FAQ - Frequanlty Asked Questions
Why measure the intake air flow when suppliers are only interested in compressor power?
The power consumed by the compressor is important, but only in combination with the measurement of the flow and pressure demand from the compressed air plant, can the actual efficiency of the production and consumption process be determined. In order to choose the right compressor, it is necessary to first learn about the actual needs of the plant. If you buy a newer compressor, it will work with losses, whose source will be very difficult to find out! By measuring the power consumed by the compressors and the demand for the air, you will know where the potential for savings really is.
If air compressor suppliers offer free audits, why do you want to be paid for them?
The result of such a 'free' audit is often a suggestion to buy a new variable speed compressor. If you really want to save on compressed air, reduce your demand and consequently try to shut down at least one of your compressors. You will save on energy, service and maintenance costs and will not have to pay for a new machine. In order to achieve this goal, our experienced, independent auditors will examine your compressed air systems and propose only those solutions that actually generate savings. The cost of the audit compared to the cost of purchasing and, above all, maintaining the compressor is negligible. On average, the return time of our proposed improvements is between 3 months and a year.
What do you mean, you're independent?
It is in the interest of every compressor distributor to promote all the products of the manufacturer, including those that are not very good. We have no interest in this. We sell your peace of mind. If we offer any equipment, it's only because it's good.
How much electricity in a compressor is converted into compressed air?
In a screw compressor, the most popular industrial device for the production of compressed air, it is assumed that about 80% of the electrical energy supplied to it is converted to heat, and only 20% is used to convert into compressed air energy. It is therefore worth measuring how much and how compressed air is used as well as how much energy is needed for this purpose. The process should be evaluated on an ongoing basis by the unit of energy consumption index e[ kWh/m3], which for positive displacement compressors should be in the range of 0.09-0.13 [kWh/m3], depending on the size and working pressure of the compressor. It is worth to regularly and systematically check the amount of leakage of compressed air.
What is the cost structure of a compressor?
Nowadays, when managing fixed assets requires the use of professional software, the users' become more aware of the truth about the cost of ownership of a compressor, which we have been talking about for many years. Well, the cost of purchasing a compressor during 5 years of operation is about 20% of the total cost, expenditure on the service of equipment consumes about 10% of the cost, while usually more than 70% of the total cost is related to electricity used to produce air. It is clear that we only spend 1/5 of our total costs when we buy a compressor, and when we make a decision to choose a compressor at this stage we determine the bulk of our future costs.
What is the average leakage rate for compressed air in industry?
In a standard compressed air system, leaks generate a loss of ~30% of the compressed air produced. It is possible to identify all of them, and while working with us, it is also possible to evaluate their size, which allows you to determine the sequence and possibility of eliminating the leaks. We are worth cooperating with. We do offer real help.
How much can I save by improving an existing system instead of buying a new high-performance compressor?
On average, leaks in industry losses amount to 30% of the energy consumed by the compressors. Even if you install a new compressor, the losses will still be 30%, i.e. 30kW for every 100kW installed!
Why should we examine the distribution system before buying a compressor?
Imagine you are the captain of a sinking ship, what do you do first? Do you first look for equipment to drain the pump water or do you command people to immediately patch up the hole? If you start by buying a compressor, you will find that the compressor is oversized or completely unnecessary when the distribution system is improved. The relatively small amount of money invested in piping upgrades generates considerable energy savings. The payback time for such an investment is calculated in months, not years, as in the case of compressors.
So does saving come down to improving the distribution network?
By no means! It is essential to start with the distribution network. Only after this work has been completed will it be clear what needs to be done in the compressor plant to achieve further savings. You may find that you do need to buy a compressor, but certainly with these improvements, it might not be as large as it would seem before the distribution network upgrade. Reducing the operating pressure in the plant by 1 bar will reduce electricity consumption for compressed air production by 7%. Moreover, it will also reduce leakage by 13%. It is not worth reducing the pressure by 1 bar at once, but by 0.1 bar per month. This is a proven practice in plants where it has been possible to reduce the pressure from 8.0 to 6.5 bar! It is worth a try.
Does the working pressure make a difference to the energy balance of a compressed air system?
Reducing the operating pressure in the plant by 1 bar will reduce electricity consumption for compressed air production by 7%. Moreover, it will also reduce leakage by 13%. It is not worth reducing the pressure by 1 bar at once, but by 0.1 bar per month. This is a proven practice in plants where it has been possible to reduce the pressure from 8.0 to 6.5 bar! It is worth a try.
How to build a leak-free compressed air network?
The Teseo modular piping system, equipped with the most suitable sealing and joints, provides much better tightness, stiffness, appropriate aluminium elements and safety than any other aluminium system. It has been tested for over 20 years and is beyond compare with any steel, bolted or welded system. The delivery is always based on the design and can be installed by the local infrastructure department. You can replace your compressor or dryer in the future, but the pipeline is an integral part of your plant. It usually stays for longer. This is what you will leave behind for your successors. Therefore, adapt the pipeline cross-section to your future needs. Properly planned pipeline is fundamental for cost effective energy policy, probably the most important of all elements of good engineering practice. Use high quality materials and don't forget to divide the valve system according to local needs. The use of original piping systems ensures consistent, high transmission efficiency and a high level of safety in your factory.
Is proper cooling of air-cooled compressors important?
YES - supply the compressors with cool air! Lowering the inlet air temperature by 3°C will generate a saving of 1% of the energy required to achieve the desired operating pressure. The inlet air in the compressor station should provide the compressors with such access to fresh compressed air as is appropriate not only for the compression of air, but also for its cooling (cooling fans capacity), so that the inlet air velocity at the inlet to the compressor station does not exceed 2.5 m/s.
Is it worthwhile to shut off non-working compressed air extraction machines with valves?
The use of manual or automatic shut-off valves can significantly reduce your electricity bill: stop feeding leaks and stopped machines. What's more, avoid improper applications! Check the performance of compressed air-based cooling, mixing, rotating and pumping systems in your plant.
What kind of experience do you have?
In addition to my educational background in compressors and blowers, I have been working in the compressed air industry for more than 22 years. I have been involved in the selection, delivery and service of more than 1,000 compressors ranging from a few kilowatts to several megawatts. I am one of the most experienced specialists in the industry. My knowledge has been tested by facts. Today, I put all my knowledge and experience into helping users to reduce their compressed air consumption, and the results increase with every audit. When you ask this question, I can say that the potential savings from the last 20 audits carried out by me amount to almost 2 megawatts.
It is well known that production plants want to reduce their own costs, and the costs of compressed air production are very high. Many entities offer such services as, e.g:
- compressed air audits
- compressed air leakage detection
- compressed air leakage removal
- air flow measurements
- designing the compressed air system
- commissioning of compressed air systems
What is your company's response to the competition's offer?
Above all, a compressed air audit is not only about measuring the air flow or pressure in the same timeline and recording the flow inside the pipeline in a report that is sent to the customer together with the report. A true and reliable audit is supposed to bring concrete benefits to the user: it is supposed to indicate the sources of the greatest air leaks. It is only when compressed air leakage is precisely detected and measured that an effective compressed air leakage elimination plan can be prepared.
The measurement of air flow gives the opportunity to obtain a lot of information about the compressed air system, so the most important thing is to interpret the results and their variability over time. Sometimes this indicates the need to rebuild the system and design the compressed air system from scratch, sometimes it is enough to introduce minor changes. A compressed air system is a combination of several processes, each with its own specific efficiency - the production, accumulation, treatment, transmission and use of compressed air.
Eliminating leaks and upgrading the compressed air system are the most important elements that help to save money. However, it is important to bear in mind that there is no guarantee of efficiency if these measures are not completed with a system that allows the compressors to adapt to a reduced and more stable consumption.
A system should be used to ensure that the plant is properly timed and regulated through: gradation of compressor sizes, system of master compressor control minimizing the costs of idle run and narrowing the scope of pressure regulation, appropriate size of tanks, variable speed drives, etc.
If there are leaks in every system, what is the point of one-time leak detection?
Indeed, there are compressed air leaks in every system. Reducing leakage rates requires regular action. However, our leak detection does not only indicate current leaks, but also diagnoses the entire system on the leak risk side. By carrying out measurements we identify areas and technologies where the risk is greater and propose solutions to reduce this risk. We prepare a repair program that brings long-term savings.
I'm thinking about carrying out a compressed air leak detection in my plant. I know that measurements should be carried out during a stoppage which, of course, costs money. How much time is needed for detailed leak detection?
It is impossible to evaluate this time explicitly. The size of the plant, itd construction , the availability of pneumatics and finally the type of machines - all these factors have a huge influence on the time of measurements. We recommend that you make an appointment with us for a local inspection, during which we will be able to estimate the exact duration of the measurements. The detection of a network powered by compressors with a total power of approximately 75 kW is possible in a relatively dense plant within one day on average.
How do you present the results of the audit? Will I know exactly what you have found and what I have to do?
Each of our compressed air audits, regardless of the scope or size of the plant, always ends with a live presentation of the results to a group of interested parties. We will be there to answer all your questions and resolve any doubts you may have. In addition to each audit, we prepare a paper and electronic version of a comprehensive report in accordance with the American standard (European standard ISO 1101). Above all, however, we remain in constant contact with our partners. We are open to telephone and e-mail contact and meetings as far as possible. We are involved in all activities in which our help may be needed. For us, measurements are not the end, but the beginning of cooperation.
There are many companies that have been doing compressed air audits for many years. What is more, it is also done by compressor companies, which have a serious background. Why should your measurements be better or more reliable than those?
Thank you very much for your question, or rather for two in one. Let me start with the first - that is, the available audits of compressed air. The most frequently performed measurements called ''audits''' are air flow measurements. In my opinion, we should take into account the definition of an audit, which should be an assessment of efficiency. In the case of compressed air we are dealing with two areas - one is the area of compressed air consumption and the other is its production. In order to assess each of these areas it is necessary to measure the 'effect' (OUTPUT) and 'contribution' (INPUT) of the energy in each area. First of all, you need to know how to assess it, according to which criteria and indicators, and on which standards to base your audit. So if the company taking measurements starts the audit, whether it is an independent company or a compressor company, it should first of all indicate its goal, methodology and expected results. It is best to do it in accordance with a standard. There is a problem here, because the available documents describing this process are only ASME standards, according to which, for example, ARIA-C company works. The standard that will have a European and global reach is ISO11011. Its release is announced for April 2013.
In our audits we use strict definitions of areas, their INPUTs and OUTPUTs, and we perform them according to the recommendations of the ASME standard. In my opinion, if someone takes measurements with one or two flow meters in a dozen or so or several dozen points - but not at the same time it is certainly not able to build an image of air intake in the entire body of the industrial plant. I think that they perform the so-called reference measurements determining the flow (hopefully also the pressure) in several points. The result of such measurements (very often solidly and honestly conducted) can only be the knowledge allowing the proper selection of the flow meter to the given point - whether audit or stationary, but I would not dare to make a diagnosis based on such measurements as they would be insufficiently documented by a reliable measurement procedure and thus they might be misleading. Drawing conclusions on this basis, that e.g. the user should buy a variable speed compressor, is by no means enough. First of all, such measurements should be performed simultaneously - on one time line. Secondly, I have seen reports on which only the flow of air was recorded, and there was no pressure - it is as if someone wanted to describe the effectiveness of electric power supply by giving only the value of current, regardless of changes in voltage values, or vice versa. Thirdly, there are also measurements which show the flow velocities in the pipeline - and do not determine the pressure drops. What is the cognitive value of the 'audit' for the ordering party?
Some of the audits performed by compressor suppliers are aimed at selling another device. I have not yet encountered in practice a situation in which a supplier of compressors has taken measurements which resulted in a chance to shut down the compressors already supplied by the compressor company, or to deliver a smaller unit or a fixed-rotary machine instead of a variable-rotary one. For many excellent engineers the fact of being employed by a compressor company is frequently only a burden associated with the obligation to meet the sales budget.
Going back to the point, our audits usually start measuring the size of leaks by ultrasonic detection of leaks using equipment of the highest class together with determining the size of leaks and evaluating the order of their removal. At the same time, we measure the air consumption in the production part, the amount of air produced and the amount of energy consumed for these needs. In this way, we also give the user a good idea of the cost of air production, the unit power consumption per 1 m3 of air and interpret the results of the measurements, giving the user other important tips that can save them significant amounts of energy. This is my area of expertise. I've been selling compressors for over 20 years, and now we're putting all our expertise into shutting down as many compressors as possible. We have been carrying out measurements and audits for 3 years. We can already talk about the millions of euros that we have saved our customers in compressed air.
My company works in a changeable way? Every quarter is different when it comes to assortment. Is it possible and reasonable to measure my compressed air system?
Indeed, the variability of the demand on the air intake system can be a problem, but how else can we diagnose it and apply solutions when we do not know the data from verifiable measurements? In this case, stationary metering is an excellent alternative to audit measurements, and the right monitoring and reporting system allows for proper analysis. We currently offer services that also include the installation of our measurement equipment and the provision of monthly or more frequent paid analyses, reports and recommendations to users. This is a solution for those who are not planning to invest in this area, but need to be efficient. Compressed air costs exceeed the costs of electricity more than 5 times. A screw compressor, or any other for that matter, is not only about the purchase price. The cost of ownership represents in 70-80 % the cost of energy used for compressed air - only for the first 5 years of use. The longer a compressor runs, the greater the share of energy costs in the cost of 1 m3 of air. It is difficult to use this knowledge unless you obtain it yourself from measurements or from independent experts.
What information do I need to include in my request for a compressed air flow meter?
There are a number of factors that influence the choice of the flow meter. In any case, the best option is to make an appointment to inspect the compressed air system and clearly identify the applications for which the flow meter is to be used. The following information should be included if your inquiry is to make a preliminary diagnosis of the subject of purchasing a compressed air flow meter: Is the measurement upstream or downstream of the drying system? What is the pressure at the measuring point? What is the diameter of the pipeline at the measuring point? What are the approximate flow rates at the measuring point? Is the flow meter to be stationary or portable? Is the flow meter to have a built-in memory for archiving measurement results? If there is a need to include compressed air flow measurements in the monitoring, how is communication to be carried out (signal 4...20mA, RS232, RS485, pulse, etc.)