|It may surprise some readers that Prendos does have a life outside of ‘weathertightness issues’. Recently, we were asked to carry out a survey of two large warehouse sized commercial freezers. Our preliminary investigations into freezer operations and dehumidification techniques led us to the truly fascinating world of Munters!|
The freezer compressors were not operating correctly in that they were running constantly in order to maintain the normal operating temperature of –25°C. Significant ice build-up to the freezer ceilings was occurring. The weight of the ice was causing ceiling mounted electrical fittings to become dislodged and was creating a health hazard for the forklift truck operators working beneath. Following confirmation from mechanical engineers that there were no problems or under-specification of the freezer plant, we turned our attention to the structure and usage of the freezers.
We initially suspected air vapour leakage through the freezer panel ceiling joints. To help prove or discount our theory, we requested assistance from a scientist at BRANZ. We conducted trials to see whether taping the upper surface of the ceiling panel joints would prevent air leakage and consequential ice build-up. This did not resolve the problem. BRANZ carried out further modelling and proposed that the cause of the problem might be due to the relatively warm moisture laden air that enters the freezers every time a forklift truck enters and exits.
Following subsequent monitoring of vapour movement into and within the freezer, we have recommended the installation of uPVC strip curtains at a cost of a few hundred dollars. This will be a far better outcome for our client than the initial prospect of re-building the freezer roof. The operation of the freezers will be reviewed over the coming months to assess our recommendation.
By Sean Marshall