In the event you work in a meals or beverage processing plant you in all probability know that your refrigeration system accounts for between 30% -70% of your electrical energy invoice…
What you in all probability do not know is that this could possibly be as much as 50% greater than you truly have to spend!
The excellent news? Fridge vegetation may be optimised for important financial savings with little capex.
The Drawback
Refrigeration vegetation are hardly ever designed, commissioned, operated or maintained as they need to be – to make sure manufacturing necessities are met whereas minimising vitality consumption. Usually, they’re designed to function optimally for 2 weeks of the 12 months – working at 32 deg C condensing temperature. The remainder of the 12 months they’re losing cash.
The issue arises when your refrigeration contractor is named out at 3 a.m. to regulate cooling at one facet of your plant and invariably reduces the suction pressure on the compressor. This solves the preliminary drawback however leaves you with a ten% power penalty. The plant could run at this decrease suction pressure for months earlier than anybody realises, whereas within the meantime all you have obtained is growing vitality payments and a failure to succeed in your vitality KPI’s.
The Answer
Fridge vegetation – particularly low temperature two stage vegetation – are fairly complicated, nevertheless with some fine tuning and dynamic controls, financial savings may be important.
This 5 step strategy exhibits you the way.
ENERGY SAVER 1 – GET TO KNOW YOUR PLANT
Take a while to take a look at how your plant operates.
• Are the compressors ramping up and down on a steady foundation?
• Is the slide valve (on a screw) opening and shutting frequently
• Are compressors swapping over frequently?
• Are 2 compressors working at 50% load i.e. load sharing?
• Do the compressors short cycle i.e. is one compressor beginning up a few occasions an hour?
These elements can drastically improve the quantity of vitality your fridge plant consumes.
Our recommendation:
1. Function vegetation on fastened suction pressure
2. Use a control system which optimally sequences compressors i.e. second compressor solely comes on at 80% loading on the lead compressor
3. Use feed ahead sign from course of to activate or off compressors upfront of main hundreds turning on and off
4. Make sure the control of glycol pumps isn’t exacerbating load fluctuations on the plant – take into account VSD control to mitigate crude on-off control
5. Guarantee liquid ranges in surge drums are properly managed and sufficiently damped
ENERGY SAVER 2 – DISCOVER YOUR PRESSURE POINT
Refrigeration vegetation have to fulfill cooling hundreds at a number of various temperatures, nevertheless many use the identical suction pressure/temperature on a regular basis whether or not the plant requires it or not. In a brewery, a refrigeration plant working on an ammonia/ glycol system has to fulfill the next essential cooling hundreds:
• Beer chilling after filtration to circa -2 deg C
• Wort cooling to 14 deg C
• Fermentation vessels at circa 21 deg C
This technique will run constantly at -4 deg glycol and -7 deg suction temperature even if many breweries solely brew throughout the week and the Fermentation load is the one weekend requirement.
By dynamically controlling the system the glycol temperature may be ramped up by a few levels to fulfill this load- Saving between 10-20% simply, at no additional value to your business!
ENERGY SAVER 3 – RELIEVE THE STRAIN
As we have discovered refrigeration vegetation are commissioned in such a manner that the commissioning engineer does not get a callout on the most popular day of the 12 months when the plant cannot make its cooling capability. Head pressure is stored too excessive for a number of pointless causes:
• have to get warmth into sizzling glycol for defrost
• have to get warmth right into a warmth restoration system on the compressor discharge
Nice for manufacturing. Dangerous for vitality consumption – however It does not must be a compromise.
Head pressure may be lowered considerably on most vegetation, saving lots of vitality. Decreasing head pressure from 10 bar to 8bar on an ammonia plant can save 30% in vitality. At any time when potential head pressure can and needs to be floated right down to the minimal stage.
ENERGY SAVER 4 – CONTROL IS KEY
When somebody makes a change in your plant (suction pressure for instance) have you learnt about it? Have you learnt the explanation for it? And most significantly – Have you learnt how a lot it’s costing you 100 wine and beverage refrigerator B087CVX2FT?
These day’s sensors and IT communications equipment are low-cost, influencing elements corresponding to ambient situations and manufacturing knowledge are simply monitored and plenty of vegetation include in-built control methods all with the goal of monitoring and monitoring the vitality consumption of a system. Regardless of all this most Power Managers are at sq. one on the subject of recognizing the best way to optimize a plant’s vitality efficiency.
Refrigeration plant management methods corresponding to these from Schneider Electric or Siemens are designed to take the effort out of huge knowledge. They warn you instantly when your plant is utilizing extra vitality than it ought to relative to each inside and exterior elements. The answer is totally built-in and simply put in with a full financial savings assure.
ENERGY SAVER 5 – PREVENTION BETTER THAN CURE
Constructing on the numerous quantities of information you are now amassing – the subsequent step is to make use of that knowledge to minimise vitality consumption and maximise reliability by driving focused O&M. examples of situation primarily based monitoring might embody:
Condenser Monitoring
A fouled coil can improve vitality use by 5-10% – Monitor for optimised control technique and set level, in addition to condenser temperature differential. Decrease condensing pressures cut back put on and failure charge undertake cleaning primarily based on fouling severity.
Refrigerant Loss
A lack of 20% refrigerant over the 12 months would end in a direct improve in working prices of 8%. So for a plant with annual electrical energy prices of £100,000 this may equate to an £8000 improve. Use knowledge monitoring to detect gradual leaks in refrigeration methods. Refrigerant loss may be detected by monitoring system delta T’s and superheats.
Fouled Evaporators
Plate Warmth exchanger evaporators may be monitored for oil fouling by monitoring temperatures throughout the plates and delta T’s between refrigerant and ammonia.