Chillers of up to 1.4 MW in cooling capacity can be tested in a controlled ambient environment of up to 50°C providing more than adequate capability for full and part load testing in compliance with ASHRAE and EU BS EN standards.
The testing process is conducted using industry standard laboratory class data acquisition software which allows reports to be provided in a robust and user-friendly format. A typical single point performance test takes around 35-60 minutes, at the end of which customers are provided with evidence in both electronic and hard copy format together with calibration certificates.
Tests can also be conducted to individual customer test parameters including for example customer-specific part-load conditions or higher ambient temperatures, or to alternative performance metrics such as EER (Energy Efficiency Ratio), SEER (Seasonal Energy Efficiency Ratio), ESEER (European Seasonal Energy Efficiency Ratio) or Airedale’s own Free Cooling Seasonal Energy Efficiency Ratio (FSEER) metric. Airedale devised FSEER as a more representative measurement that takes into account the free-cooling efficiencies possible in Northern European locations. The calculation is similar to SEER but the difference lies in the determination of the load profiles; these are calculated on hours run across four realistic temperature bands and take into account the free-cooling input at each of the band conditions.
Rising heat from the chiller on test is drawn down through a series of 14 air handling units (AHUs) by high performance EC (electronically commutated) fans and across a series of accurately controlled chilled water coils to maintain the on-coil ambient requirements. Ambient temperature is maintained via temperature sensors linked to the Airedale logic system and controls to a level of precision that is well within all relevant international standards.
Precision air conditioning (PAC) testing
The Airedale R&D facility also provides capacity for testing PAC systems up to 150 kW in a closed environment utilising the air enthalpy method of performance measurement. An air loop system incorporating inverter-controlled fans and a water cooling/heating system allows for testing of air cooled, mechanical (DX) and chilled water PAC systems, measuring air volume, supply/return temperature and relative humidity to the precise levels demanded in critical cooling environments.
The facility has been designed with an air volume capacity of up to 24m3/s delivered by two individual fans which generate air which is ducted and measured via the industry standard AMCA (www.amca.org) air loop system with data taken from pressure differential sensors on either side of the plate. Temperature is adjusted via the heating/cooling coils. Air then enters the measurement chamber where it passes through an orifice plate containing nozzles which accurately measure air flow.
End-of-line and R&D testing
The Airedale facility also has an end-of-line quality control and function test area for all products ensuring units perform to design specification before leaving site.
The centre also provides a robust ‘proof of concept’ testing facility, allowing initial design models developed using the latest CAD platforms and virtual engineering techniques such as computational fluid dynamics (CFD) analysis to be developed and refined through concepts and prototypes.
The facility houses its own water tank, a 600kW Airedale chiller and 1.4 MW boiler which is driven by two 55 kW pumps capable of providing water flow and thermal capacity to cover the largest of Airedale’s product lines; the pumps are fitted with inverter drives providing precise part-load capacity.
Airedale also expects to obtain BS EN 17025:2005 accreditation within the next 12 months which will allow it to be considered by Eurovent, amongst others, as an independent test laboratory.
Airedale’s Managing Director, Clive Parkman, said: “With capacity for testing chillers and PAC systems up to 1.4 MW, our test facility is one of the largest of its kind in Northern Europe.”
“A joint collaboration between Airedale’s R&D team who designed the test centre and air handling unit manufacturer Barkell which joined the Airedale group of companies earlier this year, the facility is a great example of the two businesses working together, pooling knowledge and expertise.
Technical Director for Airedale, George Hannah adds: “Our original test centre set the benchmark when it was first built but specifications and capacities for cooling systems have changed considerably since then. Once again we have the ideal environment, big enough to test our largest systems with plenty of capacity for the future. It also provides the ideal ground for our engineers to continue with their innovating product development programme which has seen us secure a number of highly respected industry awards in the last few years.”
