Lift Mains Supply Monitoring & Power Consumption

Lifts Mains Supply Monitoring Case Study

Customer: Confidential

As your business looks to reduce energy consumption as part of its sustainability strategy, have you considered the lifts in your buildings? Reducing the energy used by your buildings' lifts will lower carbon emissions helping you on your journey to reach net zero. Before you try to make energy savings in this area, you need to find out how much energy your lifts use.

TÜV SÜD Dunbar Boardman undertook a lift survey for a client to review the characteristics of the lift mains supplies, associated power consumption and running costs. Using the data provided by TÜV SÜD, the client could make informed decisions about whether installing new lifts or modernising existing lifts would lead to greater cost savings and a reduced carbon footprint.

The mains supplies were monitored for 21 days to ensure that full weekend and weekday activities were recorded. TÜV SÜD installed specialist test equipment in two passenger lifts in different blocks. The lifts in block A were renewed in 2021 and the block B lifts were installed in 1998 with new control systems fitted in 2009.

The following data was logged:

• Peak and average voltage
• Peak and average current tables serving up to two fixed landings
• Peak and average power (kWh)
• Energy consumption and associated cost
• Customer advised a cost of £0.17 per kWh

Both lifts are provided with variable voltage, variable frequency inverters that control the speed. The newly installed lifts in block A have a regeneration feature which uses state-of-the-art inverter drive technology. This inverter regenerates excess energy into a capacitator array accumulator unit when the lift motor is being overhauled in the out of balance conditions and acts as a generator, i.e. when a lightly loaded car is travelling upwards, or a fully loaded car is travelling downwards. The stored energy in the capacitator array accumulator device assists in reducing the starting current on subsequent journeys thus reducing the overall power consumption over time.

The graphs show there has been approx. a 50% reduction in running costs between the old and new lift systems.

Pre-Modernisation Power Consumption & Costs

Post-Modernisation Power Consumption & Costs

The graphs above show that the new lifts in block A have a significantly lower overall power consumption than the existing lifts in block B. The running cost for the new lift is approximately 50% of the existing lift, even with the new lift completing 944 more journeys than the existing lift. It’s also important to note that the new lift’s consumption figures include the lift car interior LED lighting. The lift car interior lighting of the existing lift is not incorporated due to the mains power and lighting circuit design.

Based on the running costs shown, we recommend that when considering the future upgrade of existing lifts that inverter drive systems with regeneration features are considered. These type of systems are a more sustainable choice and will help your business on the road to net zero. However, this must be balanced against the uplift cost for this feature and the associated payback time.

If you need to upgrade your existing lifts and want to reduce energy costs and your carbon footprint at the same time, please contact us or visit our lift consultancy services web pages.