One way to ensure products are performing is through the use of standards and certification programs. One program that has been driving a quiet revolution is the Liquid to Liquid Heat Exchangers (LLHE) certification program. Before the AHRI 400 standard and LLHE program was introduced a hidden problem had prevailed concerning the performance of plate heat exchangers. Fierce competition drove some manufacturers to kept costs down by minimizing component dimensions. By deliberately compromising performance this way, they could frequently offer more attractive prices. Heat exchangers sized this way often perform poorly over 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. This made it a hidden problem. A uniform system of certification allows customers to compare heat exchangers on a fully verifiable “apple-to-apple” basis. Since no on-site performance tests are needed, costs are reduced as well as energy use. Explosive global urbanization and a trend towards more extensive and powerful district cooling systems has made energy-efficient cooling a challenge. AHRI certification makes it easier to meet target levels for energy use and climate control by adequate dimensioning of the heat exchanger capacity. 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 the total system is often underestimated. Thermal performance can now be compared correctly - as can the price/performance ratio of heat exchangers from different manufactures. The LLHE Certification Program 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 certified and they have met this performance standard for over a decade. Typically, the use of certified heat exchangers in HVAC cooling systems can reduce power consumption in pumps and chillers around four per cent at full load conditions. This means a favourably short payback horizon and an attractive overall investment calculus. However, the successful implementation of the LLHE certification program depends on HVAC consultants promoting its use and end-users/plant operators specifying it in their bidding documents because investing in performance certified plate heat exchangers is a sound investment. Development timeline As far back as the late 1990s Alfa Laval and the Air Conditioning, Heating and Refrigeration Institute (AHRI) began working on the development of a uniform performance certification standard for plate heat exchangers. In 2001, the Liquid to Liquid Heat exchangers Certification programme (LLHE) was launched in North America. Then in 2012 it went global which led to Alfa Laval Australia launching the program locally. In the last 12 months interest has been growing.
