When Harvest Installations produced their Constant Humidity Controller modulating gas burner (or the CHC as it is generally known) over 30 years ago, it brought about a revolution in near ambient drying of grain in bulk on-floor stores. The advent of the humidistat some years earlier, although taking the work out of manually switching drying fans on and off, did not allow grain to be dried 24/7.
Setting the CHC to a target relative humidity related to its equilibrium moisture content of the crop being dried allows drying to commence as soon as sufficient crop is in the store. This then enables the drying to be completed before wetter and cooler weather sets in, meaning that savings in electricity costs are realised, more than off-setting the cost of the gas.
The CHC has a proven record of accuracy, efficiency and economy with thousands of units in use on all combinable crops and in many onion stores too. (Mike Bennett has been supplying CHCs since their earliest days). A range of models are offered to match your particular farm’s output and configuration using Harvest’s own designed and manufactured plate-type burner head, giving maximum output in a compact design, combined with highly efficient use of fuel. http://www.harvestinstallations.co.uk
We recommend the CHC based on nearly 30 years of supplying and servicing them. Drying without a CHC can mean running those fans until almost Christmas. Using a non-modulatory burner/heater can mean the problem of overdrying at the bottom of the stack and a crust forming on the top. Whatever problems you have drying in your grain store give Mike a call. He would be pleased to help and advise.