3.0 add_variable_speed_rtu_control_logic 7d0aebdd-58c5-4e0e-9217-5dbdc82886fd ff8bf785-5192-403c-9d9c-d96985743183 20230602T151915Z A310923F AddVariableSpeedRTUControlLogic Add Variable Speed RTU Control Logic This measure adds control logic for a variable-speed RTU to the model. The control logic is responsible for staging the fan in response to the amount of heating/cooling required. It is meant to be paired specifically with the Create Variable Speed RTU OpenStudio measure. Users enter the fan flow rate fractions for up to nine different stages: ventilation, up to four cooling stages, and up to four heating stages. The measure examines the amount of heating/cooling required at each time step, identifies which heating/cooling stage is required to supply that amount of heating/cooling, and modifies the fan flow accordingly. This measure allows users to identify the impact of different fan flow control strategies. This measure inserts EMS code for each airloop found to contain an AirLoopHVAC:UnitarySystem object. It is meant to be paired specifically with the Create Variable Speed RTU OpenStudio measure. Users can select the fan mass flow fractions for up to nine stages (ventilation, two or four cooling, and two or four heating). The default control logic is as follows: When the unit is ventilating (heating and cooling coil energy is zero), the fan flow rate is set to 40% of nominal. When the unit is in heating (gas heating coil), the fan flow rate is set to 100% of nominal (not changeable). When the unit is in staged heating/cooling, as indicated by the current heating/cooling coil energy rate divided by the nominal heating/cooling coil size, the fan flow rate is set to either 50/100% (two-stage compressor), or 40/50/75/100% (four-stage compressor). When applied to staged coils, the measure assumes that all stages are of equal capacity. That is, for two-speed coils, that the compressors are split 50/50, and that in four-stage units, that each of the four compressors represents 25% of the total capacity. The measure is set up so that a separate block of EMS code is inserted for each applicable airloop (i.e., the EMS text is not hard-coded). vent_fan_speed Fan speed fraction during ventilation mode. Double false false 0.4 stage_one_cooling_fan_speed Fan speed fraction during stage one DX cooling. Double false false 0.4 stage_two_cooling_fan_speed Fan speed fraction during stage two DX cooling. Double false false 0.5 stage_three_cooling_fan_speed Fan speed fraction during stage three DX cooling. Not used for two-speed systems. Double false false 0.75 stage_four_cooling_fan_speed Fan speed fraction during stage four DX cooling. Not used for two-speed systems. Double false false 1 stage_one_heating_fan_speed Fan speed fraction during stage one DX heating. Double false false 0.4 stage_two_heating_fan_speed Fan speed fraction during stage two DX heating. Double false false 0.5 stage_three_heating_fan_speed Fan speed fraction during stage three DX heating. Not used for two-speed systems. Double false false 0.75 stage_four_heating_fan_speed Fan speed fraction during stage four DX heating. Not used for two-speed systems. Double false false 1 HVAC.HVAC Controls Measure Type EnergyPlusMeasure string Intended Software Tool OpenStudio Application string Intended Software Tool Parametric Analysis Tool string Intended Use Case Model Articulation string Intended Use Case New Construction EE string README.md.erb erb readmeerb 703C9964 README.md md readme 86416F37 LICENSE.md md license 0DDDFB54 add_variable_speed_rtu_control_logic_test.rb rb test 7BCFD2AF OpenStudio 1.12.2 1.12.2 measure.rb rb script DDAE53AF