Reduce Costs and Energy Use Through Elevator Efficiency Upgrades

Buying or installing elevator equipment that promotes low-energy consumption can help save money and reduce a building’s environmental footprint.

Source: highrisefacilities.com

>”As part of a building’s overall energy usage, elevators consume up to 10 percent of the total energy in a building. From an environmental standpoint, the most significant impact elevators have is the electricity use while the elevator is in service. Therefore, buying or installing elevator equipment that promotes low-energy consumption can help save money and reduce a building’s environmental footprint.

Buildings and Energy

One way to measure overall energy usage is by calculating the power factor (PF) of the building and/or its energy-consuming devices. These are generally motors, transformers, high intensity discharge (HID) lighting, fluorescent devices or other pieces of equipment that require magnetism to operate. […]

Power factor is a measurement of electrical system efficiency in the distribution and consumption of electrical energy. It is the percentage of the amount of electric power being provided that is converted into real work and expressed as a number between zero and one. For example, if a device had a .70 PF, then 70 percent of the power that the utilities generate to run the device is actually being converted into real work. The lower the PF number, the poorer the PF efficiency. The higher the PF number, the greater the PF efficiency.

In some areas, utilities use PF in the computation of the demand charge. A low PF for a customer’s facility could result in a demand charge penalty that increases the monthly demand cost. This is where newer, more innovative elevator control systems can contribute to lower energy consumption and improve a buildings’ overall PF.

Because of electrical losses caused during generation, distribution and consumption of electricity, the amount of power needed to be provided by a utility company will be greater than the amount for which they get paid by consumers.

Comparative Analysis

During a recent modernization of two identical traction elevators, before and after energy data was collected. The original, first generation silicon controlled rectifier (SCR), direct current (DC) motor control was measured using a series of fixed run patterns and known loads. After modernization, the new insulated-gate bipolar transistor (IGBT)-based alternating current (AC) motor control for a permanent magnet synchronous motor system was measured using the same run patterns and known loads.

The SCR-DC system used far more energy (watts/hour) to move the exact same load through the exact same distance compared to the IGBT-based permanent magnet AC control (Chart 1). In fact, in these six load tests, the IGBT-based system used less than half the energy. An incredible 383 percent increase in power factor of the IGBT-based system compared to the SCR-DC system (Chart 2). That means more of the energy consumed was being converted into real work with less waste in terms of heat and magnetism.

These kinds of energy usage reductions and PF increases are becoming even greater as newer elevator technology gets incorporated into buildings (Chart 3).

It’s easy to see how reducing energy consumption and increasing power rating can benefit the building’s owners and operators. However, these same improvements benefit the community as well. The electricity not being used in one building can be used by other customers — allowing utilities to meet the community’s electricity demand without increasing electricity generation. That translates into no rolling blackouts or brownouts, no new power plants being built and an overall smaller environmental footprint.

Hydraulic Elevators

Up to this point, traction elevator technology was discussed where wire ropes pull the elevator from above the car. In contrast, the hydraulic elevator pushes the elevator cab through the hoistway. The way a hydraulic system works is a piston and cylinder are sunk in the ground below the elevator. To go up, a pump forces oil from an oil tank reservoir into the cylinder — causing the piston to rise, making the elevator cab go up. To go down, gravity and the weight of the cab pushes the piston down into the cylinder and forces the hydraulic oil back into the tank reservoir. Historically, hydraulic elevators (or hydros) have been installed where either the building had fewer floors (typically six to eight) or lower material and installation costs were a consideration (when compared to a traction elevator). […]

Considerations Beyond the Hoistway

Energy reduction of a building’s elevators can also impact heating, ventilation and air conditioning (HVAC) systems. Quite often, elevator machine rooms are air conditioned to support removal of the heat generated by elevator control systems. Motor-generator-based elevator controls create a tremendous amount of heat; the effect is multiplied when several systems are contained in the same machine room.

Additionally, a check should be made of the shut-down timer typically employed with motor-generators (M-G) sets. Is it working? Does the M-G set turn off after a set period of time? Or has the timer failed and no longer shuts down the motor-generator, wasting energy as the M-G set turns but no work is being done by the elevator?

The elevator cab’s lighting can impact both the energy consumption and HVAC systems. A recent survey conducted of a 34-story high rise office building with 18 elevators showed the cab lights were on 24-hours a day. There are 28 incandescent light bulbs per elevator. That worked out to 100-amps of power being consumed continuously. By replacing the incandescent bulbs with compact fluorescents, energy consumption could be cut to 30 percent. And if a 24-hour clock timer is added to shut the lights off at midnight, even more energy could be saved.

Reducing Energy Consumption

Finally, if you’re considering an elevator modernization, call your electric provider or visit their Website to explore the possibility of energy rebates from the local utility provider. It is quite common for utilities to offer dollar incentives for specific building improvements that reduce energy consumption and improve PF.

There are various benefits to building owners and facility managers who lower their power consumption and understand how power factor helps reduce the overall cost of energy, particularly the energy used to run the elevators in their buildings. These benefits go beyond the elevators themselves to include benefits derived from HVAC systems, cab lighting and energy consumed when the elevators are not moving that affect the monthly utility bill.”

 

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Study Finds Global Opportunities for Improvements in Elevator Efficiency

1259707a-d405-4e90-9e4b-4b7660c1a1d0.jpgElevators and escalators make up 2 to 5 percent of the energy used in most buildings, but can reach as high as 50 percent during peak operational times. At 5 percent, that means the yearly energy consumption of U.S. elevators is approximately five times of that used in all of Washington D.C.

 

 

 

image source: http://www.thyssenkrupp.com/en/produkte/energieeffiziente-aufzugssysteme.html

Source: aceee.org

>”Chicago—More energy-efficient elevators can significantly reduce the costs of operating a building, but the information needed to help building owners identify the appropriate elevator system—and the savings associated with it—aren’t readily available, according to a new study published by a leading policy group. The study, by the American Council for an Energy-Efficient Economy, was published with the support of UTC Building & Industrial Systems, the parent organization of Otis, the world’s largest manufacturer and maintainer of people-moving products.

[…] The technology exists today to reduce that consumption by 40 percent or more, especially by cutting energy use between trips, when an elevator is idle, according to the study. Some technologies have been found to reduce consumption by as much as 75 percent, but without a standard way to measure energy savings and a rating system to distinguish more efficient elevators, building owners may be unaware of the benefits of upgrading to a more efficient system or choosing a more efficient system for new construction.

“Enhanced visibility when it comes to elevator efficiency can help customers grasp the full value package of better controls, improved performance, reduced sound, and increased comfort,” said Harvey Sachs, ACEEE senior fellow, and the study’s lead author. Sameer Kwatra of ACEEE presented the study on Tuesday, January 27 at the 2015 American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Winter Conference in Chicago.

The study lays out a framework for industry leaders to set common standards for measuring elevator efficiency. Those standards could lead to a rating system, such as the U.S. Environmental Protection Agency’s ENERGY STAR® ratings already in place for heating, ventilating and air-conditioning systems, and many home appliances. Clear standards also could lead energy utilities and government agencies to offer incentives, such as rebates, for very efficient models. And building label programs, such as the U.S. Green Building Council’s LEED® program, could include elevator efficiency as a factor in certifying buildings. Right now, the LEED program considers elevators a part of unregulated “process loads,” and there are no direct credits for installing more efficient systems.

“Owners see elevators as an extension of the building lobby — a way to include their personality and values in the building,” said John Mandyck, chief sustainability officer, UTC Building & Industrial Systems. “As consumers and tenants better understand and value the effects green buildings have on the health and productivity of inhabitants, clear standards for measuring elevator efficiency can provide a great opportunity to reduce operating costs and showcase the environmental attributes of a building.”

The report identified energy-efficient elevator technologies that can be included in building codes and factored in elevator rating and labeling systems. […]”<

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