ENERGY EXTRACTOR

Abstract: The arrangement with a heat exchanger (V1) that is designed to extract heat energy from a source (C) of a relatively warmer primary fluid (L1) and transfer parts of this heat energy to a relatively colder secondary fluid (L2) on the opposite side of the heat exchanger (V1), with a secondary outlet is connected to a displacement device (G) with relatively higher volumetric capacity, and that again has an outlet to a reservoir (J) after first being cooled off in a heat exchanger (V3) by a fluid (L3). The displacement device (G) with a relatively higher volumetric capacity is connected to a displacement device (H) with relatively lower volumetric capacity, that has an intake from the relatively colder reservoir (J) with the secondary fluid (L2), with a displacement device (H) that has an outlet connected to the intake of the secondary of the heat exchanger (V2) that has an outlet to the heat exchanger (V1) that is connected to the displacement device (G) with a relatively higher volumetric capacity that at the same time is connected to an energy converter (W) arranged to transform mechanical energy to another form of energy, preferably electrical energy.

Description: ENERGY EXTRACTOR. Introduction The application relates to a form of energy transformer/converter, a kind of "energy-pump" that transforms energy in the form of relatively small temperature differences between the energy source and the cooling medium to energy in the form of mechanical work. This mechanical work can be further transformed to other types of energy, for example electrical energy, hydraulic energy or pneumatic pressure energy, high temperature heat energy, etc. More specifically, the application relates to a principle that applies at least one warm reservoir, one less warm/colder reservoir, preferrably three heat exchangers, and two displacement devices where one is applied as a motor and one is applied as a pump or as a hydraulic cylinder with the piston rod side working as a pump and the side without piston rod working as a motor, all this along with piping between the different units. The principle takes advantage of thermal expansion of fluids in a way that a small thermal expansion under high pressure is changed to a large movement that can be taken advantage of. The principle can be utilised to take advantage of low-temperature sources to produce or regain energy that at present is classified as waste energy or energy that is not commercially feasible to develop. The area of utilisation is wide. Waste heat from thermal power and nuclear power, waste heat from process industries, geothermal low temperature energy, solar -energy, warm currents etc. The principle is to a certain degree independent of areas of temperature and can also take advantage of small differences in temperature within low temperature areas - also far below the freezing point of water. The known art: Heat-pumps : Heat pumps can take advantage of low-temperature energy sources, but then to provide heat with a higher temperature. The heat pump is per definition a piece of equipment that extracts heat at one or several temperatures and discharge heat with a higher temperature. The heat pump works the same way as a for example a refrigerator, differing by the fact that the warm side is given priority. Thus, heat pumps extract thermal energy from some sort of energy source and discharges this heat at a higher temperature. The process in a heat pump is shown in the diagram in fig.l. A "working fluid" evaporates in an evaporator (E) and extracts heat (Qe) from the system being cooled. The steam is compressed, requiring the work (Wc) , to a pressure where the saturation temperature is higher than the discharge temperature (T2), and further condensed when the heat {Qc) is discharged in a condenser (C) . The design of a heat pump is illustrated in fig. 2. The pressure in the evaporator is maintained low enough for the working fluid' s saturation temperature to be lower than the temperature in the energy source being cooled off. When the working fluid flows through the coils in the evaporator E, heat is extracted from the energy source and the working fluid evaporates. The steam passes through a counter flow heat exchanger, often called a precooler PC, with the intention of superheating the steam (this to prevent condensing in the compressor K) while simultaneously supercooling the condensed fluid (to prevent exaggerated degassing in the choke valve CV) . The superheated steam is compressed in the compressor K and condensed in the condenser C. The working fluid which is again back in a liquid phase goes back into the precooler PC and heats the low temperature steam and is thereby supercooled. The supercooled working fluid goes through the choke valve CV and into the evaporator E for then again to be evaporated. With that the cycle is complete. Steam engines and steam turbines: The most well known examples of energy transformers are steam engines and steam turbines. These devices require high temperatures to obtain the gas pressure (steam pressure) needed to obtain the required pressure drop over the steam engine's pistons or over the rotor in the steam turbine. The technique is based upon old, relatively simple constructions that make use of the large volume changes that arise in the phase transition from liquid- to gas phase. The reason that low temperature energy sources are not particularly made use of with this method is that a substantially higher temperature than the atmospheric boiling point of the working fluid being required to obtain the necessary working pressure . The design of a steam turbine is shown in fig. 3. Heat Qe is supplied in the boiler B. The working fluid (most often water) boils and steam is formed with a steam pressure PI and temperature Tl. The steam from the working fluid drives the steam turbine ST. Pressure and temperature in the steam decreases to P2 and T2 over the turbine ST and the energy Wt is released as mechanical work. The working fluid is thereafter pumped by the water feed pump FP back to the boiler B, and the cycle is complete. Typical values for a steam turbine ST are shown in fig. 4. Some examples of patent publications describing the utilisation of energy from low temperature energy sources: The known technique for transforming of heat to useful mechanical energy and thereby also electrical power and so on, takes advantage of the phase transition from liquid to gas or fluids with unique characteristics in the liquid phase with respect to compressibility and thermal expansion, for example C02, to make kinetic energy. Liquid C02 is compressible and has a large thermal expansion and therefore has approximately gas characteristics in the liquid phase. For the present invention, these gas characteristics are not desired. UK Patent Application GB 2 049 058 A describes a method for developing energy from low temperature sources. Here the phase transition from gas to liquid is utilised to drive a turbine. To obtain a difference in temperature large enough to drive a turbine a working fluid with a boiling point below 0 °C is utilised. When the working fluid boils heat is extracted from water (the energy source) with low temperature. The water freezes and is utilised later in a freezing mixture of ice/salt to obtain a low enough temperature to condense the working fluid in the condenser. UK Patent Application GB 2 062 111 A describes a method for producing energy from LNG (liquefied natural gas) . The phase transition from gas to liquid is utilised to drive a turbine. To obtain a temperature difference large enough to drive a turbine a working fluid that has a low boiling point is used. LNG transforms from liquid phase to gas phase at a very low temperature. This temperature is utilised in the condenser so that the working fluid is condensed and then driven back to the evaporator - which extracts heat from for example water with low temperature. Offenlegungsschrift DE 27 42 372 Al, describes a method for developing energy from low energy sources by using working mediums that have a critical temperature (critical temperature is the temperature where it is not possible to make a gas to condense by increasing the pressure) between 30 °C and 70 °C Below the critical temperature the working medium will at a certain pressure be a liquid, above the critical temperature the working medium will be a gas - independent of increase in pressure. One alternates between heating and cooling in different cycles or strokes and takes advantage of the pressure increase / decrease that occurs when one goes above / below the working media' s critical temperature, to drive a sort of piston engine. Offenlegungsschrift DE 3445785 Al, describes a method for developing energy by utilizing the difference in temperature between a heat emitting and a heat absorbing medium, this by a using a working medium moving in a circuit between an evaporator and a condenser. The phase transition from gas to liquid is utilised to drive a inverted rotating vane pump. This vane pump rotates because the pressure in the gas decreases when the gas passes through. The vane pump probably needs a lower pressure than a turbine to function. The principle is built upon the usual principle of boiling in an evaporator and condensing in a condenser. US Patent 5.327.745, describes a method that utilises a liquid with very special characteristics in the liquid phase (liquid carbon dioxide) in either a heat pump or opposite, in a construction made for developing mechanical energy and transforming this to electrical energy. Liquid carbon dioxide has special characteristics with relation to thermal expansion and compressibility making it suitable to be used as a liquid in a heat pump because of the increase in temperature taking place during pressure buildup and compression. The compression heat is positively utilized when the system is used as a heat pump. The energy loss due to the compression heat lowers the efficiency when the system is utilised to develop electrical energy because of the heat loss that occurs. This reduces the efficiency of such a system with C02. The known system uses gear pumps or vane pumps as displacement devices. These can be used because liquid carbon dioxide has a thermal expansion that is larger than the displacement device's internal leakage. These types of pumps that are used in this US-patent cannot be used for approximately ideal liquids because these liquids have a thermal expansion that is less than the internal leakage in gear- or vane-pumps. Approximately ideal liquids have characteristics that are suitable in a system designed for developing electrical energy because the compression heat is very low and the heat loss is small and the efficiency high, but liquids like this have thermal expansions so low that any kind of internal leakage in the displacement devices is hardly acceptable, even though there will always be a unavoidable micro-leakage. One thereby ends up with the fact that US Patent 5.327.745 is suitable as a heat pump, but not as a system for developing electrical energy because the efficiency is too low. The US-patent actually describes a KFK-free. heat pump that may be operable, but where development of energy is brought along as a modification which is not feasible because of the mentioned disadvantages of compressible fluids and internal leakage. Problem approach: The example below illustrates which potentials of energy that is present in low energy sources. The present invention seeks to utilize parts of this illustrated energy potential residing in low temperature energy sources. With an available water current/stream of 1 litre per second and a temperature at 30 °C and an ambient temperature of 20 °C and a calculated efficiency level of 10 % in the energy extraction one has the following: Temperature of warm liquid: 30 °C Ambient temperature: 20 °C Liquid flow: 1 litre per second Efficiency: 10 % Difference in temperature: 30 °C - 20 °C = 10 °C We know that 1 kcal is required to heat 1 litre of water 1 °C. Thereby an amount of heat at 10 kcal per second is released when the temperature in a flow of 1 litre per second of water decreases by 10 °C. Further we know that 1 kcal = 4186,8 Ws, thereby giving the following: 10 kcal/s = 41868 Ws/s = 41,868 kW With an efficiency of 10 % the effect becomes 41,868 kW x 0,1 = 4,186 kW . Definition of the principle for the invention and ref. to the set of claims : Fig. 5 shows: the arrangement with a heat exchanger VI is arranged to remove heat from a source C of a relatively warmer liquid, gas or radiation - called LI, and transmit the energy to a secondary liquid L2 on the other side of the heat exchanger VI which has a secondary outlet connected to a displacement device G with relatively higher volumetric capacity which again has an outlet connected to the heat exchanger V2 which further on has a free outlet to a reservoir J that is cooled by a liquid or gas L3. The novelty about the invention comprises that the displacement device G with a relatively higher volumetric capacity is connected to the displacement device H with a relatively lower volumetric capacity, which has an inlet from the relatively colder reservoir J with the secondary liquid L2, which displacement device H having an outlet connected to the intake of the secondary side of the heat exchanger V2 which has an outlet to the heat exchanger VI which is connected to the displacement device G with relatively higher volumetric capacity, simultaneously connected to a energy transformer W arranged to transform mechanical energy to other forms of energy - preferably electrical energy. The arrangement is completely different from a heat pump through the fact that it converts heat energy to mechanical work, while the heat pump transforms heat with low temperature to heat with a higher temperature. The arrangement is different from other energy transformers in that a small thermal expansion with approximately ideal fluids under high pressure and with a high level of efficiency is transformed to mechanical power as opposed to other energy transformers that take advantage of the large increase in volume taking place by phase transition liquid / gas in the evaporator or the relatively large thermal expansion taking place in fluids with unique characteristics in the liquid phase. The thermal expansion occurring with increasing temperature in an approximately ideal fluid is very small compared to the increase in volume taking place during phase transition liquid / gas or fluids with unique characteristics in the liquid phase. The force or the pressure build up that arises from the thermal expansion taking place by an increase in temperature with approximately ideal fluids can, on the other hand, be very large compared to the force or pressure build up that takes place in the phase transition liquid / gas or by the relatively large thermal expansion within some selected fluids with especially unique characteristics in the liquid phase. This is taken advantage of in the invention. While not using the phase transition liquid/gas, the condensing heat in the condenser is not lost. If one in addition use approximately ideal fluids that are only slightly compressible, a minimal rise in temperature will occur during the increase in pressure, and thereby a reduced heat loss in V3. The plant can therefore obtain a substantially higher degree of efficiency compared to what can be obtained by taking advantage of the phase transition liquid / gas due to the fact that heat energy is transferred back from the low pressure side to the high pressure side by heat exchanger V2 in fig. 5. This heat recovery thus becomes larger when a approximately ideal fluid is used than if a more compressible fluid is used because one will never get a lower temperature on the low pressure side out of V2 than the temperature on the high pressure side into V2. I.e. a smaller amount of heat has to be removed in V3 when approximately ideal fluids are taken in use as working fluids, this again giving a higher degree of efficiency. The condensing heat transferred in the condenser in energy converters that are based on a evaporator and a condenser is lost because the temperature lies below the necessary temperature to obtain boiling in the evaporator. In many cases the energy transferred in the condenser is larger than the energy obtainable in the turbine. In this invention this is not the case because one do not work with, or use, the phase transition liquid / gas. Thus one can heat exchange outgoing low pressure fluid flow with ingoing high pressure fluid flow with a counter flow heat exchanger in V2 in fig. 5. This is further improved in that approximately ideal fluids can be used. Detailed description of the preferred layout: Figures 5 and 6 show schematically the main elements that make up a preferred embodiment of the invention. To avoid the internal leakage that characterises hydraulic pumps and hydraulic motors a preferrably differentially connected double-acting hydraulic device HA as a combined pump and motor is used. The hydraulic device HA moves in two strokes: induction stroke when the piston PI moves in the direction of a preferrably inductive sensor IU and pump stroke when the piston PI moves in the direction of the preferrably inductive sensor IT. That the sensors IU and IT are given as inductive is meant as a non-limiting example. The point with this arrangement with a fluid on both sides of the piston PI together with induction stroke and pump stroke is that one obtains approximately the same pressure on both sides of the piston PI in the cylinder resulting in the internal leakage essentially being eliminated. This is highly important when approximately ideal fluids are utilised as working fluids, as these have such a small coefficient of thermal expansion that a internal leakage of only a few percent on inpumping and / or outletting hydraulic device would result in the system being unable to work. The piston PI can be magnetically detectable or detectable in some other way, and it' s position detected on the outside be the preferentially inductive sensors IT and IU, that on detection send signals to the controller X, that can consist of for example a PLS or relays. In turn the controller will control the valves L and M. When the piston reaches the position where the inductive sensor IU is situated the valve M is closed and the valve G is thereafter opened. The pressure in the system will act on a smaller area on the piston rod side and thereby force the piston towards the inductive sensor IT, in such a way that the volume in the "H-side" (see fig. 5) of the hydraulic device is forced into the pressure side of the system via the check valve 0. When the piston reaches the inductive sensor IT the valve L will close and thereafter the valve M will open. Because of an overpressure in the hydraulic circuit, that includes an accumulator R, a hydraulic motor K and the check valves N and P along with piping between the different components, the piston PI is forced towards the inductive sensor IU when valve M is open and valve L is closed. The valves N, 0, P, and Q are check valves. R and S indicate hydraulic accumulators that mute pulsing and maintain the pressure locally. Here one single hydraulic cylinder HA is described, but several hydraulic cylinders HA can be set up in parallel. A warm reservoir C is the source for heating the fluid LI. The working fluid L2 is heat exchanged with LI in the heat exchanger VI. During heating of the working fluid L2 taking place in VI the pressure rises in the working fluid L2 when the temperature rises and the pressure propagates to VI and V2. The difference in volumetric capacity in the preferred embodiment is constituted by the piston rod, see figure 7. The area on one side of the piston is Av, the area against the fluid on the other side of the piston is Ah=Av-Ao, where Ao is the cross-sectional area of the piston rod. Cold working fluid L2 is sucked from the reservoir J into the "H-side" of the hydraulic device via the check valve N with the induction stroke, and pumped via the check valve 0 into the heat exchanger V2 in the pump stroke. The working fluid L2 is lead from the heat exchanger V2 and further into the heat exchanger VI . The heated working fluid L2 that is let out by the "G-part" of the hydraulic device via the valve M in the induction stroke is lead into the heat exchanger V2 and counter flow heat exchanged with the cold working fluid L2 in the heat exchanger V2. When the warm working fluid L2 has been heat exchanged with the cold working fluid L2 in V2 the working fluid L2 is directed to the heat exchanger V3 and there cooled down by the cold fluid L3, thereafter going to the reservoir J. Energy is released as mechanical work on the generator W via the hydraulic motor K and transformed to electrical energy with the piston rod in the hydraulic device working as a piston in a smaller cylinder that together with the piston rod functions as a pump in a hydraulic circuit that drives the hydraulic motor K. Energy that is extracted from C / LI via L2 in VI and not released as mechanical energy in W goes as heat energy with the working fluid L2 into V2 and is heat exchanged back again in V2. If V2 has a high level of efficiency and an approximately incompressible fluid is at the same time used, a large part of the energy that is absorbed in VI will not be liberated from the system as heat, but forced out as mechanical energy and can thereby in a preferred embodiment be converted to electrical energy in the generator W. It is necessary that the "G-side" of the hydraulic device (see fig. 5 and fig. 6) has a volumetric capacity that is slightly higher than the "H-side" of the hydraulic device. The ratio between the two sides H and G is calculated from the coefficient of thermal expansion of the working fluid L2, the temperature of the working fluid L2 out of VI and the temperature of the working fluid L2 into the induction side of the "H-side" of the hydraulic device. Calculation example of the ratio of volumetric capacity between inpumping hydraulic device G and outletting hydraulic device H: The following conditions apply in the example: Temperature of the fluid L2 out of VI: 35 °C. Temperature of the fluid L2 into the suction side of H: 20 °C. The working fluid is pentane with a thermal coefficient of expansion: C=0, 001608 The density of pentane at 20 °C is 0,6262g/cm 3 . The formula for thermal expansion is v2 = vl(l+cΔT) where vl is the volume prior to heating, v2 is the volume after heating, "c" is the coefficient of thermal expansion and ΔT is the heating or the difference in temperature expressed in °C. The volumetric capacity in the inpumping hydraulic device H is set as 1000 cm 3 per stroke to simplify and make the explanation more understandable. The volumetric capacity of the hydraulic device G shall thus be calculated. Based on the formula for thermal expansion, that mass = volume x density and that the density of pentane at 20 °C and atmospheric pressure is 0,6262, the following table can be set up: Temperature, °C Dt (dens, g/cm 3 ) Vt (volume, cm 3 ) Dt x vt 20 0,6262 1000 626, 2g 25 0,6212 1008 626, 2g 30 0,6163 1016 626, 2g 35 0,6115 1024 626, 2g 40 0,6068 1032 626, 2g 45 0,6021 1040 626, 2g 50 0,5975 1048 626, 2g The following equation can be set up: mass in = mass out vt in x dt in = vt out x dt out 1000 cm 3 x 0 , 6262 g/cm 3 = vt out x 0 , 6115g/cm 3 thereby giving vt out = 1024 cm 3 The concentration of mass inside the heat exchangers VI and V2 can not build up with time. Mass in is equal to mass out. The table and calculation shows that when 1000 cm 3 at 20 °C enters that equals a mass of 626,2 g. When 1024 cm 3 is let out at a temperature of 35 °C, that is equivalent of the same mass, i.e. 626,2 g. The ratio of volumetric capacity between inpumping hydraulic device and outletting hydraulic device is thereby that 1000 cm 3 pumped in relates to 1024 cm 3 let out because the mass let in equals the mass let out when temperature in is 20 °C and temperature out is 35 °C. The opposite way one obtains that by having the ratio 1000 cm 3 : 1024 cm 3 in the displacement devices, pentane as a working medium, a temperature of 20 °C in L2 into the hydraulic device H' s suction-side the temperature out of VI will not rise above 35 °C without an increase in pressure. This applies no matter how much heat is transferred to VI, because the mass balance will not allow it. The density decreases with rising temperature and if the temperature of L2 out of VI rises above 35 °C a smaller mass goes out than the mass pumped in. To be able to let out the same mass above 35 °C that is going in at 20 °C the fluid must be compressed, resulting in a high pressure build up. How high the actual pressure becomes is dependent on how much the system is loaded in W and the compressibility of the working fluid at the temperature L2 has when let out of VI. If W is not work loaded, a combination of pressure build up and increased flow rate will result, with a flow rate so high that the working fluid does not have time for getting heated above 35 °C. Examples of different fluids and how they affect the system. The curves in figure 8 show the effects of some selected fluids. The curves show the output effect with a increasing ratio of volumetric capacity between inpumping/outletting for the area of temperature ΔT = 50 °C in temperature L2 out of VI and L2 out of V3. The curves show that in the area 1/1,035 to 1/1,04 the largest output effect can be obtained for the actual range of temperature. The curves in figure 8 are calculated as follows: The formula for thermal expansion of fluids is: V2 = VI (1+β.ΔT) where: VI = volume prior to heating given in dm3 V2 = volume after heating given in dm3 β = coefficient of thermal expansion given in "C "1 ΔT = rise in temperature given in °C The formula for compressibility / change in pressure is: V2 - VI (1-k.Δp) , where VI = the initial volume prior to increasing or decreasing the pressure, dm 3 . V2 = volume after the change in pressure has occurred, dm 3 . k = compressibility factor, Mpa -1 . (1 Mpa = 10 bar) Δp = change in pressure, Mpa. The formula for pressure build up in a closed system is : P = B . β.ΔT , with ΔP = pressure change in Mpa (1 Mpa = 10 bar) B = bulk module, which again is 1/compressibilityfactor k: B=l/k, β = coefficient of thermal expansion in °C _1 . The formula for hydraulic power is: P = Q • p / 600, with P = effect in kW. Q = flow given in dirήnin "1 . P = pressure given in bar. The factor 1/600 arises because the flow rate is applied in dπAαin "1 rather than dm 3 sec _1 and pressure in bar rather than MPa. Reference to literature on hydraulics is made concerning the conversion factor. Table 2, some physical characteristics of the fluids in fig. 8: Coefficient Compressibility Specific of expansion factor heat capacity Trans-1, 2- dichloro- ethylene 1, 36.10- 3o C _1 1, 12. lO^MPa "1 l,2kWs/kg°C Methanol l,4910- 3O C _1 1, 211(T 3 MPa- 1 2,46kWs/kg°C Pentane 1,641CΓ 30 C _1 2, 1310- 3 MPa _1 The example below shows a calculation of the pressure build up that occurs with the following parameter values: Trans-1, 2-dichlorethylene as a liquid, in a closed system when the temperature rises above 50 °C. The compressibility factor for trans-1, 2- dichloroethylene is 1,1210 "3 MPa "1 . The coefficient of thermal expansion for trans-1, 2- dichloroethylene is 1, 3610 "3o C _:L . ΔT = 50°C Δp = B.β.ΔT Δp = 1/1,12 • 10 "3 MPa "1 • 1,36-lCr 3 C "1 • 50 C ΔP= 60,7 MPa = 607 bar. The calculation example below shows the change in volume taking place when heating up 1000 cm 3 of trans-1, 2- dichloroethylene in an open system at atmospheric pressure. The coefficient of thermal expansion for trans-1, 2- dichloroethylene is 1, 3610 "3o C _1 . The increase in temperature is from 10 °C to 60 °C, i.e. ΔT = 50 °C VI = 1000 cm 3 ved 10 °C V2 = VI . (1 +β.ΔT) . V2 = 1000 cm 3 • (1 + 1,36" 10 "3 C "1 • 50 C) . V2 = 1068 cm 3 . The calculation example below shows the pressure build up taking place in a system filled with trans-1, 2- dichloroethylene, when the temperature rises from 10 °C to 60 °C and the volume is allowed to increase with 4 % : V2 = VI ■ (1-k.Δp) . Δp = -(V2-V1) /(k.Vl) . VI = 1040 cm 3 . (the volume increases by 4 %) V2 = 1068 cm 3 . (the volume would increase by 6,8 % in an open system) Δp = - (1040-1068) / (1,12 ' 10 "3 • 1040) Δp = 24,0 MPa = 240 bar For a ΔT of 50 °C the calculations show that trans-1, 2- dichloroethylene expands from 1000 cm 3 to 1068 cm 3 if the system is open. Further, it can be seen that for a ΔT of 50°C the pressure increases from 0 bar to 607 bar in a closed system filled with trans-1, 2-dichloroethylene. For a ΔT of 50 °C it is further calculated that the pressure increases from 0 bar 240 bar in a system where the volume is allowed to increase by 4 % . This shows that if inpumping displacement device gives 100 volume units, outletting displacement device lets out 104 volume units, the temperature of trans-1, 2-dichloroethylene into the high pressure side of V2 is 10°C, the temperature of trans-1, 2- dichloroethylene into the low pressure side of V2 is 60 °C and the pressure is 240 bar, the same mass is entering and leaving out of the system. The volume of the fluid flow out is then 4 % higher than the fluid flow in. 4 % of the fluid flow from the pressure increase calculated above can thereby be taken out as or utilised as mechanical work. The formula for hydraulic power is: P = Q ■ p / 600 Based on the inpumping hydraulic device in the example giving 100 dm 3 min -1 and outletting hydraulic device letting out 104 dm 3 min _1 , one obtains: Q = 104 dm 3 min "1 - 100 dm 3 min "1 =4 dm 3 • min "1 p = 240 bar P = 4 • 240/600 P = 1,6 kW To give an explanation of the curves in figure 8, the calculation can be repeated, but with a different ratio (1/1,02) on inpumping / outletting displacement device. The following is then obtained: V2 = VI. (1 -kΔp) Δp = -(V2-V1) / (kΔVl) VI = 1020 cm 3 (the volume increases by 2 %) V2 = 1068 cm 3 (the volume would increase by 6,8 % in an open system) Δp = -(1020-1068)/ (1,12 • 10 ~3 - 1020) Δp = 42 MPa = 420 bar Q = 102 dm 3 • min -1 - 100 dm 3 • in -1 =2 dm 3 , min "1 p = 420 bar P = 2 • 420 / 600 P = 1,4 kW Each point on the curves in figure 8 is calculated with varying ratios in the volumetric capacities of inpumping / outletting displacement device in the same way as the calculations above. Calculation of efficiency: To find the efficiency of the system the specific heat capacity must be brought into the calculations. Efficiency ratio is hereby defined as: Α~ ^released / E tot where : η (Greek: "Eta") indicates efficiency ratio, Eliberated is liberated mechanical work, and E tot is the total energy taken from an energy source. The formula for transferred heat is E = M ■ Cp • ΔT , with E = heat given as kJ or kWs M = the mass of the medium to be heated or cooled, given in the unit kg sec "1 Cp = specific heat capacity, given in kWs kg "1 °C "1 ΔT = difference in temperature, given in C Ratio of volumetric capacity between inpumping and outletting displacement device in the example is 1/1,04. The temperature of cold trans-1, 2-dichloroethylene into the high pressure side of V2 = 10 °C. The temperature of warm trans-1, 2-dichloroethylene into the low pressure side of V2 = 60 °C. Cold flow L2 the high pressure side of V2=100 dm 3 min "1 . Warm flow L2 into the low pressure side of V2 = 104 dπAτiin "1 . The density of trans-1, 2-dichloroethylene = 1,28 kgd "3 . Qι_ .berated =104 dm 3 • min "1 - 100 dm 3 .min "1 =4 dm 3 , min "1 . p = 240 bar P iterated = 4 - 240 / 600 P liberated = 1 6 kW A power of 1,6 kW is released. To calculate the efficiency ratio the heat loss in V3 (E lost V3) must be calculated. The reason being that the absorbed energy from the warm medium LI goes two ways, partly out as mechanical work and partly out as heat loss in V3. Flow into the high pressure side of V2 is 100 dm 3 min "1 with a temperature of 10 °C. Mass into the V2 high pressure side = 100 13kg'sec "x . Flow out of the low pressure side of V2 has a temperature of 12 °C. Specific heat capacity of trans-1, 2-dichloroethylene is Cp = 1,2 kWs kg "10 C "x . The heat transferring area in V2 is in the example large enough for the heat exchange to give a ΔT of 2 C, implicating that ingoing L2 on the high pressure side is 10°C and outgoing L2 on the low pressure side is 12 °C E lost V3 = M • Cp • ΔT. E ι ost V3 = 2 , 13 kg ' sec "x • 1 , 2 kWs kg "1 C "1 • 2 °C . E lo3t V3 = 5 , 12 kW . E tot = E liberated + E lostV3. E tot = 1, 6kW + 5, 12 kW. E tot = 6,72 kW. Η — -^liberated ' ^tot * η= 1, 6kW/6,72 kW. η= 0,238 = 24 % The lower ΔT one is able to get in and out of V2, the higher the efficiency ratio becomes. To illustrate this, the calculation example above is repeated, but calculated with a ΔT out of and into V2 set to 1 °C. All values are similar with exception for ΔT out of and into V2 set to 1 °C. E lo3t V3 = M • Cp ΔT. E i ost V3 =2,13 kg -sec "x • 1,2 kWs .kg "1 C "1 • 1 °C. E lo3t V3 = 2, 56 kW. E tot = E liberated + E ι os tV3 . E tot = 1 , 6kW + 2 , 56 kW . E tot = 4 , 1 6 kW . " n = E liberated E tot η= 1, 6kW / 4, 16 kW η= 0,38 = 38 % The efficiency consequently increases considerably when ΔT out of and into V2 decreases, because the heat loss in V3 also decreases. The rise in temperature in trans-1, 2- dichloroethylene with pressure increase is disregarded in the calculation because this is relatively small. The efficiency is highly influenced by the temperature increase in the fluids with pressure build up. The lower this rise in temperature is, the higher the potential of increasing the efficiency. This because the temperature in L2 on the low pressure side of V2 cannot become lower than the temperature of L2 into the high pressure side of V2. For example, if one has a temperature in L2 out of V3 at 10 °C and this temperature rises to 20 °C during the pressure build up the temperature of L2 on the low pressure side of V2 will never become lower than 20 °C. With that L2 must be cooled down to 10 °C in V3 and ElostV3 will be disproportionately high in proportion to E liberated so that the efficiency will be low. This is the reason that liquid carbon dioxide is not suitable as a fluid in a layout constructed to develop energy. The heat loss in V3 becomes too large.

Claims: C l a i m s 1. A device with a heat exchanger (VI) arranged to extract heat energy from a source (C) with a primary fluid (LI) with relatively higher temperature, and transfer a part of this heat energy to a secondary fluid (L2) with a relatively lower temperature on the other side of the heat exchanger (VI), with its secondary outlet connected to a displacement device (G) with relatively higher volumetric capacity, and further having an outlet to a reservoir (J) after first being cooled down in a heat exchanger (V3 ) by a fluid (L3 ) , c h a r a c t e r i s e d i n that the secondary fluid (L2) in all essentials is not very compressible, and that the displacement device (G) with a relatively higher volumetric capacity is connected to a displacement device (H) with relatively lower volumetric capacity, which has an inlet from the relatively colder reservoir (J) with the secondary fluid (L2) , with its displacement device (H) having an outlet connected to the intake of the secondary side of the heat exchanger (V2) that has an outlet to the heat exchanger (VI) which is connected to the displacement device (G) with a relatively higher volumetric capacity that at the same time is connected to an energy converter (W) designed to convert mechanical energy to other forms of energy, preferably electrical power. 2 . The arrangement according to claim 1 c h a r a c t e r i s e d i n that the two displacement devices (G) and (H) consist of a double acting hydraulic cylinder with a piston (PI), with essentially the same pressure on both sides of the piston (PI) to essentially eliminate the internal leakage in the two displacement devices (G) and (H) to be able to utilise approximately ideal fluids as working fluids, arranged with a relationship between the piston rod side's (RH) cross- sectional area and the area of the piston (PI) that is calculated so that the ratio of volumetric capacity between the displacement device (G) and the displacement device (H) adjust to the secondary fluid's (L2) coefficient of thermal expansion and compressibility factor. 3 . The arrangement according to claim 2 , c h a r a c t e r i s e d b y that the displacement device (H) consists of the cylinder side with the piston rod (RH) with the fluid flow being controlled by the check valves (0) and (N) , that the displacement device (G) consists of the cylinder side without the piston rod (RH) and that the fluid flow out from and in to (G) is determined by the positions of the valves (L) and (M) , with the position of the valves (L) and (M) being controlled by a controller (X) that receives its control signals from inductive sensors (IT) and (IU) which registers the position of the piston in the cylinder, and that the piston rod (RH) goes further into a new cylinder (S2) where (RH) functions as a piston and that the cylinder (S2) and piston rod (RH) function as a reciprocating pump in a hydraulic circuit that further involves check valves (P) and (Q) , the accumulator (R) and the hydraulic motor (K) that drives the generator (W) . 4. The method for transforming energy from heat energy to other forms of energy, with one heat exchanger (VI) arranged to extract heat from a source (C) with a relatively hotter primary fluid (LI) and transfer this to a relatively colder secondary fluid (L2) on the other side of the heat exchanger (VI) , that because of thermal expansion in the secondary fluid (L2) in the heat exchanger (VI) forces heated secondary fluid (L2) out of the heat exchanger (VI), and leading the fluid (L2) with a mass m per time unit of secondary fluid to run a motor or displacement device (G) with relatively higher volumetric capacity which thereafter lets the secondary fluid (L2) out to a reservoir (J) with lower pressure, that is cooled down by a fluid or gas (L3) , c h a r a c t e r i s e d b y that a fluid (L2) that is essentially very little compressible is utilised; that the motor or the displacement device (G) with relatively higher volumetric capacity is preferably mechanically connected to a pump or displacement device (H) with relatively lower volumetric capacity, and that a part of the power from the motor or pump (G) is utilised to run the pump (H) to pump preferentially the equivalent mass m per time unit av of secondary fluid (L2) with higher density from the relatively colder reservoir (J) into the secondary side of the heat exchanger (V2) , and lead the secondary fluid (L2) to the heat exchanger (VI) that again leads the fluid to the displacement device (G) , and that the motor or pump (G) with a relatively higher volumetric capacity at the same time is mechanically connected to a energy transformer (W) which thereby transforms the mechanical energy to other forms of energy, preferably electrical power.

Inventors: ONSOEYEN GEIR, ONSOEYEN, GEIR
Applicants: ONSOEYEN GEIR, ONSOEYEN, GEIR
Application year: 1999
Main classification: F01K25
IPC codes: F01K25