A low profile design air tunnel system and method for providing uniform air flow in a refractance window dryer are disclosed. According to one embodiment, a system comprises a conditioned air supply manifold that provides air into a drying chamber. The system has a drying belt directed through the drying chamber. A feed application tray at a first end of the drying belt applies a liquid to the drying belt. The system has an exhaust manifold located at the first end of the drying belt.

A low profile design air tunnel system and method for providing uniform air flow in a refractance window dryer are disclosed. According to one embodiment, a system comprises a conditioned air supply manifold that provides air into a drying chamber. The system has a drying belt directed through the drying chamber. A feed application tray at a first end of the drying belt applies a liquid to the drying belt. The system has an exhaust manifold located at the first end of the drying belt.

An oil sludge treatment system includes: a reduced-pressure fermentation dryer; a filtration apparatus; and a cleaner. The reduced-pressure fermentation dryer is configured to: store oil sludge in an airtight container; heat and stir the oil sludge under reduced pressure so that a temperature of the oil sludge is within a predetermined temperature range; decompose organic matter contained in the oil sludge using microorganisms while evaporating water; and obtain volume-reduced dried product. The filtration apparatus filters oil from the dried product. The cleaner cleans, by steam, the dried product from which the oil has been filtered.

A hybrid kiln system and method for drying material, such as lumber, logs, and timber. A solar air heater uses solar radiation to heat air. The heated air is pushed into a kiln using one or more solar air heater fans. A dehumidifier is also provided to dehumidify and heat the air within the kiln. A method for determining when the solar air heater fans and the dehumidifier should be activated is also provided, and is based upon the temperature difference between the solar air heater's interior and exterior, as well as the relative humidity within the kiln.

A hybrid kiln system and method for drying material, such as lumber, logs, and timber. A solar air heater uses solar radiation to heat air. The heated air is pushed into a kiln using one or more solar air heater fans. A dehumidifier is also provided to dehumidify and heat the air within the kiln. A method for determining when the solar air heater fans and the dehumidifier should be activated is also provided, and is based upon the temperature difference between the solar air heater's interior and exterior, as well as the relative humidity within the kiln.

A low profile design air tunnel system and method for providing uniform air flow in a refractance window dryer are disclosed. According to one embodiment, a system comprises a conditioned air supply manifold that provides air into a drying chamber. The system has a drying belt directed through the drying chamber. A feed application tray at a first end of the drying belt applies a liquid to the drying belt. The system has an exhaust manifold located at the first end of the drying belt.

A low profile design air tunnel system and method for providing uniform air flow in a refractance window dryer are disclosed. According to one embodiment, a system comprises a conditioned air supply manifold that provides air into a drying chamber. The system has a drying belt directed through the drying chamber. A feed application tray at a first end of the drying belt applies a liquid to the drying belt. The system has an exhaust manifold located at the first end of the drying belt.

A heat pump drying system includes a first drying compartment, a second drying compartment, a compressor having a compressor, a first heat exchanger, a second heat exchanger, a third heat exchanger, a first air conduit, a second air conduit, a first fan and a second fan. The first fan is arranged to draw air to flow in the first air conduit from the first drying compartment to sequentially pass through the third heat exchanger and the first heat exchanger and back to the first drying compartment. The second fan is arranged to draw air to flow in the second air conduit from the second drying compartment to sequentially pass through the second heat exchanger and the third heat exchanger and back to the second drying compartment. Refrigerant is arranged to sequentially flow through the compressor, the first heat exchanger, the second heat exchanger and back to the compressor.

A heat pump drying system includes a first drying compartment, a second drying compartment, a compressor having a compressor, a first heat exchanger, a second heat exchanger, a third heat exchanger, a first air conduit, a second air conduit, a first fan and a second fan. The first fan is arranged to draw air to flow in the first air conduit from the first drying compartment to sequentially pass through the third heat exchanger and the first heat exchanger and back to the first drying compartment. The second fan is arranged to draw air to flow in the second air conduit from the second drying compartment to sequentially pass through the second heat exchanger and the third heat exchanger and back to the second drying compartment. Refrigerant is arranged to sequentially flow through the compressor, the first heat exchanger, the second heat exchanger and back to the compressor.

A heat pump dryer includes a main casing, a compressor, a first heat exchanger having a first portion and a second portion, and a second heat exchanger. The main casing has an air inlet, a first outlet conduit, a second outlet conduit, a first air outlet, and a second air outlet. Air is arranged to enter the main casing through the air inlet, and is arranged to be bifurcated to pass through the first outlet conduit and the second outlet conduit. The air in the first outlet conduit is arranged to sequentially flow through the second heat exchanger and the first portion of the first heat exchanger, whereas the air in the second outlet conduit is arranged to flow through the second portion of the second heat exchanger.