AU2013205786A1

AU2013205786A1 - Method and apparatus

Info

Publication number: AU2013205786A1
Application number: AU2013205786A
Authority: AU
Inventors: Rune Midttun
Original assignee: RM ENERGY AS
Current assignee: RM ENERGY AS
Priority date: 2006-05-11
Filing date: 2013-05-09
Publication date: 2013-05-30

Abstract

An energy transferring system comprises a sealed circuit 20 for a transfer medium and containing a condenser/absorber 22, a liquid pump 24, an evaporator 26, a superheater 28, and 5 an energy-consuming device 30. The circuit has a low pressure side 32 and a high pressure side 34, with the medium being converted from a liquid phase to a gaseous phase in the side 34 and back in the side 32. The condenser/absorber 22 includes an absorbent of solid material, for example coal 10 powder or nanotubes, and may be combined with the evaporator 26 to form a modular unit.

Description

METHOD AND APPARATUS This invention relates to a method of, and apparatus for, transferring energy. Energy transferring cycles are knon in which a liquid is vapourised by heat supplied to an evaporating device, the vapour so produced is employed to output energy, particularly to drive a vapour engine, such as a turbine? the vapour output from the turbine is condensed in a condensing device, and the liquid so produced is pumped back to the evaparating I0 device. Such systems are dinslosed In, for example, BE-A 95,148; DE-A-3,445, 785; OB-A9160/l899; and GB-A-1535154. It is known for the circulated medium to take the form of a mixture of a liquid of low volatility and a liquid of high volatility and for the latter liquid to be condensed in 15 a condenser/absorer wherein the latter liquid is absorbed back into the liquid of low vnlatilitv. Examples of such a system are disclosed in 5E-A-131,275; EP-A-32|8,lQ; GB-A- 294,832; CPA---085 j04 JP-A-56-132, 410; JP-A-05-059,908; and US-A-5,007,m0 20 According to one aspect of the present invention, there is provided a method of transferring energy comprising causing a fluid substance to flow through a circuit and, in sequence, Converting said substance from a liquid phase to a gaseous phase by inputting energy from a source and while 25 said substance is under relatively high pressure, and converting said substance from said gaseous phase to said liquid phase by outputting energy and while said substance is under relatively low pressure relative to said high pressure, wherein said converting of said substance from said gaseous 30 phase to said liquid phase comprises reducing the saturation vapour pressure of said gaseous phase, and said covering of said substance from said gaseous phase to said liquid phase comprises sorbing said gaseous phase uti.1is i|ng solid sorbent. 35 According to another aspect of the present invention, theta is provided apparatus for transferring energy, komprisng a circuit, a displacing desi-e aranged to displace a fluid substance arond said circuit, an evaporating device in said circuit and arranged to convert said substaciie from a liquid phase to a gaseous phase by inputting energy from a source, a condensing device in said crcuit and arranged to convert said substance from said gaseous phase to said liquid phase by outputting energy, said displacing device comprising a pump arranged to act directly 10 upon said liquid phase, said pump being downstream of saio condensing device and upstream of said evaporating device, wHerein said condensing device serves to reduce the saturation vapour pressure of said gaseous phase and comprises solid sorbent material for said gaseous phase. 15 Owing to the invention, it is possible to increase the proport ion of total energy supplied which is available for use, in other words to reduce the proporAion of the total energy supplied to the system which is lost in achieving the 20 transfer. Advantageously, the condensing device is in the form or a condenser/absorber having a sorbent of solid material. This has an advantage over the systems using a medium mixture that the need to provide heat to split the mixture into vapour and 25 liquid is avoided. Furthermore, the psernt system can be relatively smp Elfied by combining the condensing device with the evaporating device as a single assembly, preferably as a modular unit. 30 In order that the invention may be clearly and completely disclosed, reference will now be made, by way of example, to the accompanying drawings, in which: Figure ± is a diagram showing a prior art refrigeration system, 35 Figure 2 is a diagram of an embodiment of the system 2 according to the present invention, Figure 3 is a diagram illustrating various applications of the system of Figure 2, Figure 4 is a diagram illustrating in detail a version 5 of the embodiment of Figure 2, and Figure 5 is a diagram ilAstrating in detail another version of the embodliment of Figure 2 Referring to Figure 1, the system comprises a sealed circuit 2 including a compressor 4, a condenser 6, an 10 expansi on valve 8, and an evaporator 10, in series. The circuit 2 has a low pressure side 12 containing the evaporator 10 whereby thermal energy is input into the refrigerant, for example the substance R22 (a si ngle iydrochilorof luorocarbon), and a high pressure side 14 15 containing the condenser 6 and whereby thermal energy is emitted from the refrigerant. A disadvantage of this system is that it requires a gaseous phase conoressor 4 which requires a significant power input, as well as being bulky and expensive. In this prior art system, the compresson 4 20 increases the pressure of the gaseous phase refrigerant, whereafer the gaseous phase refrigerant is converted into the liquid phase in the condenser , from which therral energy is emitted and the refrigerant arrives at the expansion vaive S which has a cooling effect on the substance 25 owing to the pressure drop, causing conversion of the substance into partially gaseous phase and partially liquid phase. In the evaporator 10, the cold liquid substance receives thermal energy from the exterior and the substance is supplied to the compressor 4 in its gaseous phase. Thus, 30 the substance converts from its liquid phase to its gaseous phase under low pressure and converts from its gaseous phase to its liquid phase under high pressure. Referring to Figure 2, this system again includes a sealed circuit 20, but this contains a condenser/absorber 35 combination 22, a liquid pump 24, an evaporator 26, a 3 superheater 28 and an energy-cnsuming device 30, which may be a turbine, a propeller, a piston-in-cylnder drive device, or a gas engine. Again, the circuit 20 has a low pressure side 32 and a high presure side 34, but the substance is converted from its liquid phase to its gaseous phase in the high presure side 34 and from its qaseocs phase to its liquid phase in the S pressure sidc 32. Setting asicie losses, the heat input into the superheater 28, where the substance in vapour phase may receive thermal energy from the 10 ambient envionment, is consumer by Lhe device 30 The substance in the circuit 20 may be any suitable substance that has an evaporation temperature level at atmospheric pressure wh ic is at least 30C lower than the temperature of the ambient source supplying thermal energy to the 15 superheater 28. The ambient source may be air near the ground, or sea, lake or river water. Preferably, the evaporation temperature level is sigrficantly lower than the temperature of the source, for example at least SW lower for water and at least 10 ler for air. Examples of such 20 substances are F22, carbon dioxide and nitrogen. An advantage of this system is that the liquid pump 24 which, correspondingly to the compressor 4, provides the motive power for driving the substance round the circuit, has a much lower power requirement than the compressor 4 and is 25 also more compact and inexpensive . Referring to Figure 3, this illustrates that the thermal energy input into the superheater 28 may be from ambient air, or ambient water. such as from a river or from the sea. In particular, the superheater 28 could replace the water cooler 30 of an air conditioning plant of a building, especially a large oulildinq such as an hotel. The Picure also illustrates that the energy-consuming device 30 may drive an electrical generator 38, a marine propeller 40, or replace the engine of a vehicle 42. The electrical generator 3 may be used to 35 supply the hotel 36, a house 44, and/or the pump 24. 4 Referring to Figure 4, the condenser/absorber 22 comprises a shell 46 containing an absorbent 48 of solid material of a capillary nature, for example charcoal or coal powder, or nanAubes. Through the shell 46 and the absorbent 5 48 extends the evaporator 26 which is in the form 0f a coil 5O. Thus the condenser/absorber 22 and the evaporator 26 constitute an assembly with only four inlets and outlets. The effect of the absorbent 43, which is in contact with the coil 50, is to reduce the saturation vapour pressure of t-e 10 substance entering the absorbent. inside the coil 50, the vapaur phase is created under a higher pressure than exists in the absorbent 48 Normally in a thermodynamic cycle, the condenser pressure is nigher than the evaporator pressure, but, owino 15 to the use of the absorbent 43, in the system shown in Figure 4 the condenser pressure is lower than the evaporator pressure. The thermal energy released during condensing of the vapour in the absorbent 4 balances the heat requirement for the evaporator 26. The internal surface area of the coil 20 50 is a major factor in determining the mass flow of the vapour into the superheater 23. The superheater 28 transfers thermal energy into the substance in the circuit from, say, ambient air or water, because the temperature of the gaseous substance therein is lower than the ambient temperature The 25 superheated vapour enters the turbine 30 through a pressure regulating, solenoid valve 52. The output vapour rom. the turine 30, at low pressure, enters the condenser/absorer 22 for condensing and thus releasing thermal energy. The turbine 30 is used to drive the electrical generator 38 which may 30 drive a compressor 54 having a significantly lower power consumption than the power generation by the turbine 30 for example 10 to 1Y% of the power generated by the turbine. The compressor 54 creates in a liquid reservoir 56 the lowest pressure in the circuit 20. At the bottom of the shell 46 is 35 a flow connection 57 to the e 56 for the Liquid ndensate As the condensate leaves the absobnt 48, some of the liid immediately eva-orates and forms "flash" vapour, whien as about 10% of the mass flow ,e compressor 54 draws ff rm the reservoir 56 this "flash" vapour and, 5 by ay or an aux. .iary condenser 5v8 and an exoansio valve 60, and with the ai.d of those items concerts the "flash" vapour into liquid condensate,* which is delivered to te renerort r56. A. liquid pump 62 p mps the condensate In the reservoir 56 to the coi 50 via a nonreturn valve 4 The 10 pump 62 may be a gear or centrifugal pump. The compressor 54 may be driven mechanically from the device 0, or electrically from the generator 23| or from an external power supply 66 by way of switches 68 and 70, A pressure-relief valve 72 bypasses the turbine 30 and the solenoid valve 52. 15 The version shown in Figure 5 differs from tnat of Figure 4 in a nmber of respects, Fistly, the auxiliary co reu-t 61, which is active particularly during start-up phases of *Lhe system, instead of containing the reservoir 56, ancsudes an evaporator 24 inside the reservoir 56 andf 20 a main super-cooler, so that the circuit 61 is totally separate .rom the circuit 20, with the "flash" vapour neing thereby condensed in the eservoir 56 i-tself. Moreover, the liquidi is pumped by the pump 62 to the coil 50 via an. auxIliary supercooler 76 in the reservoir 5 , whereby the 25 heating of the liquid by the pump 62 is counteracted. Furthermre, the device-0 has an output gearbox aid power sn-af' 7% Moreover, ithe Io-resr vapour output from the device 30 passes directly into them too of the shell 46 instead of--via piping. 30

Claims

1. A method of transferring energy, comprising causing a fluid substance to flow through a circuit and, in sequence, converting said substance from a liquid phase 5 to a gaseous phase by inputting energy from a source and while said substance is under relatively high pressure, and converting said substance from said gaseous phase to said liquid phase by outputting energy and while said substance is under low pressure relative to said high 10 pressure, wherein said converting of said substance from said gaseous phase to said liquid phase comprises reducing the saturation vapour pressure of said gaseous phase, and said converting of said substance from said gaseous phase to said liquid phase comprises sorbing 15 said gaseous phase utilising solid sorbent.

2. A method according to claim 1, wherein said substance has a transition temperature level between said liquid phase and said gaseous phase at atmospheric pressure which is at least 5 0 C lower than the temperature of said 20 source, which is ambient water.

3. A method according to claim 1, wherein said substance has a transition temperature level between said liquid phase and said gaseous phase at atmospheric pressure which is at least 10 0 C lower than the temperature of 25 said source, which is ambient air.

4. A method according to any preceding claim, wherein the output from said sorbing constitutes a mixture of said liquid phase and said gaseous phase and the gaseous phase of said mixture is separated from said liquid 30 phase of said mixture and is then compressed.

5. Apparatus for transferring energy, comprising a circuit, a displacing device arranged to displace a fluid substance around said circuit, an evaporating device in said circuit and arranged to convert said substance from 35 a liquid phase to a gaseous phase by inputting energy 7 from a source, a condensing device in said circuit and arranged to convert said substance from said gaseous phase to said liquid phase by outputting energy, said displacing device comprising a pump arranged to act 5 directly upon said liquid phase, said pump being downstream of said condensing device and upstream of said evaporating device, wherein said condensing device serves to reduce the saturation vapour pressure of said gaseous phase and comprises solid sorbent material for 10 said gaseous phase.

6. Apparatus according to claim 5, wherein said condensing device is in contact with said evaporating device.

7. Apparatus according to claim 6, wherein said sorbent material is in contact with said evaporating device. 15

8. Apparatus according to any one of claims 5 to 7, and further comprising, in said circuit, a superheating device for said gaseous phase downstream of said evaporating device, and an energy-consuming device downstream of said superheating device, said condensing 20 device being downstream of said energy-consuming device.

9. Apparatus according to claim 8, wherein said energy consuming device comprises a driving device.

10. Apparatus according to claim 9 and further comprising an auxiliary circuit including a gaseous-to-liquid phase 25 change device and serving to convert into said liquid phase said gaseous phase flowing from said condensing device.

11. Apparatus according to claim 10, wherein said auxiliary circuit is in fluid communication with the first 30 mentioned circuit.

12. Apparatus according to claim 10, wherein said auxiliary circuit is out of fluid communication with the first mentioned circuit.

13. Apparatus according to any one of claims 5 to 12, and 35 further comprising a supercooling device downstream of 8 said pump.

14. Apparatus according to any one of claims 5 to 13 and further comprising a compressing device communicating with said condensing device and serving to compress said 5 gaseous phase of a mixture of the liquid phase and gaseous phase output from said condensing device. 9