seminar meeting 11/2013
DESCRIPTION
Seminar Meeting 11/2013. Christopher Price Component Level HVAC Control NIST Project. Overview. Motivation Background Cascaded Control Air Volume Systems Hydronic Radiators Future Work. Motivation. DMPC Control Project (NIST) Advanced control algorithms to generate system set points - PowerPoint PPT PresentationTRANSCRIPT
Seminar Meeting 11/2013
Christopher PriceComponent Level HVAC Control
NIST Project
Overview
• Motivation• Background• Cascaded Control• Air Volume Systems• Hydronic Radiators• Future Work
Motivation
• DMPC Control Project (NIST)–Advanced control algorithms to
generate system set points–Reduced energy consumption and
cost through improved efficiency–Full energy savings when
components have adequate tracking
Motivation
• Where I Fit
Background
• Vapor Compression Cycle
(2010) Eliot & Rasmussen: On Reducing Evaporator Superheat Nonlinearity
Background
• Expansion Valves
http://image.ec21.com/image/zjwanjie/OF0008152543_1/Sell_capillary_tube_with_nut.jpg
Capillary Tube
http://neilorme.com/pics/aev1.jpg
http://www.swtc.edu/Ag_Power/air_conditioning/lecture/expansion_valve.png
Automatic Expansion
ValveThermostatic
Expansion Valve
Background
• Hybrid Expansion Valve
(2009) Eliot & Rasmussen: Evaporator Superheat Regulation Via Emulation of Semi-Active Flow Control
Cascaded Control
• Block Diagram
Cascaded Control
Valve Position to Mass Flow
Mass Flow to Pressure
Mass Flow to
Superheat
(2009) Eliot & Rasmussen: Evaporator Superheat Regulation Via Emulation of Semi-Active Flow Control
Air Volume Systems
• Apply same control idea to air handlers
• Two main types:–Constant Volume Systems
• Flow rate constant, temperature varied
–Variable Air Volume Systems*• Varied flow rate, temperature
constant
VAV Systems
• Schematic
VAV Systems
• Damper Types
2009 ASHRAE Handbook FundamentalsArrow United Industries
Parallel Blade
Opposed Blade
Single Blade
VAV Systems
• Damper Characteristics
2009 ASHRAE Handbook Fundamentals
Parallel Blade
Opposed Blade
VAV Systems
• Traditional PID vs. Cascaded Control
VAV Systems
• Simulation Model
• Damper Model
(2010) Yamakawa: Compensation of Manual Reset for PID Controller
VAV Systems – Traditional PID Control
VAV Systems – Cascaded Control
PID Control Cascaded Control
Case MAE RMS Case MAE RMS
20% 0.4461 0.1239 Low Flow 0.743 0.263
35% 0.4274 0.1052 Mid Flow 0.351 0.097
50% 0.8246 0.2489 High Flow 0.268 0.047
80% 1.9682 0.5446
Hydronic Radiators
• Shown cascaded control works for refrigerant and air mediums
• Apply control design to water radiator systems
• Currently working on validating results from Tahersima 2013 paper
Hydronic Radiators
• Equations–Radiator:
–Room:
–Valve:
(2013) Tahersima: Analytical Solution for Stability-Performance Dilemma for Hydronic Radiators
Hydronic Radiators
• Motivation
(2013) Tahersima: Analytical Solution for Stability-Performance Dilemma for Hydronic Radiators
Future Work
• Study the effect of sampling rate on performance of cascaded loop
• Proper tuning of cascaded loop control• Application of cascaded control to
positive displacement components (fans/pumps)
• Alternate control structures (e.g. feed forward control)
Questions?