Industrial Utility Efficiency

# Refrigerated Dryers Tested by the CAGI Performance Verification Program

Compressed Air Best Practices® (CABP) Magazine and the Compressed Air and Gas Institute (CAGI) cooperate to provide readers with educational materials, updates on standards and information on other CAGI initiatives. CABP recently caught up with Rick Stasyshan, Technical Director for the Compressed Air and Gas Institute (CAGI) to provide readers with some insights into the benefits of CAGI’s Verified Performance Program for refrigerated compressed air dryers.

CABP: We understand the expansion of the CAGI Verification Program started several years ago with refrigerated compressed air dryers.  Why start there?

CAGI: Removal of water from compressed air systems is a fundamental requirement of a well-designed compressed air system. Excess water can reduce product quality, increase maintenance costs, and reduce productive life of equipment. End users, distributors, and specifying engineers must be certain that the actual performance of their compressed air dryers matches their expected performance, as deficient dryer performance will negatively affect financial and operational performance.

There are several ways to remove excess water from compressed air systems, with one of the most popular being refrigerated compressed air dryers. Refrigerated dryers remove water from compressed air by cooling the compressed air, condensing the water vapor in the compressed air, and removing it from the system. With the popularity of this type of dryer, it was logical to start here.

##### Products participating in the CAGI Refrigerated Dryer Performance Verification Program feature the appropriate label on the cabinet.

CABP: Many of our readers focus on air compressor performance.  Why should consideration also be given to the refrigerated dryer?

CAGI: As with most equipment, purchasers of refrigerated compressed air dryers face an initial purchase price as well as ongoing operational expenses, which typically exceed the initial purchase price by a wide margin over time. These expenses include the power to run the dryer and pressure drop that arises as the compressed air flows through the dryer. Understanding the dryer performance will make the overall system efficiency better managed and understood.

CABP: So can we assume there is an industry standard established to measure and report the performance?

CAGI: Reputable manufacturers of compressed air dryers rate their equipment to the ISO 7183 standard, Compressed Air Dryers -- Specifications and Testing. The ISO 7183 standard provides a uniform means of testing dryers to determine the critical performance parameters of outlet pressure, dew point, and flow (also referred to as capacity or size), as well as the power consumption and pressure drop ratings that affect the ongoing costs of operating compressed air dryers.

The Air Drying and Filtration Section of CAGI recognizes the need for purchasers, specifying engineers, and users of refrigerated dryers to receive accurate performance data, including flow, power consumption, dew point, and pressure drop ratings. The section members agreed  to publish ratings in accordance with ISO 7183. CAGI member companies also publish Refrigerated Dryer Performance Data Sheets which are posted on their product websites with quick links via the CAGI website (www.cagi.org). The data sheets provide nice performance comparisons for the equipment purchasers.

CARP:  Will there be Performance Verification on these products like there is for air compressors?

CAGI: There already is.  Many members took the additional step of developing and participating in a performance verification program through which individual participating company performance, published on standard CAGI datasheets, is verified by a third party test lab. Visit the CAGI website, http://www.cagi.org/performance-verification/, for more information about the performance verification program, datasheets, and a list of participating companies.

Someone who purchases a dryer from a company participating in the CAGI Performance Verification Program can be assured the performance of the purchased unit will match their expectations.

CABP: But what about dryers that are produced by manufacturers that do not participate in the CAGI performance verification program?

CAGI: That thought was thoroughly discussed. CAGI decided to purchase and test a unit from such a company.

The unit was purchased directly by Intertek, the same third party test lab that CAGI uses to administer its performance verification programs, and the unit was shipped directly to the test lab. Intertek obtained performance claims from product brochures on the manufacturer's website. The lab tested the unit to the ISO 7183 standard, using the same requirements that apply to units tested in the CAGI program. Here are the results, copied from the official test report generated by the lab:

 Performance Item Claimed Performance Actual Performance Difference Result** Outlet Pressure Dewpoint 35.00 °F 49.60 °F +14.6 ∆°F Fail Pressure Drop 3.2 psi ∆ 5.00 psi ∆ + 1.80 psi Fail Power Consumption* 1.15 kW/100 cfm 1.01 kW/100 cfm 88.21% Pass

*Specific Power Input at Full Flow, kW/100 CFM

**Considering Allowable Tolerance in Standard, Result if Manufacturer was Participant in CAGI Performance Verification Program.

CABP: Can you elaborate on what this means to a purchaser?

CAGI: End users that purchase this dryer model based on the claims of the manufacturer would have far more water in their systems than they were promised by the manufacturer. The difference in dew point is significant and could result in potential damage to end user equipment and facilities; i.e. pneumatic tools, piping, etc., and a negative impact on work product or manufacturing quality. The increased pressure drop through the dryer would reduce system pressure, leading users to increase air compressor operating pressure to compensate, thereby increasing power consumption of the air compressor.

The performance of this 200 CFM dryer is disappointing when compared to the manufacturer's claimed performance, but imagine extrapolation of these deficiencies to larger dryers. For example, assuming similar failures in a 1000 CFM dryer, an additional 5.3 gallons of water would be introduced into the compressed air system per day. Economic losses due to additional pressure drop (above claimed performance) alone would be approximately \$1,300 per year at \$.07/KWH.

A distributor who sold this dryer to customers would have a lot of explaining to do, as poor product, potentially damaged production equipment and facilities, excess corrosion, and decreased profitability most likely would damage the distributor / customer relationship. Continued reliance on such dryers could lead to a distributor's reputation and expertise being questioned in the market.

CABP: Who can participate in CAGI’s program? Do you have to be a member and how is a Participating Manufacturer recognized for participation?

CAGI: Participation is voluntary and is open to all manufacturers, whether they are a CAGI member or not.  Any manufacturer of Refrigerated Compressed Air Dryers from 200-1000 SCFM is invited to participate.

Participating manufacturers and the results of the verification tests will be posted on the CAGI website. Participating Manufacturers that pass the verification program test procedures will be allowed to utilize the CAGI Program Verification Seal on the models' specification sheets, in its product literature, and a decal placed on the product itself. This is the Participant's public representation that the stated refrigerated dryer performance and efficiencies have been verified by an independent laboratory.

CABP:  How does the Independent Verification process work?

CAGI:   On a regular basis the administrator will select and test samples of the equipment to verify that they meet the Manufacturers' certified published performance ratings. Two units will be tested annually per participant. The units will be selected by the program administrator from manufacturer or distributor available stock. If a tested unit does not pass, the manufacturer has the option to have a second unit, which was previously chosen by the administrator tested. If this unit also fails, the manufacturer must re-rate the unit based on the test results within 30 days or be ejected from the Verification program.

CABP:  Our feedback on the CAGI compressor data and verification program has been favorable and we look forward to input from CAGI on this program. Do you have any closing thoughts?

CAGI: The CAGI Refrigerated Dryer Performance Verification Program has been operating for several years now, and manufacturers have had ample opportunity to join the program. With the number of products tested and verified, we determined the timing was right to provide further market education on the program and the resulting benefits. The users of the refrigerated dryer products deserve to get the performance they are promised when buying a compressed air dryer. As a compressed air dryer user, a distributor, and/or compressed air system assessor, by purchasing a refrigerated dryer only from participants in the CAGI Performance Verification Program, you can be assured of getting published performance.