REFRIGERANTS


After careful consideration, multiple circuits charged with Opteon XL40 with a GWP of 239 (AR4) were chosen. These off ered signifi cant savings in terms of CapEx and OpEx when compared to centralised plant using CO2


or NH3 , with an


additional benefi t of built-in redundancy ensuring product safety and quality in the event of a loss in refrigerant charge during times of high ambient temperatures. The use of an A2L refrigerant did require some thought in terms of risk assessment, particularly as the design called for such a large charge size on site. Fortunately for this particular project there were no limits to charge size due to large room volumes, equipment location and class of occupancy. (EN 378-3 location Cat II, access Cat C and <1 person per 10m²).


Five chambers Totalling 1700m3


split between fi ve rooms fi ve chambers was


phase 1 of the refurbishment project. The result is a truly groundbreaking installation by SK Heating and Cooling Ltd (part of the MECSIA group) of Gloucester, and one that has led to a multimillion-pound business segment and a very healthy forward order book for both medium and low temperature storage in the food sector.


The pipe run is in the ceiling void; the internal volume of which is suffi cient to prevent reaching lower fl ammability limit, and ventilation to fresh air provided at both ends of the space. Additional safety measures were incorporated by installing leak detection at the valve station. Visual alarms fi tted at each evaporator and audible alarm in each room. As a new installation there wasn’t an opportunity to make


a realistic comparison between performance old and new. However, we did make some comparisons based on operating


conditions, refrigerant characteristics and volumetric and isentropic effi ciency of the compressors used.


Marshalling area The new installation completed July 2023 is shown to the left


and the legacy system to the right, consisting of two Grasso compressor sets running on R-134a. The old evaporators were installed over the loading docks and required frequent. cleaning due to lorry exhaust fumes. The new instal has dual discharge evaporators located along the centre axis of the room supplied from 3 semi hermetic condensing units. As predicted, signifi cant improvements can be made when


moving from R-134a to R-454A. Most signifi cantly the reduction in compressor displacement required. The legacy units having a displacement of 844m3/hr with the new having a total of 234m3/hr. Low GWP A2L refrigerants have been proven to be a good, safe alternative to use in Cold Storage applications, off ering benefi ts in terms of effi ciency and environmental credentials. They provide an excellent alternative option for customers who prefer to avoid centralised plant, thereby providing an additional off ering to contractors. No additional skill sets are required of the service engineer when using low GWP Opteon refrigerants as system architecture and equipment are familiar. In comparison to the situation when A2L refrigerants were


fi rst being tested, a lot of progress has been made. It is clear that low GWP HFO blends can now be seen as a routine solution for a variety of applications including the cold storage sector where cost and product security are major concerns. This case study shows we now have readily available low GWP HFO technology to roll out rapidly and at scale.


The good news is there are refrigerant solutions available that can help us contribute to governments’ drive towards net zero as well as off er benefi ts to both our own businesses and those of our


customers.


FANS


Pipe Run in Ceiling Void


Leak Detection


"5 Chambers" Room 1


Visual Alarm at Evaporator


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