AHRI performance certification of plate heat exchangers goes global!
Already in the late nineties, the US subsidiary of Alfa Laval initiated the first contacts with AHRI (the Air conditioning, Heating and Refrigeration Institute) in order to make them develop a uniform performance certification standard for plate heat exchangers.
In 2001, this Liquid to liquid heat exchangers certification program was launched on the US and Canadian markets. From 2012 it may be used globally. This will have consequences for how plate heat exchangers will be specified and purchased in the future.
The AHRI 400 performance certification is currently the only performance standard available in the world for plate heat exchangers.
A problem undisclosed
Before the AHRI 400 standard and the liquid to liquid heat exchangers certification program were introduced in the US and Canada, somewhat of a hidden problem had prevailed concerning the performance of plate heat exchangers. Since competition had long been fierce, some manufacturers kept their costs down by minimizing component dimensions. By deliberately compromising performance this way, they could frequently offer the market attractive prices.
In a long-term perspective, however, the low prices frequently turned out a delusion. Heat exchangers sized this way often performed poorly during extended periods of time, thus generating high operational costs. During prolonged periods of peak utilization (e.g. during the sweltering summer heat in New York City) quite a number of heat exchangers were working far below the adequate level of heat transfer capacity, thereby forcing pumps and chillers to compensate by working harder. The obvious result: a considerable waste of electrical power. Not only at peak loads, but at all times.
Since the heat exchangers were “doing their job” anyway (although at a high level of energy use) this mismatch of heat transfer capacity was seldom observed nor addressed. You could rightfully describe it as a problem well concealed.
A quiet revolution
The AHRI standard is now applicable globally, which we do not hesitate to describe as a quiet revolution with multiple effects upon our industry. For our customers, consequences (even in the short run) are obvious. By a uniform system of certification, they will be able to compare heat exchangers on a fully verifiable “apple-to-apple” basis. Since no on-site performance tests will be needed, considerable cost reductions can be achieved also apart from reduced energy costs.
Obviously, energy-efficiency turns out a key factor - from a financial as well as an ethical perspective. Explosive global urbanization and a trend towards more extensive and powerful district cooling systems make energy-efficient cooling a challenge for all parts involved - in the production as well as in the chain of decision. AHRI certification makes it easier to meet target levels for energy use and climate control by adequate dimensioning of the heat exchanger capacity. This is especially important in applications like district cooling substations, ice storage systems and free cooling, where a close temperature approach is required.
A small change of specified temperature - significant change in heat transfer area required
Relatively small temperature shifts in the cooling/heating media have great impact upon the heat transfer area needed to keep the heat exchanger working at the specified level of performance in HVAC-systems. The need for sufficient capacity margins in heat exchangers - and their impact on the energy-efficiency of total system - has often been underestimated. With the gradual implementation of AHRI certification in the global HVAC industry, the potential aggregate reduction of electrical power is indeed impressive.
The American “green building” standard LEED (Leadership in Energy and Environmental Design) implies AHRI 400 certification of plate heat exchangers in both heating and cooling applications. The “green building” concept is spreading rapidly all over the world and many countries are now working with standards similar to LEED. Performance certified plate heat exchanger means a green solution.
Energy-efficiency from a new perspective
In the long run, a gradual global use of the AHRI 400 standard will increasingly set focus on energy-efficiency and make manufacturers vouch for their published ratings. Thermal performance can be compared correctly - as can the price/performance ratio of heat exchangers from different manufactures. The AHRI 400 is currently the only performance standard available in the world for plate heat exchangers. The Alfa Laval AlfaQ™ series were the first heat exchangers to be AHRI 400 certified and they have met this performance standard for over a decade.
It also seems logical to predict, that the replacement of obsolete equipment will be stimulated - simply because it pays of handsomely. Typically, replacement with certified heat exchangers in HVAC cooling systems will reduce the power consumption in pumps and chillers with around 4 % at full load conditions. This means a favourably short payback horizon and an attractive overall investment calculus.
In the end, open and verifiable declaration of product performance is a matter of business ethics. However, the successful implementation of AHRI 400 and the certification program will be depending on HVAC consultants promoting its use and end-users/plant operators specifying it in their bidding documents. Investing in performance certified plate heat exchangers is a sound investment.
Technical information on AHRI certified plate heat exchangers from Alfa Laval
New York City - the ultimate test laboratory for heat exchangers in cooling applications
Heat exchanger performance - a crucial but long neglected parameter for energy-efficiency in cooling systems.
AHRI is an organization promoting quality and safety within the North American HVAC industry. It is one of the largest trade associations in North America, representing more than 300 manu-facturers within the global HVAC industry.
AHRI members account for more than 90 percent of the residential and commercial air conditioning, space heating, water heating and commercial refrigeration equipment manufactured and sold in North America. It runs around eighty different certification programs whereof AHRI 400 for liquid-to-liquid heat exchangers is one.