Select and add if your HVAC system has heating or cooling air handler equipment. Identify the appropriate Heating and Cooling equipment types present and complete the inputs below for air handlers. If an air handler is served by plant loops, then those should be created first.
Note: additional data inputs will be available if either of the ‘Advanced System Parameters’ or ‘Generate a verified Total HVAC System Performance Ratio’ boxes are checked in Settings.
Energy Asset Score Data Entry Options for Air Handlers
Name – Default component text and counters are automatically added. This entry may be edited to include other descriptive or identifying text.
System Type – Nine common types of HVAC systems are available to select when adding Air Handler Unit distribution equipment to a building. After making a selection, select the appropriate Heating and Cooling sources and distribution type of the system. Refer to the HVAC System Types section for a table of suggested configurations, and guidance regarding System Type selections, including Dedicated Outdoor Air Systems (DOAS).
Cooling Source – Pull-down menu selections of cooling equipment types:
No Cooling – If no mechanical cooling equipment is installed
Central DX – Packaged or Built-up systems using DX coils. Available selection for Packaged Rooftop Air Conditioner, Packaged Rooftop Heat Pump, Packaged Rooftop VAV with Hot-Water Reheat, Packaged Rooftop VAV with Electric Reheat, DOAS, or Other Systems.
Plant – Available selection for VAV with Hot-Water Reheat, VAV with Electric Reheat, DOAS or Other Systems. Select if a Plant was previously entered. The Plant Loop name and type (Chiller or District) will be available to select under the Plant Loop field.
Heating Source – Pull-down menu selections of heating equipment types:
No Heating – If no mechanical heating equipment is installed
Central Furnace – System where a furnace heats the air, and heated air is distributed through the building using ducts. Available selection for Packaged Rooftop Air Conditioner, VAV with Electric Reheat, Warm Air Furnace, DOAS, or Other Systems. Select "Single Zone" or "Multiple-Zone" for the Distribution Type.
Heat Pump – One or more factory-made assemblies that normally include an indoor conditioning coil, compressor(s), and an outdoor refrigerant-to-air coil or refrigerant-to-water heat exchanger. These units provide both heating and cooling functions. Available selection for Packaged Rooftop Heat Pump, DOAS, or Other Systems.
Plant – Available selection for VAV with Hot-Water or Electric Reheat, DOAS, or Other Systems. Select this type if a Plant was previously entered. The Plant Loop name and type (Boiler or District) will be available to select under the Plant Loop field.
DOAS Maximum SAT Setpoint – The maximum setpoint to which the DOAS cooling coil is controlled. This input is only displayed if a cooling coil is specified for a DOAS system. Values should be greater than or equal to 72 oF and less than 100 oF.
DOAS Minimum SAT Setpoint – The minimum setpoint to which the DOAS heating coil is controlled. This input is only displayed if a heating coil is specified for a DOAS system. Values should be less than or equal to 65 oF, and lower than or equal to the ERV Bypass Supply Air Temperature Setpoint.
Fuel Type – Menu item available if central furnace or heat pump selected as the heating type. Pull-down menu selections: Natural Gas (default for central furnaces; not available for heat pumps), Fuel Oil, Propane or Electricity (only option for heat pumps).
Condenser Type – Menu item available if heat pump is selected as the heating type. Pull-down menu selections: Air (default) or Water.
Equipment Details (a set of optional heating/cooling fields for further specifying equipment characteristics of DX units, furnaces or Heat Pumps).
Distribution
Distribution Type – Pull-down menu selections:
Single Zone – Select if the cooling source and heating source serves a single zone (controlled through a single thermostat). This is the default value for Central DX with Heat Pump.
Multiple Zone – Select if the cooling source and heating source serve multiple zones.
Terminal Unit – Menu item available if "multiple zone" is selected as a Distribution Type (except DOAS). Pull-down menu selections:
I don't know – If selected, the terminal unit will be set to reheat.
Reheat – Select if reheat coils are provided for each individually controlled zone, regulating the temperature of the air being furnished.
Parallel Powered Induction Units – Select if parallel powered induction units are installed and in use. These are air system terminal units that mix varying amounts of secondary (recirculated) air and primary (conditioned supply) air to produce a variable total flow of air to a zone.
Series Powered Induction Units – Select if series powered induction units are installed and in use. These are air system terminal units that mix varying amounts of secondary (re-circulated) air and primary (conditioned supply) air to produce a fixed flow of air to a zone.
Note: for additional information regarding VAV zone terminal unit types, including Powered Induction Units (PIU), see https://designbuilder.com//helpv2/Content/VAV_Terminal_Units.htm.
Reheat Source – Menu item available if 'multiple zone' is selected as a Distribution Type (except DOAS). Pull-down menu selections include I don't know, Gas Fired, Electric Resistance, and Hot Water Plant. See details:
I don't know – If selected, and if the 'Heating Source' selected is 'Plant', the default Reheat Source will be 'Hot Water Plant', with the selected Plant type; if the 'Heating Source' selected is 'Furnace' or 'no heating', the default Reheat Source will be 'Electric Resistance'.
Hot Water Plant – If selected, an additional pull down menu for Hot Water Plant will be presented. Select from any heating plants that have been created (either Boiler or District).
Minimum Air Flow Fraction – Menu item available if "multiple zone" is selected as a Distribution Type (except DOAS), and Reheat is selected as the Terminal Unit. Pull-down menu selections:
I don't know – If selected, the fraction will be set to 0.4 by default.
0.3 – Select if the minimum airflow rate of the terminal unit damper is set to 0.3. Energy savings can be realized by lowering the minimum airflow rate to a level that still provides adequate ventilation air for the occupants, but will result in reduced fan and reheat energy used by the system.
0.4 – Select if the minimum airflow rate of the terminal unit damper is set to 0.4.
Fan Systems
Fan motor efficiency – Motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor
Fan mechanical efficiency – Fan efficiency is the power delivered to the air divided by the shaft power (from EnergyPlus Input Output Reference).
Economizer – Check box: Should be checked if an economizer is installed and in use. Available input for all system types except Dedicated Outdoor Air Systems. An economizer helps to provide free cooling to a building by increasing the intake of outside air when conditions are amenable. The economizer may be operated based on either the dry bulb temperature or enthalpy of the outside air, and requires the appropriate sensors.
Demand Control Ventilation – Check box: Should be checked if a demand control ventilation control (DCV) system is installed and in use. A DCV system provides for the automatic reduction of outdoor air intake below design rates when the actual occupancy of spaces served by the system is less than design occupancy. This menu item is only available if the Distribution Type selected is 'Multiple Zone'.
Energy Recovery Ventilation – Check box: Should be checked if an energy recovery ventilation (ERV) system is installed and in use. Energy recovery ventilators, which transfer energy between the outgoing exhaust/relief and incoming outside air streams, can help reduce energy usage. These systems are more cost-effective in extreme climates, with hot, humid summer and/or cold winters. ERV is not available to select if Demand Control Ventilation has been selected. ERV is the only fan system option available for DOAS systems.
Fan Control – Pull-down menu selections:
I don't know – If selected, the fan control will be set to constant air volume by default.
Constant Air Volume – Select if the fan systems are supplying the same volume of air at all times, based on the HVAC system operation schedule. For systems with no heating and no cooling, and for DOAS system types, this will be the only available option.
Variable Air Volume – Select if the fan systems vary the air flow rate based on zone heating or cooling demand. This will be the only selection available if the Distribution Type selected is 'Multiple Zone'.
Supply Air Temperature (SAT) Reset – Pull-down menu item available if the Distribution Type selected is 'Multiple Zone'. Available input for all system types except Dedicated Outdoor Air Systems. The supply air temperature setpoint is typically reset based on either outside air temperature or an indication of zone demand. OAT (Outside Air Temperature) or Warmest Zone should be selected if systems include hardware to support controls that automatically reset the supply-air temperature in response to changes in building loads or outdoor air temperature. Select none if no SAT reset is applied.
Fan Static Pressure Reset – Check box: Menu item available if the Distribution Type selected is 'Multiple Zone'. Should be checked if systems with direct digital controls are installed and in use that can reset the static pressure setpoint based on zone cooling demand. Fans using these controls are able to deliver the same amount of air flow with lower power consumption.