A well-sealed store will decrease your energy bills, and increase the efficiency on sprout suppressants like ethylene and spearmint oil. In this article, Adrian Cunnington, Head of Sutton Bridge Crop Storage Research at AHDB Potatoes shares some tips for assessing and improving your potato store.
The loss of approval of CIPC will inevitably mandate change within the potato industry. For many it may mean using alternative sprout suppressants, such as mint oil, maleic hydrazide or ethylene. Others, particularly in the fresh sector, may choose to go chemical-free, moving to varieties with a longer dormancy period, or by storing at lower temperatures. For all though, optimising storage conditions and reducing operating costs are likely to be high priorities. Taking some simple steps to improve store efficiency may help to offset the potential increase in operating costs resulting from the use of more expensive sprout suppressants or greater use of refrigeration.
The first step should be creating as well-sealed a store as practically and financially feasible. No matter how well insulated a store is, insulation of the store is compromised if the structure is leaky: energy and sprout suppressant is escaping, adding cost to the business. Those familiar with applying CIPC as a hot fog will likely have seen it escaping from the store through any areas inadequately sealed. Be aware that leakage does not cease when the fogging stops; it is merely much less visible.
Air and, crucially, new and invisible sprout suppressant will continue to find their way through cracks and gaps in the structure. Feeling a draught is a sure sign of air leakage, so check that personnel and roller doors seal tightly against the building and add or replace seals where necessary. Similarly, intake and exhaust louvres should close fully, with no daylight visible from inside. Replace any perished or missing rubber strips on the edge of the blades or doors to ensure a tight seal when closed.
Some areas of air leakage are not always immediately obvious to the naked eye. However, an energy efficiency assessment with a thermal imaging camera or a building pressure test may highlight otherwise unseen issues. Cracks or gaps in the structure can be identified as hotspots on a thermal image and should then be filled. A pressure test provides an assessment of the whole building, generating an AP50 value which is an indicator of how tightly the store is sealed.
Once the store is well-sealed, the next step is to insulate. While sealing prevents air moving directly between the store and the external environment, insulation is important to prevent heat transfer through the fabric of the store. Where there is no insulation, adding anything will be an improvement, but be aware that not all insulation materials are equal.
It is worth looking at the specification of material properties, particularly the U-value, which is a measure of the rate of energy loss