Prior to considering the SRS Frigadon chiller ‘Secondary Refrigerant Systems’ utilising the Hycool potassium formate heat transfer fluids the initial cooling specification was based on an ammonia installation with propylene glycol as the circulating fluid through the cooling coils.
The client John Williams having given it further consideration after seeing other such SRS Frigadon system installations in both Michigan USA and New York State then realised that there were issues associated with ammonia that needed to be addressed.
Issues such as Health & Safety, ammonia being toxic potentially higher insurance premiums and the then difficulties in obtaining planning permission the client concluded that the simple solution of using Hycool fluids with the SRS Frigadon chillers could be the better option.
He was also aware of the increasing skill shortage because engineers were becoming more reluctant to install and service ammonia systems and finally decided that he would rather avoid any potential problems and risks associated with ammonia.
Whilst initial consideration was given to the use of propylene glycol but since having realised that the efficiency of Hycool fluids being far superior to glycol due to its increased thermodynamic heat transfer capabilities knowing that it would enable a much more rapid removal of field heat after harvesting.
There was the added benefit with using Hycool because with its lower viscosity compared with glycol gave the opportunity of reducting pump energy consumption and costs which again was considered to be a very important factor.
Product temperature ‘pull-down’ and having chillers with 3, 4, 5 or 6 circuits gave the opportunity of minimising energy consumption further due to the reducing steps of capacity control once the required storage temperatures had been achieved.
Furthermore the client being an environmentalist wanted to use a food safe fluid which was biodegradable, non toxic and zero GWP (Global Warming Potential) – HYCOOL therefore ticked all the right boxes.
With the SRS Frigadon Secondary Refrigerant System utilising Hycool fluids enabled good storage in order to prevent excessive dehydration, decay and sprouting it also prevented high sugar concentrations.
Minimising shrinkage was also a determining factor.
The installation with its fully flooded coils (compatible with Hycool) was designed to ensure that there was adequate humidification and properly designed controls for maintaining an accurate storage atmosphere.
The client had emphasised the importance of temperature, humidity and air movement as being one of the most important environmental factors affecting the storage of potatoes.
His other concern at the time was that potatoes could easily be damaged by freezing knowing that low temperature storage permits little leeway if air circulation is inadequate to maintain uniform temperatures throughout the chilled storage.
Tubers can freeze at temperatures as high as -1ºC therefore correct fully flooded cooling coil selection was also an important feature within the engineering design. In addition to the SRS Frigadon stainless steel chillers and coils the installation was completed with Georg Fischer ABS plastic pipe work throughout because with Hycool being a potassium formate fluid it can be corrosive to certain metals if mixed with air.
In conclusion having used the Hycool fluids in conjunction with the SRS Frigadon chiller systems the client soon realised that he had made the right decision. It was critical for him to be reassured of the overall efficiencies of the system knowing that the main aim was to maintain tuber quality and provide a uniform flow of tubers to the supermarkets throughout the autumn, winter and spring. This proved to be so - good storage prevents excessive dehydration, decay and sprouting.
