ASHRAE Guideline 36 Advanced HVAC Control Sequences

ASHRAE Guideline 36 Advanced HVAC Control Sequences Rick Stehmeyer - Senior Engineer Matt Napolitan, P.E., CCP, CPMP, LEED AP BD+C - Principal Image Source: http://worldatdistance.com/2013/10/07/the-complete-noobs-guide-to-making-a-website//

Presentation Overview Guideline 36 is 176 pages. We will not cover EVERYTHING! GL 36 advocates for: Using technology, experience and science, even if it results in complexity, to reduce energy use. Using Closed Loop Controls Using the variable you are trying to control to inform your control system. Identifying potential problems before they become alarms.

Concepts in this Presentation Purpose and Scope of Guideline 36 Document Arrangement Zone Grouping and Control with Reheat Control Multizone AHU Mixing Box Control Closed Loop SAT Reset Using an Importance Multiplier and Heating and Cooling Requests SAT Trim and Respond Controls Network Architecture Smart Alarming FDD

4 Current State of Affairs

Efficiency Current State of Affairs 5 Equipment Life (Operational Hours)

6 Get outside the box. No really.

Current state of HVAC Design RAF EA RA N.C. VFD AI: RAT AO: ECON N.O. N.C. PF CC-1 SAF OA VFD AI: MAT DI: FRZ CHWS AI: SAT AO: HEAT CHWR N.O. AO: CHWV V-1 24 V-2 7

8 We ve always done it this way

9 The most dangerous phrase

BREAK THE CYCLE The same old thinking New thinking The same old results Different Results New Perspective 10

The 2030 Challenge We're a non-profit think tank transforming climate change problems into solutions through the design of the built environment

The 2030 Challenge

Energy Production in USA

Energy Production in USA 81% Net Carbon Emitters

Energy Consumption in USA

The AIA Is On Board

ASHRAE Is On Board

Guideline 36

20 Air side systems only

Guideline 36 Field Verified

Guideline 36 Verified on the West Coast

Guideline 36 In New England

Smart Application Minimal Additional Hardware

Guideline 36 Sequences are more complex and more involved than the status quo.

Document Arrangement Guideline 36 is a collection of sequences: Standardization is the goal Contains Definitions Point Layouts Sequences FDD

28 Guideline Overview and Systems

Designers and Implementers Working Together 29

30 PURPOSE!

31 Born out of research

32 Born out of research

33 Application

Starting Point AHU Zone Group Zones 34

35 Spaces? Zones?

36 Zone Control Characteristics

37 Zone Control Characteristics

38 Deviation from Status Quo

Simultaneous Heating and Cooling 39

This is what we always do, it works! 40

Deviation from Status Quo Cooling Set Point Deadband Room Temperature Deadband Heating Set Point Cooling Demand Heating Demand 41

42 Another Deviation from Status Quo

Grouping AHU Zone Group Zones 43

Grouping Zone Group 2 (Offices) Zone Group 1 (Processing) 44

with Reheat We are covering this because it is the most common piece of equipment The Guideline: Links the sequence to the Zone definition and zone Group definition Provides point layout

46 s!

47 s Covered

48 with Reheat

49 Important Inputs / Outputs

50 Here is why

51 Now in Color!

52 MAX Discharge ASHRAE 62.1

Logic is the beginning, not the end, of Wisdom. - Spock Room Temp Cooling Setpoint PID 0-100% Temp Demand Signal Damper Actuator Mr. Scott we need more power! Room Temp Heating Setpoint PID 0-50% Temp Demand Signal Heating Valve Damper Actuator 53

Grouping AHU Zone Group Zones 54

Multizone AHU Mixing Box Control The guideline provides some key differences that are important to know about. We will be covering mixing box control and supply air control There are other new control strategies that the guideline implements for multizone AHU s that we will not be covering today.

56 Mulitzone AHUs

57 Mulitzone AHUs

Deviation from Status Quo Individual Analog Outputs for each actuator on the economizer dampers! 58

Status Quo Mixing Box Control AHU SAT AHU SAT Set Point PID 0-100% Temp Demand Signal 25% Demand EAD 25% Open RAD 75% Open OAD 25% Open

Damper Position % Open Mixing Box Control Traditional 100 % RAD OAD EAD OA Minimum 0% 0% Supply Air Control Loop signal 100 %

GL36 Mixing Box Control AHU SAT AHU SAT Set Point PID 0-100% Temp Demand Signal 25% Demand EAD 100% Open RAD 100% Open OAD 25% Open

62 New Mixing Box Control

63 Mixing Box Control with AFMS

RP-1455 Supporting Data Source: 4/19/2016 Seminar at PEC 64

Example S.Q. Mixing box PID 0-100% 0% Temp Demand Signal 20% Open Return Fan EA 80% Open CC-1 Supply Fan OA 20% Open 65

Example S.Q. Mixing box PID 0-100% 60% Temp Demand Signal 60% Open Return Fan EA OA 40% Open 60% Open CC-1 Supply Fan Call for Cooling Drop in SAT 66

Example GL36 Mixing box PID 0-100% 60% Temp Demand Signal 100% Open Return Fan EA OA 80% Open 100% Open CC-1 Supply Fan Call for Cooling Drop in SAT 67

68 GL36 Building Pressure Control

69 No Building pressure Control?

Guideline 36 vs Status Quo Mixing Box Control Status Quo Dependent Damper Control

Multizone AHU Supply Air Control How is GL 36 Different? We just saw changes in mixing box control The GL uses space demand to inform the AHU supply air temp. Not OAT. Space demand is weighted to better reflect the demand's potential impact on the system.

OAT Guideline 36 vs Status Quo SAT Control Status Quo OAT Reset (Maybe) 70 F 35 F 55 F 75 F Air Handler Discharge Air Set Point

Guideline 36 vs Status Quo SAT Control Status Quo OAT Reset (Maybe)

Guideline 36 vs Status Quo

Guideline 36 vs Status Quo SAT Control Status Quo

Guideline 36 vs Status Quo SAT Control GL 36

Open vs Closed Loop Control This is a key concept to bringing modern day control to life Being able to identify open / closed loop control is essential to understanding why they implemented some of these sequences Lets talk about it in terms of Supply air temperature reset

Status Quo Open Loop SAT Reset OAT AHU SAT SPACE TEMP

Open Loop No Feedback OAT AHU SAT SPACE TEMP TRYING TO CONTROL THIS

Open Loop No Feedback OAT AHU SAT SPACE TEMP BY RELYING ON THIS INPUT TRYING TO CONTROL THIS

Open Loop No Feedback OAT AHU SAT SPACE TEMP THE LOOP IS OPEN (BROKEN) BY RELYING ON THIS INPUT TRYING TO CONTROL THIS

Open Loop at Home Clothes Dryer is Open Loop Heat Setting plus Timer = Hopefully Dry

Closed Loop at Home Refrigerator is Closed Loop Too Warm Inside, Turn on the Compressor

Status Quo Open Loop SAT Reset OAT Determines SAT OAT AHU SAT SPACE TEMP

How to Close the Loop OAT AHU SAT SPACE TEMP

Guideline 36 Closed Loop SAT Reset SAT Control GL 36 Heating / Cooling Requests Closed Loop AHU SAT SPACE TEMP

Importance Multiplier SAT Control GL 36 Heating / Cooling Requests Closed Loop SPACE DMD SPACE DMD AHU SAT SPACE DMD SPACE DMD

Importance Multiplier SAT Control GL 36 Weighted Heating / Cooling Requests Closed Loop SPACE DMD! X AHU SAT SPACE DMD SPACE DMD! X! X SPACE DMD! X Importance Multiplier

Guideline 36 vs Status Quo SAT Control GL 36 Weighted Heating / Cooling Requests Closed Loop SPACE DMD! X AHU SAT SPACE DMD SPACE DMD! X! X SPACE DMD! X Importance Multiplier

Guideline 36 vs Status Quo SAT Control Status Quo 1) Supply air temperature will be reset proportionally based on the outside air temperature per the following schedule: OAT SAT 35 75 70 55

Guideline 36 vs Status Quo SAT Control GL 36 Importance Multiplier Example 1) Supply air temperature will be reset using a weighted heating and cooling request and response. A PID will handle the response portion to the summed heating and cooling requests where: 1) Heating and cooling requests cancel each other out. 2) The heating/cooling request value is calculated as the difference between room and overage of the current heating or cooling set point as seen in Figure 3 - Heating Cooling Request Graph (Zone level Logic). A pseudo logical block diagram of this can be found in ATC 1.11. 3) The request value is multiplied by the design CFM of the box. This multiplication is called an importance multiplier and will be referenced in other sequences. 4) The result of the multiplied value is then summed with all the other requests from all the other s. 5) The result of that summation is then divided by the discharge total CFM provided by the AHU. 6) The result of the division is then used as the input of a PID with a fixed set point of zero. This result may be multiplied by 10 or 100 if required by the specific PID being used. The PID shall be configured in such a way that the loop will output 50% when its input is equal to set point (or PID Bias will equal 50%). 7) The result of the PID is then used as the input of a linear reset. This reset shall use the PIDs output range (0-100) to reset the supply air temperature set point between SAT-min and SAT-max. 8) The calculated supply air temperature set point shall be able to be overridden at the user interface.

Importance Multiplier in Action SPACE DMD! X SPACE DMD SPACE DMD! X! X SPACE DMD! X Importance Multiplier

Importance Multiplier in Action 2.0 0.0 3.0 1.0 Space Demand 4 1 10 3 Importance Multiplier 8.0 0.0 3.0 3.0

Importance Multiplier in Action 2.0 0.0 3.0 1.0 Space Demand 4 1 10 3 Importance Multiplier 8.0 0.0 3.0 3.0 14.0 Demand Sent to AHU

Importance Multiplier in Action One Step Further Include CFM 2.0 4 600 2400 0.0 10 200 0 3.0 1 2100 2100 1.0 3 250 750 Space Demand Importance Multiplier Space Design CFM

Importance Multiplier in Action One Step Further Include CFM Space Design CFM 2.0 4 600 2400 0.0 10 200 0 3.0 1 2100 2100 1.0 3 250 750 Space Demand Importance Multiplier 3150 5250

Importance Multiplier in Action One Step Further Include CFM Space Design CFM 2.0 4 600 2400 0.0 10 200 0 3.0 1 2100 2100 1.0 3 250 750 Space Demand Importance Multiplier 3150 5250 5250 3150 1.7 Demand Sent to AHU

Importance Multiplier Quick Review GL 36 uses an integer importance multiplier. Requires user / designer input Allows for future modification Can default to 1 for all zones at turnover We suggest including the zone design CFM. Implementer has this information readily available Direct reflection of zone s potential demand on AHU

First the Zones AHU SAT SPACE TEMP

Now the AHU AHU SAT SPACE TEMP

Trim and Respond

Trim LOWER STATIC SETPOINT FAN SPEED DROPS CFM DROPs WAIT X MINUTES

Trim LOWER STATIC SETPOINT FAN SPEED DROPS CFM DROPs Damper Opens

Trim Requests more static LOWER STATIC SETPOINT FAN SPEED DROPS CFM DROPs WAIT X MINUTES

and Respond Requests more static Requests more static

Respond INCREASE STATIC SETPOINT FAN SPEED RAISES CFM INCREASES WAIT X MINUTES

Trim and Respond

From the Horse s Mouth

Guideline 36 vs Status Quo Trim and Respond Lot s O Variables

Network Traffic Guideline 36 is a collection of sequences, and doesn t give much guidance in terms of the controls network All these new sequences create more dependency on a fully networked control system Therefore, it s important to discuss the network architecture when talking about implementing the guideline.

Controls Network Architecture 115

Controls Network Architecture LAN / Internet / Cloud SERVER PC GLOBAL AHU-1 EXH. FAN AHU-2 116

Controls Network Architecture Enterprise / Campus Level Building Level Equipment Level Zone Level SERVER PC GLOBAL AHU-1 AHU-2 EXH. FAN 117

Controls Network Architecture Enterprise / Campus Level SERVER PC GLOBAL Has Ethernet Has RS-485 Building Level AHU-1 Has Ethernet, Has Modbus, Attached to meters AHU-2 Equipment Level Zone Level EXH. FAN End Device Sensor Actuator Relay Lights 118

119 Controls Network Architecture

120 Controls Network Architecture

121 Controls Network Architecture

122 Controls Network Architecture

123 Controls Network Architecture

Controls Network Architecture LAN / Internet / Cloud SERVER PC GLOBAL AHU-1 EXH. FAN AHU-2 124

Controls Network Architecture LAN / Internet / Cloud SERVER PC AHU-1 GLOBAL EXH. FAN AHU-2 125

126 If it ain t broke

Why Is this important? LAN / Internet / Cloud SERVER PC GLOBAL AHU-1 EXH. FAN AHU-2 127

Why Is this important? LAN / Internet / Cloud SERVER PC GLOBAL AHU-1 EXH. FAN AHU-2 128

Why Is this important? LAN / Internet / Cloud SERVER PC GLOBAL AHU-1 EXH. FAN AHU-2 129

Controls Network Architecture LAN / Internet / Cloud SERVER PC AHU-1 GLOBAL EXH. FAN AHU-2 130

Controls Network Architecture LAN / Internet / Cloud SERVER PC AHU-1 GLOBAL EXH. FAN AHU-2 131

132 You can no longer not know that

Network Architecture Quick Review GL 36 sequences require more network traffic that usual ASHRAE GL 13 architecture limits failure impact Easy to implement, requires planning Collaborate with your implementer (this may be new to them). Yes Traffic is increased, however, not beyond the capacity of a modern day control system using a industry standard open communications protocol.

Efficient Alarming

Traditional Alarming Alarming Status Quo Alarm Everything AHU Chiller Pump AHU

How do we Prevent the Unnecessary Alarms?

Use a Hierarchy Alarming GL 36 Hierarchical Alarming There s always a bigger fish

Use a Hierarchy Alarming GL 36 Hierarchical Alarming Source Load

Remember This? AHU Chiller Pump AHU

Source Alarms Suppress Load Alarms Alarming GL 36 Hierarchical Alarming AHU Chiller Pump AHU

Smart Alarming Quick Review Guideline 36 provides a source / load alarm relationship Creates significantly fewer alarms in the system Makes the system more time efficient from a troubleshooting perspective Aims at using a bit more logic to inhibit alarms intelligently No more boy cried wolf alarm logs

Fault Detection and Diagnostics

Fault Detection and Diagnostics Fault Detection and Diagnostics Defined in GL 36 as: Assessing equipment performance

Fault Detection and Diagnostics Fault Detection and Diagnostics Defined in GL 36 as: Assessing equipment performance By comparing BAS inputs and outputs

Fault Detection and Diagnostics Fault Detection and Diagnostics Defined in GL 36 as: Assessing equipment performance By comparing BAS inputs and outputs To potential fault conditions

Fault Detection and Diagnostics Fault Detection and Diagnostics A Binary Comparison PASS / FAIL

FDD Implementation Equipment Operating State (OS) Operating State Heating Valve Position Cooling Valve Position Outdoor Air Damper Position #1: Heating >0 =0 =MIN #2: Economizer Cooling, Modulating OA =0 =0 Min < X <100% #3: Mechanical + Economizer Cooling =0 >0 =100% #4: Mechanical Cooling + Min OA =0 >0 =MIN #5: Unknown or Dehumidification No other OS applies

FDD Implementation Variable Definition Variable Name Description Default Value ΔT SF Temperature rise across supply fan 2 F ΔT MIN Minimum difference between OAT and RAT to evaluate economizer error 5 F conditions θ SAT Temperature error threshold for SAT sensor 2 F θ RAT Temperature error threshold for RAT sensor 2 F θ MAT Temperature error threshold for MAT sensor 2 F θ OAT Temperature error threshold for OAT sensor 2 F θ F Airflow Error threshold 3% θ VFD SPD VFD Speed Error threshold 5% θ DSP Duct static pressure error threshold 0.2" ΔOS Max Mode Delay Maximum number of changes in Operating State Time in minutes to suspend fault condition evaluation after a change in operating state. 7 90 Alarm Delay Time in minutes that a fault condition must persist before triggering an alarm 60

FDD Implementation - AHU Example Supply Air Temperature Fault (operating state)

FDD Implementation - AHU Example Mixed Air Temperature Fault Equation MAT AVG - θ MAT > MAX [(RAT AVG - θ RAT ), (OAT AVG - θ OAT )] FC #3 Description MAT too high; should be between OAT and RAT RAT sensor error Possible MAT sensor error Diagnosis OAT sensor error Applies to: OS #1- #5

FDD Implementation - AHU Example Mixed Air Temperature Fault MAT AVG - θ MAT > MAX [(RAT AVG - θ RAT ), (OAT AVG - θ OAT )] Variable Name Example Value RAT AVG 68 F MAT AVG 52 F OAT AVG 28 F θ RAT 2 F θ MAT 1 F θ OAT 2 F

FDD Implementation - AHU Example Mixed Air Temperature Fault MAT AVG - θ MAT > MAX [(RAT AVG - θ RAT ), (OAT AVG - θ OAT )] Variable Name Example Value RAT AVG 68 F MAT AVG 52 F OAT AVG 28 F (52-1) > MAX [(68 2), (28-2)] θ RAT 2 F θ MAT 1 F θ OAT 2 F

FDD Implementation - AHU Example Mixed Air Temperature Fault MAT AVG - θ MAT > MAX [(RAT AVG - θ RAT ), (OAT AVG - θ OAT )] Variable Name Example Value RAT AVG 68 F MAT AVG 71 F OAT AVG 28 F θ RAT 2 F θ MAT 1 F θ OAT 2 F (71-1) > MAX[(68 2), (28-2)] Is (70) > (66)? YES, Fault (But no Alarm!)

FDD Implementation Using the Inputs Average Temperatures From the GL (and in your specs) The following values must be continuously calculated by the FDD routines for each AHU: There is a LONG list. This is just a small portion of it.

FDD Implementation Using the Inputs Average Temperatures From the GL (and in your specs) The following values must be continuously calculated by the FDD routines for each AHU: Five minute (default) rolling averages, one minute samples of the followings point values; operator shall have the ability to adjust the averaging window and sampling rate for each point independently SAT AVG = rolling average of supply air temperature MAT AVG = rolling average of mixed air temperature RAT AVG = rolling average of return air temperature OAT AVG = rolling average of outdoor air temperature DSP AVG = rolling average of duct static pressure

In conclusion

168 Questions?

Thank You for attending! Rick Stehmeyer - Senior Engineer Matt Napolitan - Principal