UK: Precision Refrigeration, the foodservice equipment manufacturer, is trialling a new low GWP HFO refrigerant blend in high-temperature refrigerated display units in a new Mexican fast food restaurant in London.
The Thetford-based company pioneered the use of the pure HFO 1234ze in a blast chiller last year and has since been working with N40, one of Honeywell's prototype low GWP blend replacements for R404A.

The installation in the Chilango restaurant in the City of London is one of a number of N40 trials that Precision Refrigeration is conducting around the country. The system was initially developed using R404A but was converted to N40 and retested in Precision's test labs. The results are said to have shown better energy efficiency than the previous R404A refrigerant along with a slightly improved pull down and recovery after defrost.

N40 is one of a number of low GWP blends that Honeywell is developing. Compared to R404A, which has a GWP of 3922 and is likely to come under strict controls under future F-gas regulations, N40 has a GWP of around and is classified as non-flammable. While Honeywell would not confirm the exact components of the blend or their proportions, ACR News believes that this new blend to be a mixture of R32, R125, R134a and R1234yf.

The unit was installed in November 2012 and is reported to be running very well. 'We are keeping a close eye on the site to ensure the systems are preforming to specification,' commented Precision's refrigeration design engineer Steve Goldsmith. 'We also have N40 cabinets running at various test locations throughout the UK and so far all results are very good with no failures to report,' he added.

According to Honeywell, Solstice N40 offers better refrigeration performance than R404A with lower energy consumption, a faster pull-down time than both R404A and R290 (propane) and a similar discharge temperature to R290. It is one of two proposed Honeywell refrigerants for the replacement of R404A. The other gas - L40 - has a GWP of under 300 but is A2L (mildly flammable).

The effectiveness of the new N40 blend was demonstrated in an earlier in-house trial in a standard Precision LCU323 three-door freezer counter cabinet. The objective was to evaluate the temperature performance and energy consumption using R404A as baseline compared to Solstice L40, Solstice N40 and R290 at climate class 4 (30ºC and 55% rh).

The cabinet was commissioned to achieve as close as possible to an L1 temperature class. Temperature performance and energy consumption was tested to EN153 over a 24hour period, with the cabinet empty of product and the door closed. The tests focused on four areas: pull-down time, recovery time after defrost, maximum discharge temperature and energy consumption.

Precision found that Solstice N40 offers better refrigeration performance than R404A with a lower energy consumption. Solstice N40 also exhibits lower recovery time after defrost and significantly better pull-down time alongside a reduction of about 65% in GWP over R404A.

'We expect further performance improvements with gas charge expansion valve adjustments,' says Steve Goldsmith, refrigeration engineer at Precision.

According to Precision, further optimization can be expected with gas charge expansion valve adjustments.

Precision manufactures a broad range of equipment from gastronorm cabinets and counters to blast chillers and bottle coolers.