Cost reduction in buildings

Cost Reduction in Buildings

Cost reduction in building services engineering

Major increases of energy costs make electrical energy a driving force in costing. A first step to escape from the cost trap is the precise collection of all energy data, electrical and electrical parameters. The modern energy measurement technology ensures the necessary amount of transparency in your energy supplies. Concepts can be developed on the basis of the data e.g. electricity cost reductions and the introduction of measures. These targeted improvements can also be monitored and recorded.

There are a great number of cost-saving potentials in building facility management. One important cost factor is the electricity bill for plant and equipment, buildings and the infrastructure. But the electric bill is merely the immediately noticeable part of costs, which can be much higher when one considers a ‘dirty’ and unreliable power supply. Along with the direct electricity costs, the effective utilization of power distribution plants and equipment along with a reliable power supply also play an important role in
economic efficiency. As these costs are not as obvious, they are also referred to as ‘hidden costs’.

Cost-saving potentials to be achieved with modern power analyzers:

  • kWh consumption reduction
  • Reduction of reactive power cost (improvement of poor power factor, reduction of penalties)
  • Eliminating demand charges
  • Identify "energy gluttons"
  • Reduce maintenance costs
  • Extend the service life of electronic and electric equipment
  • Exactly register demand per cost centre (e. g. how much electricity is used in which office?)
  • Stabilize the power supply to prevent computer down times
  • Pro-active measures by means of a higher transparency of the electricity distribution

Reduction of electricity costs

Direct, consumption oriented energy costs can be significantly reduced:

For property managers, that means improving the precision of the electricity sub-billing plus customer-oriented invoicing (cost - centre - management). With appropriate power measurement engineering, energy consumption reports can be comfortably generated to verify the electricity bill from the power utility. On top this offers an excellent tool for a more precise forecasting of energy demand and allows negotiating tailor made energy supply contracts with Power Utilities which may cut-down electricity cost substantially. Integrated power management systems across the various network levels facilitate detecting uneconomical consumers and energy wasting. Identifying energy ‚sinners‘ is only possible with the right network transparency and consequently initiating the corresponding countermeasures. See an example for this statement.

Peak Load Monitoring

In the feeders of the incoming transformers UMG507E power analyzers have been used (see Pic 3). Priority hear was the monitoring of load profiles and power quality parameters (short term interruptions,harmonic loading, unbalanced loading, ...) as well as peak demand supervision. By temporary switching-off consumers, e.g., in the canteen kitchen, it was possible to lower the effective power maximum (demand), reducing the demand charges and consequently the
electricity bill by up to 20%. The 400V sub-feeders to the individual offices and building sections were monitored using UMG96S power analyzers (see Pic 3) with interface and field bus communication. That improved the transparency and facilitated the corresponding allocation of the consumed electricity to the individual cost centres and tenants.

“For us the highest importance was allocating the individual electricity
costs to the individual cost centres in order to create the awareness
with departments and people in order to make a first step in
energy saving. Furthermore, exact knowledge of the power consumption
of individual consumers or consumer groups helped us a
lot in discovering inefficient electrical loads (consumers) and in
initiating countermeasures in energy saving."

On top of that, networking the meters through a field bus enables automatic measurements downloading and makes them available for utilization in network control as well as for the management. To keep installation costs down (e.g., peripheries for the field busses), the decision fell in favour of Ethernet TCP/IP as the backbone for data communications. As network analyzers with Ethernet interfaces are expensive to acquire, and in companies sometimes monthly fees for each LAN point arise, one originally doubted that this could be implemented with the available budget. The solution was to combine the UMG507E network analyzers with a Modbus gateway feature and the UMG96S Modbus devices, see Pic. 8 below. With that, one adapted the high-end UMG507E in the central feeding points to the increased requirements placed on the measurement technology. Simultaneously, with the UMG507E it was possible to connect the more economical UMG96S devices via Modbus to the Ethernet through the Modbus gateway function. The EtherModbus gateway allows serial Modbus to communicate and interoperate with Modbus/TCP devices. The Modbus standard protocol is an asynchronous protocol designed to connect directly to computer asynchronous ports. Modbus has been extended to operate over Ethernet using the IP protocol suite. The Modbus gateway of the UMG507E converts between the Modbus TCP/IP protocol and Modbus RTU protocols transparently. With this method it is possible to combine field busses with Ethernet, which is growing rapidly, and showing it’s strength is reliability, speed and availability.

Get informed anywhere and anytime via email and homepage

Nearly everyone has experienced it: barely out of the office and the first calls come about problems in the computers, computers are failing or the power supply crashes – the web server integrated in the power analyzers create direct access to the data at the individual measuring points. All authorized employees in the electrics department and the management can quickly get extensively informed directly through the homepage of each power analyzer. All you need to do that is a web browser and the IP addresses in the network assigned to each power analyzer. With the latest product development, the UMG604, even a complete costing tool has been implemented with the homepage.

Collect, save and analyze data

The data gained from the various measuring points needed to be collected, saved, processed, visualized and made available. One first tool here is the topology view to get an overview of the running application. Measurement data can be freely selected and limits set to give a fast optical indication of any critical situation. Online analysis tools for graphic analysis of the data, e.g., comparing load curves as well as analysis tools for historical data and report generation were installed. The measuring points were placed on the topology views and now provide a quick overview of the entire power distribution system. It is possible to localize network malfunctions by comparing the individual measuring points and in order to check the defined tolerances at a glance. By storing graphics files (e.g. JPG) with circuit diagrams and building plans, and by linking the associated meters with drag and drop to their actual locations, one can implement a cost effective and customer specific solution. Out of limit conditions (e.g. THD-V too high!) and conditions in the inputs and outputs can also be displayed.

A mySQL database was installed to save the data. The availability of historic data makes it simple for the electrics department employees to create load curves for the procurement department for negotiating with the public utility.

As costly electric supply interruptions had already occurred in the past, great importance was placed on a high degree of data reliability. For that reason, a separate data server with correspondingly high speed and redundancy was used in the data backups. The PSWprofessional energymanagement software was installed on the client computers in the electrics department and in the pro-curement department.


Online values and analyzing historical data

The graphic continuous-line recorder feature makes quick online display of selected measurements feasible. The chart in this function is continuously expanded with new measurements. By analyzing historical data, just a few mouse clicks are needed for, e.g., fault analysis by comparing various parameters.

Future prospects

By integrating functionalities, modern power analyzers are advancing far beyond the limits of digital multimeters, e.g. including following functions all in one device

  • Energy meter (kWh, kVArh)
  • Harmonic analyzer
  • Transient recorder
  • Event recorder
  • Demand controller
  • PLC functions
  • Data logger
  • Condition monitoring

Rapid improvements in the field of integrated circuits permit continuously faster and compacter network analyzers at affordable prices. So the brand-new UMG604 power analyzer, equipped with a 500MHz DSP (digital signal processor), is a power analyzer that is exceedingly fast and powerful while maintaining the smallest dimensions.

Constantly sampling the eight channels with 20kHz per channel facilitates registering all electrical parameters (more than 800 values), min and max values, the basic power quality values such as harmonic content (up to 40th, per phase with direction detection) and short term voltage interruptions.

Even transients (> 50μs) can be reliably identified. By using modern communication architectures, integrated web servers and the supplied GridVis network analyzer software, comprehensive smart energy management systems (SEMS) for detecting and repairing potential power supply problems - often even before the fact happens - can be generated.

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