Heat exchanger, heat pump, dehumidifier, and dehumidifying method

A heat exchanger comprising:

• a first compartment for a first fluid flowing therethrough;
• a second compartment for a second fluid flowing therethrough;
• first flow passages passing through the first compartment and for a third fluid flowing therethrough, the third fluid exchanging heat with the first fluid;
• and
• second flow passages passing through the second compartment and for the third fluid flowing therethrough, the third fluid exchanging heat with the second fluid;
• wherein the third fluid flows through from the first flow passage to the second flow passage, the third fluid evaporates on the heat transfer surfaces located on the flow passage side of the first flow passages at specific pressures and condenses on the heat transfer surfaces located on the flow passage side of the second flow passages at approximately the same pressures as the specific pressures;
• the first flow passages are provided in a plurality;
• and the specific pressures in the plurality of flow passages are different from each other.

A heat pump comprising a heat exchanger including:

• a first compartment for a first fluid flowing therethrough;
• a second compartment for a second fluid flowing therethrough;
• a first flow passage passing through the first compartment and for a third fluid flowing therethrough, the third fluid exchanging heat with the first fluid;
• and
• a second flow passage passing through the second compartment and for the third fluid flowing therethrough, the third fluid exchanging heat with the second fluid;
• wherein the first and second flow passages are formed as an integral passage;
• the third fluid flows through from the first flow passage to the second flow passage, and the third fluid evaporates on a heat transfer surface located at a flow passage side of the first flow passage at a specific pressure, the flow passage side being for the third fluid flowing therein, and condenses on a heat transfer surface located at a flow passage side of the second flow passage at approximately the same pressure as the specific pressure, the flow passage side being for the third fluid flowing therein;
• a pressure raiser for raising the pressure of the third fluid in vapor phase;
• a first heat exchanger for taking heat from the third fluid in vapor phase, the third fluid in vapor phase having been boosted with the pressure raiser, with a high temperature fluid, thus causing the third fluid in vapor phase to condense under a first pressure;
• a first throttle for reducing the third fluid in pressure, the third fluid having been condensed with the first heat exchanger, to the specific pressure and for leading the third fluid to the first flow passage;
• a second throttle for reducing the third fluid in pressure, the third fluid having been condensed at the specific pressure, to a third pressure;
• and
• a third heat exchanger for evaporating the third fluid, the third fluid having been reduced in pressure with the second throttle, by imparting heat to the third fluid from a low temperature fluid under the third pressure.

A heat pump comprising a heat exchanger including:

• a first compartment for a first fluid flowing therethrough;
• a second compartment for a second fluid flowing therethrough;
• a first flow passage passing through the first compartment and for a third fluid flowing therethrough, the third fluid exchanging heat with the first fluid;
• and
• a second flow passage passing through the second compartment and for the third fluid flowing therethrough, the third fluid exchanging heat with the second fluid;
• wherein the first and second flow passages are formed as an integral passage;
• the third fluid flows through from the first flow passage to the second flow passage, and the third fluid evaporates on a heat transfer surface located at a flow passage side of the first flow passage at a specific pressure, the flow passage side being for the third fluid flowing therein, and condenses on a heat transfer surface located at a flow passage side of the second flow passage at approximately the same pressure as the specific pressure, the flow passage side being for the third fluid flowing therein
• a compressor for compressing the pressure of the third fluid in vapor phase;
• a first heat exchanger for taking heat from the third fluid in vapor phase, the third fluid in vapor phase having been compressed with the compressor, with a high temperature fluid, thus causing the third fluid in vapor phase to condense under a first pressure;
• a first throttle for reducing the third fluid in pressure, the third fluid having been condensed with the first heat exchanger, to the specific pressure and for leading the third fluid to the first flow passage;
• a second throttle for reducing the third fluid in pressure, the third fluid having been condensed at the specific pressure, to a third pressure;
• and
• a third heat exchanger for evaporating the third fluid, the third fluid having been reduced in pressure with the second throttle, by imparting heat to the third fluid from a low temperature fluid under the third pressure.

A heat pump comprising;

• a pressure raiser for raising the pressure of a refrigerant;
• a first heat exchanger for condensing the refrigerant, the refrigerant having been boosted with the pressure raiser, by taking heat from the refrigerant with a high temperature fluid under a first pressure;
• a first throttle for reducing the refrigerant in pressure, the refrigerant having been condensed with the first heat exchanger, to a second pressure;
• a second heat exchanger for evaporating the refrigerant, the refrigerant having been reduced in pressure with the first throttle, by the heat from the first fluid under the second pressure, and for condensing the refrigerant, after the evaporation, by taking heat from the refrigerant with a second fluid;
• a second throttle for reducing the refrigerant in pressure, after being condensed with the second heat exchanger, to a third pressure;
• and
• a third heat exchanger for evaporating the refrigerant, the refrigerant having been reduced in pressure with the second throttle, by imparting heat to the refrigerant from low temperature fluid under the third pressure.

A heat pump comprising;

• a compressor for compressing a refrigerant;
• a first heat exchanger for condensing the refrigerant, the refrigerant having been compressed with the compressor, by taking heat from the refrigerant with a high temperature fluid under a first pressure;
• a first throttle for reducing the refrigerant in pressure, the refrigerant having been condensed with the first heat exchanger, to a second pressure;
• a second heat exchanger for evaporating the refrigerant, the refrigerant having been reduced in pressure with the first throttle, by the heat from the first fluid under the second pressure, and for condensing the refrigerant, after the evaporation, by taking heat from the refrigerant with a second fluid;
• a second throttle for reducing the refrigerant in pressure, after being condensed with the second heat exchanger, to a third pressure;
• and
• a third heat exchanger for evaporating the refrigerant, the refrigerant having been reduced in pressure with the second throttle, by imparting heat to the refrigerant from low temperature fluid under the third pressure.

A dehumidifier comprising:

• a moisture adsorber having a desiccant for adsorbing moisture in the process air;
• and
• a process air cooler, disposed on the downstream side of the process air flow relative to the moisture adsorber, for cooling the process air from which moisture has been adsorbed with the desiccant;
• wherein the process air cooler cools the process air by the evaporation of a refrigerant, the evaporation being at a specific pressure,
• wherein all of the refrigerant is forced to flow generally in one direction and the process air cooler condenses the evaporated refrigerant at approximately the same pressure as the specific pressure in the process air cooler, cooled with a cooling fluid.

A method of dehumidifying process air, comprising:

• a first step of cooling the process air with a refrigerant that evaporates at a low pressure;
• a second step of raising the pressure of the refrigerant, that has evaporated in the first step, to a high pressure;
• a third step of heating regeneration air for regenerating a desiccant with the refrigerant that condenses at the high pressure;
• a fourth step of regenerating the desiccant by desorbing moisture from the desiccant with the regeneration air heated in the third step;
• a fifth step of adsorbing moisture in the process air with the desiccant regenerated in the fourth step;
• a sixth step of cooling the process air, from which moisture has been removed by adsorption in the fifth step, by evaporating the refrigerant, that has condensed in the third step, at an intermediate pressure between the low pressure and the high pressure;
• and
• a seventh step of condensing the refrigerant, that has evaporated at the intermediate pressure, at a pressure which is approximately the same as the intermediate pressure.

A dehumidifier comprising:

• a first refrigerant-air heat exchanger having a first refrigerant inlet-outlet port and a second refrigerant inlet-outlet port, and for causing heat exchange between a refrigerant and a process air;
• a compressor having an intake port and a discharge port for taking in and discharging the refrigerant, with the second refrigerant inlet-outlet port being disposed to be selectively connectable to either the intake port or the discharge port;
• a second refrigerant-air heat exchanger having a third refrigerant inlet-outlet port and a fourth refrigerant inlet-outlet port, and for causing heat exchange between the refrigerant and the process air, with either the intake port or the discharge port, that has not been connected to the second refrigerant inlet-outlet port, being disposed to be connectable to the third refrigerant inlet-outlet port;
• a third refrigerant-air heat exchanger, disposed on the upstream side of the process air flow flowing through the first refrigerant-air heat exchanger, having a fifth refrigerant inlet-outlet port and a sixth refrigerant inlet-outlet port, and for causing heat exchange among the refrigerant, the process air, and a cooling fluid, with the fourth refrigerant inlet-outlet port being disposed to be selectively connectable to either the fifth refrigerant inlet-outlet port or a sixth refrigerant inlet-outlet port, and
• a moisture adsorber disposed on the upstream side of the process air flow passing through the third refrigerant-air heat exchanger and having a desiccant for adsorbing moisture in the process air,
• wherein:
• either the fifth refrigerant inlet-outlet port or the sixth refrigerant inlet-outlet port that has not been connected to the fourth refrigerant inlet-outlet port is connected to the first refrigerant inlet-outlet port, and
• the third refrigerant-air heat exchanger cools the process air passing through the third refrigerant-air heat exchanger by the evaporation of the refrigerant supplied from the fourth refrigerant inlet-outlet port to the fifth refrigerant inlet-outlet port when the fourth refrigerant inlet-outlet port and the fifth refrigerant inlet-outlet port are interconnected, and cools and condenses the evaporated refrigerant with the cooling fluid, so that the condensed refrigerant can be supplied to the first refrigerant-air heat exchanger.

A dehumidifier comprising:

• a first refrigerant-air heat exchanger having a first refrigerant inlet-outlet port and a second refrigerant inlet-outlet port, and for causing heat exchange between a refrigerant and a process air;
• a compressor having an intake port and a discharge port for taking in and discharging the refrigerant, with the second refrigerant inlet-outlet port being disposed to be selectively connectable to either the intake port or the discharge port;
• a second refrigerant-air heat exchanger having a third refrigerant inlet-outlet port and a fourth refrigerant inlet-outlet port, and for causing heat exchange between the refrigerant and the process air, with either the intake port or the discharge port, that has not been connected to the second refrigerant inlet-outlet port, being disposed to be connectable to the third refrigerant inlet-outlet port;
• a third refrigerant-air heat exchanger, disposed on the upstream side of the process air flow flowing through the first refrigerant-air heat exchanger, having a fifth refrigerant inlet-outlet port and a sixth refrigerant inlet-outlet port, and for causing heat exchange among the refrigerant, the process air, and a cooling fluid, with the fourth refrigerant inlet-outlet port being disposed to be selectively connectable to either the fifth refrigerant inlet-outlet port or a sixth refrigerant inlet-outlet port, and
• a moisture adsorber disposed on the upstream side of the process air flow passing through the third refrigerant-air heat exchanger and having a desiccant for adsorbing moisture in the process air,
• wherein:
• either the fifth refrigerant inlet-outlet port or the sixth refrigerant inlet-outlet port that has not been connected to the fourth refrigerant inlet-outlet port is connected to the first refrigerant inlet-outlet port,
• the third refrigerant-air heat exchanger cools the process air passing through the third refrigerant-air heat exchanger by the evaporation of the refrigerant supplied from the fourth refrigerant inlet-outlet port to the fifth refrigerant inlet-outlet port when the fourth refrigerant inlet-outlet port and the fifth refrigerant inlet-outlet port are interconnected, and cools and condenses the evaporated refrigerant with the cooling fluid, so that the condensed refrigerant can be supplied to the first refrigerant-air heat exchanger
• a first switching mechanism for switching the selective connecting relation of the intake and discharge ports of the compressor to the second and the third refrigerant inlet-outlet ports;
• a second switching mechanism for switching the selective connecting relation of the fifth and the sixth refrigerant inlet-outlet ports to the fourth and the first refrigerant inlet-outlet ports
• an expansion valve disposed in the refrigerant passage between the sixth refrigerant inlet-outlet port and the second switching mechanism, the expansion valve having a first temperature sensor and a second temperature sensor,
• wherein the first temperature sensor is disposed in the refrigerant passage between the second refrigerant inlet-outlet port and the first switching mechanism, and the second temperature sensor is disposed in the refrigerant passage between the first switching mechanism and the third refrigerant inlet-outlet port, and the first and the second temperature sensors can be selectively switched.

A dehumidifier comprising:

• a first refrigerant-air heat exchanger having a first refrigerant inlet-outlet port and a second refrigerant inlet-outlet port, and for causing heat exchange between a refrigerant and a process air;
• a compressor having an intake port and a discharge port for taking in and discharging the refrigerant, with the second refrigerant inlet-outlet port being disposed to be selectively connectable to either the intake port or the discharge port;
• a second refrigerant-air heat exchanger having a third refrigerant inlet-outlet port and a fourth refrigerant inlet-outlet port, and for causing heat exchange between the refrigerant and the process air, with either the intake port or the discharge port, that has not been connected to the second refrigerant inlet-outlet port, being disposed to be connectable to the third refrigerant inlet-outlet port;
• a third refrigerant-air heat exchanger, disposed on the upstream side of the process air flow flowing through the first refrigerant-air heat exchanger, having a fifth refrigerant inlet-outlet port and a sixth refrigerant inlet-outlet port, and for causing heat exchange among the refrigerant, the process air, and a cooling fluid, with the fourth refrigerant inlet-outlet port being disposed to be selectively connectable to either the fifth refrigerant inlet-outlet port or a sixth refrigerant inlet-outlet port, and
• a moisture adsorber disposed on the upstream side of the process air flow passing through the third refrigerant-air heat exchanger and having a desiccant for adsorbing moisture in the process air,
• wherein:
• either the fifth refrigerant inlet-outlet port or the sixth refrigerant inlet-outlet port that has not been connected to the fourth refrigerant inlet-outlet port is connected to the first refrigerant inlet-outlet port,
• the third refrigerant-air heat exchanger cools the process air passing through the third refrigerant-air heat exchanger by the evaporation of the refrigerant supplied from the fourth refrigerant inlet-outlet port to the fifth refrigerant inlet-outlet port when the fourth refrigerant inlet-outlet port and the fifth refrigerant inlet-outlet port are interconnected, and cools and condenses the evaporated refrigerant with the cooling fluid, so that the condensed refrigerant can be supplied to the first refrigerant-air heat exchanger,
• wherein air is used as the cooling fluid, and liquid state water is supplied together with the air before condensing the refrigerant in the third refrigerant-air heat exchanger.

An operation method of a dehumidifier including

• a first refrigerant-air heat exchanger having a first refrigerant inlet-outlet port and a second refrigerant inlet-outlet port, and for causing heat exchange between a refrigerant and a process air;
• a compressor having an intake port and a discharge port for taking in and discharging the refrigerant, with the second refrigerant inlet-outlet port being disposed to be selectively connectable to either the intake port or the discharge port;
• a second refrigerant-air heat exchanger having a third refrigerant inlet-outlet port and a fourth refrigerant inlet-outlet port, and for causing heat exchange between the refrigerant and the process air, with either the intake port or the discharge port, that has not been connected to the second refrigerant inlet-outlet port, being disposed to be connectable to the third refrigerant inlet-outlet port;
• a third refrigerant-air heat exchanger, disposed on the upstream side of the process air flow flowing through the first refrigerant-air heat exchanger, having a fifth refrigerant inlet-outlet port and a sixth refrigerant inlet-outlet port, and for causing heat exchange among the refrigerant, the process air, and a cooling fluid, with the fourth refrigerant inlet-outlet port being disposed to be selectively connectable to either the fifth refrigerant inlet-outlet port or a sixth refrigerant inlet-outlet port, and
• a moisture adsorber disposed on the upstream side of the process air flow passing through the third refrigerant-air heat exchanger and having a desiccant for adsorbing moisture in the process air,
• wherein:
• either the fifth refrigerant inlet-outlet port or the sixth refrigerant inlet-outlet port that has not been connected to the fourth refrigerant inlet-outlet port is connected to the first refrigerant inlet-outlet port,
• the third refrigerant-air heat exchanger cools the process air passing through the third refrigerant-air heat exchanger by the evaporation of the refrigerant supplied from the fourth refrigerant inlet-outlet port to the fifth refrigerant inlet-outlet port when the fourth refrigerant inlet-outlet outlet port and the fifth refrigerant inlet-outlet port are interconnected, and cools and condenses the evaporated refrigerant with the cooling fluid, so that the condensed refrigerant can be supplied to the first refrigerant-air heat exchanger,
• said method comprising the steps of:
• interconnecting, in the cooling operation mode, the second refrigerant inlet-outlet port and the intake port, the discharge port and the third refrigerant inlet-outlet port, the fourth refrigerant inlet-outlet port and the fifth refrigerant inlet-outlet port, and the sixth refrigerant inlet-outlet port and the first refrigerant inlet-outlet port, respectively;
• interconnecting, in the heating mode, the second refrigerant inlet-outlet port and the discharge port, the intake port and the third refrigerant inlet-outlet port, the fourth refrigerant inlet-outlet port and the sixth refrigerant inlet-outlet port, and the fifth refrigerant inlet-outlet port and the first refrigerant inlet-outlet port, respectively;
• and
• setting the third refrigerant-air heat exchanger at inoperative state.

A dehumidifier comprising:

• a moisture adsorber having a desiccant for adsorbing moisture in the process air;
• and
• a process air cooler for cooling the process air from which moisture has been removed by adsorption with the desiccant;
• wherein the process air cooler has a construction of cooling the process air by the evaporation of the refrigerant, and the evaporated refrigerant is cooled and condensed with a cooling fluid at substantially the same pressure as the evaporating pressure;
• and
• the process air cooler has a plurality of evaporation pressures of the refrigerant for cooling the process air and a plurality of condensation pressures of the refrigerant cooled and condensed with the cooling fluid corresponding to the evaporation pressures, the plurality of evaporation pressures being different from each other.

A dehumidifier comprising:

• a moisture adsorber having a desiccant adsorbing moisture from the process air and being regenerated with the regeneration air;
• a heat pump, having a compressor for compressing a refrigerant, for pumping up heat from a low temperature heat source to a high temperature heat source using the process air as the low temperature heat source and the regeneration air as the high temperature heat source;
• and
• a process air cooler, disposed on the downstream side of the process air flow relative to the moisture adsorber, for cooling the process air from which moisture has been removed by adsorption with the desiccant;
• wherein the refrigerant before being taken into the compressor is heated by the refrigerant after being compressed with the compressor subsequently exchanging heat with the regeneration air before regenerating the desiccant, and
• the process air cooler has a construction of cooling the process air by the evaporation of the refrigerant, and of cooling to condense the refrigerant with a cooling fluid at substantially the same pressure as the evaporating pressure.

A dehumidifier comprising:

• a moisture adsorber having a desiccant adsorbing moisture from the process air and being regenerated with the regeneration air;
• a heat pump, having a compressor for compressing a refrigerant, for pumping up heat from a low temperature heat source to a high temperature heat source using the process air as the low temperature heat source and the regeneration air as the high temperature heat source;
• and
• a process air cooler, disposed on the downstream side of the process air flow relative to the moisture adsorber, for cooling the process air from which moisture has been removed by adsorption with the desiccant;
• wherein the refrigerant before being taken into the compressor is heated by the refrigerant after being compressed with the compressor subsequently exchanging heat with the regeneration air before regenerating the desiccant, and
• the process air cooler has a construction of cooling the process air by the evaporation of the refrigerant, and of cooling to condense the refrigerant with a cooling fluid,
• wherein the process air cooler has a construction such that air is used as the cooling fluid, and liquid state water is supplied together with the air.

A dehumidifier comprising:

• a moisture adsorber having a desiccant for adsorbing moisture in process air, with the adsorbed moisture being desorbed with regeneration air;
• a first heat pump for pumping up heat from a first evaporation temperature to a first condensation temperature by circulating a refrigerant, the first heat pump evaporating the refrigerant at a first intermediate temperature between the first evaporation temperature and the first condensation temperature, followed by condensing the refrigerant at a temperature that is approximately equal to the first intermediate temperature;
• and
• a second heat pump for pumping up heat from a second evaporation temperature which is lower than the first evaporation temperature to a second condensation temperature which is lower than the first condensation temperature by circulating a refrigerant, the second heat pump evaporating the refrigerant at a second intermediate temperature between the second evaporation temperature and the second condensation temperature, followed by condensing the refrigerant at a temperature that is approximately equal to the second intermediate temperature;
• wherein the process air from which moisture has been removed by adsorption with the desiccant is first cooled with the refrigerant that evaporates at either the first intermediate temperature or the second intermediate temperature whichever higher, then cooled with the refrigerant that evaporates at the lower intermediate temperature, then cooled with the refrigerant that evaporates at the first evaporation temperature, then cooled with the refrigerant that evaporates at the second evaporation temperature;
• the regeneration air is heated with the refrigerant that condenses at either a temperature that is approximately equal to the first intermediate temperature or a temperature that is approximately equal to the second intermediate temperature, whichever is lower, then heated with the refrigerant that condenses at the higher temperature, then heated with a refrigerant that condenses at the second condensation temperature, then heated with a refrigerant that condenses at the first condensation temperature, and then the moisture is removed from the desiccant by desorption with the heated regeneration air.

A dehumidifier comprising:

• a moisture adsorber having a desiccant for adsorbing moisture in process air, the moisture being desorbed with regeneration air;
• a process air cooler, disposed on the downstream side of the process air flow relative to the moisture adsorber, for cooling the process air;
• a first condenser for heating the regeneration air by condensing a refrigerant at a first condensing pressure;
• and
• a second condenser for heating the regeneration air by condensing a refrigerant at a second condensing pressure which is lower than the first condensing pressure;
• wherein the process air cooler has a construction of cooling the process air by the evaporation of the refrigerant, and of cooling to condense the evaporated refrigerant with the regeneration air before removing moisture from the desiccant in the moisture adsorber;
• the second condenser and the first condenser are disposed in that order in the passage from the regeneration air between the process air cooler and the moisture adsorber;
• the process air cooler has, as evaporation pressures of the refrigerant for cooling the process air, a first intermediate pressure which is lower than the first condensation pressure and a second intermediate pressure which is lower than the first intermediate pressure;
• the process air cooler has a construction of cooling the refrigerant with the regeneration air to condense the refrigerant at approximately the first intermediate pressure and at approximately the second intermediate pressure;
• the process air cooler has a construction of cooling the process air with the refrigerant that evaporates at the second intermediate pressure after the regeneration air is cooled with the refrigerant that evaporates at the first evaporation pressure, and heating the regeneration air with the refrigerant that condenses approximately at the first intermediate pressure, after heating the regeneration air is heated with the refrigerant that condenses approximately at the second intermediate pressure;
• and
• the refrigerant condensed with the first condenser is supplied so as to be evaporated at either one of the first or the second intermediate pressures, and the refrigerant condensed with the second condenser is supplied so as to be evaporated at the other one of the first or the second intermediate pressures.

A dehumdifier comprising:

• a moisture adsorber having a desiccant for adsorbing moisture in process air, the moisture being desorbed with regeneration air;
• a process air cooler, disposed on the downstream side of the process air flow relative to the moisture adsorber, for cooling the process air;
• a first condenser for heating the regeneration air by condensing a refrigerant at a first condensing pressure;
• and
• a second condenser for heating the regeneration air by condensing a refrigerant at a second condensing pressure which is lower than the first condensing pressure;
• wherein the process air cooler has a construction of cooling the process air by the evaporation of the refrigerant, and of cooling to condense the evaporated refrigerant with the regeneration air before removing moisture from the desiccant in the moisture adsorber;
• the second condenser and the first condenser are disposed in that order in the passage from the regeneration air between the process air cooler and the moisture adsorber;
• the process air cooler has, as evaporation pressures of the refrigerant for cooling the process air, a first intermediate pressure which is lower than the first condensation pressure and a second intermediate pressure which is lower than the first intermediate pressure;
• the process air cooler has a construction of cooling the refrigerant with the regeneration air to condense the refrigerant at approximately the first intermediate pressure and at approximately the second intermediate pressure;
• the process air cooler has a construction of cooling the process air with the refrigerant that evaporates at the second intermediate pressure after the regeneration air is cooled with the refrigerant that evaporates at the first evaporation pressure, and heating the regeneration air with the refrigerant that condenses approximately at the first intermediate pressure, after heating the regeneration air is heated with the refrigerant that condenses approximately at the second intermediate pressure;
• and
• the refrigerant condensed with the first condenser is supplied so as to be evaporated at either one of the first or the second intermediate pressures, and the refrigerant condensed with the second condenser is supplied so as to be evaporated at the other one of the first or the second intermediate pressures,
• wherein the first intermediate pressure further includes a plurality of pressures.

A dehumidifier comprising

• a moisture adsorber having a desiccant for adsorbing moisture in process air, the moisture being desorbed with regeneration air;
• a process air cooler, disposed on the downstream side of the process air flow relative to the moisture adsorber, for cooling the process air;
• a first condenser for heating the regeneration air by condensing a refrigerant at a first condensing pressure;
• and
• a second condenser for heating the regeneration air by condensing a refrigerant at a second condensing pressure which is lower than the first condensing pressure;
• wherein the process air cooler has a construction of cooling the process air by the evaporation of the refrigerant, and of cooling to condense the evaporated refrigerant with the regeneration air before removing moisture from the desiccant in the moisture adsorber;
• the second condenser and the first condenser are disposed in that order in the passage from the regeneration air between the process air cooler and the moisture adsorber;
• the process air cooler has, as evaporation pressures of the refrigerant for cooling the process air, a first intermediate pressure which is lower than the first condensation pressure and a second intermediate pressure which is lower than the first intermediate pressure;
• the process air cooler has a construction of cooling the refrigerant with the regeneration air to condense the refrigerant at approximately the first intermediate pressure and at approximately the second intermediate pressure;
• the process air cooler has a construction of cooling the process air with the refrigerant that evaporates at the second intermediate pressure after the regeneration air is cooled with the refrigerant that evaporates at the first evaporation pressure, and heating the regeneration air with the refrigerant that condenses approximately at the first intermediate pressure, after heating the regeneration air is heated with the refrigerant that condenses approximately at the second intermediate pressure;
• and
• the refrigerant condensed with the first condenser is supplied so as to be evaporated at either one of the first or the second intermediate pressures, and the refrigerant condensed with the second condenser is supplied so as to be evaporated at the other one of the first or the second intermediate pressures,
• wherein the first and the second condensers are positioned vertically above the process air cooler.

A dehumidifier comprising

• a first air flow passage having a first intake port at its one end and a first discharge port at the other end, for flowing first air from the first intake port toward the first discharge port;
• a second air flow passage having a second intake port at its one end and a second discharge port at the other end, for flowing regeneration air from the second intake port toward the second discharge port;
• a desiccant wheel, having a desiccant for the process air to pass through, with its rotation axis directed vertically;
• and
• a third heat exchanger for cooling the process air, wherein the desiccant removes moisture from the process air before being cooled by the third heat exchanger;
• and
• wherein the first air passage mainly includes a downward flow passage portion directed vertically downward and an upward flow passage portion directed vertically upward;
• and
• wherein moisture of the desiccant is removed by the regeneration air, and the second air flow passage mainly includes a flow passage portion directed vertically upward.

A dehumidifier comprising:

• a process air blower for blowing process air;
• a regeneration air blower for blowing regeneration air;
• a compressor for compressing a refrigerant;
• a refrigerant condenser for heating the regeneration air by condensing the compressed refrigerant;
• a refrigerant evaporator for cooling the process air by evaporating the refrigerant condensed with the refrigerant condenser;
• and
• a desiccant wheel, having a desiccant which is regenerated by the regeneration air heated with the refrigerant condenser as the regeneration air passes through the desiccant and which processes the process air as the process air passes through the desiccant;
• wherein the process air blower, the regeneration air blower, and the compressor are positioned vertically below the desiccant wheel, and
• the refrigerant condenser is positioned vertically above the desiccant wheel.