Watts the Big Deal?
Slashing kiosk energy consumption
By David Mackenzie, Editor, KIOSK EUROPE
Our future energy supply is a contentious issue for people all over the world. Although the issues of nuclear catastrophe, global warming and CO2 emissions are prominent in the public consciousness, these concerns inevitably take place against the backdrop of the satisfaction of ever increasing demands for energy. By taking measures to reduce energy consumption within their self-service projects, businesses have the opportunity to save vast amounts of money, while protecting public interests.
The Status Quo
Highly integrated kiosks such as ticket machines typically contain 15 or more separate assemblies. These commonly include an interface, monitor, computer, printer, cash acceptor, card reader, lighting, and a battery for UPS. Each of these elements has a different load profile and consumption value. With today’s machines, each individual function is always in standby mode. The built-in power supply units are generally designed to cover all conceivable peak loads and, as a result, the power units are oversized in relation to the average power consumption of the machine. This means very poor efficiency in the partial load range, which is the predominant operating mode.
Increasing kiosk efficiency requires an integrated approach. In addition to the obvious requirement for safe operation, it is important that the customer is not inconvenienced in any way and that the measures taken to increase efficiency do not negatively impact costs.
FG-Elektronik is a high-profile developer and manufacturer of power supply and energy management solutions for the industry. The company recently initiated a project to investigate and optimise the energy efficiency of kiosks based on a modern ticket machine.
Perhaps the most important finding was that kiosks consume the majority of their total energy usage in standby mode. Even with machines in frequent use, the amount of energy consumed during standby mode is many times higher than that consumed when the machine is actually in use. In view of this fact, the recommended measures to reduce energy consumption include: the use of energy efficient components, power/ peak load measurement, highly efficient circuits, and a modular concept.
During the project, all electrical components were investigated to determine whether energy-efficient alternatives were available on the procurement market and, wherever possible, they were subsequently replaced. When selecting and developing electronic assemblies for the power supply unit, particular importance was attached to energy efficiency and optimising energy consumption in standby mode.
The findings recommend that components are switched off while not in use, with their reactivation controlled by demand. By avoiding or easing peak load situations, a small power unit can be used for the intermediate circuit voltage. This can be operated predominantly in the rated load range in which it functions at maximum efficiency. A sophisticated sensor system and a bus-supported communication architecture in the machine should form the basis for optimising operating parameters.
The current prototype being tested in the field has achieved energy savings of well over 50 percent. Simulation results indicate further potential savings of 15 to 20 percent. The energy concept developed for ticket machines can also be used for other kiosks. The modular design of the power supply unit with plug-in modules for switches, a communication assembly, DC/DC converter and DC supply largely reduces the fulfilment of customer-specific requirements to software modifications.
The project team has demonstrated that considerable savings can be made in many everyday processes. A turning point in energy policy will only be achieved if it is not only based on environmentally-friendly energy generation but also exhausts all possibilities for improving energy efficiency.
The project was based on a detailed analysis of assemblies that are commonly used in self-service solutions. A test machine was built at the Institute for Electromagnetic Fields at the Friedrich-Alexander University in Erlangen. This machine determined and documented typical processes, such as ticket selection and purchase, according to process steps, energy consumption and load curve under realistic operating conditions. The efficiency, voltage curve and power consumption over time were also measured for all electrical assemblies. The process findings and performance data of the individual assemblies were used to simulate processes.
In an independent series of measurements, standard 240W power supply units were measured. PowerBoost capability, overcurrent performance and efficiency in the partial load range were key measuring points. From a technical point of view, kiosks commonly have the following characteristics: • Different load profiles, depending on the installation location • 24/7 operation in a variety of climates • Several subsystems with different voltages (5, +-12, 24V) • Distinct standby and partial load operation • Distinct peak load requirements • Use of control processors (EPC) • LAN or WAN connection to communicate with higher-level systems
Wednesday, March 21, 2012