ADASS Spring Seminar ADASS Spring Seminar 18 April 2013 2013 Title
Seminar Meeting 11/2013
description
Transcript of Seminar Meeting 11/2013
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?