Smart Buildings Systems for Architects, Owners and Builders

n Historical reports

n Alarm reporting

n Analysis of electric power waveforms

n Determination and initiation of power load-shedding strategies

n Communication with HVAC and lighting control systems

n Usage billing software

EPMS implementations have evolved to the infrastructure foundations of
smart buildings. Backbone EPMS network connections can use standardized,
unshielded, twisted-pair copper and fiber optic cables, supplemented with
shielded, twisted-pair copper cable. Physical topologies can be bus, star or
daisy-chain configurations.
Many of the lower-level network communications use RS-485 communica-
tions while higher network levels use TCP/IP protocols. EPMS network com-
ponents and devices connect to the Ethernet network directly or through
connectivity to a network router or gateway, essentially converting or encapsu-
lating other network protocols such as Modbus. Databases for EPMS environ-
ments typically adhere to SQL standards. Systems also allow for connectivity
to remote-client personal computers and PDAs. The EPMS is an important
facility operational tool and a critical element in a smart building.

Demand Response

An EPMS is particularly useful in allowing for demand response. Demand
response refers to mechanisms that manage the consumption of electricity
based on electricity supply availability and pricing. An EPMS can initiate
power consumption reduction schemes when certain levels of power demand
are reached.
At certain times of the day known as the “peak” hours electricity demand
spikes and power plants fire up their peaking power units. This peak electricity
is generally more expensive than the base electricity that is produced because it
is usually provided by a quickly fired source such as a gas turbine. This is
because it is not cost effective to size a power plant based on the peak load;
the unnecessary capital costs far outweigh the more expensive peaking fuel.
Thus, it is in the electricity provider’s best interest to reduce the amount of
peak electricity they have to produce.
Demand response can be explained using a quantity (Q) versus price (P)
graph (Fig. 5.2). Price elasticity of demand (PED) is a measure of how consu-
mers react to a change in the price of a certain commodity, in this case electricity.

62 Smart Building Systems for Architects, Owners, and Builders