simulate an energy mix with air to water hp (eir) and gas boiler ?

[alexandrecuer]

For example, air to water heat pump and gas boiler

[alexandrecuer]

First idea is to use parallel branches and Plantequipmentoperation but could not manage to make it work...

Each loop is only allowed to have one splitter and one mixer ? Do we have to understand half-loop ?

https://bigladdersoftware.com/epx/docs/24-1/engineering-reference/plant-condenser-loops.html#plantcondenser-supply-side

[alexandrecuer]

another option is to use ems and on/off supervisor field

• if outdoor temperature is above 0, heatpump is producing
• if outdoor temperature is under 0, gas_boiler is producing

building_name: batiment_600m2

verbose:

name: air2water_hp_35KW_w_gas_backup
suffix: single_loop

os_ep_path: "C:/openstudioapplication-1.8.0/EnergyPlus"

sensors:
  outdoor_air_temperature:
    type: "Site Outdoor Air Drybulb Temperature"
    controls: [hpatw_eir, gas_boiler]
    stop_below: 0        # bascule chaudière
    start_above: 2       # bascule PAC
    hp_on: 1
    hp_off: 0
    boiler_on: 1
    boiler_off: 0

zones:
  - "RDC"
  - "RPLUS1"

loops:
  - water_heating_loop

equipments:
  - hpatw_eir
  - inside_variable_pump
  - gas_boiler

water_heating_loop:
  setpoint: water_law_set_point
  operation: [hpatw_eir, gas_boiler]
  branches:
    plant: [inside_variable_pump, hpatw_eir, gas_boiler]

water_law_set_point:
  Setpoint_at_Outdoor_Low_Temperature: 70
  Outdoor_Low_Temperature: -5
  Setpoint_at_Outdoor_High_Temperature: 40
  Outdoor_High_Temperature: 15

hpatw_eir:
  force_side: Load_Side
  #Reference_Capacity : 35000
  cop: 3.2
  # x = water temp / y = air temp
  capacity_c: 0.794900878202383
  capacity_x: 0.00388524034840032
  capacity_x2: -0.0000575169230965453
  capacity_y: 0.0278109488428528
  capacity_y2: 0.000318168
  capacity_xy: -0.000130572089253355
  eir_c:  0.530730392560108
  eir_x: 0.00655164780603528
  eir_x2: 0.000263599226028026
  eir_y: -0.03620668194737
  eir_y2: 0.00126617163409192
  eir_xy: -0.000791224057761721

gas_boiler:
  force_side: Boiler_Water
  efficiency_c: 0.96
  efficiency_x: 0.04 # x=PLR
  efficiency_x2: -0.03
  efficiency_y: -0.004 # y=Twater
  efficiency_y2: -0.00004
  efficiency_xy: 0

but once the pac has to start, the demand blows up, so it seems that the solver does not converge

The order of equipments in the branch is probably incorrect

branches:
    plant: [inside_variable_pump, hpatw_eir, gas_boiler]

[alexandrecuer]

tested with the same yaml (without any sensor/ems control) with the order of equipments modified in the plant branch :

branches:
    plant: [inside_variable_pump, gas_boiler, hpatw_eir]

heatpump control_type on Load !!!

PlantEquipmentList

PlantEquipmentOperation:HeatingLoad

simulation output

[alexandrecuer]

it finally also works when gas_boiler is after the heat pump on the branch

the order is important when there is no real operation scheme, as in that case, energyplus chooses the most efficient equipement