Lighting Controls
•
Lighting controls offer the ability for systems to
be turned ON and OFF either manually or
automatically.
•
There are several control technology upgrades
for lighting systems, ranging from simple
(installing manual switches in proper locations)
Lighting Controls
•
The standard manual, single-pole switch was the
first energy conservation device. It is also the
simplest device and provides the least options.
•
One negative aspect about manual switches is that
people often forget to turn them OFF.
•
If switches are far from room exits or are difficult to
find, occupants are more likely to leave lights ON
when exiting a room.
•
If switches are located in the right locations, with
Lighting Controls
• Another opportunity for upgrading controls exists when lighting systems are designed such that all circuits in an area are controlled from one switch, yet not all circuits need to be activated.
• For example, a college football stadium’s lighting system is designed to provide enough light for TV applications. However, this intense amount of light is not needed for regular practice nights or other non-TV events. Because the lights are all controlled from one switch, every time the facility is used all the lights are turned ON.
Time Clocks
•
Time clocks can be used to control lights when their
operation is based on a fixed operating schedule.
•
Time clocks are available in electronic or mechanical styles.
•
However, regular check-ups are needed to ensure that
the time clock is controlling the system properly.
•
After a power loss, electronic timers without battery
backups can get off schedule—cycling ON and OFF at the
wrong times.
Photocells
•For most outdoor lighting applications, photocells (which turn lights ON when it gets dark, and off when sufficient daylight is available) offer a low-maintenance
alternative to time clocks.
•A photocell is inexpensive and can be installed on each fixture, or can be installed to control numerous fixtures on one circuit.
•Photocells can also be effectively used indoors, if daylight is available through skylights.
•The least expensive type of photocell uses a cadmium
cells lose sensitivity after being in service for a few sulfide cell, but these years by being degraded from their exposure to sunlight.
Lumen Depreciation Compensation
• Lighting systems are usually over-designed to compensate for light losses that normally occur during the life time of the system.
• Alternatively, the “lumen depreciation compensation strategy” allows the design light level to be met without over-designing, thereby
providing a more efficient lighting system.
• The control system works in a way similar to daylight harvesting
controls. A photo-sensor detects the actual light level and provides a low-voltage signal to electronic dimming ballasts to adjust the light level.
• When lamps are new and room surfaces are clean, less power is required to provide the design light level.
• As lamps depreciate in their light output and as surfaces become dirty, the input power and light level is increased gradually to
compensate for these sources of light loss.
Occupancy Sensors
• Occupancy sensors save energy by turning off lights in spaces that are unoccupied.
• When the sensor detects motion, it activates a control device that turns ON a lighting system.
• If no motion is detected within a specified period, the lights are turned OFF until motion is sensed again.
• With most sensors, sensitivity (the ability to detect motion) and the time delay (difference in
time between when sensor detects no motion and lights go OFF) are adjustable.
• Occupancy sensors are produced in two primary types: Ultrasonic (US) and Passive Infrared (PIR).
• Dual-Technology (DT) sensors, that have both ultrasonic and passive infrared detectors, are
• also available.
• With remote sensors, a low-voltage wire connects each sensor to an
electrical relay and control module, which operates on common voltages. • Ceiling-mounted units are appropriate in corridors, rest rooms, open offi ce
areas with partitions
PROCESS TO IMPROVE
LIGHTING EFFICIENCY
•
The three basic steps to improving the
efficiency of lighting systems:
1. Identify necessary light quantity and quality to
perform visual task.
2. Increase light source effi ciency if occupancy is
frequent.
Energy Economics
•
The micro-economic concerns of energy supply
and demand
•
The macro-economic concerns of investment,
financing and economic linkages with the rest
of the economy form an essential part of the
subject.
•
Environmental concerns of energy use and
The energy and multidimensional
interactions
•
Energy trade
•
International institutional influences
•
Supply of energy and other goods and
Energy trade
•
All transactions involving energy commodities
(especially that of oil and to lesser extent that of
coal and gas) are due to differences in the natural
endowments of energy resources aross countries
and the gaps in domestic supply and demands.
•
Similarly flow of technologies, human resources,
International institutional influences
•
Various influences through international
institutions among countries and govern
transactions.
•
These include the legal frameworks, treaties
and conventions, international organisations
such as the union nations (UN), the world
Other interaction
•
Other interactions among countries
(co-operation, competition and conflicts) involving
their governments or other entities (such as
The key role of energy sector in the economic
activities
•
The energy sector uses inputs from various
other sectors (industry, transport, households
etc.,) and it also a key input for most of the
sectors.
•
These interrelations influence the demand for
•
Supply of energy and other goods and services,
investment decisions, and the macro-economic
variables of a country (economic output,
balance of payment situations, foreign trade,
inflation, interest rate etc.,)
•
The national institutions (including the rules
The role of discount rates in energy system analysis
The harmonisation of present and future values within an economic assessment of investment opportunities or economic systems requires
discounting of payment and income streams. This allows a conversion of
future outcomes into annualised costs at present value. Thus, outcomes
such as overall (social) costs of different policy options or the
assessment of energy efficiency potentials are highly influenced by the
choice of discount rate. With regard to energy system analysis, two
types of discount rate need to be distinguished [1]. The first one reflects
the perspective of an individual investor (descriptive approach),
whereas the second one reflects a social perspective (prescriptive
Why are discount rates so important and high in
the current climate and energy debates? What
are they?
Discount rates reflect the capital cost and
expected rate of return of investments, and are
thus paramount to assess the costs and
The role of discount rates in energy system analysis
with two perspectives
•
Social discount rates are applied for evaluating total
costs and benefits of energy systems from a societal
perspective;
•
Individual discount rates are applied to model
investment decision making reflecting the expected
For the use of social discount rates in energy system analysis:
•
Considering the methodology to derive social discount rates, the
applied discount rates by government agencies as well as discount
rates used in the analysed energy scenarios, social discount rates
for EU Member States can be assumed to be in a range between 1
% - 7 %.
•
The social perspective should be reflected by risk-free discount rate
declining over long time horizons. Interest rates of government
bonds with long-term maturity can serve as a good proxy which is
For the use of individual discount rates of investors in energy
system analysis
•
Discount rates should be differentiated according to different
investors.
•
For households, discount rates should reflect the market price of
capital. Considering that the market price rather depends on the
individual economic situation of the household than on the
applied technology, a differentiation of discount rates by
For the use of individual discount rates of investors in energy system analysis
• Following the concept of expected rate of return, higher discount rates should be
assumed for commercial and industrial investors, than for private investors in the
household sector. The level of discount rates for commercial and industrial
investors applied in the analysed studies range from 6 % to 15 %. For
households, the range is between 3 % and 6 %, except in the PRIMES model.
• The use of high discount rates to map non-economic barriers and bounded
rationality is not suitable. In order to simulate real-world investment decisions, it
is rather recommended to apply behavioural models which consider individual
Payback Period
•
The payback period of an investment is generally
taken to mean the number of years required to recover
the initial investment through net project returns.
•
The payback period is a popular measure of investment
worth and appears in many forms in economic analysis
literature and company procedure manuals.
•
Unfortunately, all too frequently, payback period is used
inappropriately and leads to decisions which focus exclusively on
short term results and ignore time value of money concepts.
Internal Rate of Return
• One of the problems associated with using the Present
worth or the annual worth measures of worth is that they
depend upon knowing a value for MARR.
• As mentioned in the introduction to this section, the
“proper” value for MARR is a much debated topic and
tends to vary from company to company and decision
maker to decision maker.
• If the value of MARR changes, the value of PW or AW
must be recalculated to determine whether the
attractiveness/unattractiveness of an investment has
