Tuesday, November 27, 2018

Revit Energy Settings - HVAC Systems Defined

When editing the Energy Settings dialog in Revit, one of the options is HVAC System, as shown in the image below.


Additionally...

For those in the know, the descriptions provided are enough to discern between the options. For others, this is not enough... thus, Autodesk provides a detailed breakdown of what is included in each system and assumptions made. This, in turn, is what becomes the BIM Setting when the Revit-generated energy model is pushed out to Autodesk Insight for dynamic energy analysis - see image below.


Of course, it is a little confusing that the named HVAC Systems in Insight do not match the Revit options. But, you can tell what you selected by the BIM Setting label and then easily compare that option to those adjacent... knowing lower is better.

But, be careful not to get too focused on the details of the system i.e. the purpose of that range of systems is not to show that range of systems but the range of systems. It’s about the shape and slope of that curve, not the points on it. So instead of thinking about the actual points, what this factor shows is the overall impact HVAC system efficiency has on Energy from low, medium and high efficiency – how that’s achieved is up the mechanical engineer and more detailed system analysis.

If the detailed descriptions are still not enough, then consider sitting down with a mechanical engineer and note the various project types and efficiencies each option may be suited for.

The list below comes from this Revit help document: HVAC Systems

2-Pipe Fan Coil System, Chiller 5.96 COP, Boilers 84.5 eff

  • Water cooled centrifugal chiller (COP 5.96)
  • Open, atmospheric pressure cooling tower with variable speed fan and 5-degree Fahrenheit (2.8 degree Celsius) approach
  • Forward curved constant volume fan and premium efficiency motor
  • 0.25 inch of water gauge (62.3 pascals) static pressure Constant Volume duct system
  • Gas-fired hot water boiler with draft fan >2500 kBtuh, 84.5% combustion efficiency
  • Variable volume hot water pump
  • Hot water coil
  • Variable volume chilled water pump
  • Chilled water coil
  • Variable volume condenser water pump
  • Domestic hot water unit (0.575 Energy Factor)

4-Pipe Fan Coil System, Chiller 5.96 COP, Boilers 84.5 eff

  • Water cooled centrifugal chiller (COP 5.96)
  • Open, atmospheric pressure cooling tower with variable speed fan and 5-degree Fahrenheit (2.8-degree Celsius) approach
  • Forward curved constant volume fan and premium efficiency motor
  • 0.25 inch of water gauge (62.3 pascals) static pressure Constant Volume duct system
  • Gas-fired hot water boiler with draft fan >2500 kBtuh, 84.5% combustion efficiency
  • Variable volume hot water pump
  • Hot water coil
  • Variable volume chilled water pump
  • Chilled water coil
  • Variable volume condenser water pump
  • Domestic hot water unit (0.575 Energy Factor)

11 EER Packaged VAV, 84.5% boiler heating

  • Efficient 11 EER, >20-ton Packaged Variable Air Volume (VAV) Unit, Water Reheat, with Variable Speed Drive (VSD)
  • Forward curved fan with VSD and premium efficiency motor
  • 3.5 inch of water gauge (871.8 pascals) static pressure VAV duct system
  • Integrated differential dry-bulb temperature economizer
  • Gas-fired hot water boiler with draft fan >2500 kBtuh, 84.5% AFUE
  • Constant volume hot water pump
  • Hot water coil
  • Hot water reheat boxes
  • Domestic hot water unit (0.575 Energy Factor)

12 SEER/0.9 AFUE Split/Packaged Gas, 5-11 Ton

  • Efficient 12 SEER, 90% AFUE furnace split system with gas heat
  • Forward curved constant volume fan and premium efficiency motor
  • 2.0 inch of water gauge (498 pascals) static pressure Constant Volume duct system
  • Integrated differential dry-bulb temperature economizer
  • Domestic hot water unit (0.575 Energy Factor)

12 SEER/7.7 HSPF Split Packaged Heat Pump

  • Efficient 12 SEER/7.7 HSPF (Heating Seasonal Performance Factor) < 11.25-ton split/packaged heat pump system
  • Forward curved constant volume fan and premium efficiency motor
  • 2.0 inch of water gauge (498 pascals) static pressure Constant Volume duct system
  • Integrated differential dry-bulb temperature economizer
  • Domestic hot water unit (0.575 Energy Factor)

12 SEER/8.3 HSPF Packaged Terminal Heat Pump (PTHP)

  • 12 SEER/8.3 HSPF (Heating Seasonal Performance Factor) packaged terminal heat pump (PTHP)
  • Forward curved constant volume fan and premium efficiency motor
  • 0.25 inch of water gauge (62.3 pascals) static pressure Constant Volume duct system
  • Domestic hot water unit (0.575 Energy Factor)

Central VAV, Electric Resistance Heat, Chiller 5.96 COP

  • Water cooled centrifugal chiller (COP 5.96)
  • Open, atmospheric pressure cooling tower with variable speed fan and 5-degree Fahrenheit (2.8-degree Celsius) approach
  • Forward curved fan with Variable Speed Drive (VSD) and premium efficiency motor
  • 3.5 inch of water gauge (871.8 pascals) static pressure Variable Air Volume (VAV) duct system
  • Integrated differential dry-bulb temperature economizer
  • Resistance reheat boxes
  • Variable volume chilled water pump
  • Chilled water coil
  • Variable volume condenser water pump
  • Domestic hot water unit (0.575 Energy Factor)

Central VAV, HW Heat, Chiller 5.96 COP, Boilers 84.5 eff (default)

  • Water cooled centrifugal chiller (COP 5.96)
  • Open, atmospheric pressure cooling tower with variable speed fan and 5-degree Fahrenheit (2.8-degree Celsius) approach
  • Forward curved fan with Variable Speed Drive (VSD) and premium efficiency motor
  • 3.5 inch of water gauge (871.8 pascals) static pressure Variable Air Volume (VAV) duct system
  • Integrated differential dry-bulb temperature economizer
  • Gas-fired hot water boiler with draft fan >2500 kBtuh, 84.5% combustion efficiency
  • Variable volume hot water pump
  • Hot water coil
  • Hot water reheat boxes
  • Variable volume chilled water pump
  • Chilled water coil
  • Variable volume condenser water pump
  • Domestic hot water unit (0.575 Energy Factor)

Residential 14 SEER/0.9 AFUE Split/Packaged Gas <5.5 ton

  • Efficient 14 SEER/90% AFUE furnace <5.5-ton split/packaged system with gas heat
  • Residential constant volume cycling fan
  • 2.0 inch of water gauge (498 pascals) static pressure Constant Volume duct system
  • Domestic hot water unit (0.575 Energy Factor)

Residential 14 SEER/8.3 HSPF Split/Packaged Heat Pump

  • Efficient 14 SEER/8.3 HSPF (Heating Seasonal Performance Factor) <5.5-ton split/packaged heat pump system
  • Residential constant volume cycling fan
  • 2.0 inch of water gauge (498 pascals) static pressure Constant Volume duct system
  • Integrated differential dry-bulb temperature economizer
  • Domestic hot water unit (0.575 Energy Factor)

Residential 17 SEER/9.6 HSPF Split HP <5.5 ton

  • 17.4 SEER/9.6 HSPF <5.5-ton split/packaged air source heat pump, intermittent fan mode
  • Residential constant volume cycling fan
  • 2.0 inch of water gauge (498 pascals) static pressure Constant Volume duct system
  • Premium efficiency, on-demand tankless domestic hot water heater (0.85 Energy Factor)

Underflow Air Distribution

  • Packaged Variable Air Volume (PVAV) system with under floor air distribution
  • Forward curved fan with Variable Speed Drive (VSD) and premium efficiency motor
  • 3.5 inch of water gauge (871.8 pascals) static pressure VAV duct system
  • Gas-fired hot water boiler with draft fan >2500 kBtuh, 84.5% combustion efficiency
  • Integrated differential dry-bulb temperature economizer
  • Variable volume hot water pump
  • Hot water coil
  • Hot water reheat boxes
  • Improved efficiency domestic hot water heater (85% thermal efficiency)


Insight HVAC Systems Defined

Here are the definitions of the systems listed in Insight. Any of the options above can occupy the BIM space listed below (which would be selected in the Energy Settings dialog in Revit).

The list below comes from this Revit help document: HVAC Systems

ASHRAE Package System
  • ASHRAE 90.1-2010 minimum efficiency Packaged Single Zone System, 11 EER, 70F economizer
High Eff. Heat Pump
  • Heat Pump, 17.4 SEER, 9.6 HSPF, Electric Heat
ASHRAE Heat Pump
  • ASHRAE 90.1-2010 minimum efficiency Heat Pump, 9.5 EER, COP 3.2 Electric Heat, 70F economizer
High Eff. Package System
  • Packaged Single Zone System, small unit, 20 SEER 85% AFUE
ASHRAE VAV
  • ASHRAE 90.1-2010 minimum efficiency Variable Air Volume, COP 6.10 Chiller, Gas Boiler, 75F economizer
High Eff. VAV
  • VAV, Underfloor Air Distribution, COP7.5 Chiller, 95% Eff. Gas Boiler, economizer
ASHRAE Package Terminal Heat Pump
  • ASHRAE 90.1-2010 minimum efficiency Package Terminal Heat Pump 11.9 EER
High Eff. Package Terminal AC
  • Package Terminal Air Conditioner unit, 12.7 EER, 90.4% Gas Boiler
BIM
  • The setting in your model (Building Information Model)





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