The invention relates to a drying system (1) comprising a drying plant (2) and a heat pump assembly (3) comprising one or more heat pumps operating with a primary fluid and being connected to at least two heat sources and at least one heat sink by means of a number of heat exchangers in a fluid network, in which a secondary fluid circulates. The heat sources may comprise dew point dehumidification in at least one heat exchanger (41) of process gas entering the drying plant; and recovery in another heat exchanger (42) of latent and/or sensible heat from exhaust gas leaving the drying plant. The heat sink may comprise pre-heating in a heat exchanger (51) of process gas used within the plant. Further, a method of integrating a heat pump assembly into a drying system is devised. By the invention, it is possible to increase the capacity of the drying plant while reducing the specific energy demand.

A heat pump dryer includes a main casing having an air inlet channel and an air outlet channel, a compressor, a first heat exchanger positioned in the air inlet channel, a second heat exchanger positioned in the air outlet channel, a fan provided in the air inlet channel, and an energy efficient heat exchanger. The energy efficient heat exchanger has a first portion partially exposed to the air inlet channel, and a second portion partially exposed to the air outlet channel. Air is arranged to enter the air inlet channel to sequentially perform heat exchange with the first portion of the energy efficient heat exchanger and the first heat exchanger. Air passing through the air inlet channel is arranged to enter the air outlet channel to sequentially perform heat exchange with the second portion of the energy efficient heat exchanger and the second heat exchanger.

A drying apparatus of a wet matrix includes air insufflation/suction means, suitable for generating a drying flow directed towards the wet matrix in at least one drying chamber, to facilitate removal of water from said wet matrix, and means for conveying the wet matrix inside the drying apparatus, having a conveyor belt that carries the wet matrix along a longitudinal direction (X-X). Advantageously, the drying apparatus has at least one heat exchanger cooled below dew temperature to condense humidity of air coming from the wet matrix.

A drier for drying boards comprises at least one conduit for directing airflow towards one of the faces of the board. The drier is configured such that at least a portion of the airflow travels across the face of the board along the longitudinal axis of the drier, the longitudinal axis of the drier being the axis along which the board travels as it is dried.

A dryer (100), comprising a dryer chamber (101) coupled to a closed loop gas-circulating system for circulating gas through the dryer chamber (101); wherein the closed loop gas-circulating system recirculates the gas and comprises: a compressor (113) coupled to receive return gas from the dryer chamber (101) and to compress the return gas to provide compressed gas; a separator (109) sitting in the gas-circulating system for draining condensate from the gas; and a gas discharger (103; 104) coupled to receive compressed gas from the compressor (113) and to discharge the compressed gas through a discharger exit (118). The separator sits in the closed loop gas-circulating system downstream of the compressor to receive compressed gas and upstream of the gas discharger (103;104). Thereby drying efficacy is improved and is advantageous at relatively low drying temperatures such as below 40 degrees Celsius. There is also provided a door for a dryer, a method of operating a dryer and a method of drying, such as a method of drying pharmaceutical substances, compounds, ingredients or products.

An energy efficient a drying system and process using heated, dry air. The system includes an air inlet, a heat pump evaporator unit, a heat pump condenser unit, a drying unit, a heat exchanger unit, a fan, and air channels for transport of airflow from the air inlet through the system. The fan causes air to flow into the air inlet through the heat pump evaporator unit and to maintain an airflow through the system. The heat pump evaporator unit is configured to use a refrigerant to absorb heat from air that flows into the system through the heat pump evaporator unit. The heat pump condenser unit is configured to release the heat absorbed at the evaporator to the airflow. The heat exchanger unit is arranged to transfer heat from the airflow leaving the drying unit to the cold, dehumidified air flowing from the heat pump evaporator unit.

Disclosed is a method for thermally drying pasty products, in particular wastewater sludge, and a belt dryer implementing such a method. The principle consists of partitioning the drying operations and using, for each of the successive operations, a different quality of air: (i) hot air for searing the sludge, (ii) low temperature air, then (iii) cold air for quenching the sludge before the extraction of same. Also proposed are loops of air supply circuits making it possible to optimize the energy consumption of the dryer by reusing energy produced within these circuits. Moreover, the loops make it possible to recover unavoidable low temperature energy or cheap energy, further optimising the consumption of the dryer.

A heat pump dryer includes a main casing having an air inlet channel and an air outlet channel, a compressor, a first heat exchanger positioned in the air inlet channel, a second heat exchanger positioned in the air outlet channel, a fan provided in the air inlet channel, and an energy efficient heat exchanger. The energy efficient heat exchanger has a first portion partially exposed to the air inlet channel, and a second portion partially exposed to the air outlet channel. Air is arranged to enter the air inlet channel to sequentially perform heat exchange with the first portion of the energy efficient heat exchanger and the first heat exchanger. Air passing through the air inlet channel is arranged to enter the air outlet channel to sequentially perform heat exchange with the second portion of the energy efficient heat exchanger and the second heat exchanger.

A method for drying drying-stock includes separating solvent-containing drying stock within a drying unit into a base material and a solvent with the aid of a first heat transfer medium that flows through a first circuit, where after the solvent has been taken up by the first heat transfer medium, the solvent is extracted from the heat transfer medium via heat energy (condensation), where the heat energy is transferred by a heat exchanger with the aid of an evaporation unit to a second circuit and made available to a second heat transfer medium, and where the heat energy is fed in a condensation unit of the heat pump back to the first circuit with the aid of a heat pump.

A control method and control device for a heat pump-type double-circulation hot-air drying system, relating to a device for supplying or controlling air or gas for drying solid materials or products, and in particular to a control method and control device for a heat pump-type hot-air drying system. The method comprises: configuring a temperature control parameter, and saving a preset temperature control curve parameter; detecting and monitoring an outlet air temperature, and the temperature and humidity of a drying room; dynamically adjusting a set temperature according to a preset temperature control curve; and selecting, according to a current set temperature, a double-circulation dynamic operation mode of a system. The control device uses a micro-processor to realize program control. By building an inner circulation loop for large-volume air circulation, the latent heat of condensation in a refrigerant is fully absorbed, to improve the basic air temperature.