Energy efficiency versus sustainability?

At the moment, energy efficiency is a huge topic – also in the lift sector. Unfortunately, sustainability is suffering under this, but it should be taken just as seriously as energy efficiency, since it tackles the topic far more comprehensively.

By Jan König and Ulrich Nees

What exactly is energy efficiency? The German Environment Agency (UBA) defines it as the relationship between a particular use to its energy deployment. "The less energy that has to be deployed, the more efficient a product or service is." This connection is obvious.

Let us take a look at standardisation. How is energy efficiency determined there? This can be found in VDI 4707 Sheet 1: 2009 "Lifts, energy efficiency" or currently in DIN EN ISO 25745-1: 2015 "Energy performance of lifts, escalators and moving walks – Part 2: Energy calculation and classification for lifts". However, both regulations have their weaknesses. This is because assumptions have to made, for example, about lift use. These assumptions have a great potential for errors. For example, the buildings were standardised for the purposes of comparison – but this frequently does not reflect actual use.

This is why it makes sense to treat energy calculations that fail to take objective trip numbers into account with healthy scepticism. Reliable evaluation of energy efficiency is only possible based on energy measurements that take actual trip numbers (over a lengthy period) into account. The loading of the car, number of operating hours and frequency of motor starts, for example, naturally also play a role.

Incidentally, the regulation also provides the tools needed here – in the form of DIN EN ISO 25745-1: 2015 "Energy performance of lifts, escalators and moving walks—Part 1: Energy measurement and verification". By the way: the standard is in the process of being revised, you can read more about this here.

Evaluation of sustainability

And how is sustainability defined? "Sustainability or sustainable development means satisfying the needs of the present without restricting the options of future generations," according to the German Federal Ministry for Economic Affairs. At the same, giving equal weight to the three dimensions of sustainability – economically efficient, socially just, ecologically viable – is important.

The question of potential evaluation of sustainability also arises here. Happily, this is possible with a green balance sheet. The product category regulation (PCR) for lifts - c-PCR-008 Lifts (elevators) – published at the end of 2022 prescribes the framework for the green balance sheet. Unfortunately, this framework also has a defect that various - unfortunately, also vital - assumptions have to be made. And these assumptions then have an important influence on the result of the green balance sheet.

Consequently, the question remains to what extent the green balance sheets currently on the market are comparable and as a result reliable. Does that then mean there are no reliable considerations regarding the sustainability of products? Precisely the opposite is the case! However, one has to fall back on classic methods, since the regulations presented are only helpful to a limited extent.

And in the practice?

What could this look like specifically? For example, DIN EN 60034-30-1 // item 5.3.4 calls for this note being present on every rating plate of a drive: "The measured efficiency and IE code must be permanently stated on the rating plate e.g. "IE2-84%". Unfortunately, complete information is missing on most drives.

If one asks manufacturers the reasons for this, there are normally two answers:
1. Our customers are not interested in the information about efficiency classes
2. Too much information leads to confusion.

But why are these technical data so important? Operators cannot objectively assess sustainability without this information. Efficiency is an important criterion – i. e. the relationship between energy input and energy output. This is energy efficiency pure – but still not sustainability.

"Those who buy cheap, buy twice"

Sustainability involves very much more – for example, the production conditions, use phase, disposal and the associated up- and downstream processes, such as the acquisition and production of the raw materials, auxiliary materials and operating supplies, including the associated emissions.

The wear margin (see DIN 31051) of lifts and the components installed, which determines their service life, is also part of sustainability. Can low-cost lift products with low energy needs therefore be sustainable? This is questionable. According to an old German saying, "Those who buy cheap, buy twice." If lifts and components are of high quality and as a result have a high wear reserve, they are more sustainable and in the long term therefore also more economic. Sustainability is becoming more important

Fortunately, sustainability is playing an increasingly important role for building owners and operators of late – big industry also reports this in official statements. But the observance or non-observance of quality has a tremendous influence on sustainability.

Let us take drives as an example. A poor drive has
• low efficiency and as a result poorer energy efficiency
• fewer pole pairs and as a result poorer travel behaviour, which affects the entire lift.
• Incidentally, the latter has considerable negative consequences on noise insulation.

Carbon concrete – the future?

An increasingly long service life and as a result sustainability is being pursued for buildings. One example: whereas conventional steel reinforced concrete structure have a service life of 40 to 50 years, engineers claim a service life of up to 200 years would no longer be an illusion with carbon concrete. A long service life as part of sustainability during the entire life cycle "from cradle to grave" should of course also be pursued in the case of lifts.

This means specifically: lifts and their components should
• have a long service life
• be easy to repair; this includes components being capable of repair and replacement
• capable of modernisation (also in sub-section).

These are admirable approaches. But how can they be implemented in practice and what criteria have to be observed in this regard? These questions will be illustrated in this year’s subject series in LIFTjournal.

Jan König is the owner of the engineering firm (VDI) Ing4Lifts.
Ulrich Nees is the owner of "Aufzug-Systeme + Beratung Ulrich Nees".

More information: ing4lifts.de
aufzugsystemeberatung.de