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Cool to below 15°C within 2 weeks to prevent the saw-toothed grain beetle breeding;
to below 10°C within a further 2 months to prevent the grain weevil breeding;
to below 5°C by winter (xmas) to prevent mites breeding and kill insects.
Cooling targets for UK stores using low volume aeration at 10 m 3 /tonne/hr
Has cooling become more difficult? – climate change
Climate change will bring;
Earlier, hotter harvests
Shorter milder winters
Extreme weather events
Issues for cooling?
High harvested temperatures
Fewer “windows” of cold night
time air available
Challenge to meet targets; speed
and temperature achieved
Comparison of mean monthly temperatures from 1961 to the present day. (Source: Manley, 1974; Parker et al ., 1992 – updated by the Hadley Centre for Climate Prediction and Research, Met. Office, Berkshire, UK.)
Minimum temperatures for the period immediately after harvest. (Source: Manley, 1974; Parker et al ., 1992 – updated by the Hadley Centre for Climate Prediction and Research, Met. Office, Berkshire, UK.)
Adaptation to climate change – demonstration project Objectives – “ How well are we doing?” “ How can we do things better?”
Measure on-farm cooling profiles in grain stores on 15 farms distributed throughout the UK from harvest 2007
To compare the performance of automated differential fan control with manual control at 3 sites using identical paired stores
To illustrate potential problems and “best practice”
Part 1. Efficient control – using differential thermostats
Site 1 – Results; Temperatures at Darlington site and progress against cooling targets
Site 1 – Results; Cumulative fan hours run Up to 40% energy saving!
Comparison of insect control costs PROCESS COST FUNCTIONS Fumigation 150-200p/t - Disinfests Bulk insecticide admixture 50-75p/t - Prevents and disinfests Cooling (manually) 50 p/t - Prevents mc Cooling (automatic) 29 p/t movement - Prevents infestation - Preserves quality - Disinfests over a season
Trial detail – differential thermostats vs manual control.
Focusing on 2 sites -
Site 2 -
Co-operative store, Cambridgeshire
Two 6000t silos of wheat at 14-15%mc
Cooled with upward aeration system
One silo controlled by 4°C differential
One silo controlled by manual operation of fans
Site 2 – Results; Temperatures at Cambridgeshire site and progress against cooling targets
Part 2. Monitoring exercise – how well are growers doing?
Monitoring exercise overview iButtons monitoring ambient and fan temperature
Results – monitoring 12 sites across the country
Only 1 site achieved the 15°C target on time
3 sites achieved the 10°C target on time
3 sites achieved the target of 5°C on time
11 stores cooled to 10°C
Only 4 stores cooled to 5°C and below
Location Air flow P=Pedestal U=Under-floor Differential Target ( o C) Target met Best performing Berwickshire ~10m 3 /t/h P No 15 10 5 On time 1 week early 1 week early Worst performing Suffolk ~10m 3 /t/h U No 15 10 5 10 weeks late Not met Not met
Five day running mean of ambient temperatures at monitoring locations