New generation of energy efficiency audits – tools for large companiesAuthor Jussi Jääskeläinen
In recent years energy efficiency audits have been at a turning point in large companies. In many places they have been conducted at least once according to the Motiva model, in addition to which, the EU Energy Efficiency Directive and Finnish legislation have introduced new demands for auditing. As a result, many companies have started looking at new ways of surveying their energy efficiency potential?
Most large industrial companies have conducted energy audits in the last five years as prescribed by the EU Energy Efficiency Directive. The obligation has pushed many companies to implement an ISO 50001 energy efficiency management system. ISO 50001 compliant systems require auditing, but companies have more room to influence the scope and frequency of the audits.
The audit has to be conducted about every four years (depending on choice of model). It is, therefore, important to consider which implementation method best suits a company’s operations.
Factory and production plant audits traditionally cover entire facilities. Once such comprehensive audits have been conducted, other approaches may provide a more cost effective way of achieving good results. In selecting the audit model, at least the following factors need to be considered:
- Have any changes been implemented at the plant/factory since the last audit?
- Are there changes in the pipeline at the facility that will affect energy efficiency?
- Did the previous audit produce concreate optimisation measures?
- Was staff know-how increased in conjunction with the audit?
- Is the energy efficiency level directly correlated to the process efficiency?
Audit models for different needs?
Energy efficiency audits can roughly be divided into the following three main categories:
- Standard-based energy audits (e.g. audits according to the Motiva model)
- Sub-process audits/mill service system audits
- Customised energy audits
Standard-based audits are often cumbersome to implement for an entire facility, even if only a monitoring audit is conducted.
Sub-process audits and mill service system audits, on the other hand, can focus on a chosen system or entity which results in optimisation suggestions that are sufficiently concrete. The targets of such audits include, for example, electrical motors, pumping systems, compressed air systems, steam and condensation systems, cooling systems, air conditioning, heat recovery, and heat transfer systems.
In such audits process efficiency or even maintenance needs can be taken into consideration, while field analyses can identify much broader cost savings than traditional models.
The third audit model is customised energy audits, of which a saving potential study is an example. Based on initial data, it focuses on optimisation areas with the most potential and examines the selected targets in sufficient detail. The implementation of a customised energy audit could be done as displayed below.
In the first phase existing materials are reviewed comprehensively, possible changes since the last audit are identified, and scheduled energy efficiency investments as well as those under consideration are checked. Field analyses are typically done in one week by the plant staff in cooperation with an energy audit consultant.
Site inspections generally include:
- Site measurements for chosen targets
- Data logging for chosen targets
- Checking connections and operations of audited entities
- Smaller tests/trial runs
- Interviewing plant staff
- Analysis of results and reporting
A description of the facility’s energy efficiency, measurement results, suggested actions as well as potential savings calculations are added to the final report already during the site inspection. Typically, the goal is to have 90 % of the report complete by the time the final site inspection meeting is held. In order to reduce reporting time MS PowerPoint can be used. The benefit of this reporting method is that part of the materials can later be used for training purposes.
After the site inspection the report is finalised and, if necessary, calls for offers are sent out to equipment suppliers in order to provide more detailed profitability calculations.
What does the future of auditing hold?
Audits have traditionally been implemented via site measurements; the data produced is used to identify targets where efficiency gains can be achieved. The identified targets are then checked for feasibility.
In future, large enterprises will collect even greater amounts of data, which paves the way for new auditing approaches. Rapid developments in tools that can analyze big amounts of data will reduce the need for site measurements and increase the processing of existing data.
In this kind of approach data collection from different systems is essential. It creates the opportunity to unveil new phenomena and increasingly deep analysis of processes. Auditing will consist of data mining that produces new data sets, which can also be utilised in development spheres outside of energy efficiency.
A second clear developmental direction is a trend to implement ever more comprehensive audits. When optimisation work is started, it is irrelevant whether savings are generated in energy, material efficiency, maintenance costs or by augmenting process performance. When adequately efficient tools are available to handle data, fully comprehensive audits become possible. It should be remembered, however, that this approach requires greater know-how about the auditing target or process and that the audits need to be conducted as a team by site staff and a consultant.
A third development direction is audits based extensively on site work. Many companies have seen a reduction in the resources available for efficiency development and in many cases, for example, maintenance has been outsourced. This model runs the risk of missing the big picture, which can leave even good efficiency optimising measures unimplemented. A counter to this problem may be surveys/audits that cover the target on site in great detail, device by device, after which efficiency measures are introduced immediately after the survey/audit.
This can be done, for example, with cooperative agreements where an outside party takes responsibility for selected energy efficiency targets or the entirety. It is important, however, to keep matters at a sufficiently concrete level to avoid energy efficiency work that gets bogged down in scheduled meetings and document maintenance. The best end results are achieved if the service provider offers experts with diverse professional backgrounds to ensure that optimisation measures are brought from the design phase all the way to implementation.
Although interest in audits and analyses in companies has decreased in recent years, this type of information processing should not be completely discarded. By implementing projects based on needs and taking care that results are concrete enough, we can ensure that audits remain an effective way of developing operational efficiency and profitability.
Finding the full potential of CFDKirjoittanut By Hannu Karema
CFD, or Computational Fluid Dynamics, is a method that is often utilized only for the post-design phase, although it is very well suited for wider and efficient use throughout the design process. Optimal use of...Read more » Lue lisää »