What to Expect from an Effective Compressed Air Audit?
There has been a high increase in the general awareness of compressed air systems in the energy conservation field. Popularly associated with several words such as the "the fourth utility, your most expensive utility, eight times more expensive than electricity, and a quarter-inch leak costs $9,000 in wasted energy. This increasing awareness of compressed air systems has led to a relative increase in the numbers of compressed air auditors. Due to this mass availability of auditors, plant operations, engineers and maintenance managers need to fully understand what they should expect from a complete air system review.
Begin with the Basics
Costs incurred on compressed air system reviews are mostly around the mid to high four figures or low five figures, but the paybacks on it are usually measured in months and not in years. These reviews pave the way for the development of longer-term follow-up opportunities, thereby leading to a significant reduction in the operating cost. Some plants have been able to slash their operating costs by a rate of 80 percent.
Most firms are of the opinion that the expenses generated on energy are variable, while in fact, a well-managed and well-controlled compressed air system can reduce the amount spent on production energy, which signifies a reduction in fixed costs. This is mainly because as there is a decrease in the electrical power consumption, production rate increases or remains the same.
The net income effect experienced on a profit of $2,000,000 in sales at a net 5 percent margin, is similar to the impact a $100,000 energy reduction will have. If done correctly, a 25 to 50 percent reduction in air demand and power costs can be experienced almost immediately from an active plant air system survey or audit.
The following are some of the frequently asked questions and issues about what drives the energy costs in compressed air systems which are discovered during a survey:
In most situations, the usual case is all of the above, including some other reasons.
A quality overview of the compressed air system should be provided by the survey, which should be in cost proportionality with the size of the system, system complexity, and its potential recovery. Also, both short-term and long-term plans should be produced by the survey, to put in place, the essential control, and management of the air system.
There should be:
Although useful, this minimum effort cannot produce the ultimate payback which can be gotten from more complete and detailed system analysis and training. There should be additional follow-up programs, or even better, a more wholly controlled and fully managed compressed air systems after the first audit.
A minimum effort audit that is well planned can create a significant amount of savings and success needed to encourage the user in the future press for efficiency and returns to go for more in-depth programs. Any audit that does not meet up to these expectations should not be accepted.
Assessing the System from the Supply Side
Evaluation should be made on the suitability of the existing air compressors as to the application and the general apparent performance and condition, without having to disassembly of the compressed air system or any mechanical work.
The evaluation report should adequately address the efficiency ratings, suitability of unloading controls, and capacity for translating lower air demand into lower power cost. Moreover, when necessary, obtain a report on the potential for modification, plus the capability for system sequencing, installation, and support systems, like the cooling water and ventilation, and information on a more superior or more power efficient equipment and controls variants.
Also, an evaluation of the compressed air treatment equipment which includes;
Individually, data on the following should be carefully viewed:
The operating control band for the compressor capacity controls should include the primary dry air storage for the production area, to ensure that the authorities are operating concerning actual production and not about false signals from internal piping and other pressure spikes - this is of high importance.
A practical review or audit will evaluate all the compressed air generation, treatment and distribution of air to the production area. Although it is not necessary to include the recommendation of new equipment, any operating energy efficient methods that are currently available, and/or generic alternates for future considerations should be provided by the audit.
Reference should be made to the impact on productivity and quality by any recommendations provided. It should also be able to answer the question on the capability of the unloading controls of translating lower demand for airflow into lower electrical usage - this is of utmost importance. The skills of the unloading controls depend on the type of compressor, type of power, the condition of the equipment, the piping, and storage capacity.