Outputs and Analysis

OCHRE saves many time series outputs throughout the simulation. These time series outputs are used to calculate metrics that describe the simulation results. The set of time series outputs depends on the verbosity of the simulation, and the set of metrics depends on the metrics_verbosity. OCHRE also includes analysis and visualization modules for common methods.

Dwelling Time Series Outputs

OCHRE Name

OCHRE Units

Verbosity

Description

Total Electric Power (kW)

kW

1

Total dwelling real electric power

Total Electric Energy (kWh)

kWh

1

Total dwelling real electric energy for 1 time step

Total Gas Power (therms/hour)

therms/hour

1

Total dwelling gas power

Total Gas Energy (therms)

therms

1

Total dwelling gas energy consumption for 1 time step

Total Reactive Power (kVAR)

kVAR

1

Total dwelling reactive power

Total Reactive Energy (kVARh)

kVARh

1

Total dwelling reactive energy for 1 time step

Grid Voltage (-)

p.u.

5

Per-unit grid voltage

Equipment-specific Time Series Outputs

All Equipment

OCHRE Name

OCHRE Units

Verbosity

Description

<end use> Electric Power (kW)

kW

2

Real electric power of all equipment within the end use

<end use> Gas Power (therms/hour)

therms/hour

2

Gas power of all equipment within the end use

<end use> Reactive Power (kVAR)

kVAR

5

Reactive electric power of all equipment within the end use

<equipment> Mode

N/A

6

Current mode of equipment operation

<equipment> Electric Power (kW)

kW

6

Real electric power of the equipment (Lighting and Other equipment only)

<equipment> Gas Power (therms/hour)

therms/hour

6

Gas power of the equipment

<equipment> Reactive Power (kVAR)

kVAR

6

Reactive electric power of the equipment

HVAC Heating and Cooling

The following outputs are associated with the HVAC equipment.

OCHRE Name

OCHRE Units

Verbosity

Description

HVAC <Heating or Cooling> Delivered (W)

W

3

HVAC sensible heat gain delivered to indoor zone

HVAC <Heating or Cooling> Setpoint (C)

degC

6

HVAC temperature setpoint

HVAC <Heating or Cooling> Main Power (kW)

kW

6

HVAC electric or gas power excluding fan, peripherals, and backup element

HVAC <Heating or Cooling> ER Power (kW)

kW

6

HVAC backup element power (ASHPHeater only)

HVAC <Heating or Cooling> Fan Power (kW)

kW

6

HVAC fan and peripherals power

HVAC <Heating or Cooling> Latent Gains (W)

W

6

HVAC latent heat gain delivered to indoor zone

HVAC <Heating or Cooling> Capacity (W)

W

6

HVAC heat capacity of main unit

HVAC <Heating or Cooling> Max Capacity (W)

W

6

HVAC maximum heat capacity of main unit

HVAC <Heating or Cooling> COP (-)

unitless

6

HVAC coefficient of performance of main unit

HVAC <Heating or Cooling> SHR (-)

unitless

6

HVAC sensible heat ratio

HVAC <Heating or Cooling> Speed (-)

unitless

6

HVAC speed index. Fractions indicate the relative time in adjacent speeds

HVAC <Heating or Cooling> Duct Losses (W)

W

6

Heat gains to duct zone due to duct losses

The following outputs are associated with the Envelope model.

OCHRE Name

OCHRE Units

Verbosity

Description

Temperature - <zone> (C)

degC

1

Temperature of envelope zone

Unmet HVAC Load (C)

degC

1

Absolute difference between Indoor temperature and thermal comfort limit (positive if hot, negative if cold)

Occupancy (Persons)

Persons

4

Number of current occupants

Net Sensible Heat Gain - <zone> (W)

W

4

Net sensible heat injected into zone. Includes heat gains from infiltration, ventilation, radiation, HVAC, other equipment, and occupants

Window Transmitted Solar Gain (W)

W

4

Heat gains from solar transmitted through windows to Indoor zone

Infiltration Flow Rate - <zone> (m^3/s)

m^3/s

7

Infiltration flow rate between zone and outdoors

Forced Ventilation Flow Rate - Indoor (m^3/s)

m^3/s

7

Mecahnical ventilation flow rate

Natural Ventilation Flow Rate - Indoor (m^3/s)

m^3/s

7

Natural ventilation flow rate (open windows)

Infiltration Heat Gain - <zone> (W)

W

7

Infiltration heat gain into zone

Forced Ventilation Heat Gain - Indoor (W)

W

7

Heat gain from mechanical ventilation

Natural Ventilation Heat Gain - Indoor (W)

W

7

Heat gain from natural ventilation

Occupancy Heat Gain - Indoor (W)

W

7

Heat gain from occupancy

Internal Heat Gain - Indoor (W)

W

7

Heat gain from non-HVAC equipment

Radiation Heat Gain - Indoor (W)

W

7

Heat gain from radiation. Includes transmitted solar and internal radiation to zone

Net Latent Heat Gain - Indoor (W)

W

7

Net latent heat injected into zone. Includes heat gains from infiltration, ventilation, HVAC, other equipment, and occupants

Relative Humidity - Indoor (-)

unitless

7

Relative humidity of zone

Humidity Ratio - Indoor (-)

unitless

7

Humidity ratio of zone

Wet Bulb - Indoor (C)

W

7

Wet bulb temperature in zone

Air Density - Indoor (kg/m^3)

unitless

7

Air density of zone

<boundary name> Ext. Solar Gain (W)

W

8

Solar heat gain on external boundary surface

<boundary name> Ext. LWR Gain (W)

W

8

Long wave radiation heat gain on external boundary surface

<boundary name> Ext. Surface Temperature (C)

degC

8

External boundary surface temperature

<boundary name> Ext. Film Coefficient (m^2-K/W)

m^2-K/W

8

Film coefficient of external boundary surface

<boundary name> <zone> LWR Gain (W)

W

8

Long wave radiation heat gain on internal boundary surface

<boundary name> <zone> Surface Temperature (C)

C

8

Internal boundary surface temperature

<boundary name> <zone> Film Coefficient (m^2-K/W)

m^2-K/W

8

Film coefficient of internal boundary surface

Water Heating

The following outputs are associated with the Water Heater equipment.

OCHRE Name

OCHRE Units

Verbosity

Description

Water Heating Delivered (W)

W

3

Heat delivered by water heater to tank

Water Heating COP (-)

unitless

6

Water heater coefficient of performance

Water Heating Total Sensible Heat Gain (W)

W

6

Sensible heat gain from water tank to envelope zone

Water Heating Deadband Upper Limit (C)

C

6

Upper temperature limit for water heater deadband control

Water Heating Deadband Lower Limit (C)

C

6

Lower temperature limit for water heater deadband control

Water Heating Heat Pump Max Capacity (W)

W

6

Maximum capacity of HPWH heat pump element

Water Heating Heat Pump On Fraction (-)

unitless

6

Fraction of time HPWH heat pump element is on

Water Heating Heat Pump COP (-)

unitless

6

HPWH heat pump coefficient of performance

The following outputs are associated with the Water Tank model.

OCHRE Name

OCHRE Units

Verbosity

Description

Hot Water Delivered (L/min)

L/min

3

Hot water draw volumetric flow rate

Hot Water Delivered (W)

W

3

Hot water draw heat flow rate

Hot Water Unmet Demand (kW)

kW

3

Unmet hot water demand, based on flow rate and desired temperature

Hot Water Outlet Temperature (C)

degC

3

Hot water outlet temperature

Hot Water Heat Injected (W)

W

6

Water tank heat gains from water heater

Hot Water Heat Loss (W)

W

6

Water tank heat losses to envelope zone

Hot Water Average Temperature (C)

degC

6

Water tank average temperature

Hot Water Maximum Temperature (C)

degC

6

Water tank maximum temperature

Hot Water Minimum Temperature (C)

degC

6

Water tank minimum temperature

Hot Water Mains Temperature (C)

degC

6

Water mains temperature

Electric Vehicle

OCHRE Name

OCHRE Units

Verbosity

Description

EV SOC (-)

unitless

3

EV state of charge

EV Parked

N/A

3

True if EV is parked at home

EV Unmet Load (kW)

kW

3

Unmet EV demand, determined at parking End Time. Negative value

EV Start Time

N/A

6

If parked, time that EV arrived. If away, next time that EV will arrive

EV End Time

N/A

6

Next time that EV will depart

EV Remaining Charge Time (min)

minutes

7

Estimated time to fully charge, based on SOC and max charge rate

Solar PV

OCHRE Name

OCHRE Units

Verbosity

Description

PV P Setpoint (kW)

kW

6

PV real power setpoint

PV Q Setpoint (kW)

kVAR

6

PV reactive power setpoint

Battery

OCHRE Name

OCHRE Units

Verbosity

Description

Battery SOC (-)

unitless

3

Battery state of charge

Battery Setpoint (kW)

kW

6

Battery real power setpoint

Battery Efficiency (-)

unitless

6

Battery efficiency

Battery Energy to Discharge (kWh)

kWh

6

Estimated energy available for discharge, based on SOC and max discharge rate

Battery Nominal Capacity (kWh)

kWh

9

Nominal battery capacity, including degradation model

Battery Actual Capacity (kWh)

kWh

9

Actual battery capacity, including degradation and temperature models

Equivalent Battery Model

The following outputs are not reported at any verbosity, but they can be calculated using the Equipment.make_equivalent_battery_model function. Currently, this functions works for the following end uses:

  • HVAC Heating

  • HVAC Cooling

  • Water Heating

  • Battery

OCHRE Name

OCHRE Units

Verbosity

Description

<end use> EBM Energy (kWh)

kWh

N/A

Energy state of equivalent battery model (EBM)

<end use> EBM Min Energy (kWh)

kWh

N/A

Minimum energy constraint

<end use> EBM Max Energy (kWh)

kWh

N/A

Maximum energy constraint

<end use> EBM Max Power (kW)

kW

N/A

Maximum power constraint

<end use> EBM Efficiency (-)

unitless

N/A

Input/output power efficiency

<end use> EBM Baseline Power (kW)

kW

N/A

Power to maintain constant energy state

<end use> EBM Max Discharge Power (kW)

kW

N/A

Minimum power constraint (negative for discharge)

<end use> EBM Discharge Efficiency (-)

unitless

N/A

Input/output power efficiency while discharging

All Metrics

Metrics are calculated at the end of a simulation and summarize the results over the simulation period (generally a year in most use cases).

Metric

Minimum Metrics Verbosity

Description

Total Electric Energy (kWh)

1

Total dwelling real electric energy consumption

<end use> Electric Energy (kWh)

2

Real electric energy consumption of all equipment within the end use

<equipment name> Electric Energy (kWh)

5

Real electric energy consumption of the equipment

Total Reactive Energy (kVARh)

7

Total dwelling reactive electric energy consumption

<end use> Reactive Energy (kVARh)

7

Reactive electric energy consumption of all equipment within the end use

<equipment name> Reactive Energy (kVARh)

7

Reactive electric energy consumption of the equipment

Total Gas Energy (therms)

1

Total dwelling gas energy consumption

<end use> Gas Energy (therms)

2

Gas energy consumption of all equipment within the end use

<equipment name> Gas Energy (therms)

5

Gas energy consumption of the equipment

Average Temperature - <zone name> (C)

3

Average temperature of the zone

Unmet <Heating or Cooling> Load (C-hours)

4

Unmet HVAC load. Based on the difference between actual and desired temperature and the duration of the unmet load

Component Load - Internal Gains (kWh)

6

Total HVAC load (heating minus cooling) induced by internal gains

Component Load - Infiltration (kWh)

6

Total HVAC load (heating minus cooling) induced by infiltration

Component Load - Forced Ventilation (kWh)

6

Total HVAC load (heating minus cooling) induced by forced ventilation

Component Load - Natural Ventilation (kWh)

6

Total HVAC load (heating minus cooling) induced by natural ventilation

Component Load - Ducts, Heating (kWh)

6

Total HVAC heating load induced by duct losses

Component Load - Ducts, Cooling (kWh)

6

Total HVAC cooling load induced by duct losses

Average Electric Power (kW)

6

Average dwelling real electric power

Peak Electric Power (kW)

6

Peak dwelling real electric power, using simulation time resolution

Peak Electric Power - <time resolution> avg (kW)

6

Peak dwelling real electric power, using specified time resolution

Average HVAC <Heating or Cooling> Capacity (kW)

8

Average heating capacity of HVAC equipment

HVAC <Heating or Cooling> Main Energy (kWh)

5

Total electric or gas energy consumed by main HVAC element (excludes fan and other peripherals)

HVAC <Heating or Cooling> Fan Energy (kWh)

4

Total energy consumed by HVAC fan and other peripherals

Average HVAC <Heating or Cooling> COP (-)

4

Average coefficient of performance of HVAC equipment (excludes fan and other peripherals)

Average HVAC <Heating or Cooling> Duct Efficiency (-)

4

Average duct efficiency of HVAC equipment

Average HVAC Cooling SHR (-)

4

Average sensible heat ratio of HVAC cooling equipment

Std. Dev. Temperature - <zone name> (C)

8

Standard deviation of zone temperature

Average Relative Humidity - Indoor (-)

Average Relative Humidity of Indoor zone

Average Humidity Ratio - Indoor (-)

Average Humidity Ratio of Indoor zone

Total Hot Water Unmet Demand (kWh)

4

Unmet water heating load. Based on the difference between actual and desired temperature and the duration of the unmet load

Total Hot Water Delivered (gal/day)

4

Total volume of hot water delivered to water draws

Total Hot Water Delivered (kWh)

4

Total energy of hot water delivered to water draws

Total Water Heating Delivered (kWh)

4

Total energy of hot water delivered by the water heater

Average Water Heating COP (-)

4

Average coefficient of performance of water heater

Average Islanding Time (hours)

4

The average duration that the home could island using battery power given no changes in other equipment power

Battery Charging Energy (kWh)

4

Total real electric energy consumed by the battery during charging

Battery Discharging Energy (kWh)

4

Total real electric energy produced by the battery during discharging

Battery Round-trip Efficiency (-)

4

Average round-trip efficiency. Ignores differences between initial and final SOC

Gas Generator Efficiency (-)

4

Average efficiency of electricity outputs to gas inputs

Number of Outages

4

Total number of outages during simulation

Average Outage Duration (hours)

4

Average duration of outages during simulation

Longest Outage Duration (hours)

4

Duration of longest outage during simulation

<equipment name> Cycles

5

Number of cycles of the equipment (On/Off cycles only)

<equipment name> <mode name> Cycles

5

Number of cycles of the equipment with multiple modes

Data Analysis

The Analysis module has useful data analysis functions for OCHRE output data:

from ochre import Analysis

# load existing ochre simulation data
df, metrics, df_hourly = Analysis.load_ochre(folder)
# calculate metrics from a pandas DataFrame
metrics = Analysis.calculate_metrics(df)

Some analysis functions are useful for analyzing or combining results from multiple OCHRE simulations:

# Combine OCHRE metrics files from multiple simulations (in subfolders of path)
df_metrics = Analysis.combine_metrics_files(path=path)

# Combine 1 output column from multiple OCHRE simulations into a single DataFrame
results_files = Analysis.find_files_from_ending(path, 'ochre.csv')
df_powers = Analysis.combine_time_series_column('Total Electric Power (kW)', results_files)

Data Visualization

The CreateFigures module has useful visualization functions for OCHRE output data:

from ochre import Analysis, CreateFigures

df, metrics, df_hourly = Analysis.load_ochre(folder)
# Create standard HVAC output plots
CreateFigures.plot_hvac(df)
# Create stacked plot of power by end use
CreateFigures.plot_power_stack(df)

Many functions work on any generic pandas DataFrame with a DateTimeIndex.