice thermal storage is included in condenser loops
  • Check that water tank is in parallel with chiller branch(es)
• Water Loops
• • Check that supply side for water loop does not contain more than one splitter or more than one mixer unless it is a primary-secondary loop
  • Check that supply side for All-Primary loop with parallel thermal storage contains one or two splitters and the matching number of mixers.
  • Check that supply side for water does not contain more than two splitters and the matching number of mixers.

Validate Supply Side Components

• Check that an all primary water loop with no parallel branches only contains one pump
• Check that loop pumps are placed on either the supply inlet side or the supply outlet side, but not both
• Check that supply side does not have branch pumps as well as a loop pump
• Check that all parallel branches have branch pumps

Validate Demand Side Components

• Check that pumps are not placed on both supply side and demand side of an all primary system
• Check that the supply side or demand side for an all primary system contains at least one loop pump
• Check that the demand side for an all primary system does not contain more than one loop pump
• Check that the demand side does not contain both branch pumps and a loop pump
• Check that all parallel branches have branch pumps

Loop Cross Reference Check

• Check that components that have cross loop reference tags have connections assigned to other loops

Class/Type/Sub Type Check

• Check that the class, type and sub type combinations are valid

Water Loop Controls

Water Temperature Setpoint Controller

• Check that each heating and cooling coil in the water loop is connected to the water setpoint temperature controller
• Check that a temperature sensor is located at the outlet node of the last component on the supply side.
• Check that the temperature sensor is connected to the water temperature controller

Thermal Storage Control

• Check that thermal storage tank is connected to the thermal storage controller

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