Grain drying

The first prototype was installed in 2010 to wagon grain dryer manufactured in 70’s . The results were amazing. In theory, PTE-LTO decreases the oil consumption about 30%. In practice, however, an old wagon grain dryers oil consumption with PTE-LTO was over 50% less than with the next-operating almost new wagon grain dryer without heat recovery. Because of the increased efficiency in drying, very wet grain is now economically viable.

Heat recovery unit consists of temperature gauges, control valve, piping, filtration unit and effective heat exchanger. Exhaust air heat energy is recovered efficiently and used to preheat the intake air. Despite the dusty and damp conditions, we have managed to build filtering that actually works.

Typically, the filter exchange is not required during the drying season.

Heat recovery unit can be installed to almost all existing (retrofit) and new (new installation) warm-air dryers.

PTE-LTO’s effect on drying

Before the PTE -heat recovery system, to achieve the optimum temperature the oil burners 2nd nozzle needed to be open for almost all the time when the outdoor temperature was 10-20ºC, although the air flow of the blowing air was throttled. With the PTE-heat recovery system the 2nd nozzle open-time is significantly reduced, thereby reducing the consumption of oil, even without throttling the air flow at all. This greatly reduces the drying time of the grain.

The figure shows a measurement data of the grain dryer during the drying process. Thanks to PTE-LTO, when the outdoor temperature was only 7 degrees, the intake temperature to the fan was over 22 degrees, which is equivalent to drying on a warm summer day. The drying can be terminated earlier, because the blowing temperature in cooling sequence will stay above 20 degrees Celsius and therefore the relative humidity is less than 50%. The warm air is able to bind water considerably more than cold air. In August-September the average relative humidity is typically above 80%, which means that at night, when the temperatude cools down, relative humidity climbs to almost 100%. For example, if the temperature is 7 degrees Celcius and water content is 7,5g/m3, the relative humidity is 96.1%. If the air is heated to 22 degrees, the relative humidity drops to 38.7%!