Famous Swiss chocolatier expands refrigeration plant using ammonia

The creation of chocolates is a highly sophisticated technical procedure in which refrigeration plays a vital role in complying with precisely defined conditions of production and stringent hygiene demands. Swiss chocolatier Lindt & Sprüngli is world renowned for its quality confectionaries, and to ensure that top quality, the company has again extended its production facility in Aachen where the new production hall features an all-new NH₃/R134a refrigeration system supplying a total capacity of nearly 5MW. The high cooling demand comes from the need to cool production equipment as well as air conditioning of the production rooms and storage space. Changes in humidity and temperature in the production halls, like variations in cold-water temperature and quantity required for the production machines cannot be risked.

 

 

In 2013, in the initial planning stages, HSV intended for a 600kW R134a chiller for cold water (8-14°C) production for air conditioning the hall and a 500kW NH₃ plant for brine cooling (-3-2°C); however, shortly after commissioning, the chocolatier decided to significantly increase the cooling capacity to 3400kW for cold water production and 1800kW for brine cooling. HSV answered the call by developing a modular refrigeration concept around which the plant can grow. What was not able to grow, though, was the space for the cooling plant; a solution had to be found to accommodate four 840kW R134a chillers, three 600kW NH₃ chillers and all associated equipment into the originally planned for space. 

 

Fitting the NH₃ chillers would prove most difficult due to the necessarily large conventional evaporator and separator dimensions. HSV called on compact Kältetechnik to construct the seven chillers, the largest order the company had ever received. 

 

“We didn’t encounter too many problems. We were very well prepared from the beginning; every detail was spoken about and cleared from the planning phase until the delivery of the machine. It was an excellent collaboration between compact and HSV,” said Dirk Leuteritz, Project Planning and Sales at compact Kältetechnik.

 

Time was also a constraint, originally scheduled to take three years, the expansion project’s timeline was reduced to only one year. The construction of the building began in February 2013, the chillers were ordered in May, and by October, most things were constructed so Lindt could begin setting up the production lines.

 

 

“The installation is a machine unit with open type screw compressors for the brine chiller and mounted with a reliable oil control system. We used the Alfa Laval U-Turn evaporator for minimum ammonia charge, completely tubed and welded. The U-Turn evaporator is actually what helped us overcome the challenge of space restrictions; it is very space efficient equipment for ammonia applications, and we’ve had a great experience with it,” said Leuteritz.

 

“The installation has three circuits with two compressors, so there are six screw compressors type OSKA8571-K. For each circuit we also have a BITZER two-step oil separator OAC25112 installed. Our compressors fit the efficiency and capacity specifications very well,” said Andreas Riesch, Sales and Marketing Director, BITZER

 

The three separate, power controlled, air-cooled, single stage ammonia systems operate in parallel, with an evaporation temperature of -6°C and a condensing temperature of 42°C. The compressors are controlled according to the evaporation temperature. Each unit is equipped with maximum safety technology to prevent leakage of refrigerant or oil.