1. A water recovery system comprising:
a sorbing bed for receiving a first fluid stream and sorbing water from the first fluid stream, the sorbing bed comprising:
an inlet;
a sorbent; and
an outlet;
a desorbing bed aligned with and thermally connected to the sorbing bed for receiving a second fluid stream and desorbing water to the second fluid stream, the desorbing bed comprising:
an inlet;
a sorbent; and
an outlet;
a heat pump positioned between the sorbing bed and the desorbing bed for transferring heat from the sorbing bed to the desorbing bed; and
a controller for distributing power to the heat pump to maintain an area near the outlet of the desorbing bed at a temperature greater than an area of the sorbing bed aligned with the area near the outlet of the desorbing bed.
2. The water recovery system of claim 1, wherein the sorbents of the sorbing and desorbing beds are selected from the group consisting of silica gels, zeolite molecular sieves, anioncation ion exchange media, ceramic or polymeric substrates impregnated with one or more hygroscopic salts and combinations thereof.
3. The water recovery system of claim 2, wherein the one or more hygroscopic salts are selected from the group consisting of cesium carbonate, cesium fluoride, calcium chloride, lithium bromide and combinations thereof.
4. The water recovery system of claim 1, wherein the heat pump comprises a thermoelectric device.
5. The water recovery system of claim 4 further comprising:
a power source for powering the thermoelectric device and the controller.
6. The water recovery system of claim 4, wherein the sorbing and desorbing beds each have a generally equal bed length measured from the inlets to the outlets, and wherein the thermoelectric device has length between about 10% of the bed length and 100% of the bed length.
7. The water recovery system of claim 6, wherein the thermoelectric device has length between about 25% of the bed length and about 50% of the bed length.
8. The water recovery system of claim 1 further comprising:
a second heat pump positioned between the sorbing bed and the desorbing bed for transferring heat between the sorbing bed and the desorbing bed,
wherein the controller controls the second heat pump.
9. The water recovery system of claim 1, wherein the second heat pump comprises a thermoelectric device.
10. The water recovery system of claim 1, wherein a difference between the temperature of the area near the outlet of the desorbing bed and the temperature of the area of the sorbing bed aligned with the area near the outlet of the desorbing bed is between about 2\xb0 C. and about 50\xb0 C.
11. The water recovery system of claim 1, wherein the difference between the temperature of the area near the outlet of the desorbing bed and the temperature of the area of the sorbing bed aligned with the area near the outlet of the desorbing bed is between about 5\xb0 C. and about 30\xb0 C.
12. A method for recovering water from a fluid stream, the method comprising:
directing a first fluid stream through a first sorbent bed so that water in the first fluid stream is sorbed by a first sorbent within the first sorbent bed;
heating a second sorbent bed positioned adjacent to and thermally linked with the first sorbent bed with heat generated by the sorption of water in the first sorbent bed, the second sorbent bed having a fluid stream inlet, a fluid stream outlet and a bed length equal to a distance between the inlet and the outlet;
powering a heat pump located between the first sorbent bed and a second sorbent bed to actively heat the second sorbent bed and cool the first sorbent bed;
directing a second fluid stream through the second sorbent bed so that when the second sorbent bed is heated water is desorbed from a second sorbent located within the second sorbent bed and removed from the second sorbent bed by the second fluid stream; and
maintaining an area of the second sorbent bed extending from the fluid stream outlet to a length between about 10% and about 100% of the bed length at a temperature greater than a temperature of the first sorbent bed at an area adjacent to the area of the second sorbent bed.
13. The method of claim 12, wherein the first and second sorbents are selected from the group consisting of silica gels, zeolite molecular sieves, anioncation ion exchange media, ceramic or polymeric substrates impregnated with one or more hygroscopic salts and combinations thereof.
14. The method of claim 13, wherein the one or more hygroscopic salts are selected from the group consisting of cesium carbonate, cesium fluoride, calcium chloride, lithium bromide and combinations thereof
15. The method of claim 12, wherein the heat pump comprises a thermoelectric device.
16. The method of claim 15, wherein the thermoelectric device has length between about 10% of the bed length and 100% of the bed length.
17. The method of claim 16, wherein the thermoelectric device has length between about 25% of the bed length and about 50% of the bed length.
18. The method of claim 12, wherein a difference between the temperature of the area of the second sorbent bed and the temperature of the first sorbent bed at an area adjacent to the area of the second sorbent bed is between about 2\xb0 C. and about 50\xb0 C.
19. The method of claim 18, wherein the difference between the temperature of the area of the second sorbent bed and the temperature of the first sorbent bed at an area adjacent to the area of the second sorbent bed is between about 5\xb0 C. and about 30\xb0 C.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A system for monitoring a user’s or users* access at a first location to a facility at a second location remote therefrom, comprising:
a central terminal located at the first location, comprising:
a central terminal memory, arranged to store biometric templates for each user enrolled in the system, and time and identity data; and
a central terminal communication device for transmitting and receiving data;
a plurality of remote terminals each comprising:
a remote terminal memory, arranged to store at least one biometric template and time data;
a remote terminal communication device for transmitting and receiving data;
a biometric input device for measuring a biometric of a user; and
a remote terminal processor for comparing a measured biometric with a stored biometric template to thereby identify a user and for generating a biometric template from at least one biometric provided by the biometric input device;
a network via which the central terminal and the remote terminal can communicate, wherein:
each remote terminal is configured and arranged to operate in at least a first mode, in which when a user activates a first function of the remote terminal:
the biometric input device measures a biometric of the user,
the remote terminal processor identifies the user, by comparing the measured biometric with the stored biometric template corresponding to that user;
the remote terminal communication device transmits to the central communication device time and identity data, corresponding to the identity of the user and the time at which the biometric input device measured the user’s biometric; and
the central terminal memory stores the time and identity data
2. A system according to claim 1, wherein each remote terminal is configured and arranged to also operate in a second mode, in which:
when a user activates a first function of the remote terminal:
die biometric input device measures a biometric of the user;
the remote terminal processor identifies the user, by comparing the measured biometric with the stored biometric template corresponding to that user; and
the remote terminal memory stores the time and identity data;
at predetermined times when communication is possible between the remote terminal communication device and the central terminal communication device:
the remote terminal communication device transmits to the central communication device the time and identity data stored in the remote terminal memory; and
the central terminal memory stores the time and identity data.
3. A system according to claim 1 wherein the remote terminal is located at the second location.
4. A system according to claim 1 wherein:
the remote terminal comprises location determination means for determining the location of the remote terminal at the time at which the biometric input device measured the user’s biometric, and generating location data corresponding thereto;
when the remote terminal memory stores the time and identity data, the remote terminal also stores corresponding location data; and
when the remote terminal communication device transmits to the central communication device time and identity data, corresponding to the identity of the user and the time at which the biometric input device measured the user’s biometric, die remote terminal communication device also transmits to die central communication device corresponding location data.
5. A system according to claim 4, wherein the location determination means is a GPS device.
6. A system according to claim 1 wherein the remote terminal and the central terminal communicate via GPRS.
7. A system according to claim 1 wherein the central terminal periodically:
instructs the remote terminal to delete any biometric templates corresponding to users no longer permitted to work at the second location; and
transmits to the remote terminal biometric templates corresponding to users that are permitted to work at the second location, for which no biometric template is already stored.
8. A system according to claim 1 wherein the central terminal periodically transmits to the remote terminal updated biometric templates corresponding to users that are permitted to work at the second location, for which older biometric templates have been previously stored.
9. A system according to claim 1 wherein the remote terminal processor when comparing a measured biometric with a stored biometric template to thereby identify a user
generates a similarity score representative of the similarity of the measured biometric and the stored biometric template; and
compares the similarity score with a client specific threshold.
10. A system according to claim 1 wherein:
the central terminal stores, for each user, access time data recording the periods of time that the user is permitted to access the facility, and communicates, to each remote terminal the time data for only the users who are permitted to use the facility corresponding therewith; and
each remote terminal validates access to a facility only to the users for which biometric templates are stored at the remote terminal, and only for the periods of time corresponding to the access time data.
11. A system according to claim 10 wherein each remote terminal comprises access control means for controlling opening and closing of one or more entrances to the facility relating thereto and each remote terminal opens the entrance(s) to a user only for the periods of time corresponding to the access time data.
12. A system for controlling users’ access at a first location to one or more facilities at a second location remote there from, comprising:
a central terminal located at the first location; and
at least one remote terminal located at the second location, wherein:
the central terminal stores biometric templates for all users of the system and controls which biometric templates are stored at each remote terminal;
the central terminal stores, for each user, access time data recording the periods of time that the user is permitted to access the facility, and communicates, to each remote terminal, the time data for only the users who are permitted to use the facility corresponding therewith; and
each remote terminal validates access to a facility only to the users for which biometric templates are stored at the remote terminal, and only for the periods of time corresponding to the access time data.
13. A system according to claim 12 wherein:
the central terminal periodically instructs each remote terminal to delete biometric templates corresponding to users who are not permitted to use the facility corresponding thereto; and
the central terminal periodically transmits to each remote terminal biometric templates, that are not already stored in the memory of the respective remote terminal, which correspond to users who are permitted to use the facility corresponding thereto.
14. A system according to claim 12 comprising:
a plurality of remote terminals located at the second location, each configured and arranged to control access to a corresponding facility.
15. A method of monitoring, at a central terminal, a user’s or users’ access to a facility at a remote terminal remote there from, wherein:
the remote terminal carries out the steps of:
receiving a biometric representative of an individual’s identity from a biometric input device;
verifying the individual’s identity or determining the user’s identity, using the received biometric; and
recording the time at which the biometric is received by the biometric device; and
if the remote terminal can communicate with the central terminal, then the remote terminal carries out the further steps of:
communicating the individual’s identity and the recorded time via a communications network to the central terminal; and
if the remote terminal cannot communicate with the central terminal, then the remote terminal carries out the further step of:
storing the individual’s identity and die recorded time; and
when communication between the remote terminal and central terminal becomes possible, then communicating the stored individual’s identity and the stored recorded time via a communications network to the central terminal.