Whether you’re looking after green credentials or company purse strings ‘energy efficiency’ will be words you’re used to seeing. Granted it is not a new topic of conversation but information on the role that vertical transport has to play in reducing a buildings overall energy use is not frequently covered.
Therefore here is a brief directory of options to consider in language that you don’t need an engineering degree to understand.
This is where you enter your desired floor in a central control panel before being directed to a specific lift rather than jumping into the first one that arrives. This optimises traffic making it potentially possible to reduce number of lifts and or derive a better service in a building. This can achieve energy savings of up to 25 – 30 % of a lift system.
Eco Efficient Operation – Escalators
Can save up to 30% energy by slowing down or stopping when not in use or increasing the efficiency of the motor in periods of low use.
Hydraulic Lifts v Electric Traction Lifts
Hydraulic lifts are energy inefficient in comparison with electric traction lifts. Hydraulic lifts should be avoided where energy efficiency is a consideration.
Most lift and BMU installations have a design life of 20-25 years more with good maintenance. Hydraulic lifts have ‘issues’ with the oil disposal and oil leakage and ongoing maintenance etc.
Soft start & stop - electronic device to control parameters coupled with variable frequency drive systems. To the non-engineers among us, this just translates into a smooth ride.
LED and ‘eco’ efficient florescent lighting can reduce energy consumption by 80% in comparison to fluorescent lights.
Smart lighting can make additional savings meaning the lights are activated only when the lifts are in use.
Regenerative Drive Features
Regenerative drive converts the excess energy generated by an lift into electricity that can be reused elsewhere in the building. With conventional drives, this untapped energy is converted into heat, which then needs to be removed from the building by air conditioning systems.
A regenerative drive has a substantial impact on an elevator’s energy consumption and is, therefore, a must-have feature when selecting an eco-efficient elevator for a green building
When this is used in conjunction with variable frequency drive systems it can save between 40-50% energy in total.
‘Powers down’ the equipment when not in use which provides substantial reduced energy use particularly in buildings where there are periods of inactivity.
To consider the demand and movement patterns for the building by undertaking an assessment involving the design team, this determines the optimum number and size of lifts based on the anticipated passenger demand.
The total energy consumption of the installation is also dependant on planning issues. If stairs are accessible, attractive and adjacent to the lifts, there is likely to be a reduction in the use of lifts for short trips. It is also good to avoid over-sizing of lifts, as larger lifts result in greater inertia, larger motors and more energy use. However the focus should be on appropriately sized lifts rather than ‘the smaller the better’ in order not to compromise the service.
Variable Frequency Control of Lifts
VVVF (variable voltage, variable frequency) drive systems are essentially the newest form of drive system. An old drive system (i.e DC drive systems) had the motors and generator which results in energy being lost due to the number of elements/motors employed by the system. VVVF drive systems however encompass the technology of the equipment in one control system therefore reducing ‘lost’ energy.
VVVF drive systems are the key to efficient lifts. Energy Savings can be as high as 30% in comparison to older DC equipment.