Engenia Limited

Refrigeration

Installing refrigeration solutions from RDM can save large amounts of energy on a refrigeration plant by utilising optimisation technology system that can be set to alter the characteristics of the set point to ensure the system is only asking for refrigeration when necessary.

It takes the outside temperature into consideration and stops things running when they are not required.

Other energy saving benefits from RDM’s refrigeration data management solution include:

Display case lighting

By making simple adjustments to the master clock in the system, lighting can be set to be switched on to suit store trading times. The reduction in lighting running time on non-frozen display cases ranges from 20-24 hours per week. As well as a reduction in power, there will be an increase lamp life.

Centralised defrost scheduling

RDM’s system can be used to sequence all defrosting events so that high demand overlaps can be flagged up and rescheduled.

Frozen food display case trim heater control

Display cases fitted with Mercury refrigeration controllers have a built-in feature that allows for local or remote control of the trim heater electrical load. It has been found that it is possible to reduce the standing trim heater load by between 25 and 50% with no visible detriment to the display case.

Suction pressure optimisation compressor plant

RDM’s system allows the automatic adjustment of the suction control set point.  This is achieved by determining the cooling requirements of the display cases connected to the pack via the refrigeration network. 

On various site trials, it has been possible to optimise the operating set point from 12C to 8C – equating to a compressor power input reduction of 14.5%

Optimisation tests at Culverhouse X. All data and logs taken at 15 second increments.
Comparing 18th April @ 14:30 to 14:30 on 19th April with 25th April @ 14:30 to 14:30 on 26th April.

Pack C on 25th & 26th of April showing compressor 3 starts
Optimisation was turned on but with no other adjustment or checking.

Preliminary Conclusion

When Optimisation is used and set up correctly the graphs clearly show that on low load the pack optimised over 1 bar in pressure. This had a positive affect in dropping the number of compressor starts as well as greatly reducing the operation of the larger number 3 compressor.

The overall benefits are
1. Compressor life is extended by reducing the number of starts.
2. Energy savings achieved by raising the backpressure.
 
Based on compressor 3 only 15 hrs saved per 24 hours.
Compressor 3 is operating at 6.7kw /h.
Cost at 5.5 pence per kw

5.5 * 6.7 * 15 = £ 5.52 per day * 365 = £ 2,014.8 per year.
Which equates to a reduction in demand of 100.5 Kwh per day
This is a very conservative savings figure.

Simulated product sensor control

Conventional temperature control of display cases is via a combination of air on and off sensors.  By installing a simulated product sensor on to the shelf of a display case, the temperature of the case can be controlled to meet the cooling requirements of the actual product on the shelf.

The main purpose is the reduce unnecessary cooling of the product and therefore unnecessary power consumption.

Site trials have identified a saving of 12.5% in pack/condenser power estimated at £850 pa per pack when compared to cases not fitted with the product sensor control.

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