All Collections
loadmodeling.tool
Air Systems
Zone Equipment Inputs
Zone Equipment Inputs

HVAC Equipment, PTAC, PTHP, FCU, RCP, ERV, Baseboard, Zone Equipment, HVAC Zone, Thermal Zone, components, Zone component

Patrick Chopson avatar
Written by Patrick Chopson
Updated over a week ago

Zone Equipment are local components within the Zone that provide heating, cooling, ventilation, or a combination of the three. Local Systems use only Zone Equipment as the components that make up the system. Each zone equipment receives its own copy of the Zone Equipment which will be individually sized for that Zone. For example, if a Fan Coil Unit is added to the system, each Zone will include sizing results for a FCU unique to that Zone.

Fan Coil Unit - Hydronic

Air Flow Sizing Parameters

  • Max Supply Air Flow Rate [CFM (IP) | L/S (SI)]: The maximum volumetric airflow rate through the fan coil unit. This is also the design, rated airflow rate of the unit. Defaults to Autosized.

  • Max Outdoor Air Flow Rate [CFM (IP) | L/S (SI)]: If the fan coil unit uses outdoor air, this field specifies the outdoor air volumetric flow rate. This flow rate should be less than or equal to the maximum airflow rate. A value of zero specifies no outdoor air. Defaults to Autosized.

  • Fan Total Efficiency %: This value is the overall efficiency of the fan, i.e., the ratio of the power delivered to the fluid (air), to the electrical input power. It is the product of the motor efficiency and the impeller efficiency.

  • Motor Efficiency %: The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor.

  • Pressure Rise [psi (IP) | Pa (SI)]: The pressure rise in Pascals at full flow and standard conditions.

  • Capacity Control Method: This input denotes how the unit’s output is controlled in order to meet zone heating or cooling requirement. Options are:

    • Constant Fan, Variable Coil - the fan speed is held constant to produce a fixed airflow rate whenever the unit is scheduled on, while the hot water or chilled flow rate is varied.

    • Cycling Fan - the fan speed is chosen so that the unit capacity is greater than or equal to the heating/cooling load and the fan is cycled to match unit output with the load.

    • Variable Fan, Variable Coil - both air and water flow rates are varied to match the load.

    • Variable Fan, Constant Coil - the water flow rate is at full flow and the fan speed varies to meet the load.

    • Multi-Speed Fan - the water flow rate is at full flow when there is load or fully closed when there is no load, and the supply airflow rate is varied by varying the fan speed in order to match the load

    • ASHRAE 90.1 Control - the fan air flow rate is reduced according to the low speed supply air flow ratio when the zone sensible load is less than the zone sensible load multiplied by the low speed supply air flow ratio

Cooling Coil Configuration

  • Design Fluid Flow [GPM (IP) | L/S (SI)]: The maximum possible water volume flow rate through the coil. Defaults to Autosized.

  • Design Airflow [CFM (IP) | L/S (SI)]: The maximum possible air volume flow rate across the coil. Defaults to Autosized.

  • Entering Air Dry Bulb and Wet Bulb [°F (IP) | °C (SI)]: The inlet air temperature for the design flow.

  • Leaving Air Dry Bulb and Wet Bulb [°F (IP) | °C (SI)]: The outlet air condition desired for design flow.

  • Entering Fluid Temp [°F (IP) | °C (SI)]: The inlet water temperature for the design flow.

  • Cooling Coil Source: Cooling Plant acts as the cooling source for the coil.

  • Coil Configuration: Options are:

    • Cross Flow

    • Counter Flow - Chilled water coils are generally built as counter-flow

Heating Coil Configuration

  • Design Entering Temp [°F (IP) | °C (SI)]: The inlet air temperature corresponding to the rated heating capacity.

  • Design Leaving Temp [°F (IP) | °C (SI)]: The outlet air temperature corresponding to the nominal heating capacity.

  • Entering Fluid Temp [°F (IP) | °C (SI)]: The inlet water temperature corresponding to the rated heating capacity.

  • Leaving Fluid Temp [°F (IP) | °C (SI)]: The outlet water temperature corresponding to the rated heating capacity.

  • Rated Capacity[Btu/h (IP) | Watts (SI)]: The heating capacity of the coil at the rated inlet and outlet air and water temperatures. The gross rated heating capacity does not account for the effect of supply air fan heat.

  • Heating Source: Heating Plant acts as the heating source for the coil.

  • Rated Ratio for Air and Water Convection: This is the ratio of convective heat transfers between the airside and waterside of the heating coil at the rated operating conditions.

Water to Air Heat Pump (WAHP)

Air Flow Sizing Parameters

  • Supply Air Flow Rate Cooling Operation [CFM (IP) | L/S (SI)]: The supply airflow rate leaving the heat pump when the DX cooling coil is operating. Defaults to Autosized.

  • Supply Air Flow Rate Heating Operation [CFM (IP) | L/S (SI)]: The supply airflow rate leaving the heat pump when the DX heating coil and/or supplemental heater are operating. Defaults to Autosized.

  • Supply Air Flow Rate No Load [CFM (IP) | L/S (SI)]: The supply airflow rate leaving the heat pump when neither cooling nor heating is required (i.e., DX coils and supplemental heater are off but the supply air fan operates). Defaults to Autosized.

  • Outdoor Air Flow Rate Cooling Operation [CFM (IP) | L/S (SI)]: The outdoor airflow rate through the heat pump when the DX cooling coil is operating. Defaults to Autosized.

  • Outdoor Air Flow Rate Heating Operation [CFM (IP) | L/S (SI)]: The outdoor airflow rate through the heat pump when the DX heating coil and/or supplemental heater are operating. Defaults to Autosized.

  • Outdoor Air Flow Rate No Load [CFM (IP) | L/S (SI)]: The outdoor airflow rate through the heat pump when neither cooling nor heating is required. Defaults to Autosized.

Heat Pump - Heating Configuration

  • Rated Air Flow Rate [CFM (IP) | L/S (SI)]: The rated volumetric airflow rate on the load side of the heat pump. Defaults to Autosized.

  • Rated Fluid Flow Rate [GPM (IP) | L/S (SI)]: This numeric field contains the rated volumetric water flow rate on the source side of the heat pump. Defaults to Autosized.

  • Rated Heating Capacity [Btu/h (IP) | Watts (SI)]: The gross heating capacity of the heat pump at the rated condition. Does not account for the effect of supply air fan heat. Defaults to Autosized.

  • Rated Heating COP: The gross rated heating coefficient of performance of the heat pump.

  • Heating Operation Heat Rejection Loop: Defaulted to Ideal Heat Loop.

  • Max Supply Air Temp from Supplemental Heater [°F (IP) | °C (SI)]: The maximum allowed supply air temperature exiting the heat pump supplemental heating coil.

  • Max Outdoor Temp for Supplemental Heater Operation Dry Bulb [°F (IP) | °C (SI)]: The outdoor air dry-bulb temperature above which the heat pump supplemental heating coil is disabled.

  • Electric Heat Efficiency: User-inputted efficiency and can account for any loss. In most cases for the electric coil, this will be 100%.

  • Nominal Capacity [Btu/h (IP) | Watts (SI)]: The maximum capacity of the supplemental electric heating coil.

Heat Pump - Cooling Configuration

  • Rated Air Flow Rate [CFM (IP) | L/S (SI)]: The rated volumetric airflow rate on the load side of the heat pump. Defaults to Autosized.

  • Rated Fluid Flow Rate [GPM (IP) | L/S (SI)]: This numeric field contains the rated volumetric water flow rate on the source side of the heat pump. Defaults to Autosized.

  • Rated Total Cooling Capacity [Btu/h (IP) | Watts (SI)]: The gross cooling capacity of the heat pump. Should be within 20% of Rated Heating Capacity. Does not account for the effect of supply air fan heat. Defaults to Autosized.

  • Rated Sensible Cooling Capacity [Btu/h (IP) | Watts (SI)]: The gross rated sensible capacity of the heat pump. Does not account for the effect of supply air fan heat. Defaults to Autosized.

  • Rated Cooling COP: The rated cooling coefficient of performance of the heat pump.

  • Cooling Operation Heat Rejection Loop: Defaulted to Ideal Cooling Loop.

Packaged Terminal Heat Pump (PTHP)

Air Flow Sizing Parameters

  • Supply Air Flow Rate Cooling Operation [CFM (IP) | L/S (SI)]: This numeric field defines the supply airflow rate leaving the heat pump when the DX cooling coil is operating. Defaults to Autosized.

  • Supply Air Flow Rate Heating Operation [CFM (IP) | L/S (SI)]: The supply airflow rate leaving the heat pump when the DX heating coil and/or supplemental heater are operating. Defaults to Autosized.

  • Supply Air Flow Rate No Load [CFM (IP) | L/S (SI)]: The supply airflow rate leaving the heat pump when neither cooling nor heating is required (i.e., DX coils and supplemental heater are off but the supply air fan operates). Defaults to Autosized.

  • Outdoor Air Flow Rate Cooling Operation [CFM (IP) | L/S (SI)]: The outdoor airflow rate through the heat pump when the DX cooling coil is operating. Defaults to Autosized.

  • Outdoor Air Flow Rate Heating Operation [CFM (IP) | L/S (SI)]: The outdoor airflow rate through the heat pump when the DX heating coil and/or supplemental heater are operating. Defaults to Autosized.

  • Outdoor Air Flow Rate No Load [CFM (IP) | L/S (SI)]: The outdoor airflow rate through the heat pump when neither cooling nor heating is required. Defaults to Autosized.

Operating Temperatures

  • Minimum Outdoor Temperature for Operation Dry Bulb [°F (IP) | °C (SI)]: The minimum outdoor temperature below which the cooling coil is disabled.

  • Maximum Supply Air Temperature from Supplemental Heater Dry Bulb [°F (IP) | °C (SI)]: The maximum allowed supply air temperature exiting the heat pump supplemental heating coil.

  • Maximum Outdoor Temperature for Supplemental Heater Dry Bulb [°F (IP) | °C (SI)]: The outdoor air dry-bulb temperature above which the heat pump supplemental heating coil is disabled.

Heat Pump Configuration

  • Total Heating Capacity [Btu/h (IP) | Watts (SI)]: The total, full load gross heating capacity of the DX coil unit at rated conditions. Defaults to Autosized.

  • Total Cooling Capacity [Btu/h (IP) | Watts (SI)]: The total, full load gross cooling capacity (sensible plus latent) of the DX coil unit at rated conditions. When used in a heat pump, the gross rated total cooling capacity should be within 20% of the gross rated heating capacity. Defaults to Autosized.

  • Rated Heating COP: The coefficient of performance of the DX heating coil unit at rated conditions.

  • Rated Cooling COP: The coefficient of performance of the DX cooling coil unit at rated conditions. The input power includes electric power for the compressor(s) and condenser fan(s) but does not include the power consumption of the supply air fan. The gross COP should NOT account for the supply air fan.

  • Rated Air Flow Rate [CFM (IP) | L/S (SI)]: The air volume flow rate across the DX cooling coil at rated conditions. Defaults to Autosized.

  • Rated Heating Flow Rate [CFM (IP) | L/S (SI)]: The volume air flow rate across the DX heating coil at rated conditions. Defaults to Autosized.

  • Rated Sensible Heat Ratio: The sensible heat ratio of the DX cooling coil at rated conditions, and a cooling coil airflow rate defined by field rated airflow rate. Both the sensible and total cooling capacities used to define the Rated SHR should be gross. The effect of supply air fan heat is NOT accounted for. Defaults to Autosized.

  • Minimum Outdoor Temp for Cooling Operation Dry Bulb [°F (IP) | °C (SI)]: The minimum outdoor temperature below which the cooling coil is disabled.

Packaged Terminal Air Conditioner (PTAC)

Air Flow Sizing Parameters

  • Supply Air Flow Rate Cooling Operation [CFM (IP) | L/S (SI)]: This numeric field defines the supply airflow rate leaving the heat pump when the DX cooling coil is operating. Defaults to Autosized.

  • Supply Air Flow Rate Heating Operation [CFM (IP) | L/S (SI)]: The supply airflow rate leaving the heat pump when the DX heating coil and/or supplemental heater are operating. Defaults to Autosized.

  • Supply Air Flow Rate No Load [CFM (IP) | L/S (SI)]: The supply airflow rate leaving the heat pump when neither cooling nor heating is required (i.e., DX coils and supplemental heater are off but the supply air fan operates). Defaults to Autosized.

  • Outdoor Air Flow Rate Cooling Operation [CFM (IP) | L/S (SI)]: The outdoor airflow rate through the heat pump when the DX cooling coil is operating. Defaults to Autosized.

  • Outdoor Air Flow Rate Heating Operation [CFM (IP) | L/S (SI)]: The outdoor airflow rate through the heat pump when the DX heating coil and/or supplemental heater are operating. Defaults to Autosized.

  • Outdoor Air Flow Rate No Load [CFM (IP) | L/S (SI)]: The outdoor airflow rate through the heat pump when neither cooling nor heating is required. Defaults to Autosized.

DX Cooling Configuration

  • Rated Total Cooling Capacity [Btu/h (IP) | Watts (SI)]: The total, full load gross cooling capacity (sensible plus latent) of the DX coil unit at rated conditions. When used in a heat pump, the gross rated total cooling capacity should be within 20% of the gross rated heating capacity. Defaults to Autosized.

  • Rated COP: The coefficient of performance of the DX cooling coil unit at rated conditions. The input power includes electric power for the compressor(s) and condenser fan(s) but does not include the power consumption of the supply air fan. The gross COP should NOT account for the supply air fan.

  • Rated Air Flow Rate [CFM (IP) | L/S (SI)]: The air volume flow rate across the DX cooling coil at rated conditions. Defaults to Autosized.

  • Rated Sensible Heat Ratio: The sensible heat ratio of the DX cooling coil at rated conditions, and a cooling coil airflow rate defined by field rated airflow rate. Both the sensible and total cooling capacities used to define the Rated SHR should be gross. The effect of supply air fan heat is NOT accounted for. Defaults to Autosized.

  • Minimum Outdoor Temp for Cooling Operation Dry Bulb [°F (IP) | °C (SI)]: The minimum outdoor temperature below which the cooling coil is disabled.

  • Performance Curve: This connects the DX cooling coil to it's corresponding performance curve, defined in performance curve page.

Electric Heat Configuration

  • Heating Capacity [Btu/h (IP) | Watts (SI)]: The heating capacity of the coil at the rated inlet and outlet air and water temperatures. The gross rated heating capacity does not account for the effect of supply air fan heat. Defaults to Autosized.

  • Efficiency: User-inputted efficiency and can account for any loss. In most cases for the electric coil, this will be 100%.

Energy Recovery Ventilator (ERV)

Air Flow Sizing Parameters

  • Supply Air Flow Rate [CFM (IP) | L/S (SI)]: The supply airflow rate through the ERV unit at standard temperature and pressure. Defaults to Autosized.

  • Supply Fan Pressure Rise [psi (IP) | Pa (SI)]: The pressure rise at full flow and standard conditions

  • Supply Fan Efficiency %: This value is the overall efficiency of the fan, i.e., the ratio of the power delivered to the fluid (air), to the electrical input power. It is the product of the motor efficiency and the impeller efficiency. The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor. The impeller efficiency is the power delivered to the fluid (air) divided by the shaft power.

  • Supply Fan Motor Efficiency: The shaft power divided by the electrical power consumed.

  • Supply Fan Motor in Airstream Fraction: The fraction of the motor heat that is added to the air stream. A value of 0 means that the motor is completely outside the air stream. A value of 1 means that all of the motor heat loss will go into the air stream and act to cause a temperature rise

  • Exhaust Air Flow Rate [CFM (IP) | L/S (SI)]: The exhaust air flow rate through the ERV unit in cubic meters per second at standard temperature and pressure. Defaults to Autosized.

  • Exhaust Fan Pressure Rise [psi (IP) | Pa (SI)]: The pressure rise at full flow and standard conditions

  • Exhaust Fan Total Efficiency: The shaft power divided by the electrical power consumed.

  • Exhaust Fan Motor Efficiency: The shaft power divided by the electrical power consumed.

  • Exhaust Fan Motor in Airstream Fraction: The fraction of the motor heat that is added to the air stream. A value of 0 means that the motor is completely outside the air stream. A value of 1 means that all of the motor heat loss will go into the air stream and act to cause a temperature rise

Energy Recovery Module
Performance of the energy recovery module is defined by specifying sensible and/or latent effectiveness at 75% and 100% of the nominal (rated) supply airflow rate at two operating conditions, as defined below:

  • Sensible Efficiency 100% Heating Air Flow: The sensible heat exchange effectiveness at the heating condition defined above with both the supply and exhaust air volume flow rates equal to 100% of the nominal supply airflow rate.

  • Latent Efficiency 100% Heating Air Flow: The latent heat exchange effectiveness at the heating condition defined above with both the supply and exhaust air volume flow rates equal to 100% of the nominal supply airflow rate. Specify this value as 0 if the heat exchanger does not transfer latent energy.

  • Sensible Efficiency 75% Heating Air Flow: The sensible heat exchange effectiveness at the heating condition defined above with both the supply and exhaust air volume flow rates equal to 75% of the nominal supply airflow rate.

  • Latent Efficiency 75% Heating Air Flow: The latent heat exchange effectiveness at the heating condition defined above with both the supply and exhaust air volume flow rates equal to 75% of the nominal supply airflow rate. Specify this value as 0 if the heat exchanger does not transfer latent energy.

  • Sensible Efficiency 100% Cooling Air Flow: The sensible heat exchange effectiveness at the cooling condition defined above with both the supply and exhaust air volume flow rates equal to 100% of the nominal supply airflow rate.

  • Latent Efficiency 100% Cooling Air Flow: The latent heat exchange effectiveness at the cooling condition defined above with both the supply and exhaust air volume flow rates equal to 100% of the nominal supply airflow rate. Specify this value as 0 if the heat exchanger does not transfer latent energy.

  • Sensible Efficiency 75% Cooling Air Flow: The sensible heat exchange effectiveness at the cooling condition defined above with both the supply and exhaust air volume flow rates equal to 75% of the nominal supply air flow rate.

  • Latent Efficiency 75% Cooling Air Flow: The latent heat exchange effectiveness at the cooling condition defined above with both the supply and exhaust air volume flow rates equal to 75% of the nominal supply airflow rate. Specify this value as 0 if the heat exchanger does not transfer latent energy.

Control Parameters

  • Supply Air Leaving Temperature Control: This input determines if the heat exchanger’s supply air outlet is controlled to a temperature setpoint when the heat exchanger is actively conditioning the supply air. Options are Yes or No.

  • Heat Exchanger Type: This input denotes the type of heat exchanger being simulated. Options are:

    • Plate - fixed plate

    • Rotary - rotating cylinder or wheel

  • Nominal Electric Power: The electric consumption rate of the unit. Electric power is considered constant whenever the unit operates. This numeric input can be used to model electric power consumption by controls (transformers, relays, etc.) and/or a motor for a rotary heat exchanger. None of this electric power contributes thermal load to the supply or exhaust air streams.

  • Frost Control Type: Options are:

    • None,

    • Exhaust Air Recirculation - dampers are used to direct exhaust air back into the zone through the supply side of the heat exchanger when the supply (outdoor) air inlet temperature falls below a threshold temperature

    • Exhaust Only - this control cycles off the supply air flow through the heat exchanger for a certain period of time while the exhaust air continues to flow through the exhaust side of the heat exchanger

    • Minimum Exhaust Temperature - the temperature of the exhaust air leaving the heat exchanger is monitored and the heat exchanger effectiveness is decreased to keep the exhaust air from falling below the threshold temperature

  • Threshold Temperature [°F (IP) | °C (SI)]: The dry-bulb temperature of air that is used to initiate frost control. Default is 0.

  • Temperature High Limit [°F (IP) | °C (SI)]: The outdoor air temperature high limit for economizer operation. If the outdoor air temperature is above this limit, the economizer operation is terminated. This input is optional.

  • Temperature Low Limit [°F (IP) | °C (SI)]: The outdoor air temperature low limit for economizer operation. If the outdoor air temperature is below this limit, the economizer operation is terminated. This input is optional.

  • Enthalpy High Limit [Btu/lb (IP) | J/kg (SI)]: The outdoor air enthalpy limit for economizer operation. If the outdoor air enthalpy is above this value, the economizer operation is terminated. This input is optional.

  • Dew Point Temp Limit [°F (IP) | °C (SI)]: The outdoor air dewpoint limit for economizer operation. If the outdoor air dewpoint temperature is above this value, the outdoor airflow rate will be set to the minimum. This input is optional.

  • High Humidity Control Flag: Options are Yes or No.

  • Control High Indoor Humidity Based on Outdoor Humidity Ratio: Options are Yes or No.

  • High Humidity Outdoor Air Flow Ratio: The ratio of the modified supply (outdoor) airflow rate to the supply airflow rate.

  • Exhaust Air Temperature Limit [°F (IP) | °C (SI)]: Establishes whether or not there is a limit control on the exhaust air temperature. Options are:

    • Exhaust Air Temperature Limit - the controller deactivates economizer mode whenever the outdoor air temperature is greater than the exhaust air temperature

    • No Exhaust Air Temperature Limit - no limit check on the exhaust air temperature is performed

  • Exhaust Air Enthalpy Limit [Btu/lb (IP) | J/kg (SI)]: Establishes whether or not there is a limit control on the exhaust air enthalpy. Options are:

    • Exhaust Air Enthalpy Limit - the controller deactivates economizer mode whenever the outdoor air temperature is greater than the exhaust air temperature

    • No Exhaust Air Enthalpy Limit - no limit check on the exhaust air enthalpy is performed

Radiant Cooling Panel

Equipment Parameters

  • Control Type: This field specifies two different types of control categories: temperature or zone load. Options are:

    • Mean Air Temperature

    • Mean Radiant Temperature

    • Operative Temperature - the average of Mean Air Temperature and Mean Radiant Temperature

    • Outdoor Dry Bulb Temperature

    • Outdoor Wet Bulb Temperature

    • Zone Convective Load - will come close to meeting the current setpoint temperature since the convective output of the unit will be set to match the remaining zone load. However, in the long run, this will likely overcool the space since radiant energy is being absorbed by surfaces and this will impact the zone conditions at later time steps.

    • Zone Total Load - will likely undercool the space in the short term since the total output of the unit will be set to meet the remaining zone load. However, this will not fully impact the zone air temperature immediately since some of the energy is being absorbed from surfaces rather than the zone air.

  • Fraction Radiant %: Characterizes the heat transfer at the surface of the panel as either purely radiative, purely convective, or some combination of radiant and convective. A value between 0.6 and 0.7 is a reasonable estimation.

  • Entering Fluid Temperature [°F (IP) | °C (SI)]: The inlet temperature to the panel under conditions used to rate the capacity of the panel

  • Space Temperature [°F (IP) | °C (SI)]: The inlet temperature to the panel under conditions used to rate the capacity of the panel

  • Cooling Design Capacity [Btu/h (IP) | Watts (SI)]: The cooling panel unit nominal cooling capacity at the rated flow rate of water through the unit.

  • Max Cooling Fluid Flow Rate [GPM (IP) | L/S (SI)]: The maximum chilled water volumetric flow rate.

  • Cooling Control Throttling Range [°F (IP) | °C (SI)]: The range of temperature over which the radiant cooling panel throttles from zero flow rate up to the maximum defined by the maximum chilled water flow rate.

  • Condensation Control Type: Options are:

    • Off - Nothing will happen when condensation is predicted to occur. The program will simply continue on; no moisture will be removed from the zone air and there will be no adjustment of the surface temperature as a result of the condensation.

    • Simple Off - the program will predict cases where condensation will occur and shut off the radiant system to avoid this situation.

    • VariableOff - the program will attempt to reduce the inlet temperature to the panel by locally recirculating some of the water leaving the panel and mixing it with water from the overall demand-side flow. This also means that some of the demand-side water will bypass the panel. In reality, this would require a pump to achieve such mixing and recirculation, but due to the simple nature of this model, no pump definition will be required. Like the SimpleOff option, the VariableOff option uses the condensation dewpoint offset parameter to adjust when the system will try to adjust for the possibility of condensation.

  • Condensation Control Dew Point Offset [°F (IP) | °C (SI)]: Establishes the difference between the calculated dew-point temperature of the space and the allowed inlet water temperature to the radiant cooling panel before the system shuts down. This optional parameter is only valid with the Simple Off and Variable Off condensation handling algorithm in the Condensation Control Type input.

  • Cooling Coil Source: Defaulted to Cooling Plant.

Baseboard Heater - Hydronic

Equipment Parameters

  • Heating Design Capacity Method: The method used to determine the heating design capacity for scalable sizing. Options are:

    • Heating Design Capacity - user specifies the magnitude of heating capacity or the program calculates the design heating capacity if autosize is specified

    • Fraction of Autosized Heating Capacity - the program calculates the design heating capacity from user-specified fraction and the auto-sized design heating capacity

  • Heating Design Capacity [Btu/h (IP) | Watts (SI)]: The radiant-convective water baseboard rated capacity at the rated water mass flow rate.

  • Fraction of Zone Heating Design Capacity: The heating capacity as a fraction of the autosized heating capacity of the radiant-convective water baseboard.

  • Fraction Radiant: specifies what fraction of the power input to the baseboard heater is actually transferred to the space as radiant heat

  • Rated Average Fluid Temperature [°F (IP) | °C (SI)]: The rated average water temperature for the baseboard heater.

  • Rated Fluid Mass Flow Rate [lb/s (IP) | kg/s (SI)]: The rated standard water flow rate through the baseboard heater.

  • Max Fluid Flow Rate [GPM (IP) | L/S (SI)]: The maximum water volumetric flow rate. Defaults to Autosized.

  • Heating Coil Source: Defaulted to Heating Plant.

Baseboard Heater - Electric

Equipment Parameters

  • Heating Design Capacity Method: The method used to determine the heating design capacity for scalable sizing. Options are:

    • Heating Design Capacity - user specifies the magnitude of heating capacity or the program calculates the design heating capacity if autosize is specified.

    • Fraction of Autosized Heating Capacity - the program calculates the design heating capacity from user-specified fraction and the auto-sized design heating capacity.

  • Heating Design Capacity [Btu/h (IP) | Watts (SI)]: The radiant-convective electric baseboard unit nominal heating capacity. Defaults to Autosized.

  • Zone Heating Design Capacity Fraction: The heating capacity as a fraction of the autosized heating capacity for radiant/convective electric baseboard.

  • Efficiency %: the overall electrical efficiency of the electric baseboard unit. The zone load met by this unit is divided by the electrical efficiency to obtain the total electric energy used.

  • Fraction Radiant: specifies what fraction of the power input to the baseboard heater is actually transferred to the space as radiant heat

Unit Heater - Electric

Airflow Parameters

  • Fan Control Type: Options are:

    • On Off - constant air volume fan that is intended to cycle on and off in tandem with a cooling or heating system

    • Continuous - constant air volume fan that is continuously on

  • Maximum Flow Rate [CFM (IP) | L/S (SI)]: The full load air volumetric flow rate at standard temperature and pressure. Defaults to Autosized.

  • Fan Total Efficiency %: The overall efficiency of the fan, i.e., the ratio of the power delivered to the fluid (air), to the electrical input power. It is the product of the motor efficiency and the impeller efficiency.

  • Motor Efficiency %: The shaft power divided by the electrical power consumed

Heating Coil Configuration

  • Rated Capacity [Btu/h (IP) | Watts (SI)]: The heating capacity of the coil at the rated inlet and outlet air temperatures. Does not account for the effect of supply air fan heat. Defaults to Autosized.

  • Design Entering Temp [°F (IP) | °C (SI)]: The inlet air temperature corresponding to the rated heating capacity.

  • Design Leaving Temp [°F (IP) | °C (SI)]: The outlet air temperature corresponding to the rated heating capacity.

  • Electric Heat Efficiency %: User-inputted efficiency and can account for any loss. In most cases for the electric coil, this will be 100%.

Unit Heater - Hydronic

Airflow Parameters

  • Fan Control Type: Options are:

    • On Off - constant air volume fan that is intended to cycle on and off in tandem with a cooling or heating system

    • Continuous - constant air volume fan that is continuously on

  • Maximum Flow Rate [CFM (IP) | L/S (SI)]: The full load air volumetric flow rate at standard temperature and pressure. Defaults to Autosized.

  • Fan Total Efficiency %: This value is the overall efficiency of the fan, i.e., the ratio of the power delivered to the fluid (air), to the electrical input power. It is the product of the motor efficiency and the impeller efficiency.

  • Motor Efficiency %: The shaft power divided by the electrical power consumed

Heating Coil Configuration

  • Heating Coil Source: Defaulted to Heating Plant

  • Rated Capacity [Btu/h (IP) | Watts (SI)]: The heating capacity of the coil at the rated inlet and outlet air and water temperatures. Does not account for the effect of supply air fan heat. Defaults to Autosize.

  • Design Entering Temp [°F (IP) | °C (SI)]: The inlet air temperature corresponding to the rated heating capacity.

  • Design Leaving Temp [°F (IP) | °C (SI)]: The outlet air temperature corresponding to the rated heating capacity.

  • Entering Fluid Temp [°F (IP) | °C (SI)]: The inlet water temperature corresponding to the rated heating capacity.

  • Leaving Fluid Temp [°F (IP) | °C (SI)]: The outlet water temperature corresponding to the rated heating capacity.

  • Rated Ratio for Air and Water Convection: This is the ratio of convective heat transfers between the airside and waterside of the heating coil at the rated operating conditions.

Variable Refrigerant Flow (VRF)

Airflow Parameters

  • Max Cooling Air Flow [CFM (IP) | L/S (SI)]: The full load air volume flow rate at standard temperature and pressure in cooling mode. Defaults to Autosized.

  • Min Cooling Air Flow [CFM (IP) | L/S (SI)]: minimum air volume flow rate at standard temperature and pressure in cooling mode. Defaults to Autosized.

  • Max Heating Air Flow [CFM (IP) | L/S (SI)]: The full load air volume flow rate at standard temperature and pressure in heating mode. Defaults to Autosized.

  • Min Heating Air Flow [CFM (IP) | L/S (SI)]: minimum air volume flow rate at standard temperature and pressure in heating mode. Defaults to Autosized.

  • Outdoor Air Flow Rate During Cooling Operation [CFM (IP) | L/S (SI)]: The outdoor airflow rate through the heat pump during cooling mode operation. Defaults to Autosized.

  • Outdoor Air Flow Rate During Heating Operation [CFM (IP) | L/S (SI)]: The outdoor airflow rate through the heat pump during heating mode operation. Defaults to Autosized.

  • Outdoor Air Flow Rate No Load [CFM (IP) | L/S (SI)]: The outdoor airflow rate when no cooling or heating is needed. Defaults to Autosized.

System Settings

  • Heating Capacity Sizing Ratio: The rated total heating capacity ratio. Defaults to 1.

  • Max Supply Air Temperature From Supplemental Heater [°F (IP) | °C (SI)]: Setpoint for electric supplemental heater. Defaults to Autosized.

  • Total Fan Efficiency %: This value is the overall efficiency of the fan, i.e., the ratio of the power delivered to the air, to the electrical input power. It is the product of the motor efficiency and the impeller efficiency. The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor.

  • Total Cooling Capacity [Btu/h (IP) | Watts (SI)]: The total, full load gross cooling capacity (sensible plus latent) of the VRF terminal at rated conditions. Defaults to Autosized.

  • Rated Sensible Heat Ratio: The sensible heat ratio of the VRF at rated conditions, and a cooling coil airflow rate defined by field rated airflow rate. Defaults to Autosized.

  • Rated Air Flow Rate Cooling [CFM (IP) | L/S (SI)]: The supply airflow rate leaving the VRF terminal during cooling operation . Defaults to Autosized.

  • Total Heating Capacity [Btu/h (IP) | Watts (SI)]: The total, full load gross heating capacity (sensible plus latent) of the VRF terminal at rated conditions. Defaults to Autosized.

  • Rated Air Flow Rate Heating [CFM (IP) | L/S (SI)]: The supply airflow rate leaving the VRF terminal during heating operation . Defaults to Autosized.

  • Pressure Rise [psi (IP) | Pa (SI)]: The pressure rise in Pascals at full flow and standard conditions.

  • Motor Air Stream Fraction: The fraction of the motor heat that is added to the air stream. A value of 0 means that the motor is completely outside the air stream. A value of 1 means that all of the motor heat loss will go into the air stream and act to cause a temperature rise

  • Max Flow Rate [CFM (IP) | L/S (SI)]: The full load air volumetric flow rate at standard temperature and pressure. Defaults to Autosized.

  • Motor Efficiency %: The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor.

  • Source: Defaults to VRF plant

Did this answer your question?