Page 30 - Climate Control News Dec-Jan 2020

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Smart valve to manage oil regulation
GERMAN MANUFACTURER, ARMATUREN- WERK Altenburg, has released AWA OLC, a smart valve for oil regulation in compressors.
AWA OLC guarantees the optimum oil level in refrigeration compressors and is used in com- pound systems with reciprocating or scroll com- pressors. Its functionality is essentially based on the almost infinitely variable level measurement by means of an electronic float sensor.
Itcanbeusedinsystemsofupto120barfora variety of refrigerants and oils and ensures per- manent and instantaneous level detection. In addition to the level, the speed of change of the level is also evaluated for the first time.
The electronic float is insensitive to foaming and swashing oil. Other features of the OLC in- clude the large sight glass for better level recogni- tion, an LED display on the front for fast status recording and the modular adapter system for connection to all common compressor types. The installation dimensions, reduced by up to 25 per cent, enables plant constructors to design more compact composite plants.
Innovative algorithms of the autonomous electronics enable two new special functions to protect the refrigeration compressors: the Power ON Logic and the Emergency Injection.
The AWA OLC can be used in systems of up to 120 bar for a variety of refrigerants and oils.
DRY STARTUP
The Power ON Logic is activated the first time the compressor and AWA OLC are switched on. If the compressor level falls within the alarm range in less than ten seconds, the OLC immedi- ately sprays oil into the compressor until the nor- mal range is reached again. If the oil level does not fall within the alarm range when switching
on, the Power ON monitoring is deactivated again and the OLC operates in normal mode.
When there is a sudden increase in oil de- mand, which can occur with frequency-modu- lated compressors, for example, the oil level drops abruptly from the normal to the alarm range. This rapid oil level change is detected by the OLC: It deactivates the useful delay in nor- mal operation and injects oil immediately.
PERMANENT MONITORING
For optimum lubrication of the compressor, the AWA OLC regulates oil quantity to a level of 40 to 60 per cent. If the value falls below the normal range, a delay counter is activated. During nor- mal operation, this prevents the system from swinging up and the compressor from overfilling.
After ten seconds the injection of oil begins. If the oil level drops below the critical range (40 to 25 per cent) despite active filling, an alarm coun- ter starts which switches an alarm relay after 80 seconds. This relay contact can be tapped and used, for example, to switch off the compressor or trigger an alarm routine.
Armaturenwerk Altenburg was founded in 1879 and has been part of the BITZER Group since 2013.
Food processor increases cooling capacity with ammonia
ICS installed two BITZER ACPs for the production of ice water at one of Denmark’s largest food-processing companies.
ONE OF DENMARK’S largest food processors has selected Ammonia Com- pressor Packs made by BITZER (ACPs).
Last year they initiated another big pro- ject: since early 2018, two ACPs with three IQ modules each catering for the produc- tion of ice water with +1°C, is now serving the customer’s production processes.
This was undertaken by ICS Industrial Cooling Systems, the Danish system manufacturer that has been partnering with BITZER since 1987.
ICS project manager, Mikael Olsen, said two ACPs were introduced after they disposed of a refrigeration capacity of 4 MW at their central cooling plant.
“Concept and implementation were convincing, so planning for the final completion with BITZER ACPs with a to- tal capacity of 12 MW began,” he said.
“A requirement was the use of products from BITZER, since some years ago ICS delivered and installed a rack which was constructed with BITZER components.”
Olsen said ammonia is highly efficient and has no global warming potential.
“This was a very important argument for our customer. At their premises, there are also more than 20 BITZER screw compressors in operation using ammo- nia as well,” he said.
“Currently, we have four BITZER ACP units running there which are meant for refrigeration and four of our own heat pump units using BITZER screw com- pressors. BITZER provides excellent ser- vice for all of them.”
For this new application, system re- quirements were very clear: the solution had to fulfil specific claims regarding the capacity demand of a high COP and com- pact sizes. Now this design performs at a COP of 6.2.
Knowing that COP was important, BITZER Nordic regional manager, Claus Groenne, said he knew right away that ACPs would be the best solution to go with in this special case.
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