Energy savings with freezer control system

Gea has recent­ly con­clud­ed tests prov­ing the effec­tive­ness of its award-win­ning Cal­lifreeze sys­tem which improves prod­uct qual­i­ty and pro­vides ener­gy sav­ings by auto­mat­i­cal­ly con­trol­ling and mon­i­tor­ing the con­di­tion of frozen prod­ucts as they exit the freez­er. Because Cal­lifreeze uses Aquan­tis sen­sors, frozen food proces­sors can ensure accu­rate prod­uct qual­i­ty con­trol and avoid prod­uct wastage. The sys­tem cal­i­brates freez­er para­me­ters through the con­tin­u­ous mea­sure­ment of a product’s lev­el of frozen­ness (Lof). This allows reten­tion time, air tem­per­a­ture and fan speed to be con­trolled so that the required and pre­cise lev­el of freez­ing can be achieved with min­i­mum ener­gy con­sump­tion. To-date, Cal­lifreeze is the world’s first in-line sys­tem to autonomous­ly mon­i­tor and con­trol frozen prod­uct qual­i­ty in this man­ner, help­ing Gea cus­tomers meet their Indus­try 4.0 strate­gies as well as their envi­ron­men­tal targets.

Tests on different french fries varieties

The Cal­lifreeze tests, which took place in Jan­u­ary 2019 at Bergia Frites, a mar­ket-lead­ing french fry man­u­fac­tur­er in Roer­mond, The Nether­lands, were per­formed on 7mm x 7mm shoe­string, 9mm x 9mm straight-cut and 13mm x 13mm crin­kle-cut fries. The results prove that sav­ings can be achieved when freez­ing french fries by increas­ing the evap­o­rat­ing tem­per­a­ture and via the con­tin­u­ous mon­i­tor­ing and con­trol of the Lof con­di­tions accord­ing to qual­i­ty targets.

Automatic setting of the optimum evaporation temperature

The Cal­lifreeze sys­tem was installed at the exit of the Gea Iqf tun­nel freez­er to con­tin­u­ous­ly mon­i­tor the Lof. The tech­nol­o­gy was able to mea­sure the per­cent­age of frozen water in a 80 to 120mm prod­uct lay­er con­veyed from the freez­er to the pack­ing area. The evap­o­rat­ing tem­per­a­ture of the CO₂ refrig­er­a­tion instal­la­tion, also pro­vid­ed by the com­pa­ny, was con­trolled accord­ing to opti­mized set­tings defined by the Cal­lifreeze system.

The results show that crin­kle-cut fries are suf­fi­cient­ly frozen when the evap­o­ra­tion tem­per­a­ture is increased by 3 degrees Cel­sius (-33 C to ‑30 C) with the orig­i­nal reten­tion time. For 7mm x 7mm straight-cut fries, the evap­o­ra­tion tem­per­a­ture could be increased by 5 degrees Cel­sius, which rep­re­sents a 15% ener­gy sav­ings in refrig­er­a­tion sup­ply, with­out a reduc­tion in Lof.

Tak­ing into account the abil­i­ty to increase the evap­o­ra­tion tem­per­a­ture by 3 C for crin­kle-cut fries, for exam­ple, the reduced ener­gy usage would result in sav­ings of rough­ly € 41,000 per year, for a com­pa­ny oper­at­ing a 10 tones/hour plant, with­out affect­ing prod­uct qual­i­ty. This would mean a 18-month Return on Invest­ment (Roi) peri­od for the Cal­lifreeze equip­ment; for larg­er plants the sav­ings would be even greater and the Roi much quick­er. This lev­el of ener­gy reduc­tion rep­re­sents an impor­tant con­tri­bu­tion to the sus­tain­abil­i­ty of a plant and can make a sig­nif­i­cant con­tri­bu­tion in reduc­ing industry’s over­all ener­gy usage if applied globally.

It was also demon­strat­ed that prod­uct Lof vari­a­tion fol­lowed the same trend as prod­uct tem­per­a­ture. With con­tin­u­ous mea­sure­ment and log­ging of prod­uct Lof, and the cor­re­la­tion between Lof and tem­per­a­ture, Cal­lifreeze was shown to pro­vide a solu­tion for in-line prod­uct qual­i­ty track­ing. This sig­nif­i­cant­ly reduces the prod­uct waste often asso­ci­at­ed with batch sys­tems oper­at­ing via man­u­al control.