Hi all,

I would like to hear different opinions on effective evaporator fan control. When I first joined this company the fans were set to be on 24/7. Using the danfoss controller I set the fans to come on when cooling/heating is asked for and a few minutes after cooling/heating is stopped. There were many advantages to this method but mainly the cost saving - £5000 in a two week period.

However, after this two week period some management and customers started to panic that there was something wrong with the equipment and even after I fully explained the method behind the set up they still did not like the change. They asked for a consultant to analyse the data from the two weeks and compare it to last years data to make sure the fruit was not being compromised. Whilst waiting for this I had to revert back to the original set up.

The humidity given off by some of the fruit in the higher temp stores generally holds the correct temperature a lot of the time and so the fans are not required, they are simply circulating the ambient air around the room. Some stores are set to 4 degrees and so the fans are required to be on most of the time but the average saving across all of the stores along with the other benefits surely makes the set up very desirable to any company. When I spoke to a colleague about this they said this method is very popular with supermarkets who have huge chilled warehouses and is not a new idea at all but is a very effective way of energy saving and cutting unnecessary costs.

We have had the report back from the consultant which concluded there was no temperature difference between the two set ups, but they didn't have any summer time danfoss fan control data to compare against last years records so I will hopefully be testing it again in June to gather some data.

There are 9 stores here ranging from 4-14 degrees with a total of 179 3PH fans that can be controlled by danfoss. I would be interested in hearing if anyone else is in control of a similar site and what method they use or anyone who may know of any side effects of using this method, thanks in advance.