3.0 create_variable_speed_rtu 7fb36b3a-5591-4627-a2b0-7709fbeae593 b4784727-b8f2-46e2-92ad-219ecd2e1c5a 20200229T024317Z A9D5932A CreateVariableSpeedRTU Create Variable Speed RTU This measure examines the existing HVAC system(s) present in the current OpenStudio model. If a constant-speed system is found, the user can opt to have the measure replace that system with a variable-speed RTU. 'Variable speed' in this case means that the compressor will be operated using either two or four stages (user's choice). The user can choose between using a gas heating coil, or a direct-expansion (DX) heating coil. Additionally, the user is able to enter the EER (cooling) and COP (heating) values for each DX stage. This measure allows users to easily identify the impact of improved part-load efficiency. This measure loops through the existing airloops, looking for loops that have a constant speed fan. (Note that if an object such as an AirloopHVAC:UnitarySystem is present in the model, that the measure will NOT identify that loop as either constant- or variable-speed, since the fan is located inside the UnitarySystem object.) The user can designate which constant-speed airloop they'd like to apply the measure to, or opt to apply the measure to all airloops. The measure then replaces the supply components on the airloop with an AirloopHVAC:UnitarySystem object. Any DX coils added to the UnitarySystem object are of the type CoilCoolingDXMultiSpeed / CoilHeatingDXMultiSpeed, with the number of stages set to either two or four, depending on user input. If the user opts for a gas furnace, an 80% efficient CoilHeatingGas object is added. Fan properties (pressure rise and total efficiency) are transferred automatically from the existing (but deleted) constant speed fan to the new variable-speed fan. Currently, this measure is only applicable to the Standalone Retail DOE Prototype building model, but it has been structured to facilitate expansion to other models with a minimum of effort. object Choose an Air Loop to change from CAV to VAV. Choice true false *All CAV Air Loops* {42167619-c2eb-4812-a9e5-9b286d7beef8} *All CAV Air Loops* cooling_coil_type Choose the type of cooling coil. Choice true false Two-Stage Compressor Two-Stage Compressor Two-Stage Compressor Four-Stage Compressor Four-Stage Compressor rated_cc_eer Rated Cooling Coil EER Double false false three_quarter_cc_eer Cooling Coil EER at 75% Capacity Double false false half_cc_eer Cooling Coil EER at 50% Capacity Double false false quarter_cc_eer Cooling Coil EER at 25% Capacity Double false false heating_coil_type Choose the type of heating coil. Choice true false Gas Heating Coil Gas Heating Coil Gas Heating Coil Heat Pump Heat Pump rated_hc_gas_efficiency Rated Gas Heating Coil Efficiency (0-1.00) Double false false rated_hc_cop Rated Heating Coil COP Double false false three_quarter_hc_cop Heating Coil COP at 75% Capacity Double false false half_hc_cop Heating Coil COP at 50% Capacity Double false false quarter_hc_cop Heating Coil COP at 25% Capacity Double false false HVAC.Whole System Measure Type ModelMeasure string Intended Software Tool Apply Measure Now 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 example_model.osm osm test 69467654 README.md md readme 839520ED README.md.erb erb readmeerb 703C9964 LICENSE.md md license E0468DD6 create_variable_speed_rtu_test.rb rb test B199E2FA OpenStudio 1.12.2 2.7.0 measure.rb rb script 13C7C1EA