Energy Audit in Building A Regional Training Workshop 1 - 5 June, 2010

1. Control Concepts & BMS
Bassem El-Arabawy

2. Controls

3. Types of Controls
• Manual Controls
Switches
Dimmers
• Basic Automatic Controls (Open Loop)
Timers
Photo sensors
• Basic Automatic Controls (Closed Loop)
Thermostat
Humidistat
Dimmable ballast with photo sensor

4. • Programmable Controllers (Open loop or closed
loop)
Lighting timers (open loop)
Lighting controllers with sensors (closed loop)
Demand limiters (closed loop)
Temperature, pressure, level, flow, etc (all closed
loop)
• Energy Management Computer Control Systems
Level 1, Level 2, Level 3, Level 4

6. Basic Closed Loop Automatic Control
Systems (Feedback Control Systems)
1. Basic aspects of closed loop – or feedback control
systems – for maintaining a physical variable such
as temperature, pressure, humidity, flow, etc at a
specified value.
2. Elements of a closed loop feedback control system:
Sensors
Controllers
Actuators
Controlled devices

7. Block diagram, Closed loop
Controller Control device
Set
point Set point + Compn-
Actuator Valve Process
converter sation unit
_
Sensor

8. Diagram of a Feedback Control System
CONTROLLER
SET
POINT RC
CONTROLED
DEVICE
SENSOR
T
AIR FLOW
HEATING COIL

9. Control Modes
• Two position control system
• The system (e.g. a heater)
is either OFF or ON.
• Accomplished with a relay
whose contacts are either
open or closed, or a valve
whose stem position is
either open or closed.

10. Control Modes
• Proportional control system
• A variation from the set
point produces a
proportional movement in
the actuator.
• Pneumatic controls vary the
air pressure.
• Electric controls use a
potentiometer (a type of
variable resistor).

11. Control Technologies
• Pneumatic
• Electric
• Direct Digital Control

12. Pneumatic Controls
• Use compressed air to operate the control system.
• Require the use of very clean, dry and oil-free air.
• Have been used in many HVAC applications
Advantages
• Are well understood by designers and maintenance
people
• Are inherently proportional, inexpensive and very
reliable.

13. Pneumatic Controls
Disadvantages
• Not very precise.
• Required frequent calibration to achieve acceptable
accuracy.
• Pneumatic control algorithms are hard to change
e.g. changing a P loop to a PI loop.

14. Electric Controls
• Can be analog electric or electronic controls
• Use a variable, but continuous, electrical voltage or
current to operate the control system.
• Transmit signals quickly and accurately.

15. Advantages
• Can be very accurate and very stable.
• Do not require field calibration, and are drift-free, if
good quality sensors are used.
• Relatively easy to implement proportional plus
integral (PI) control electronically.
Disadvantages
• Often more expensive than pneumatic controls
• History of reliability problems.
• Difficult to easily interchange parts because of the
many different systems.

16. Direct Digital Controls
• Use electrical pulses to send signals.
• Interface directly with microprocessors and
microcomputers (PCs).

17. Advantages
• Extremely flexible because the control algorithms are
implemented in software instead of hardware.
Changes are made by keyboard entries, not by adding
or modifying hardware elements.
• Very precise; recalibration is not necessary.
• No controller drift.
• Costs have dropped dramatically for DDC
components in recent years.
• Analog sensors may still require periodic recalibration,
but early reliability problems have been cured.

18. Direct Digital Controls
Disadvantages
• Not well understood by many maintenance people
and facility managers.
• Different programming languages also a problem.
BACNET should help this concern.
• BACNET: Building Automation Central Control
System Network

19. Direct Digital Controllers Input/ Outputs
Digital Inputs Examples:-
Differential Pressure Switch is an example of Digital Input. Usually
installed across a fan or a filter. If the contact is closed the DDC
can detect either the fan is running or the filter is clogged.
Smoke Detector installed in the duct to allow the controller to
stop the Air Handling Unit in case of Fire.
Auxiliary contact from contactor to indicate if the contactor is
energized or NOT.

20. Direct Digital Controllers Input/ Outputs
Analog Inputs Example:-
Temperature Sensors/ Setpoint Modules for Rooms.
Temperature Sensors for Ducts.
Immersion temperature Sensors for water Pipes.
Humidity Transmitters for Rooms and Ducts.
Differential Pressure Transmitters for Clean
Rooms.

21. Direct Digital Controllers Input/ Outputs
Analog Output Examples:-
DDC produce a voltage signal ranged from 0 to 10 Volt. According
to the value the controlled device respond.
To Control the Fan Speed via inverter (Speed Drive).
To Modulate water Valve .
To Modulate Damper Motor and control Air Flow.

22. Direct Digital Controllers Input/ Outputs
Digital Output Examples:-
Digital output is a relay output controlled by DDC
To Energize contactor in the motor control center in order to start
Fan or Pump.
To Start a condensing unit when using DX Air
Handling Units.
To energize Heater Battery Stages via contactors

23. Glossary of Control Terminology

24. Glossary of Control Terminology
• Control Point– The actual value of the controlled
variable (e.g. temperature, pressure, flow, etc.).
• Dead-Band—The range over which the output of
the controller remains constant as the input varies,
with the output changing only in response to an
input outside the differential range.
• Direct Acting Controller—A controller for which an
increase in the level of the sensor signal
(temperature, pressure, etc.) results in an increase
in the level of the controller output.

25. Glossary of Control Terminology
• Equal Percentage Valve—A valve with a plug
shaped so the flow varies as the square root of the
lift.
• Gain—The gain of a controller is defined as the
ratio of the output of the controller to the input.
In a pneumatic temperature controller, for example,
the gain would be expressed as:
gain = Controller Output (kPa)
Throttling Range (degrees)

26. Glossary of Control Terminology
• Linear Percentage Valve—A valve which has a plug
shaped so that the flow varies directly with the lift.
• Modulating Controller—A type of controller for
which the output can vary infinitely over the range of
the controller.
• Offset—The difference between the set point and
the control point or the actual value of the controlled
variable.
This is sometimes called drift, deviation, or control
point shift.

27. Glossary of Control Terminology
• Set Point—The Value of the controlled variable that
is to be maintained.
• Throttling Range—The amount of change in the
controlled variable required to run the actuator of
the controlled device from one end of its stroke to
the other end.
If the actual value of the controlled variable lies
within the throttling range of the controller it is said
to be in control.
When it exceeds the throttling range it is said to be
out of control.

28. Control Algorithms
• Proportional Control (P)
With proportional control, the controller output
varies in proportion to the error.
The system output is: O = A + Kp × e
where Kp = Proportional Gain Constant

29. Control Algorithms
• Proportional Plus Integral Control (PI)
With proportional plus integral control, an integral
term is added to the output equation.
The system output is: O = A + Kp × e + Ki × ∫ edt
where Ki = Integral Gain Constant

30. Control Algorithms
• Proportional Plus Integral Plus Derivative Control
(PID)
With PID control, a derivative—or prediction—term
is added.
The system output is:
O = A + Kp × e + Ki × ∫ edt + Kd × de/dt
where Kd = Derivative Gain Constant

31. Energy Consumption (per Sector)
● Energy use split
37% 35% 10%
Industry Building Government
& shops
• Main energy consumption is for motors, cooling, lighting, electronics and
appliances

32. Solutions for Building and
Industry Sector
Enabling products Buildings & Industy
Renovation can yield up to
– Variable speed drives for HVAC, pumps, 30% of energy savings
fans, motors Building management Power factor
systems correction
– Power compensation and filtering products
– Dimmers, timers, movement and presence
detectors, switches.
– Thermostat for climate control
Management systems HVAC
control
Climate
control
Lighting
control
– Building management systems
– Power management systems

33. Energy Efficiency Improvement Steps
1 Measure
2 Fix the basics
3 Automate
4 Monitor and Improve

34. 1 Measure ●Energy meters
What we can not measure we can not control ●Power quality meters
2 Fix the basics
3 Automate
4 Monitor and Improve

35. 1 Measure
2 Fix the basics ●Power quality
●Insulation material
●Low consumption devices
●Power reliability
3 Automate
4 Monitor and Improve

36. P(kW)
ϕ P(kW)
Q(kvar)
S(KVA) S(kVA)
App.
power

37. 1 Measure
2 Fix the basics
3 Automate ●Variable speed derives
●Motor control systems
●Building Management Systems
4 Monitor and Improve

38. 1 Measure
4 Monitor and Improve ●Energy management software
●Remote monitoring systems
2 Fix the basics
3 Automate

39. Building Management Systems

40. Centralized System
HVAC
Car Park
Management
COMMON SITEWIDE NETWORK
Intruder
Energy
Detection
Metering
Fire Alarm Lighting Control CCTV Systems
Lift Monitoring
Access Control Systems Systems

41. ISO Standard Levels Model
Approved Standard System Control
BACnet/LonTalk Workstation,
Graphical User
Management Level Interface (GUI)
Main Plant, AHUs,
BACnet/LonTalk Chillers, Boilers
Automation Level
BACnet, Terminal Units,
LONTalk, EIB, VAVs, FCU’s
Field Level
Profibus etc.. Heat Pumps
(to be merged with Automation Level)

42. Distributed Energy Management System Architecture

43. Open Systems and multiple standards
Open protocols are the basis of open systems:

44. Energy Management System Functions
Monitoring/Surveillance
• Building conditions
• Equipment status
• Utility demand
• Climate data
• Fire and security

45. Energy Management System Functions
Control
• Schedule events
• Optimized start/stop
• Enthalpy optimization
• Boiler/chiller optimization
• Temperature setback/setup

46. Energy Management System Functions
Demand Limiting
• Load shedding
• Duty cycling
Maintenance
• Remote operation and control of equipment
• Generation of maintenance schedules
• Diagnosing breakdowns

47. Energy Management System Functions
Record Generation
• Trends and operation logs
• Utility demand profile
• Modification/replacement analysis
• Energy conservation documentation

48. Power Monitoring
Power Factor Demand
Consumption

49. Peak Demand shedding
How it contributes to Energy Efficiency?
Before After

50. Energy Centre
2 off 5MW CHP Engines
2 Dual Fuel Boilers
2 Heat Recovery Boilers
Plant Rooms
34 Air Handling Units
Chillers
LPHW systems
CWS Storage Tanks
Life Safety
Smoke Control
Sprinklers
Emergency Lighting Battery
Chargers
Fire Hydrant Systems
Terminal Services
Escalators / Auto walks
Lifts
Pump Stations *
Surface Water Drainage
Sewage Pump Stations
Fire Training Ground
Apron Services
Airbridge Alarms
FEGP
Substations
HV Switchgear Monitoring
Metering
Standby Generators
Access Control
200 Doors
Attendance monitoring

51. Sample of Building Management Graphical
Presentation
Air Handling Display

52. Chillier Plant Display

53. CHARTS

54. Alarm Logs

55. EMS Feature Descriptions
1. Scheduled Start/Stop—Starting and stopping
equipment based upon the time of day, and the day
of the week.
2. Optimum Start/Stop—Adjust equipment operating
schedule based upon space temperature, outside
air temperature, humidity, etc.
3. Duty Cycling—Shutting down equipment for
predetermined short periods of time during normal
operating hours.

56. EMS Feature Descriptions
4. Demand Limiting—Temporarily shedding electrical
loads to prevent exceeding a peak value.
5. Day/Night Setback—Lowering the space heating
setpoint or raising the space cooling setpoint during
unoccupied hours.
6. Outside Air Economizer—Brings in outside air when
the OA dry bulb temperature is less than the
required mixed air temperature for the building.
7. Enthalpy Economizer—Brings in outside air when
the OA enthalpy is less than that of the return air.

57. EMS Feature Descriptions
8. Warm Up/Cool Down Ventilation and Recirculation
—Controls operation of the OA dampers when the
introduction of OA would impose an additional
thermal load during warm-up or cool-down cycles
prior to occupancy of a building.

58. EMS Feature Descriptions
10. Steam Boiler Optimization—Implemented in heating
plants with multiple boilers. Boiler plant optimization
is accomplished through the selection of the most
efficient boiler to satisfy the space temperature
requirements during the building occupied period.
11. Reheat Coil Reset—Selects the zone/area with the
greatest need for reheat, and establishes the
minimum temperature of the heating hot water so
that is is just hot enough to meet the reheat needs
for that time period.

59. EMS Feature Descriptions
12. Hot Water Boiler Optimization—Same technique as
Steam Boiler Optimization.
13. Hot Water OA Reset—The heating hot water
temperature is reduced as the heating need for the
facility decreases.
14. Chiller Optimization—For facilities with multiple
chillers, the most efficient chiller or chillers are
selected to meet the existing load with minimum
demand and or energy.

60. EMS Feature Descriptions
15. Chiller Demand Limiting—The chiller electrical load
is reduced at certain times to meet a maximum pre-
specified chiller kW load.
16. Lighting Control—Turns lighting off and on
according to a pre-set time schedule.
• Remote Boiler Monitoring and Supervision—Uses
sensors at the boiler to provide inputs to the EMS
for automatic central reporting of alarms, critical
operating parameters, and remote shutdown of
boilers.

61. EMS Feature Descriptions
18. Maintenance Management—Provides a
maintenance schedule for utility plants, mechanical
and electrical equipment based on run time,
calendar time, or physical parameters.
19. Fire/Security Management Control—When allowed
by local building codes, these functions can be
combined with the Energy Management System
functions in a cost effective manner.

62. Building Management System
Direct Digital Controller Applications

63. Constant volume air handling unit with return fan,
heating and cooling coils and mixed air dampers.

64. Constant volume air handling unit with return fan,
heating and cooling coils and mixed air dampers.
Equipment List
Item QTY
Duct Temperature Sensor 4
Modulating Valves 2
DP Switch 3
Modulating Damper Actuators 3
Duct Smoke Detector 2
RH Transmitter 2
Direct Digital Controller with 7 DI, 2 DO, 6 1
AI, 5 AO
20% Extra points is recommended

65. Constant volume air handling unit with return
fan, heating and cooling coils and mixed air
dampers.
Control Sequence -1

66. Constant volume air handling unit with return fan, heating
and cooling coils and mixed air dampers.
Control Sequence -2

67. Constant volume air handling unit with return fan,
heating and cooling coils and mixed air dampers.
Control Sequence -3

68. Constant volume air handling unit with return fan,
heating and cooling coils and mixed air dampers.
Control Sequence -4

69. Monitors chiller loading and failure status to control a
lead and lag chiller system.

70. Monitors chiller loading and failure status to control a
lead and lag chiller system.
Equipment List
Item QTY
Immersion Temperature Sensor 3
Water Flow Sensor 2
Direct Digital Controller with 4 DI, 4 DO, 4 1
AI.
20% Extra points is recommended

71. THANK YOU