Class Notes - Year 4 - 2020-2021
Year 4

Lesson 414

Energy Management and Building Automation Including Latching Relays

IEC Manual 414


See text

414.1 List Methods Utilized to Conserve the Usage of a Facility’s Electric Energy Consumption

Energy Efficiency

Lighting is about 5% of resi. load, 10% of commercial
Fluorescent is still common in commercial
Switch to LED
Longer life
Lower energy use
More durable
Better quality light
Motors are about 70% of energy use in manufacturing
Most efforts to reduce energy use focus on motor, but opportunities to improve exist in other components
Controller, mechanical couplings, driven equipment, interaction with process operation
There can be manual control, time clock/thermostat
Standalone, to tie into other systems
BAS is better method

Daylight Harvesting

Also known as daylighting
Improves employee performance and retail sales
Sensor measures amount of illumination at task surface or in space
Side lighting versus top lighting
Sensor signals control device to dim or switch off
Can be central or fixture mounted
2 Types
Closed loop
Measures natural light and fixture light
Adjusts to maintain desired level
Primarily used in smaller areas
Open loop
Measure only natural light
Used in larger, high bay applications
Hubbell NX


Uses heat byproduct of electricity generation
Combined heat and power (CHP)
Can be used to heat water or air
Absorption chillers can use heat for cooling purposes
Plant producing electricity, heat and cold is called tri-generation or poly-generation plant

Distributed Energy Resources (DERs)

Electric generation sources located within electrical distribution system
Generators, backup generators, on-site power systems
Distributed generation - any technology producing power outside of utility grid
PV or microturbines
Distributed power - any technology that produces or stores power
Batteries or flywheels
Distributed Energy Resources
Combined heat & power
Internal combustion engines
Fuel cells
Energy storage / UPS systems
Wind turbines
Hybrid systems

Load Shedding

Energy management system monitors rate of usage
When upper threshold approached, certain loads are de-energized
Monetary and ecological
Peak hour utility billing
Some utility companies install load shedding devices and connect customer equipment through it. Usually water heaters

414.2 Explain Building Management Systems as Used for Automation, Energy Conservation, and Redundant Equipment Systems

Energy Management

BAS: building automation system
EMCS: energy management and control system
Integrating component to control setpoints for fans, pumps, heating, cooling, dampers, t-stats
Can also include monitoring of power, security, lighting, window blinds, air quality, fire alarm,

HVAC Systems

See text

Building Management System

Maintain temp. and operate lighting
Based on occupancy and scheduling
Frequently settings are overridden which can decrease efficiency
Example of operation
When reduced occupancy is detected:
Chiller and airflow is reduced
Lighting is reduced


BAS can signal operated about scheduled maintenance or required maintenance according to sensors
Example: Pressure switches behind AHU indicate filter change required
Known as O&M
Increases safety
Increases health
Maintains equipment life expectency
Complies with laws and regulations

Article 750

750.20: EMS shall not override any equipment for life safety
750.30: EMS can monitor and control loads
750.50: When remote means is employed, EMS equipment must be field marked with directory

414.3 Identify and Use a Mechanically Held (Latching) Relay, Explain How these Lighting Contactors are Used with Building Automation Systems

BAS frequently use lighting contactors to control lighting load
Electrically held could be used, but mechanically held have several advantages
Coil is energized only when latching and unlatching
This means no magnetic hum
Will not switch off upon power failure
Available with up to 12 poles
Coil has “C” and “O” terminal
Momentary signal only
Maintained signal
Power contacts usually up to 30 amps, NO or NC
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