Cooling towers help Novo Nordisk reduce carbon footprint

Novo Nordisk Cooling towers Kalundborg 
 Photo: COWI.
Novo Nordisk has achieved an annual saving of almost 5 million kWh by expanding its existing cooling tower system with four new cooling towers and optimising operations of its insulin production in Kalundborg . The project is one of the largest energy-saving projects ever carried out by COWI.
It started with COWI carrying out an in-depth analysis of the need for cooling water and the production of cooling water for the Novo Nordisk fermentation factory in Kalundborg, and today Novo Nordisk has realised the largest energy-saving project in company history while having gained a larger and better cooling tower system.
The 4 new cooling towers were put into operation in July 2007, and in October the expanded and optimised cooling tower system was ready to produce energy-efficient cooling water and to contribute an annual energy saving of 4.9 million kWh - corresponding to the annual power consumption of some 1000 homes.

New cooling concept Together with an ammonia cooling system, the cooling tower system is used to remove excess heat from Novo Nordisk's production of insulin culture fluid. The cooling towers are part of the first step of the process of cooling hot cooling water of about 24 ºC from the factory down to 10 °C, before it is redirected back into the factory.
Prior to this project, the cooling tower system functioned as a traditional cooling tower system in which heated cooling water is distributed evenly through all the cooling towers and is cooled down in one passage.

Following the execution of the project, lowering the temperature of cooling water can be carried out in two steps. In step one, all cooling water is circulated through the first half of the cooling towers, after which it is pumped over to the other section for further cooling.

The advantage of two-step cooling is that the outside temperature need only be 6-7 ºC for the cooling tower system to provide 10 ºC cooling water. In the traditional cooling tower system, the outside temperature has to be below freezing point.

The possibility of producing 10 ºC cooling water at higher outside temperatures means that 2500-3000 operating hours are transferred annually from the ammonia cooling system with low energy efficiency to the cooling tower system with high energy efficiency.

CO2 reduction
In addition to saving money, Novo Nordisk saves the environment about 4,200 tons CO2 from coal-fired power production annually. This has been a major incentive for Novo Nordisk, which was the first Danish company to enter into an agreement with the World Wildlife Fund (WWF) on voluntarily reducing the company's CO2 emissions. 

For COWI, this project is one of the largest energy-saving projects ever. COWI acted as lead consultant and was in charge of the entire process from finding and developing the energy-saving project to designing and supervising the construction of the plant.

LAST UPDATED: 18.09.2017