22-08-2013, 02:43 PM
Energy Efficient Technologies
Energy Efficient .ppt (Size: 644 KB / Downloads: 47)
Energy and the Environment
Energy production causes particulate emission, acid rain and global warming
Energy efficient technologies help the environment & are cost effective
Other green initiatives may not be cost effective but have intangible benefits and improve corporate image, e.g. renewable energy
Energy efficiency of a country should be considered under 3 issues:
Economic efficiency is a measure of the energy required to support economic activities (MW/GDP)
Societal efficiency is a measure of the amount of energy used by each citizen (MW/GDP)
Environmental efficiency is a measure of the amount of emission to produce unit energy (CO2 emission per MW)
Energy Efficiency in Buildings
Architectural measures
Lighting
Air-conditioning
Electrical
Lifts and escalators
Plumbing & drainage
Architectural Measures
Building orientation to enhance natural ventilation and natural lighting and to reduce solar gains
Sun shading devices
Central location of plant rooms to minimize losses
Stacking of plant rooms on different floors
Improving OTTV (overall thermal transfer value)
Better glazing: low-E & reflective glass
Green roof
Better insulation of external facade
Reduce infiltration
Lighting
T8 with electronic ballast
High efficiency T5 (T5 HE)
High output T5 (T5 HO)
Induction lamp
Self luminous exit sign
Compact fluorescent lamp
Dimmable electronic ballast
Occupancy sensor
Advantage of T5
Energy efficient with pay back within 2 years
Fits exactly into ceiling grid
Suitable for viewing computer monitor
Better lumen maintenance and longer lamp life
Optimum performance at 350C
T5 fitting is only 50 mm deep and can suit congested ceiling space
More environmental friendly due to less mercury, material in production and packaging (1xT8=2.5T5)
Self luminous exit sign
Rely on non-electrical
illumination technology
Beta ray on fluorescent
coating
Rated life: 15 years
Radioactive tritium gas in glass tube
Payback less than 2 years if licensing fee is excluded
Eliminates power supply & wiring
Eliminates maintenance on battery
Approved for use by FSD
Requires licensing by EPD (Radioactive)
Occupancy sensor
Occupancy sensors are installed to switch off lighting when the occupants have left the room
It can be a CO2 sensor (detects occupant) or a infrared sensor (detects motion)
It can save more than 20% energy
VAV
VAV system is most suitable for space with variable load conditions, e.g. east or west external zones, conference room with variable occupancy.
The motor of the VAV air handling unit is served by a variable speed drive (VSD)
VAV system can save up to 30% of the fan power
The supply air to a room is delivered by a VAV box that supplies variable volume of air to suit the loading requirement. If the air required is reduced during part load, the pressure within the main supply air duct will be increased and this signal is detected by a pressure sensor and transmitted to the VSD controller to cause the fan to reduce its speed.
Energy Efficient Cabling System
The Government promoted the use energy efficient cabling system that will reduce energy consumption through lower copper losses and improve safety through better power quality at the same time.
The location of the transformer room and main switch room should be immediately adjacent to, above or below each other.
The copper losses should not exceed 0.5% of the total active power transmitted along the circuit conductors at the rated circuit current.
The design of the system can be found in the COP for Energy Efficiency of Electrical Installations
Plumbing & Drainage
Energy efficiency in P&D systems aims at reducing the consumption or wastage of water. Examples are:
Self-closing taps
Taps with sensor control
Automatic flushing cisterns with sensor control
Low flow WC