Pulling out all the stops to save energy
A future-proof refrigerant, higher cooling capacity and significant energy conservation: Those were the goals of Koenigsdorf Oberflächentechnik GmbH & Co. KG in Wolfhagen when they decided to purchase a new cooling system. These goals were achieved; the new system designed and built by L&R operates much more efficiently.

Since 1969, Koenigsdorf has been focussing on the process steps of powder coating and anodising and, as evidenced by its steady growth, has been very successful in doing so. The company invests continuously and proactively in new plant technology, and decided in 2011 to purchase a new refrigeration system for cooling the anodising baths. There were two reasons for this. Operations Manager, Jakob Neufeld: “The existing refrigeration system operated on R22 refrigerant, which was banned in 2015. Due to its age, it was also no longer state of the art in terms of energy efficiency. Furthermore, we needed additional cooling capacity due to an increase in capacity.”

Effective energy saving measures
These requirements were implemented by L&R. Georg Hesse from the company’s Planning and Sales department: “We documented the current situation on site and, on the basis of the data obtained, designed a system that differs quite fundamentally from the old system in key aspects.”

Firstly, the refrigerant used is R 134a, which is characterised by low ozone depletion potential and – in conjunction with the Bitzer CSW screw compressors specially developed for this refrigerant – by very good efficiency.

Secondly, numerous energy-saving measures were implemented when planning the plant. These measures included, among others, speed-controlled consumer pumps and ventilators, as well as “winter relief” via two self-draining, free cooling units that operate on pure water without glycol additives. These coolants can provide the full cooling capacity at ambient temperatures that are 5 °C below the selected intake temperature. At higher temperatures, the system saves energy, because the variable condensing temperature control always allows the compressors to operate at the most economical operating point in accordance with the outside temperature.

New heat exchangers
Thirdly, L&R redesigned the heat exchangers for the anodised baths and replaced them so that the cooling systems could operate in a more economical range. Georg Hesse: “This allows the cold water temperature to be raised from 8 °C to around 13 °C, which results in much better system efficiency and therefore lower energy consumption.” The heat exchangers are equipped with a temperature control system that allows precise regulation of the temperatures in the anodising baths.

Optimally controlled and quickly installed
Fourthly, the complete system is equipped with a Siemens PLC and is controlled by the “Frigocontrol” programming developed by L&R. L&R has designed the plant – and this is the fifth and final feature – in container construction and supplied it with a condenser mounted on the container roof. As such, the new cooling plant could be completed even before the old plant was dismantled. Only the free cooling units were installed after the old condensers had been removed. This reduced the operational shutdown to one weekend.

Result: An efficient and future-proof plant

The plant is now in operation and the operator is completely satisfied. Dieter Matthaei, Head of Maintenance at Koenigsdorf: “The system works perfectly and the energy savings can be clearly measured. The energy consumption required by compressors with a total output of 200 kW has been demonstrably reduced.” Dieter May, Managing Director of Koenigsdorf, adds: “The smooth completion of the project and short operational shutdown subsequently confirmed that our decision to work with L&R was the right one. In summary, we can attest that the advice, planning, service and quality we received were optimal.”

Plant and mechanical engineering

System solution
Compact refrigerating machine