News
What’s new for AHUs?
Change is afoot for the Eurovent Certified Performance programme for Air Handling Units (AHUs). 2024 has seen two big improvements with the introduction of a new test methodology and new energy class calculations. We spoke to Project Manager, Donatien Lambert, about the evolution of the AHU programme and what the changes mean for manufacturers and HVAC professionals alike.
Changes to test methodology
The AHU programme has evolved in response to manufacturer feedback. Donatien explained, “We have taken steps to reduce the number of tests required, streamlining the process for manufacturers, while ensuring the tests we do undertake are more representative of actual performance.” It’s win-win for manufacturers and HVAC professionals, as the programme attains a more integrated approach to product evaluation, with certified data bearing even more realistic results.
Hi Donatien, can you tell us about the changes to supply and exhaust testing?
Donatien: “Our main aim in re-thinking the test methodology was to evaluate AHUs more holistically. Previously, the supply and exhaust AHUs were tested separately. Now both the supply and exhaust units are tested at the same time, with all points tested together. This offers a much more cohesive and efficient approach to product testing."
Has there been reductions in the tests required?
Donatien: “Yes. Simplifying and streamlining the programme was also a priority. Previously we regularly tested both real units and model boxes. From 2024 there will be no surveillance tests for model boxes, and model box tests will only be required if the unit undergoes changes or is new to certification. The process has been simplified to avoid unnecessary testing.”
Can you tell us about the addition of humidity efficiency testing?
Donatien: “We have introduced humidity efficiency testing for heat recovery systems (HRS). Prior to 2024, laboratory tests included the efficiency of the HRS and its capacity to recover heat under dry conditions. From now on, humidity efficiency under summer conditions will be tested. This is because humidity efficiency plays an important role in energy class rating.”
What’s in store for internal leakage test requirements?
Donatien: “Amends have also been made to the testing of the internal leakage of the unit. The more airflow that is lost, the harder the fan must work, and the more energy is consumed. Besides, for hygienic reasons, leakages shall be minimised. It is therefore vital that the results gained for internal leakage tests gives an accurate and reliable result. The units are now tested to include the Outdoor Air Correction Factor (OACF) as well as the Exhaust Air Transfer Ratio (EATR).”
Changes to energy class calculations
Moving onto energy class, Donatien described the latest developments to ensure the accuracy of calculations.
Can you tell us about the changes to reference cities?
Donatien: “In the past, manufacturers were able to pick their own winter design temperature when it came to energy class calculations. We now have set reference cities for both summer and winter energy efficiency class. This ensures that AHUs can been compared fairly and accurately by those using certified data.”
We hear you have expanded the calculations; can you explain what has changed and why?
Donatien: “The newly introduced summer calculations examine the impact of the heat recovery systems bypass pressure drop on the energy efficiency class. Pressure drop adds to the consumption of energy of the fan and the overall efficiency of the HRS. For example, in winter when the HRS is in operation, the unit will experience some pressure drop. While the pressure drop will affect performance, the AHU is also gaining efficiency via the reuse of heat from the HRS, thus negating the impact. However, in warmer temperatures when the HRS is not in use, pressure drop can also be experienced when the bypass is open.
“This new calculation deciphers the influence on the system between the pressure drop of the HRS when in use, and the pressure drop of the bypass when it is left open, and the HRS is not in use. It provides information on the balance between HRS and bypass pressure drop.”
That’s a lot of changes! Thank you for your time Donatien.
So, there you have a roundup of the new test methodology for AHUs and new energy class calculations. Thanks to these developments, the testing regime has been made more efficient and effective, for the benefit of both manufacturers and their customers.
If you want to know more about AHU certification hit the links below or email Programme Manager, Donatien Lambert.
View the Eurovent Certified Performance programme for AHUs