Heat transfer device

Abstract

The invention relates to a device for transferring heat and a method of controlling such a device, the device comprising a stator chamber containing: a liquid; an input heat exchange surface; an output heat exchanger; and a rotor arranged to be rotated by vapour bubbles.

1 . A heat transfer device having a housing, the housing containing an evaporator and a rotor, the rotor rotationally drivable by bubbles produced when a liquid is heated by the evaporator, the rotor further arranged proximate to a surface of the evaporator so as to aid removal of bubbles from the surface. 
     
     
         2 . A device according to  claim 1  wherein the removal of bubbles is by scraping, brushing or turbulence. 
     
     
         3 . A heat transfer device having a housing, the housing containing an evaporator and a rotor, the rotor rotationally drivable by bubbles produced when a liquid is heated by the evaporator, wherein the rotor is further arranged to have successive compartments for containing bubbles and each successive compartment in the direction of bubble travel has increased volume so as to accommodate bubble growth. 
     
     
         4 . A device according to  claim 3 , wherein the rotor has multiple rotor sections which are coupled together, each successive rotor section having larger compartments than the preceding rotor section. 
     
     
         5 . A device according to  claim 3 , wherein the rotor is arranged to provide a mechanical drive output and/or an electrical power output. 
     
     
         6 . A device according to any preceding  claim 3 , wherein the rotor has a plurality of at least partially radial vanes around its circumference, so forming cells. 
     
     
         7 . A device according to  claim 6  wherein the rotor comprises a one-way valve arranged to allow fluid displaced by bubble growth to flow out of a rotor cell in a direction contrary to the direction of rotor rotation. 
     
     
         8 . A device according to  claim 7 , wherein the rotor rotational axis is substantially horizontal and the rotor vanes are curved so as to trap bubbles in the cells for an extended range of rotor rotational angles in operation. 
     
     
         9 . A device according to  claim 8  wherein the rotor axis is inclined from about 0 degrees to about 45 degrees from horizontal. 
     
     
         10 . A device according to  claim 8 , wherein the housing comprises a downward duct to deliver condensate near the descending side of the rotor. 
     
     
         11 . A device according to  claim 6 , wherein the rotor rotational axis is substantially vertical. 
     
     
         12 . A device according to  claim 11  wherein the rotor axis is inclined from about 0 degrees to about 45 degrees from vertical. 
     
     
         13 . A device according to  claim 11 , wherein the housing incorporates shrouding around the rotor, providing first and second ports for bubble release and condensate return, respectively. 
     
     
         14 . A device according to  claim 13  wherein the ports communicate with upward and downward ducts for conveying bubbles from the evaporator to the condenser, and from the condenser to the evaporator, respectively. 
     
     
         15 . A device according to  claims 1 , wherein the rotor comprises a screw having a vertical component to its axis of rotation, and the compartments are formed between screw vanes. 
     
     
         16 . A device according to  claim 15  wherein the rotor screw comprises downwardly facing projections for capturing bubbles. 
     
     
         17 . A device according to  claim 15 , wherein the rotor is an Archimedes screw. 
     
     
         18 . A device according to  claim 17  wherein the screw rotor has an axial skew, such that the screw vanes extend from the axis of rotation in a direction, which when viewed side-on in cross-section through a diameter of the screw, the direction is inclined from perpendicular. 
     
     
         19 . A device according to  claim 17 , wherein the screw rotor has a radial skew, such that the screw vanes extend from the axis of rotation in a direction which when viewed end-on in cross-section is inclined from a radius. 
     
     
         20 . A device according to  claim 17 , wherein the screw rotor further comprises a plurality of blocking members radiating from the axis, the outer edge of each member extending from a radially outer end of a first vane of a pair of adjacent vanes, towards a radially inner position and towards a second vane of the pair, the outer edge of each blocking member arranged so as to close with a liquid/gas surface, when the blocking member is oriented maximally down/up in use, so as to isolate a gas/liquid portion between adjacent vanes in use. 
     
     
         21 . A device according to  claim 20  wherein the number of blocking members per screw rotation is between about 6 and 12. 
     
     
         22 . A device according to  claim 15 , wherein the rotor screw has an expanding cross-sectional area in the direction of bubble travel. 
     
     
         23 . A device according to  claim 22  wherein the expanding cross-sectional area is achieved by increasing the screw pitch, increasing the screw outer diameter, decreasing the screw inner core volume, and/or decreasing the volume of a projection located between the screw vanes. 
     
     
         24 . A device according to  claim 15 , wherein the rotor screw has a co-rotating tube around it. 
     
     
         25 . A device according to  claim 24  wherein a rotating seal is arranged between the co-rotating tube and the housing of the screw. 
     
     
         26 . A device according to  claim 1 , wherein the rotor comprises an internal duct. 
     
     
         27 . A device according to  claim 1 , wherein the rotor has a bubble-repellant coating. 
     
     
         28 . A device according to  claim 1 , wherein the housing comprises an upward duct for conveying bubbles from the evaporator to a condenser. 
     
     
         29 . A device according to  claim 1 , wherein the housing comprises a downward duct to carry condensate from the condenser to the evaporator. 
     
     
         30 . A device according to  claim 29  wherein the downward duct is positioned and angled so as to direct condensate onto the rotor in the direction of rotation. 
     
     
         31 . A device according to  claim 1 , wherein the housing is arranged to shroud at least one rotor cell at a position close to the evaporator. 
     
     
         32 . A heat transfer device having a housing, the housing containing an evaporator and a rotor, the rotor rotationally drivable by bubbles produced when a liquid is heated by the evaporator, wherein the rotor has a plurality of radially arranged cells, the housing and rotor are arranged to close at least one cell when the cell is rotated adjacent to the evaporator, and the cell has a one-way valve arranged to allow fluid displaced by bubble growth to flow out of the cell in a direction contrary to the direction of rotor rotation. 
     
     
         33 . A heat transfer device having a housing, the housing containing an evaporator and a rotor, the rotor rotationally drivable by bubbles produced when a liquid is heated by the evaporator, wherein the rotor has a plurality of radially arranged cells, the housing and rotor are arranged to close at least one cell when the cell is rotated adjacent to the evaporator, and the housing has a duct positioned adjacent to the evaporator to allow fluid displaced by bubble growth to flow out of the cell. 
     
     
         34 . A device according to  claim 33  wherein the duct incorporates a one-way valve. 
     
     
         35 . A heat transfer device according to  claim 32  when used for cooling exhaust gas from an internal combustion engine. 
     
     
         36 . A device according to  claim 35  wherein multiple devices are arranged in series, and optionally wherein successive devices are arranged to operate at lower temperatures and/or exhaust gas pressures. 
     
     
         37 . A device according to  claim 35 , wherein the device incorporates a screw rotor having increasing cross-sectional areas between screw vanes in the direction of gas travel. 
     
     
         38 . A heat transfer device according to  claim 33 , wherein the rotor is arranged to drive a fan for increasing air flow over a heat source. 
     
     
         39 . A device according to  claim 38  wherein the heat source is a domestic hot water radiator, refrigeration condenser, refrigeration compressor, LED, photo-voltaic cell, solar collector, heat exchanger or any suitable source of heat having a higher temperature than the housing. 
     
     
         40 . A heat transfer device according to  claim 33 , wherein the rotor provides mechanical power and electrical power using electrical generating means. 
     
     
         41 . A heat transfer device according to  claim 33  further comprising a pressure regulator device, the regulating device comprising a spring and piston, or a bellows arrangement, and optionally wherein the spring is bi-metallic. 
     
     
         42 . A heat transfer device according to  claim 33  further comprising a vacuum pump. 
     
     
         43 . A heat transfer device according to  claim 33  further comprising a rotor shroud arranged direct bubbles into the rotor. 
     
     
         44 . An Archimedes screw having vanes formed from a spiral which is arranged around a rotational axis within a cylinder, the screw further comprising a plurality of blocking members radiating from the axis, the outer edge of each member extending from a radially outer end of a first vane of a pair of adjacent vanes, towards a radially inner position and towards a second vane of the pair, the outer edge of each blocking member arranged so as to close with a liquid/gas surface, when the blocking member is oriented maximally down/up in use, so as to isolate a gas/liquid portion between adjacent vanes in use. 
     
     
         45 . An Archimedes screw having vanes formed from a spiral which is arranged around a rotational axis within a cylinder, the screw further comprising a plurality of blocking members radiating from the axis, the outer edge of each member extending from a radially outer end of a first vane of a pair of adjacent vanes, towards a radially inner position and towards a second vane of the pair. 
     
     
         46 . An Archimedes screw according to  claim 45  wherein the first and second vanes are respectively upper and lower in use, such that the outer edge of the member closes with a gas/liquid surface to isolate a gas portion between adjacent vanes when the member is oriented maximally downwards in use. 
     
     
         47 . An Archimedes screw according to  claim 45  wherein the first and second vanes being respectively lower and upper in use, such that the outer edge of the member closes with a gas/liquid surface to isolate a liquid portion between adjacent vanes when the member is oriented maximally upwards in use. 
     
     
         48 . An Archimedes screw according to  claim 45 , wherein the number of blocking members per screw rotation is between about 6 and 12. 
     
     
         49 . An Archimedes screw having vanes, wherein the vanes have a radial skew, such that the vanes extend from the axis of rotation in a direction which when viewed end-on in cross-section is inclined from a radius. 
     
     
         50 . An Archimedes screw having vanes, wherein the vanes have an axial skew, such that the vanes extend from the axis of rotation in a direction, which when viewed side-on in cross-section through a diameter of the screw, the direction is inclined from perpendicular. 
     
     
         51 . (canceled) 
     
     
         52 . A method of controlling the transfer of heat through a heat transfer device, the heat transfer device having a housing containing a condenser and an evaporator arranged to boil a liquid by heat input, the method comprising controlling the rate of transfer of heat by carrying out one or more of the following steps:
 a) controlling the level of heat input to the system;   b) changing the level of vacuum or pressure in the housing;   c) changing the level of heat transfer out of the system;   d) changing the size of the system by closing off parts of the condenser or removing some liquid from circulation;   e) restricting circulation between parts of the system, in particular by reducing the flow of liquid from the condenser to the heat input (evaporator)  170 ;   f) actively introducing hot water from the evaporator to higher parts of the rotor, thereby increasing vapour generated within the rotor; and   g) reducing or increasing air flow over the condenser.