Elevators and Escalators: What are the Strategies to Promote Energy Efficiency?
Published on : Friday 06-01-2023
Elevator modernisation which includes upgradation of components and technologies help to create a comfortable and pleasant experience, says K Suresh.
The invention of elevators and escalators has shaped the landscape of the vertical mobility sector in a remarkable manner. Availability of elevators at almost every residential and commercial space has paved away the challenges like chaos, longer delays and inconvenience. Elevator systems have evolved to be more efficient and reliable as we progress towards advanced technologies.
India is a developing country which is heading towards its industrialisation and urbanisation process and hence it also looks up for its concern about saving energy sources and attaining sustainable development in the near future. According to the media reports, “Over the last eight years, per capita electricity consumption has reported consistent growth from 914 kWh in 2012-13 to 1208 kWh in the last fiscal year, which marks an increase of 32% as per the official data”. Demand was merely 16 kWh at the time of India’s independence in 1947. This rising demand has awakened the society which resulted in a progressive step ahead towards a greener India, it is important to be devoted towards renewable sources, start the usage of sustainable products and focusing more on energy saving resources.
Pioneers of the vertical transportation segment are producing high-quality, extremely energy-efficient and technologically advanced elevator systems for the multi-story buildings. These elevator systems come with updated hardware, controls, and other technologies that not only consume less energy but are also compact, effective and easy to maintain and modernise. Although elevators only use around 5% of energy in a building, upgrading or modernising elevators at a fixed span of time can result in even better performance and efficient outcomes.
Conventional or older elevator systems tend to face various operational issues, consume double the required power and are less efficient. Rapid advancements have made it possible to modernise an elevator system rather than replacing the whole unit with a new machine which saves the time and cost involved in the process. Modernisation of elevators allows refurbishment of the elevator system by replacing some of its components so that usable components can be retained and reused. This helps in energy saving, improved traffic efficacy, minimal wastage of high costing parts and safety of elevator cars.
Below are the major strategies that are when implemented can make elevator system energy efficient:
• Switching out old DC motors with AC motors can result in energy savings of up to 50%
• If an elevator isn't used for a predetermined amount of time, standby mode is a feature which can automatically turn off all non-essential operations. As soon as the button is pressed, it powers back on immediately which results in saving maximum amount of energy
• Data logging is a feature which enables traffic study to be carried out, using information such as usage frequency, floors traversed, and peak vs. idle periods to estimate energy consumption and develop more effective control strategies
• Regenerative Converter (PCNV): Elevators travel using power from a power source (powered operation); however, when elevators travel down with a heavy carload or travel up with a light car load (regenerative operation), the traction machine acts as a power generator. Although most of the power generated by traction machines during its operation is lost as heat, the regenerative converter transmits the power back to the distribution transformer and feeds it into the building's electrical network along with electricity from the power supply. When compared to a similar elevator without a regenerative converter, this system can save up to 35% of energy.
• Allocation Control – Energy-saving Operation (ESO-W): This system selects an elevator from a group that balances the best operational efficiency and energy consumption.During peak hours, operational efficiency is prioritised, while energy efficiency is prioritised during non-peak hours. This system allows building owners to save energy costs without sacrificing passenger convenience by reducing energy consumption up to 10% in comparison to the conventional elevator systems.
• Light Emitting Diodes: LEDs are used in ceiling lights and hall lanterns to boost the building's overall energy efficiency. Furthermore, a long service life eliminates the need for lamp replacement on a regular basis. Usage of LED lighting results in around 90% lesser energy consumption.
• Auto-Shutdown of the Car Fan (CFO-A) & Automatic Shutdown of the car lights (CLO-A): If there are no calls for a certain amount of time, the car ventilation fan and lighting will turn off to save energy.
Mitsubishi Elevator India offers features listed below which make their devices energy efficient:
1. Electrical and electronic solution manufacturers like Mitsubishi Elevator India have been working on developing elevators that reduce energy consumption and contribute to environmental sustainability. The company uses regenerative converter in its elevators, which is a device that transmits power generated by a traction machine via distribution transformer to the electrical network in the building, so that it can be reused by the building’s power supply for other electrical systems. This initiative helps in saving energy by almost 35%.
2. Mitsubishi Electric elevator devices in India are designed with an electricity recycling system, which is designed to store electricity generated during regular elevator operations. The electricity stored in nickel-hydrogen rechargeable batteries can be used as an auxiliary power supply for running elevators, providing approximately 20% power saving. Variable traveling speed of an elevator system is another important feature of Mitsubishi elevators which allow elevators to travel faster than their rated speed depending on the number of passengers in the car, thereby improving transport efficiency. This feature allows to improve traffic without increasing power supply capacity and ultimately contribute to sustainability.
3. Permanent Magnet motor with Stator in traction machines allows coils to be wound around the core more densely, resulting greater motor efficiency and compactness, thereby helping in saving energy by 20%. The direct-drive PM door motor and the VVVF inverter realise efficient door opening and closing.
4. Mitsubishi Electric offers vertical mobility solutions that focus on improving traffic efficiency, without increasing power consumption through the ΣAI group control system, which allows for effective control of multiple elevators. Its energy-saving operation smart control technology has a system wherein according to each car’s location and passenger load, the group control system assigns a call to the elevator that best balances operational efficiency. This saves energy consumption by 10%.
5. The Destination Oriented Allocation System developed by Mitsubishi Elevator is an advanced system which saves the time and energy consumed as it automatically registers the destination floor when a user places their ID card over a reader at the security gate or elevator lobby. Besides, passengers going to the same floors are directed to the same elevator to minimise stops, shorten riding time and improve operational efficiency.
Strategies adopted by Mitsubishi Elevator India to make escalators energy efficient are mentioned below:
1. Modernising an escalator enhances its safety, comfort and saves energy.
2. Updated drive systems with energy-efficient technology comes with a reduced friction loss in the drive system and other advanced methods have reduced the power consumption up to 20%.
3. VVVF (Variable voltage variable frequency) inverter control and automatic operation feature conserve energy by running slowly in Stand-by. If there are no passengers on an escalator, the escalator goes into Stand-by and runs at a reduced speed. However, when the escalator detects a passenger approaching the entrance landing, it gradually increases up to the rated speed.
The vertical mobility industry has shifted its focus towards producing the features and technologies that can save energy and resources. Energy efficient features will uplift the industry by reducing energy consumption and contribute to sustainability and promote reliability while maintaining the high-quality of the products. Elevators and Escalators offered by Mitsubishi Electric have always been at the forefront of design, technology and innovation and now it is leading to reshape the vertical mobility industry by bringing in the energy efficient technologies in the sector.
K Suresh is Deputy Managing Director, Mitsubishi Elevator India Pvt Ltd.