SE537137C2

SE537137C2 - An apparatus, a system installation and a method for generating electricity from gas streams in a building

Info

Publication number: SE537137C2
Application number: SE1050630A
Authority: SE
Inventors: David Zazi
Original assignee: David Zazi
Priority date: 2010-06-18
Filing date: 2010-06-18
Publication date: 2015-02-17
Also published as: SE1050630A1; WO2011159247A1; BR112012032353A2; CN103003566A; EP2582974A4; CA2802497A1; JP2013532255A; EP2582974A1

Abstract

24 ABSTRACT The invention relates to a device for generatíng electrical power, wherein thedevice (3) is adapted to be installed in connection With a building or aconstruction provided With at least one first gas source (7a, 719, 7 c, 7d)adapted to provide at least one first gas stream, vvherein the device comprisesa gas turbine (13) adapted to receive at least a part of the at least one first gasstream (9) from the at least one first gas source and to convert at least a partof the kinetic energy of the gas stream into electrical power. The inventionalso relates to a system installation comprising such a device and a method of converting Wind into electrical power With such a device. (Fig. la)

Description

Applicant: David ZaziOur reference: P9 199815300 A DEVICE, A SYSTEM INSTALLATION AND A METHODTECHNICAL FIELD The present invention relates to a device for generating electrical power. Theinvention also relates to a system installation of the device in connection witha building or a construction provided with at least one first gas sourceadapted to provide at least one first gas stream. The invention also relates to a method for generating electrical power with the device.PRIOR ART Due to environmental issues it is desirable to generate power from renewableand clean energy sources. One such energy source is wind power, which isknown to be extracted by use of a wind turbine, generally comprising a rotorwhich is rotated by the wind and is connected with or forms a part of agenerator. One problem with wind power is that the amount of energy thatmay be withdrawn from wind at a given wind speed is limited, known as theBetz limit. In principle the power extractable from wind is proportional to thesquare of the Velocity decrease over the wind turbíne. The theory of Windpower and wind turbines may be found in for example "Wind Energy in theBuild Environment", Sander Mertens, 2006, ISBN 0906522358. Anotherproblem is that the power generation is dependent on the present weatherconditions. One known method of alleviating this drawback is to provide abattery as a buffer, wherein a more stable electrical current may be withdrawn.

In US 2007/0222225 a wind turbine is shown positioned at the top of abuilding next to the edge of a roof. The side surfaces of the building collect wind and direct it to the edge of the roof, and thus the location of the wind turbine, so that the wind turbine may be fed with a larger air ﬂow.Alternatively the Wind turbine may be positionecl next to a mountain wall orsimilar structure. One drawback with this arrangement is that the Wind is still intermittent, and thus the power generation Will ﬂuctuate greatly.

In the article "The Development of a Ducted Turbine Simulation Model", byAndy Grant et al., Eight International IBPSA Conference, Eindhoven, NLAugust 11-14, 2003, a model for arranging a channel opening in the sidesurface of a building for achieving a more concentrated wind flow for thepurposes of feeding a Wind turbine is shown, utilising the same principles as above for concentrating the wind.

In the article "Modelling of the Performance of a Building-Mounted DuctedWind Turbine", S J Watson et al. Journal of Physics: Conference Series 75(2007) 012001, the results of a computer simulation is shown of the resultingwind flow when arranging a wind turbine inside a channel on top of a building.

In patent document US 6,365,985 a gas turbine is shown connected with theexhaust of a ventilation system. In one of its embodiments the gas turbine isarranged at a distance from the exhaust, but due to that the gas flow dropsoff with distance only a small efficiency can be achieved. In another of itsembodiments a shroud is arranged to connect the gas turbine with theexhaust, but this however leads to that the pressure increases so that theventilation fan needs to work harder, offsetting the energy gain fromgeneration with the wind turbine. In US 7,538,447 another example of a Windturbine receiving a flow from a ventilation exhaust is shown, in which aguiding body is arranged to lead the exhaust flow on the outside of the body to the wind turbine. However, the efficiency of this device is questionable.

In patent document US 2009/ 0230691 a wind turbine is shown comprising acombination of a rotor, a mixer in the form of a shroud and an ejector, the construction of which is assumed to increase the efficiency of a free standing wind turbine. The mixer mixes the part of the wind going through the rotor and the part that flow around the rotor and into the mixer.

In patent document US 4,499,034 a cooling tower according to known designis shown cornprísíng a 100 m tall, hollow tower, whereín air is supplied at thebottom through a pluralíty of smaller Channels, whereín the air is heated bywaste heat from an industrial process and rises upwards to escape the tower.The document shows the creation of a vortex inside the tower, which vortexcontinues above the escape opening and thus raises the effective height of thetower. Gas turbines are further arranged inside the smaller channels in the bottom for regenerating power from the waste heat.

SUMMARY OF THE INVENTION One objective of the present invention is to indicate an improved device for generating electrical power from a gas stream.

According to one aspect of the invention this objective is achieved with thedevice according to claim l, which is further shaped in accordance with the characterizing partof the same claim.

According to another aspect of the invention this objective is also achieved with a system installation according to claim 14.

According to yet another aspect of the invention this objective is also achieved with a method according to claim 15.

By arranging the device to receive at least one second gas stream and shapingthe device to influence the second gas stream to generate a sub~pressure inconnection with exhausting the first gas stream from the gas turbine severaladvantages may be achieved. One advantage is that since the pressuredifference across the rotor becomes larger than if the secondary stream wouldhave been absent the efficiency of the gas turbine may be increased. This may partly also be due to that the second gas stream may indirectly contribute to the energy available for Conversion by the gas turbine. Another advantage isthat since the pressure is lower on the exhaust side of the gas turbine thefirst gas stream encounters less resistance against its ﬂow, wherein thedevice according to the invention may be used in conjunction with sources ofgas streams which are more Vulnerable to, or could be subjected to adverseeffects from, working against a high flow resistance for the gas stream. Yetanother possible advantage is that the flow of the gas stream may beincreased with the aid from the second gas stream. Preferably the device isalso arranged to allow mixing of the first and the secondary gas streams atthe exhaust of the first gas stream. This may help in the creation of the sub~ pressure.

According to one embodiment the device comprises a main gas channel,wherein the gas turbine is arranged inside the main gas channel. Preferablythe main gas channel is adapted to conduct at least the first gas stream tothe gas turbine inside the main channel. This will improve the efficiency ofthe device, since the turbine may then work with an efficiency beyond the Betz limit.

The device is preferably adapted to be installed in connection with a buildingor a construction. Preferably the device is adapted to be installed in or on theupper part of a building, more preferably on the roof of the building, andpreferably the building is a high~rising building. A construction may be anyconstruction such as a factory, scaffolding or a chimney. The construction orbuilding may also be a tunnel, such as a road-tunnel, which usually areprovided with high power ventilation, or a train or tram tunnel, in which windmay be created by the trains or trams running inside the tunnel. Preferablythe construction or building is located on a high altitude, and/or being provided with strong wind sources to ensure a high power generation.

The building preferably comprises one or more gas sources, which gassources may or may not be independent from each other. According to oneembodiment the building or construction comprises at least one first gas source. The first gas source is preferably therefore external from the device intended to be installed in connection With the building, but once installed,the device and the gas source are preferably at least to some extentassociated With each other, and the device is preferably adapted for receivíngthe gas stream of streams from the gas source. Preferably the device ispositioned in fluid connection With the gas source, Wherein at least a part ofthe first (or second) gas stream may be communicated to the device,preferably into the device, and most preferably at least a major part of thefirst gas stream of the gas source may be transferred into the device.Preferably the second gas stream originates from a second gas source otherthan the gas source for the first gas stream. Preferably the device thenreceives the second gas stream from at least one secondary gas channel.Preferably the device also receives the first gas stream from a first gas channel, separate from the secondary channels.

In one embodiment the first or second gas source may be formed by theshape of the building or construction itself. In another embodiment the gassource may be formed by including an arrangement or system in the building.The gas stream from the gas source may be generated by natural phenomena,such as Wind, or may be generated artificially, such as With a fan. Accordingto a preferred embodiment the building comprises at least one gas channelarranged to carry a gas stream and forming at least a part of the first gassource. As a rule of thumb the gas channel Would then carry the gas stream irrespective of the presence of the device.

With the term sub-pressure a pressure is intended that is lower than thepressure that Would result if the second gas stream Would be shut off. Thesub-pressure could in one embodiment be achieved by the second gas streamblovving past an opening to a channel With the first gas stream, similar to theaction of a venturí tube. In another embodiment the sub-pressure could beachieved by arranging an exhaust opening for the first gas stream to open inthe second gas stream in the dovvnstream direction of the second gas stream, similar to a traditional Persian Wind catcher.

According to a preferred embodiment the device is shaped to influence the atleast one secondary gas stream to generate a vortex in connection Withexhaustíng the first gas stream from the turbine. By creating a vortex theVelocity of the second gas stream increases, wherein the pressure of thesecond gas stream decreases. The second gas stream also affects the first gasstream to become a part of the vortex, wherein the eye of the vortex, Whichshould be located at the exhaust from the gas turbine, will have a very lowpressure, aiding the exhaustion of the first gas stream from the turbine. Avortex also gives a low noise when the first and second gas streams areexhausted to the atmosphere. This is important since the device is intendedto be positioned on buildings, such as in connection with a domestic or office building.

According to one embodiment the device comprises at least one ﬂow directingelement arranged to direct at least a part of the secondary gas stream to flowin a helical path around the exhausted first gas stream in order to contributeto the generation of the vortex. Preferably the flow directing elementcomprises at least one vane arranged to direct at least a part of the secondarygas stream to ﬂow in an angle relative to the ﬂow direction of the exhaustedfirst gas stream in order to contribute to generation of the vortex. Vanes arevery efficient in directing gas streams into desired directions. Thus the vanesmay direct the second gas stream to ﬂow in the direction of forming thevortex. Preferably, the vane or vanes are arranged to direct the secondary gasstream to flow along a helical path for forming the vortex. Hence thesecondary gas stream will form the outer circumferential ﬂow of the vortex.Preferably, the vane or vanes extends outwardly from the body of the gasturbine, wherein the second gas stream is directed to form the vortex close tothe exhaust of the first gas stream. In one preferred embodiment the vane orvanes are also arranged to support and attach the gas turbine inside thedevice. Preferably the vanes support and attach the gas turbine to the inner walls of a main gas channel in which the turbine is arranged.

According to one embodiment the gas turbine comprises a tubular body containing a rotor, and which tubular body is arranged to separate the first and the secondary gas streams. Preferably the first gas stream flows insidethe tubular body, While the secondary gas stream flows outside the tubularbody. Preferably the device mixes the first and the secondary gas streams bythe tubular body ending so that it no longer separates the gas streams.Preferably the tubular body is shaped to compress the first gas stream in itsflow direction after the rotor. Thus the Velocity of the first gas streamincreases and its pressure rises. Preferably the tubular body is also arrangedto expand the secondary gas stream before allowing contact between the firstand the secondary gas streams. Preferably the outside of the tubular body isfurther shaped so as to influence the secondary gas stream to form a sub- pressure at the exhaust of the first gas stream from the tubular body.

According to one embodiment the gas turbine further comprises a second,tubular body positioned inside the first tubular body, Wherein the secondtubular body is shaped to split the first gas stream into an inner and an outerpart. Thus the mixing of the first and secondary gas streams is Simplifiedsince the mixing may be carried out in two steps, and hence the creation of a sub-pressure or a vorteX is also simpler to achieve.

According to one embodiment the device comprises a main gas channel forconducting both the first and the second gas streams, wherein the gasturbine is positioned inside the main gas channel. By conducting bothstreams inside the sanne channel the control of the ﬂow of the gas streams isSimplified since the common volume is fixed. Thus the concentration of thegas streams and their ﬂow may more easily be estimated so that the devicemay be optimized. This leads to that a lower sub-pressure may be achieved with the device.

According to one embodiment at least one secondary gas channel is arrangedto carry the at least one secondary gas stream into the main gas channel,Wherein the secondary gas channel opens into the main gas channel in aposition after an opening for the first gas stream into the turbine. Thus anincrease in pressure due to the entrance of the secondary stream is avoided before the opening for the first gas stream into the turbine, which could otherwise present an obstacle for the first gas stream and decrease theefficiency of the device. Preferably the secondary gas channel also opens intothe main gas channel in a position within the extension of the turbine,and/ or the tubular body surrounding the turbine. ln another embodimentthe secondary gas channel opens into the main gas channel in a positionWithin 1 m from before or after the exhaust opening of the first gas streamout of the turbine and into the main gas channel. Preferably the secondarygas channel opens so as to blow the secondary gas stream into a gap formedbetween an outer surface of a tubular body of the turbine and the inner surface of the main gas channel.

According to one embodiment at least one secondary gas channel is arrangedto exhaust the secondary gas stream to ﬂow in a spiral path around andalong the ﬂow direction of the first gas stream in order to contribute to thegeneration of the sub-pressure. Preferably the at least one secondary gaschannel is arranged to exhaust the secondary gas stream to ﬂow in a spiralpath around and along the ﬂow direction of the first gas stream in order tocontribute to the generation of the vortex. By arranging the secondary gaschannel to connect with for example a main channel at an angle to the mainchannel it is possible to easily control the beginning ﬂow path of the secondgas stream. Preferably the secondary channel is arranged in an anglecorresponding to the desired ﬂow path of a tangential gas package in thevortex. Preferably, the at least one secondary gas channel is arranged todirect the secondary gas stream in a helical path, preferably around theturbine, and along and / or beyond the turbine, for creating a spiral motion and the vortex.

According to one embodiment the device is adapted to be connected with andto receive the at least first or second gas stream from a gas source comprisingat least one ventilation exhaust from the building. A ventilation exhaust givesa constant and predictable flow in difference to a wind source, and thus thereliability of the device is improved. Furthermore, a lot of energy whichotherwise would have been wasted may be regained. In case the ventilation exhaust is arranged to provide the first gas stream intended to enter into the gas turbine the use of a secondary ﬂow for decreasing the pressure behind'the gas turbine makes it possible to connect the gas turbine closer to theventilation exhaust, or possibly in direct gas-tight connection with theventilation exhaust, without obstructing the flow and forcing a ventilation fanto work harder. ln case the ventilation exhaust is connected to provide thesecondary gas stream the existence of an aiding secondary gas stream is ensured.

According to one embodiment the building or construction is arranged toform a gas source by amassing wind, and that the device comprises at leastone wind collector adapted to collect the first and/ or the secondary gasstream from the gas source of the amassed wind. By using Wind as a gassource an almost free energy supply is utilised, apart from possíbly its size,and which energy supply is both clean and renewable. By amassing the Windits flow will increase, so that energy may more effectively be gained from thewind. Amassing wind may be achieved by arranging a large surface, such as aside surface of a building, to guide the wind ﬂow towards the wind collector of the device.

According to one embodiment the wind collector comprises a spoiler adaptedto be arranged at one end of a side surface of the building, and which isshaped for guiding the wind to the first and/ or the secondary gas channel.Wind usually amasses at an edge of a surface, but due to that the wind ﬂowsparallel to the surface its momentum will make the majority of the wind toﬂow a distance past the edge before turning around the edge. Hence byarranging a spoiler comprising a curved surface adapted to the expectedtravel path of the wind at the edge the amassed wind may be guided towardsthe device and its ﬂow improved. Preferably the wind collector in the form of aspoiler further comprises an opening leading the wind ﬂow into the device,either into a secondary gas channel, into the first gas channel or the gas turbine, or into the main gas channel.

According to another embodiment the wind collector comprises a wind channel having a wind opening arranged with its mouth close to an end of a l0 side surface of the building for collecting and acquiring wind. By letting theWind into a Wind channel the wind cannot escape once the Wind has enteredthe channel, wherein the Wind is both arnassed and efficiently collected. TheWind channel may then lead the wind into either the first gas channel, thegas turbine, the secondary gas channel, or the main channel. Preferably, theWind channel is provided in the building or construction, wherein, in oneembodiment, the device is adapted to be connected With such a Windcollector, rather tliaii comprising t ie wind Collector. In one embodiment ofthe system installation however, the system installation preferably comprisesboth the wind collector in the form of the tunnel and the device connectedWith the Wind collector. This may also be the case with the previous Windcollector if the spoiler is provided permanently attached onto the construction or the building.

According to one embodiment, which is at the time of Writing believed to bethe best mode of the invention, the device is adapted to be connected withand to receive the first gas stream from a first gas source in the building orconstruction comprising a first ventilation exhaust, and to be furtherconnected with two secondary gas sources of Which one is at least one secondventilation exhaust and the other is at least one wind collector, in order toreceive the at least one secondary gas stream. Since the first gas source is aventilation exhaust the device Will receive an almost constant supply of thefirst gas stream with a fairly constant flow rate and pressure. Furthermorethe device receives a secondary gas stream from one of two gas sources.Hence in case the weather is Windy, the secondary gas stream may originatefrom wind and enhance the energy extraction from the first gas streamoriginating from the first ventilation exhaust. This is advantageous since thewind is most likely stronger than the gas stream from ventilation, and also,the kinetic energy from the wind may be extracted without any concern for ifa ventilation fan is worked against. ln case there is no wind however, thesecondary gas stream may originate from a second ventilation exhaust, andhence the device may continue to operate and regain energy from theventilation system. Due to that the secondary gas stream creates a sub- pressure the first ventilation fan will not be worked against to such a degree 11 as to render the energy gain by the device useless. Furthermore, since thesecond gas stream is let out of the device without any further turbinesdrawing energy from the secondary gas stream, the device will likewise notWork against the second ventilation fan. Preferably the device also comprisesa selector arranged to select one of a plurality of gas sources for a gas stream.In this case the device comprises a selector arranged to select one of thesecond ventilation exhaust or a wind collector as a source for the second gas the most optimal source for the present *weather fi) stream. Henc conditions may be selected.

According to one embodiment the generator of the gas turbine is surroundedby a shroud and positioned inside the tubular body. Preferably the shroud isshaped to provide an aerodynamically low friction, and is thus preferablyprovided With smooth and rounded surfaces. In one embodiment the shroudis narrowing along the ﬂow direction of the first gas stream, leading to adecreasing gas pressure along its length, aiding in providing a lower pressuredrop. In another embodíment the shroud may be convex shaped, and is preferably shaped to inﬂuence the first gas stream to follow a spiral path, leading to a better mixing with the second gas stream.

BRIEF DESCRIPTION OF THE ATTACHED DRAWINGS The invention is now to be described as a number of non-limiting examples of the invention With reference to the attached drawings.

Fig. la shows a system installation of a device according to the inventioninstalled in a building.

Fig. lb shows one view of the device in fig. la.

Fig. lc~d shows views from the side of a tubular body forming part of the gas turbine according to one example of the invention. 12 Fig. 2a-b shows views from the side of a tubular body forming part of thegas turbine according to another example of the invention.

Fig. Sa shows one example of a gas source and wind catcher for a systeminstallation of the device in connection with a building.

Fig. Sa shows another example of a gas source and wind catcher for a system installation of the device in connection with a buildin .DETAILED DESCRIPTION ln fig. la a system installation l is shown comprising a device 3 forgeneration of electrical power installed in connection with a construction, inthis example in the form of a building 5. The system installation comprises aplurality of gas sources 7a-d adapted to generate gas streams. The gassources 7a-d are in this example formed through cooperation between thedevice 3 and the building 5. In another example the gas sources couldinstead be formed completely by the building alone, or completely by thedevice alone. In this example the device isuadapted to receive at least one firstgas stream 9 and one or more secondary gas streams lla-c from the pluralityof gas sources. The device comprises a gas turbine 13 cornprising a rotor 15connected with a generator 17, and which is arranged to receive the first gasstream 9 to pass through the turbine, and to generate electrical power byconverting a part of the kinetic energy of the first gas stream into electricity.The gas turbine may be of standard or non-standard type, but should be selected to have a suitable size and capacity.

According to one aspect of the invention the device 3 is arranged to receivethe at least one secondary gas streams lla-c into the device, and is furthershaped to inﬂuence the second gas streams 1 la-c to generate a sub-pressurein connection with exhausting the first gas stream 9 from the gas turbine.Thus the first gas stream 9 experiences less resistance against its flow whenpassing through the turbine, Which may allow a larger or faster flow of the first gas stream, an increased Conversion efficiency for the generator, and/ or 13 simply a decreased resistance experience by the gas source '7a whengenerating the ﬂow of the first gas stream. A sub~pressure may be created bythe phenomena that the secondary gas streams lla-c may Capture part of thefirst gas stream to follow with the secondary streams when passing theexhaust of the first gas stream, and thus creating a sub-pressure. In thisexample however the device 3 is shaped to control the movement path, thevolume, and the speed of the secondary gas streams 1 la-c, and hence also itspressure, so as to create the sub~pressure for the first gas stream. Whenincreasing the speed of the secondary gas streams the pressure of the gasstreams simultaneously decreases due to energy Conversion in accordance with the law of Bernoulli.

In this example the device is shaped to inﬂuence the at least one secondarygas streams 11a-c to generate a vortex 21 in connection with the exhaust 19of the first gas stream 9 from the turbine. The vortex thus creates a lowerpressure at the exhaust 19, wherein the first gas stream 9 may more easilyexit and ﬂow through the turbine. ln this example the vortex 21 is generatedto circle around the exhaust 19 of the first gas stream from the turbine, withthe exhaust located in the center of the vortex, and to helically flow in adirection generally away from the exhaust 19, so as to aid in bringing the first gas stream out of the turbine.

The system installation 1 and the device 3 comprises a main gas channel 23for conducting the first gas stream, and for housing the gas turbine 13 insidethe channel. The main channel 23 is arranged to conduct at least a majorpart of the first gas stream towards and into the turbine. This increases theefficiency of the turbine, since the first gas stream cannot as easily escapefrom passing the rotor 15. The turbine 13 is in this example shaped with asmaller diameter than the inner diameter of the main channel 23 in order tofit inside the channel. In this example the device is shaped With a smalldiameter, so as to form a gap 25 between the outer wall of the gas turbineand the inner wall of the main channel 23. Hence a small part of the first gasstream 9 may pass on the outside of the turbine without experiencing the pressure drop from passing the rotor. This is advantageous in case there for 14 some reason is temporarily no aíding secondary gas stream, wherein the firstgas stream will not have to pass the rotor unaided Which would lead to a highpressure drop and the working against the gas source generating the first gasstream. Possibly a flow control member may be arranged to control the sizeof, or the portion of, the first gas stream that bypasses the gas turbine,possibly dependent on the availability and strength of the second gas stream.

The system installatinn and the device further comprise at least onesecondary gas channel 27a~c for conducting the secondary gas streams. lnthis example the system installation and the device comprises threesecondary gas channels 27a-c, but any appropriate number of channels maybe provided. The secondary gas channels are arranged to conduct thesecondary gas streams from their respective gas sources and into the maingas channel. In this example the secondary gas channels 27 a-c open into themain gas channel in level with, but after the intake opening 29 to, the gasturbine. The exhaust openings 31a~c of the three secondary channels into themain channel 23 are equidistantly spaced around the circumference of themain channel. The three secondary gas channels 27 a-c are furthermoreangled relative to the direction 'of the main channel, so that their exhaustspoints in the direction of forming the tangential ﬂow components of the vortex21. Hence the three secondary channels will exhaust the three secondary gasstreams in a direction for forming the helical vortex, and thus to create the sub~pressure.

The building 5 is in this example provided with several gas sources, in thisexample four gas sources '7a-d. The first 7a and second '7b gas sources aresimilar to each other and best shown in fig. la, the third gas source 7c is bestshown in fig. la in combination with fig. Sa, and the fourth gas source 7 d is best shown in fig. la in combination with fig. 3b.

The first gas source 7a, which in this example generates the first gas stream9, comprises a ventilation exhaust 33 comprísing a first gas channel 35 and aventilation fan 37 arranged inside the first channel. The ventilation fan 37 is arranged to provide forced ventilation for the building. The first gas channel 37 is further connected with the main gas channel 23 for transferring the firstgas stream 9 into the main gas channel and into the device and the gasturbine. The first channel is thus connected to the beginning of the main gaschannel 23 at a position before the intake opening 29 into the gas turbine.The second gas source 7b comprises a similarly arranged ventilation exhaust39, but is in this example arranged to generate a secondary gas stream 1 lb.The second gas source 7 b is thus connected with a secondary gas channel27b for trarisfer-riiig the gas stream further inte the device and the rnain channel behind the intake opening 29 to the gas turbine.

Coinmonly for the third 7c and fourth 7d gas sources of the systeminstallation is that they are partly formed by the building 5 being arranged toamass wind. In this example the building amasses wind by the side surfaces4la, 4lb of the building forcing the wind to follow the extension of thesurfaces, and thus concentrating the wind flow. In case of building a newconstruction or building the side surfaces may be adapted to form a gassource by angling the surfaces to direct the wind in a desired direction, or byforming curved side surfaces, such as convex side surfaces, for catching thewind. In this example, the side surfaces 4la, 4lb forces the wind upwardly along the building to gather on top of the building.

In fig. Sa the device comprises a wind collector 43a comprising a windchannel 43a for collecting the amassed wind, which is also shown in fig. laon the left hand side of the building. The wind channel 43a comprises a windopening 45 arranged with its mouth close to the upper end of the side surface41a of the building. The wind opening 45 hence receives an amassed windfrom nearly the entire side surface of the building and leads the wind into thewind channel 43a, which in turn is connected with a secondary gas channel 27 a leading the wind further to the main gas channel.

In fig. Bb the device comprises a wind collector 43b comprising a curvedprofile 43b for collecting the amassed wind, which is also shown in fig. la onthe right hand side of the building. The curved profile is arranged on theupper end of the side surface 41b of the building, and is shaped for guiding 16 the amassed wind to the inlet of a secondary gas channel 27b. Due to thatthe amassed wind flows along the surface of the building 5 the momentum ofthe wind forces the amassed wind to extend a distance out from the edge ofthe building before turning to assume the general direction of thepredominant wind. The curved surface 43b is hence in this example adaptedto follow the natural path of the amassed wind, which would be followed incase the profile had been absent. The curved profile thus collects theamassed vvind and guides it towards the inlet of a secondary channel 27b,and further into the main channel 23. This curved profile is advantageous to use on already existing buildings or constructions, which have not already been provided with a wind channel, to avoid reconstruction costs.

Yet another alternative for a wind collector is to form a wind channel (notshown) simply arranged on top of the building, having an inlet opening facingoutwardly, and being connected to a secondary channel. Preferably, the windchannel is positioned somewhat raised from the roof of the building, similarto the height of the curved profile, in order to collect a larger part of the amassed wind.

The gas turbine 13 comprises a rotor 15 being connected with a generator 17for generation of electrical power. The rotor 15 is housed inside a tubularbody 47, wherein the tubular body 47 thus comprises an inner hollow 49 forconducting the first gas stream 9 through the gas turbine. The tubular body47 is further shaped to allow the secondary gas stream to pass on the outsideof the tubular body. The tubular body is thus arranged to separate the firstand the secondary gas streams from each other. The tubular body 47 alsocomprises a first intake opening 29 for admittíng the first gas stream into thehollow and a second exhaust opening 19 for exhausting the first gas streamout of the hollow. The rotor 15 is positioned at the front end of the tubularbody and within a short distance from the intake opening 29, in this examplewithin the front most 20 % of the tubular body. The tubular body comprisesthin walls 51, so that, at the end of the tubular body, the distance betweenthe first and second gas streams is short to allow easier mixing of the two gas streams after the gas turbine. The mixing of the first and the secondary gas 17 streams aids in creating the sub-pressure and the vortex after the exhaust opening from the tubular body.

The generator 17 is in this example covered and surrounded by a shroudhaving an outer surface which is formed to provide an aerodynamically lowfriction to the first gas flow. The outer surface of the shroud is in thisexample smoothly narrowing with a concave shape along the flow direction of få 1^^ .A _ N12111: 11131 55813 stream. The vanes of the rotor fan 15 are furthermoreaerodynamically Shaped, and are in this example adapted for receiving a firstgas stream moving in a slightly helical manner into the gas turbine. Since thefirst gas stream is generated by the fan 37, the first gas stream 9 willinevitably be provided with a slightly helical motion, and by angling the vanesof the gas turbine to take this motion in consideration, the efficiency of the gas turbine 13 increases.

The tubular body 47 is provided with an inner surface 53 defining the shapeof the inner hollow 49. In this example the inner surface is convex so as todecrease the diameter of the hollow along the movement direction of the firstgas stream. Hence the first gas stream will be compressed after passage ofthe rotor and before being exhausted from the tubular body and the turbine.The tubular body also forms an outer surface 55 defining the shape of the gasturbine. The outer surface 55 is shaped to contribute to inﬂuencing thesecond gas stream to form said sub~pressure and vortex. In this respect theouter surface has a decreasing diameter from its front towards the end of thebody in order to allow expansion of the second gas stream. The outer surface55 is also shaped to form the gap 25 between the inner walls of the main gaschannel 23 and the outer surface 55 for allowing passage of the second gasstreams lla-c, but also of the first gas stream 9 or of a part of the first gas stream if applicable.

In this example the device comprises flow directing elements 57 in the form ofthree vanes attached onto the outer surface of the tubular body 47, andwhich are arranged to direct at least a part of the secondary gas streams to form the sub-pressure, or, in this example, the vortex. The vanes 57 are 18 convex shaped and angled to direct the secondary gas streams lla-c toundertake a helical motion relative to the flow direction of the first gasstream, and with the first gas stream 9 in the center of the helix, wherein avortex 21 is created. The vanes 57 are thus arranged to direct the secondarygas streams to ﬂow in an angle relative to the ﬂow direction of the exhaustedfirst gas stream in order to contribute to the generation of the vortex. Thevanes 57 are formed from thin plates, such as metal plates, but may also beformed in plastic or any other material vfith capability to form thin, shape-resístant plates. The flow directing elements 57 are also arranged to supportand attach the gas turbíne inside the device to the inner surfaces of the mainchannel 23. I-Ience there is no need for additional supports, which otherwisecould cause an increase pressure drop. In another example the tubular bodycould be provided with other types of ﬂow directing elements for controllingthe motion or flow of the secondary gas stream, such as grooves, angledsurfaces, protrusions, vanes or similar, and of any combinations thereof. Theﬂow directing elements may also be arranged to cause turbulence in thesecondary and/ or first gas streams to allow a better mixing of the two gas streams with each other.

The device is further provided with a gas source selector 59 adapted to selectone of the several gas sources for a particular gas stream. Hence it is possibleto control from Which gas source a particular gas stream originates. Thusdepending on the prevalent wind direction a gas source located on the windside of the building may be selected. ln this example the gas source selector59 is arranged to select one of the second gas source 7b in the form of aventilation exhaust or the fourth gas source 7d in the form of the windcollector 43b comprising the curved profile as a gas source for the secondarygas stream l lb. Naturally, a device may contain any number of gas sourceselectors 59, and may be arranged to freely select any which gas source toprovide a gas stream to any of the first and/ or secondary gas channels and streams.

In figs. 2a-b a second example of a device comprising a gas turbíne adapted to be positioned inside a main channel 23 is shown. The gas turbíne 19 assembly in figs. 2a-b is similar in function With the gas turbine 13 shown infigs. 1c~d, and may be substituted for these parts in the system installation land device 3 shown in figs. la-b. Therefore, like parts in figs. 2a-b are given the same reference numbers as the corresponding parts in figs. la-d.

The device in figs. 2a-b thus compríses a gas turbine 13, including a fan, arotor, and a generator for generating electricity, and a first tubular body 47arranged around the gas turbine 13. The device in figs. 2a-b furthercompríses an additional, second, tubular body 48 arranged inside the hollowof the first tubular body 47. The second tubular body 48 is shaped to split thefirst gas stream into an inner 68 and an outer part 65. The second tubularbody 48 is thus shaped to admit a part 63 of the first gas stream to flowinside the tubular body 48, while a second part 65 of the first gas streamflows in a gap formed between the outer surface of the second tubular body48 and the inner surface of the first tubular body 47. Hence a part of the firstgas stream may be used for providing a better mixing in combination with asecond gas stream from a second gas source simultaneously flowing outside the first tubular body 47, much in the same manner and With the same advantages as described in relations to figs. la-b.

The device is further arranged to influence the second gas stream to flow in aspiral or helical path around and after the gas turbine. In this example theouter surface of the first tubular body 47 is provided With flow directingelements arranged to influence the second gas stream to assume a spiral orhelical flow path. In this example the flow directing elements comprísesgrooves forming a helical pattern on the outer surface of the first tubularbody 47, onto which surface the second gas stream is conducted. Such flowdirecting elements comprising grooves could of course also be provided on thetubular body 47 in figs. la~b, and the vanes in fig. la-b could be provided onthe surface of the tubular body in figs. 2a-b, and thirdly, a combination ofvanes and grooves could also be provided. Finally, the outer surface could also be shaped smoothly, without any flow directing elements at all.

The device further compríses a shroud 61 arranged inside the second tubularbody 48, and arranged to surround the generator of the gas turbine. ln thisexample the shroud 61 is convex shaped, and thus adapted to compress theinner part 63 of the first gas stream slightly. The device is further arranged toinfluence the inner part of the first gas stream 63 to flow in a spiral or helicalpath inside the space between the shroud 61 and the inner tubular member48. ln this example the inner tubular body 61 and/ or the second tubularbody 48 may be pr vided with flow directing elements arranged to influencethe second part of the ﬁrst gas stream to take a helical ﬂow path, wherein theinner tubular body also contributes to the creation of a vortex. This may beachieved by forming angled vanes in the space between the shroud 61 andthe second tubular body 48 and/ or by forming grooves running in a spiralpattern on the outer surface of the shroud 61 and/ or on the inner surface ofthe second tubular body 48. The turbulence thus created may lead to a lowergas pressure and/ or a better mixing between the gas streams after leaving the gas turbine.

The inventíon is not limited to the embodiments shown but may be variedfreely within the framework of the following claims. In particular, theexamples shown have been selected for enabling a clear illustration of theconcepts and principles of the invention, from which a man skilled in the artmay form a practical device or system installation, which is more optimised and ﬁtted to a local environment and conditions.

Claims

1. A device for generating electrical power, Wherein the device (3) is adapted tobe installed in connection with a building or a construction provided with atleast one first gas source (7a, 7b, 7c, 7d) comprising at least one ventilationexhaust from the building and adapted to provide at least one ﬁrst gasstream, Wherein the device comprises a gas turbine (13) adapted to receive atleast a part of the at least one first gas stream (9) from the at least one ﬁrstgas source and to convert at least a part of the kinetic energy of the gasstream into electrical power, characterized in that the device is furtherarranged to receive at least one second gas stream (lla, llb, llc) from asecond gas source comprising at least one ventilation exhaust from thebuilding and/ or a wind collector collecting wind amassed by the building orconstruction, and is shaped to inﬂuence the second gas stream to generate asub-pressure in connection with exhausting the ﬁrst gas stream from the gasturbine, wherein the device comprising at least one ﬂow directing element (57)arranged to direct at least a part of the second gas stream to ﬂow in a helicalpath around the exhausted first gas stream in order to inﬂuence the at leastone second gas stream (1 la, 1 lb, 1 lc) to generate a vortex (21) in connection with exhausting the ﬁrst gas strearn from the turbine.

2. A device according to claim 1, characterized in that the gas turbinecomprises a tubular body (47) containing a rotor and which is arranged toseparate the first and the second gas streams, Wherein the tubular body (47)is shaped to compress the first gas stream in its ﬂow direction after the rotor,and to expand the second gas stream before allowing contact between the ﬁrst and the second gas streams.

3. A device according to claim 2, characterized in that the gas turbinecomprises a second, tubular body (48) positioned inside the first tubularbody, Wherein the second tubular body is shaped to split the ﬁrst gas stream into an inner (63) and an outer (65) part. 22

4. A device according to any of the claims 1 - 3, characterized in that thedevice comprises a main gas channel (23) for conducting both the ﬁrst andthe second gas streams, Wherein the gas turbine is positioned inside the main gas channel.

5. A device according to claim 4, characterized in that at least one secondarygas channel (27a, 27b, 27c) is arranged to carry the at least one second gasstream into the main gas channel, Wherein the secondary gas channel opensinto the main gas channel in a position after an opening for the first gas stream into the turbine.

6. A device according to any of the claims 1 - 5, characterized in that at leastone secondary gas channel (27a, 27b, 27 c) is arranged to exhaust the secondgas stream to ﬂow in a spiral path around and along the ﬂow direction of the first gas stream in order to contribute to the generation of the sub-pressure.

7. A device according to any of the claims 1-6, characterized in that the deviceis adapted to be connected With and to receive the at least first or second gasstreams from a gas source (7a, 7b) comprising at least one ventilation exhaust from the building.

8. A device according to any of the claims 1 - 7, characterized in that thebuilding or construction is arranged to form a gas source (7c, 7d) byamassing Wind, and that the device comprises at least one Wind collector(43a, 43b) adapted to collect the first and/ or the second gas stream from the gas source of the amassed Wind.

9. A device according to claim 8, characterized in that the wind collectorcomprises a spoiler (43b) adapted to be arranged at one end of a side surfaceof the building, and Which is shaped for guiding the Wind to the first and/ or the secondary gas channel.

10. A device according to claim 8, characterized in that the Wind collector comprises a wind channel (43a) having a Wind opening arranged With its 23 mouth close to an end of a side surface of the building for collecting and acquiring wind.

11. ll. A system installation for generating electrical power, wherein the systeminstallation comprises a building or a construction comprising at least onefirst gas source (7a, 7b, 7c, 7d) arranged to provide at least one first gasstream (9), and is arranged to convert at least a part of the kinetic energy ofthe ﬁrst gas stream into electrical power, characterized in that the systeminstallation comprises a device according to any of the claims 1 - 13 installed in connection with the building or construction.

12. A method for generating power from at least one first gas stream with adevice according to any of the claims 1-13, the method comprising: - receiving and feeding at least one ﬁrst gas stream from at least one ﬁrst gassource formed in connection with a building or a construction to the gasturbine, - converting at least a part of the kinetic energy of the at least one first gasstream into electrical power with the gas turbine in the device, and - receiving and inﬂuencing at least one secondary gas stream to form a sub-pressure in connection with exhaustion of the first gas stream from the gasturbine by directing at least a part of the second gas stream to ﬂow in ahelical path around the exhausted first gas stream in order to influence the atleast one second gas stream to generate a vortex (21) in connection With exhausting the first gas stream from the turbine.