ASHRAE Guideline 36 Dashboard

TRC's Research & Consulting group developed this dashboard under the California Electric IOU's-supported CalNEXT program. The dashboard calculates energy savings for ASHRAE Guideline 36 air-side measures applicable to multiple-zone VAV HVAC systems. This current version applies only to existing medium and large office buildings in California climate zones 3, 4, 9 and 12.

There are 4 mandatory inputs:

Monthly Electric Consumption

Monthly Gas Consumption

Climate Zone

Building Floor Area

There are 9 optional inputs:

Zone VAV Average Minimum Flow Fraction

Supply Air Temperature Control Type

Supply Air Temperature Setpoint

Fan Total Static Pressure

Fan Control Type

Economizer Control Type

Ventilation Rate

Building Operating Hours

Building Space Type

If the optional inputs are unknown, they are completed with default values. Entering these values results in more accurate energy savings estimates and a smaller uncertainty estimate.

For any questions or feedback please contact calnext_program@trccompanies.com.

Description of Inputs:

Mandatory inputs:

Monthly Electric Consumption: Enter 12 monthly values separated by commas.

Monthly Gas Consumption: Enter 12 monthly values separated by commas.

Climate Zone: Select California Climate Zone. Limited to zones 3, 4, 9 and 12.

Building Floor Area: Enter the building conditioned floor area in square feet.

Optional inputs:

Zone VAV Average Minimum Flow Fraction: Enter the average zone VAV box minimum flow fraction. This can be calculated by dividing the sum of the minimum airflow rate for all VAV boxes by the sum of the design cooling airflow for all VAV boxes. This input is restricted to up to 0.5.

Supply Air Temperature Control Strategy: Select AHU leaving air temperature control as Fixed (constantly maintained at Supply Air Temperature Setpoint) or Warmest (reset up to 5 F when all zones meet cooling setpoint at maximum flow).

Supply Air Temperature Setpoint: Enter the design minimum supply air temperature setpoint. This input is restricted to between 50 F and 55 F.

Fan Total Static Pressure: Enter The total static pressure (TSP) of supply and return fans (combined). Where multiple AHUs are present, an average TSP may be entered weighted by AHU design supply airflow. This input is restricted to between 1 in. w.c. and 9 in. w.c.

Fan Control Strategy: Select 'VAV with Fixed Static Pressure Setpoint' for fan VSDs controlled based on a fixed duct pressure setpoint. For systems with static pressure reset select 'VAV with Static Pressure Reset'

Economizer Control Strategy: Select economizer type. The options are 'None' or 'Fixed DB Limit'. Select 'None' if there is no economizer control sequence, and 'Fixed DB Limit' if economizer control is included. Fixed DB controls are modeled per ASHRAE Guideline 36 and to meet the requirements of Title 24 Part 6.

Ventilation Rate: Enter the building average ventilation rate, over all conditioned floor area. This input is restricted to between 0.1 cfm/sf and 0.25 cfm/sf.

Building Operating Hours: Enter the number of hours the HVAC systems operate on a typical business day. This input is restricted to between 10 and 14 hours.

Building Space Types: Enter the distribution of general office and high density spaces such as conference rooms.

General Office: Most AHUs serve only office spaces and conference rooms typically do not have separately controlled VAV boxes.

Office with Separately Zoned Conference/Meeting Rooms: Most AHUs serve at least one conference room with its own VAV box(es) and controls.

Office with large meeting rooms or assembly spaces: Over 25% of the building floor area is dedicated to meeting, conference and/or assembly spaces.

Measures: Select as many measures as are applicable. The results will show the combined effect of the selected measures, including interactive effects.

VAV Min/Dual Max Control: Implement minimum flow rates for each VAV box no greater than the flow required for adequate ventilation. Where needed, Dual Max Control will ensure heating loads are still met.

Economizer Control: Implement economizer controls per ASHRAE Guideline 36 and meeting the requirements of Title 24 Part 6.

Supply Temperature Reset: Implement supply temperature reset of 5 degrees F, based on the cooling demand of the warmest zone per ASHRAE Guideline 36.

Static Pressure Reset: Implement Supply Temperature Reset based on the control sequences outlined in ASHRAE Guideline 36.

This page was last modified on 11/27/2023.