WO2018097780A1 - A whr system including an aluminium condenser - Google Patents

A whr system including an aluminium condenser Download PDF

Info

Publication number
WO2018097780A1
WO2018097780A1 PCT/SE2017/051031 SE2017051031W WO2018097780A1 WO 2018097780 A1 WO2018097780 A1 WO 2018097780A1 SE 2017051031 W SE2017051031 W SE 2017051031W WO 2018097780 A1 WO2018097780 A1 WO 2018097780A1
Authority
WO
WIPO (PCT)
Prior art keywords
working medium
condenser
whr
temperature
cooling
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/SE2017/051031
Other languages
French (fr)
Inventor
Zoltan Kardos
Matthias USSNER
Thomas TIMREN
Johan Linderyd
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Scania CV AB
Original Assignee
Scania CV AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Scania CV AB filed Critical Scania CV AB
Priority to DE112017005170.3T priority Critical patent/DE112017005170B4/en
Publication of WO2018097780A1 publication Critical patent/WO2018097780A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
    • F02G5/00—Profiting from waste heat of combustion engines, not otherwise provided for
    • F02G5/02—Profiting from waste heat of exhaust gases
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
    • F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
    • F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
    • F01K23/065—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle the combustion taking place in an internal combustion piston engine, e.g. a diesel engine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
    • F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
    • F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
    • F01K23/10—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle with exhaust fluid of one cycle heating the fluid in another cycle
    • F01K23/101—Regulating means specially adapted therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K25/00—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for
    • F01K25/08—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using special vapours
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N5/00—Exhaust or silencing apparatus combined or associated with devices profiting by exhaust energy
    • F01N5/02—Exhaust or silencing apparatus combined or associated with devices profiting by exhaust energy the devices using heat
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/02—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a heat exchanger
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • a WHR system can be used in vehicles for recovering waste thermal energy and convert it to mechanical energy or electric energy.
  • a WHR system includes a pump which pressurizes and circulates a working medium in a closed circuit.
  • the circuit comprises one or several evaporators where the working medium is heated and evaporated by one or several heat sources such as, for example, the exhaust gases from a combustion engine.
  • the pressurized and heated gaseous working medium is directed to an expander where it expands.
  • the expander generates mechanical energy which can be used to operate the vehicle or apparatuses on the vehicle. Alternatively, the expander is connected to a generator generating electric energy.
  • the working medium leaving the expander is directed to a condenser.
  • the working medium is cooled down in the condenser to a temperature at which it condenses.
  • the liquefied working medium is redirected to the pump which pressurizes the medium.
  • a WHR-system can reduce the fuel consumption of a combustion engine.
  • a condenser in a WHR system is made by stainless steel in order to be resistant against high pressures, high temperatures and a corrosive working medium such as ethanol.
  • Stainless steel is a relatively expensive material and it heat transfer properties are not exceptional. Consequently, a condenser of stainless steel is heavy and expensive.
  • US 2013/0186087 shows a waste heat recovery system for use with an internal combustion engine.
  • the system comprises a recuperator operatively connected to a working fluid circuit downstream of an expander and upstream of a condenser to recover heat from the working fluid before the working fluid flows through the condenser.
  • the recuperator delivers heat energy from the expanded working fluid to the working fluid downstream of the condenser.
  • the object of the present invention is to provide a WHR system including an inexpensive condenser which has a low weight.
  • the above mentioned object is achieved by the WHR system according to claim 1.
  • Aluminum is a relatively inexpensive material and it has exceptional heat transfer properties. In view of these facts, aluminum is a very suitable material to use in a condenser. However, it is not suitable to use an aluminum condenser at too high temperatures and pressures. Furthermore, aluminum may corrode in contact with certain working mediums. The corrosion resistance of aluminum is strongly related to the temperature of the working medium. It has been found that the corrosive resistance is acceptable when the temperature of the working medium entering the condenser is not too high.
  • the WHR system comprises a cooling arrangement configured to cool the working medium such that the temperature of the working medium is prevented from rising to a level where it can be harmful to the aluminum condenser.
  • the WHR system can be provided with a condenser of aluminum.
  • a condenser of aluminum In view of the initially mentioned properties of aluminum, such a condenser can have a low weight and be inexpensive.
  • the cooling arrangement is configured to prevent that the working medium entering the condenser at a temperature above a maximum allowable temperature. It is possible to determine a maximum temperature where the working medium is harmless to the aluminum condenser.
  • the cooling arrangement can be activated during operating conditions when the temperature of the working medium approaches the maximum allowable temperature. During remaining operating conditions when the temperature of the working medium is well below the maximum allowable temperature, the cooling arrangement is not activated.
  • the cooling arrangement comprises a cooling component configured to cool the working medium in a position downstream of the expander and upstream of the condenser. In order to prevent that the working medium entering the condenser at a too high temperature, it is suitable to cool the working medium in said position.
  • the cooling arrangement is able to cool the working medium with a variable cooling capacity.
  • the cooling arrangement may comprise a temperature sensor sensing the temperature of the working medium, a control unit configured to receive information from the temperature sensor about the temperature of the working medium and a to control the supply of a cooling fluid to the cooling component in order to restrict the temperature of the working medium entering the condenser.
  • the cooling component may be a heat exchanger in which the working medium is cooled by a coolant flow.
  • the cooling component is a cooling coil in which the working medium is cooled by a cooling air flow.
  • the cooling arrangement has a simple and reliable design.
  • a heat exchanger and cooling coil are manufactured by stainless steel.
  • the heat exchanger and the cooling coil may be relatively small in relation to the condenser since they only have the task to reduce the overheating of the gaseous working medium before it enters the condenser.
  • the condensation process of the working medium has to be performed in the condenser.
  • the control unit may be configured to control the speed of a fan forcing an air flow towards the cooling coil. In this case, it is possible to vary the cooling capacity of the working medium by varying the cooling air flow rate towards the cooling coil.
  • the working medium in the WHR- system is ethanol.
  • Ethanol has an evaporation temperature of about 78°C at 1 bar. It is relatively easy to accomplish a coolant temperature at a suitable level below the evaporation temperature of ethanol and cool the ethanol in a condenser to a condensation temperature just above 78°C.
  • ethanol is very corrosive to aluminum at high temperature. In this case, it is very important to restrict the temperature of the working medium to a suitable maximum temperature where the ethanol is harmless to the aluminum condenser.
  • a maximum acceptable temperature at about 150°C is suitable in this case.
  • the temperature of the working medium leaving the expander is lower than 150°C. Higher temperature of the working medium may, for example, occur when the expander is pre-heated for a start up to avoid condensation on a cold surface of the expander. However, it is possible to use other working mediums such as for example R245fa.
  • the working medium is heated in an evaporator of the WHR-system by means of exhaust gases from a combustion engine.
  • the exhaust gases from a combustion engine contains a lot of heat energy, which usually is supplied to the environment.
  • the WHR system may comprise an evaporator manufactured by stainless steel.
  • FIG. 1 shows a WHR system according to a first embodiment of the invention
  • Fig. 2 shows a WHR system according to a second embodiment of the
  • Fig. 1 shows a combustion engine 2 powering a schematically disclosed vehicle 1.
  • the combustion engine 2 may be a diesel engine.
  • the vehicle 1 may be a heavy vehicle.
  • the vehicle is provided with a WHR-system (Waste Heat Recovery system).
  • the WHR- system comprises a pump 3 which pressurizes and circulates a working medium in a closed a circuit 4.
  • the working medium is ethanol.
  • the pump 3 circulates the working medium to an evaporator 5.
  • the working medium is heated in the evaporator 5 by exhaust gases directed out the combustion engine 2 in an exhaust line 6.
  • the exhaust line 6 comprises a bypass line 6a and a valve 6b by which it is possible to direct a variable part of the exhaust gases past the evaporator 5.
  • An exhaust line 6 directs exhaust gases from the combustion engine 2.
  • the exhaust line 6 may comprise components which are not indicated in Fig. 1 such as a turbine of a turbo charger and exhaust gas treatment components.
  • the working medium is heated in the evaporator 5 by the exhaust gases to a temperature at which it evaporates.
  • the evaporator is made of stainless steel.
  • the working medium is circulated from the evaporator 5 to an expander 7.
  • the pressurized and heated working medium is expanded in the expander 7.
  • the expander 7 generates a rotary motion which is transmitted, via a suitable mechanical transmission 8a, to a shaft 8b of the power train of the vehicle 1.
  • the expander 7 may be connected to a generator transforming mechanical energy into electrical energy.
  • the electrical energy may be stored in a battery.
  • the working medium After the working medium has passed through the expander 7, it is directed to a cooling coil 9 where it may be cooled by a cooling air flow provided by a 10.
  • the fan 10 is driven by an electric motor 11.
  • the electric motor 11 may drive the fan 10 with a variable speed.
  • the speed of the fan 10 and the air flow rate directed to the cooling coil 9 may be changed in a stepless manner.
  • the cooling capacity of the working medium in the cooling coil 9 may also be changed in a stepless manner.
  • a temperature sensor 12 senses the temperature of the working medium in a position downstream of the cooling coil 9 and upstream of a condenser 13.
  • the condenser 13 is made by aluminum.
  • a control unit 14 receives information from the temperature sensor 12 and controls the electric motor 11 and the fan 10 in view of this information such that the working medium is cooled to a suitable temperature before it enter the condenser 13.
  • the control unit 10 may also control the operation of the pump 3 and the expander 7.
  • the working medium is cooled in the condenser 13 by coolant circulating in a cooling circuit 15 to a temperature at which it condenses.
  • the coolant may have a temperature of about 70°C.
  • the condensed working medium is directed from the condenser 13 to a tank 16.
  • the pump 3 sucks working medium from the tank 16 and direct it to the evaporator 5.
  • the WHR-system makes it possible to transform thermal energy from the exhaust gases to mechanical energy or electrical energy.
  • a condenser of a conventional WHR system is made by stainless steel such that it is able to withstand high pressures, high temperatures and a corrosive working medium such as ethanol.
  • stainless steel has lower heat transfer properties than aluminum, it is more expensive than aluminum and it has a higher weight.
  • a condenser of stainless steel with corresponding capacity as a condenser made of aluminum has to be significantly larger, heavier, and more expensive.
  • a condenser of aluminum have a lower resistance to high temperatures and pressures.
  • aluminum is very corrosive to certain a working medium such as ethanol at high temperatures.
  • the temperature of the working medium shall not be higher than a maximum allowable temperature.
  • a maximum allowable temperature is in this case about 150°C. At higher temperatures of the working medium, there is a great risk of corrosion of aluminum condenser.
  • the working medium is to be cooled in the condenser 13 to a
  • condensation pressure as low as possible. However, it is suitable to avoid negative pressure in the WHR-system by practical reasons. In view of these facts, it is suitable to cool of the working medium in the condenser 13 to a condensation pressure just above 1 bar. Consequently, in order to maintain a high thermal efficiency, the control unit 14 may control the temperature and/or the coolant flow in the circuit 15 to the condenser 13 such that the condensation pressure will be just above 1 bar.
  • the working medium ethanol has a condensation temperature of 78°C at the condensation pressure 1 bar. In this case, it is suitable to accomplish a condensation temperature of just above 78°C in the condenser 13.
  • the control unit 14 receives continuously information from the temperature sensor 12 about the temperature of the working medium entering the condenser 13. As soon as the control unit 14 receives information indicating that the working medium has a temperature which is well below 150°C, there is no reason to start the fan 9.
  • control unit 14 During operating conditions when the control unit 14 receives information from the temperature sensor 12 indicating that the working medium has a temperature close to the maximum allowable temperature, it activates the electric motor 11 and the fan 10 such that it forces a suitable cooling air flow through the cooling coil 9.
  • the cooling air flow cools the working medium such that it obtains a somewhat lower than said maximum allowable temperature.
  • the control unit 14 may control the electric motor 11 and the fan 10 such a variable air flow rate cools the working medium in the cooling coil 9. In this case, it is possible to maintain a suitable temperature of the working medium with a high precision.
  • the control unit 14 receives information from the temperature sensor 12 indicating that the working medium has temperature well below the maximum allowable temperature, it does not activate the electric motor 11 and the fan 10.
  • Fig. 2 shows an alternative embodiment of the WHR system.
  • the working medium is cooled in a heat exchanger 17 by a circulating coolant.
  • the coolant circulates in a circuit 18 connected to a cooling system cooling the combustion engine 2.
  • the coolant may have a temperature of about 90-110°C when it enters the heat exchanger 17.
  • the control unit 14 controls the supply of the coolant to the heat exchanger 17 by means of a valve 19.
  • the heat exchanger 17 is made of stainless steel.
  • the heat exchanger 17 is small in relation to the condenser 13 since the task of the heat exchanger 17 is only to cool overheated gaseous working medium such that it does not have a temperature above 150°C when it enters the condenser 13. Also in this case, it is possible to provide a WHR system comprising aluminium condenser 13.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Engine Equipment That Uses Special Cycles (AREA)

Abstract

The present invention relates to a WHR-system for a vehicle. The WHR-system comprises a pump (3) configured to pressurize and circulate a working medium in a closed circuit (4), an evaporator (5) in which the working medium is configured to be heated and evaporated, an expander (7) in which the working medium is configured to expand and a condenser (13) in which the working medium is configured to be cooled and condensed. The condenser (13) is made by aluminum and that the WHR system comprises a cooling arrangement configured to cool the working medium such that it has a temperature when it enters the aluminum condenser at which the working medium is deemed to be harmless to the aluminum condenser (13).

Description

A WHR SYSTEM INCLUDING AN ALUMINIUM CONDENSER
BACKGROUND OF THE INVENTION AND PRIOR ART
The present invention relates to a WHR system for a vehicle according to the preamble of claim 1. A WHR system (Waste Heat Recovery System) can be used in vehicles for recovering waste thermal energy and convert it to mechanical energy or electric energy. A WHR system includes a pump which pressurizes and circulates a working medium in a closed circuit. The circuit comprises one or several evaporators where the working medium is heated and evaporated by one or several heat sources such as, for example, the exhaust gases from a combustion engine. The pressurized and heated gaseous working medium is directed to an expander where it expands. The expander generates mechanical energy which can be used to operate the vehicle or apparatuses on the vehicle. Alternatively, the expander is connected to a generator generating electric energy. The working medium leaving the expander is directed to a condenser. The working medium is cooled down in the condenser to a temperature at which it condenses. The liquefied working medium is redirected to the pump which pressurizes the medium. Thus, the waste heat energy from, for example, the exhaust gases from a combustion engine in a vehicle can be recovered by means of a WHR-system.
Consequently, a WHR-system can reduce the fuel consumption of a combustion engine. Usually, a condenser in a WHR system is made by stainless steel in order to be resistant against high pressures, high temperatures and a corrosive working medium such as ethanol. Stainless steel is a relatively expensive material and it heat transfer properties are not exceptional. Consequently, a condenser of stainless steel is heavy and expensive.
US 2013/0186087 shows a waste heat recovery system for use with an internal combustion engine. The system comprises a recuperator operatively connected to a working fluid circuit downstream of an expander and upstream of a condenser to recover heat from the working fluid before the working fluid flows through the condenser. The recuperator delivers heat energy from the expanded working fluid to the working fluid downstream of the condenser. SUMMARY OF THE INVENTION
The object of the present invention is to provide a WHR system including an inexpensive condenser which has a low weight.
The above mentioned object is achieved by the WHR system according to claim 1. Aluminum is a relatively inexpensive material and it has exceptional heat transfer properties. In view of these facts, aluminum is a very suitable material to use in a condenser. However, it is not suitable to use an aluminum condenser at too high temperatures and pressures. Furthermore, aluminum may corrode in contact with certain working mediums. The corrosion resistance of aluminum is strongly related to the temperature of the working medium. It has been found that the corrosive resistance is acceptable when the temperature of the working medium entering the condenser is not too high. The WHR system comprises a cooling arrangement configured to cool the working medium such that the temperature of the working medium is prevented from rising to a level where it can be harmful to the aluminum condenser. With a suitable restriction of the temperature of the working medium directed to the condenser, the WHR system can be provided with a condenser of aluminum. In view of the initially mentioned properties of aluminum, such a condenser can have a low weight and be inexpensive.
According to an embodiment of the invention, the cooling arrangement is configured to prevent that the working medium entering the condenser at a temperature above a maximum allowable temperature. It is possible to determine a maximum temperature where the working medium is harmless to the aluminum condenser. In this case, the cooling arrangement can be activated during operating conditions when the temperature of the working medium approaches the maximum allowable temperature. During remaining operating conditions when the temperature of the working medium is well below the maximum allowable temperature, the cooling arrangement is not activated.
According to an embodiment of the invention, the cooling arrangement comprises a cooling component configured to cool the working medium in a position downstream of the expander and upstream of the condenser. In order to prevent that the working medium entering the condenser at a too high temperature, it is suitable to cool the working medium in said position.
According to an embodiment of the invention, the cooling arrangement is able to cool the working medium with a variable cooling capacity. In this case, it is possible to control the temperature of the working medium entering the condenser with a high precision. The cooling arrangement may comprise a temperature sensor sensing the temperature of the working medium, a control unit configured to receive information from the temperature sensor about the temperature of the working medium and a to control the supply of a cooling fluid to the cooling component in order to restrict the temperature of the working medium entering the condenser. By means of such a cooling arrangement it is relatively easy to control the temperature of the working medium entering the condenser. According to an embodiment of the invention, the cooling component may be a heat exchanger in which the working medium is cooled by a coolant flow. In this case, it is possible to use coolant circulating in an existent cooling system cooling a combustion engine in a vehicle. Alternatively, the cooling component is a cooling coil in which the working medium is cooled by a cooling air flow. In this case, the cooling arrangement has a simple and reliable design. Preferably, such a heat exchanger and cooling coil are manufactured by stainless steel. The heat exchanger and the cooling coil may be relatively small in relation to the condenser since they only have the task to reduce the overheating of the gaseous working medium before it enters the condenser. The condensation process of the working medium has to be performed in the condenser. The control unit may be configured to control the speed of a fan forcing an air flow towards the cooling coil. In this case, it is possible to vary the cooling capacity of the working medium by varying the cooling air flow rate towards the cooling coil.
According to an embodiment of the invention, the working medium in the WHR- system is ethanol. Ethanol has an evaporation temperature of about 78°C at 1 bar. It is relatively easy to accomplish a coolant temperature at a suitable level below the evaporation temperature of ethanol and cool the ethanol in a condenser to a condensation temperature just above 78°C. However, ethanol is very corrosive to aluminum at high temperature. In this case, it is very important to restrict the temperature of the working medium to a suitable maximum temperature where the ethanol is harmless to the aluminum condenser. A maximum acceptable temperature at about 150°C is suitable in this case. During the most operating conditions, the temperature of the working medium leaving the expander is lower than 150°C. Higher temperature of the working medium may, for example, occur when the expander is pre-heated for a start up to avoid condensation on a cold surface of the expander. However, it is possible to use other working mediums such as for example R245fa.
According to an embodiment of the invention, the working medium is heated in an evaporator of the WHR-system by means of exhaust gases from a combustion engine. The exhaust gases from a combustion engine contains a lot of heat energy, which usually is supplied to the environment. By means of a WHR-system, it is possible to recover a large part of the heat energy in the exhaust gases. Due to the high temperatures of the exhaust gases, the WHR system may comprise an evaporator manufactured by stainless steel. BRIEF DESCRIPTION OF THE DRAWING
In the following a preferred embodiment of the invention is described, as an example, with reference to the attached drawing, in which: Fig. 1 shows a WHR system according to a first embodiment of the invention and
Fig. 2 shows a WHR system according to a second embodiment of the
invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
Fig. 1 shows a combustion engine 2 powering a schematically disclosed vehicle 1. The combustion engine 2 may be a diesel engine. The vehicle 1 may be a heavy vehicle. The vehicle is provided with a WHR-system (Waste Heat Recovery system). The WHR- system comprises a pump 3 which pressurizes and circulates a working medium in a closed a circuit 4. In this case, the working medium is ethanol. However, it is possible to use other kinds of working mediums such as for example R245fa. The pump 3 circulates the working medium to an evaporator 5. The working medium is heated in the evaporator 5 by exhaust gases directed out the combustion engine 2 in an exhaust line 6. The exhaust line 6 comprises a bypass line 6a and a valve 6b by which it is possible to direct a variable part of the exhaust gases past the evaporator 5. An exhaust line 6 directs exhaust gases from the combustion engine 2. The exhaust line 6 may comprise components which are not indicated in Fig. 1 such as a turbine of a turbo charger and exhaust gas treatment components. The working medium is heated in the evaporator 5 by the exhaust gases to a temperature at which it evaporates. The evaporator is made of stainless steel. The working medium is circulated from the evaporator 5 to an expander 7. The pressurized and heated working medium is expanded in the expander 7. The expander 7 generates a rotary motion which is transmitted, via a suitable mechanical transmission 8a, to a shaft 8b of the power train of the vehicle 1. Alternatively, the expander 7 may be connected to a generator transforming mechanical energy into electrical energy. The electrical energy may be stored in a battery. After the working medium has passed through the expander 7, it is directed to a cooling coil 9 where it may be cooled by a cooling air flow provided by a 10. The fan 10 is driven by an electric motor 11. The electric motor 11 may drive the fan 10 with a variable speed. The speed of the fan 10 and the air flow rate directed to the cooling coil 9 may be changed in a stepless manner. Thus, the cooling capacity of the working medium in the cooling coil 9 may also be changed in a stepless manner.
A temperature sensor 12 senses the temperature of the working medium in a position downstream of the cooling coil 9 and upstream of a condenser 13. The condenser 13 is made by aluminum. A control unit 14 receives information from the temperature sensor 12 and controls the electric motor 11 and the fan 10 in view of this information such that the working medium is cooled to a suitable temperature before it enter the condenser 13. The control unit 10 may also control the operation of the pump 3 and the expander 7. The working medium is cooled in the condenser 13 by coolant circulating in a cooling circuit 15 to a temperature at which it condenses. The coolant may have a temperature of about 70°C. The condensed working medium is directed from the condenser 13 to a tank 16. The pump 3 sucks working medium from the tank 16 and direct it to the evaporator 5. The WHR-system makes it possible to transform thermal energy from the exhaust gases to mechanical energy or electrical energy.
A condenser of a conventional WHR system is made by stainless steel such that it is able to withstand high pressures, high temperatures and a corrosive working medium such as ethanol. However, stainless steel has lower heat transfer properties than aluminum, it is more expensive than aluminum and it has a higher weight. Thus, a condenser of stainless steel with corresponding capacity as a condenser made of aluminum has to be significantly larger, heavier, and more expensive. On the other hand, a condenser of aluminum have a lower resistance to high temperatures and pressures. Furthermore, aluminum is very corrosive to certain a working medium such as ethanol at high temperatures. In order to provide a WHR system comprising a small, lightweight and inexpensive aluminum condenser and a working medium in the form of ethanol, the temperature of the working medium shall not be higher than a maximum allowable temperature. Such a maximum allowable temperature is in this case about 150°C. At higher temperatures of the working medium, there is a great risk of corrosion of aluminum condenser.
During operation of the combustion engine 2, it is desired to maintain a high thermal efficiency in the WHR-system. In order to maintain a high thermal efficiency of the WHR system, the working medium is to be cooled in the condenser 13 to a
condensation pressure as low as possible. However, it is suitable to avoid negative pressure in the WHR-system by practical reasons. In view of these facts, it is suitable to cool of the working medium in the condenser 13 to a condensation pressure just above 1 bar. Consequently, in order to maintain a high thermal efficiency, the control unit 14 may control the temperature and/or the coolant flow in the circuit 15 to the condenser 13 such that the condensation pressure will be just above 1 bar. The working medium ethanol has a condensation temperature of 78°C at the condensation pressure 1 bar. In this case, it is suitable to accomplish a condensation temperature of just above 78°C in the condenser 13. The control unit 14 receives continuously information from the temperature sensor 12 about the temperature of the working medium entering the condenser 13. As soon as the control unit 14 receives information indicating that the working medium has a temperature which is well below 150°C, there is no reason to start the fan 9.
During operating conditions when the control unit 14 receives information from the temperature sensor 12 indicating that the working medium has a temperature close to the maximum allowable temperature, it activates the electric motor 11 and the fan 10 such that it forces a suitable cooling air flow through the cooling coil 9. The cooling air flow cools the working medium such that it obtains a somewhat lower than said maximum allowable temperature. The control unit 14 may control the electric motor 11 and the fan 10 such a variable air flow rate cools the working medium in the cooling coil 9. In this case, it is possible to maintain a suitable temperature of the working medium with a high precision. During operating conditions when the control unit 14 receives information from the temperature sensor 12 indicating that the working medium has temperature well below the maximum allowable temperature, it does not activate the electric motor 11 and the fan 10.
Fig. 2 shows an alternative embodiment of the WHR system. In this case, the working medium is cooled in a heat exchanger 17 by a circulating coolant. The coolant circulates in a circuit 18 connected to a cooling system cooling the combustion engine 2. The coolant may have a temperature of about 90-110°C when it enters the heat exchanger 17. The control unit 14 controls the supply of the coolant to the heat exchanger 17 by means of a valve 19. The heat exchanger 17 is made of stainless steel. The heat exchanger 17 is small in relation to the condenser 13 since the task of the heat exchanger 17 is only to cool overheated gaseous working medium such that it does not have a temperature above 150°C when it enters the condenser 13. Also in this case, it is possible to provide a WHR system comprising aluminium condenser 13.
The invention is not restricted to the described embodiment but may be varied freely within the scope of the claims.

Claims

Claims
1. A WHR-system for a vehicle (1), wherein the WHR system comprises a pump (3) configured to pressurize and circulate a working medium in a closed circuit (4), an evaporator (5) in which the working medium is configured to be heated and evaporated, an expander (7) in which the working medium is configured to expand and a condenser (13) in which the working medium is configured to be cooled and condensed, characterized in that the condenser (13) is made by aluminum and that the WHR system comprises a cooling arrangement configured to cool the working medium such that it has a temperature when it enters the aluminum condenser at which the working medium is deemed to be harmless to the aluminum condenser (13).
2. A WHR system according to claim 1, characterized in that the cooling arrangement is configured to prevent that the working medium entering the condenser (13) at a temperature above a maximum allowable temperature.
3. A WHR system according to claim 1 or 2, characterized in that the cooling arrangement comprises a cooling component (9, 17) configured to cool the working medium in a position downstream of the expander (7) and upstream of the condenser (13).
4. A WHR system according to any one of the preceding claims, characterized in that the cooling arrangement is able to cool the working medium with a variable cooling capacity.
5. A WHR system according to claim 3 or 4, characterized in that the cooling arrangement comprises a temperature sensor (12) sensing the temperature of the working medium, a control unit (14) configured to receive information from the temperature sensor (12) about the temperature of the working medium and a to control the supply of a cooling fluid to the cooling component (9, 17) in order to restrict the temperature of the working medium entering the condenser (13).
6. A WHR system according to claim 5, characterized in that the cooling component is a heat exchanger (17) in which the working medium is cooled by a coolant flow.
7. A WHR system according to claim 5, characterized in that the cooling component is cooling coil (9) in which the working medium is cooled by a cooling air flow.
8. A WHR system according to claim 7, characterized in that the control unit (14) is configured to control the speed of a fan (10) forcing an air flow towards the cooling coil (9).
9. A WHR system according to any one of the preceding claims, characterized in that the working medium in the WHR-system is ethanol.
10. A WHR system according to any one of the preceding claims, characterized in that the working medium is heated in an evaporator (5) of the WHR-system by means of exhaust gases from a combustion engine (2).
11. A vehicle, characterized in that it comprises a WHR system according to any one of the preceding claims.
PCT/SE2017/051031 2016-11-25 2017-10-19 A whr system including an aluminium condenser Ceased WO2018097780A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE112017005170.3T DE112017005170B4 (en) 2016-11-25 2017-10-19 WHR system with aluminum condenser

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE1651544A SE540641C2 (en) 2016-11-25 2016-11-25 A WHR system for a vehicle and a vehicle comprising such a system
SE1651544-7 2016-11-25

Publications (1)

Publication Number Publication Date
WO2018097780A1 true WO2018097780A1 (en) 2018-05-31

Family

ID=62196207

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2017/051031 Ceased WO2018097780A1 (en) 2016-11-25 2017-10-19 A whr system including an aluminium condenser

Country Status (3)

Country Link
DE (1) DE112017005170B4 (en)
SE (1) SE540641C2 (en)
WO (1) WO2018097780A1 (en)

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005103453A1 (en) * 2004-04-09 2005-11-03 Armines System for recovering heat energy from a heat engine vehicle
CN201837261U (en) * 2010-10-12 2011-05-18 无锡市广运环保机械有限公司 Special device for power generation by using high-temperature high-dust-content flue gas waste heat in metallurgical furnace
EP2397659A2 (en) * 2010-06-21 2011-12-21 Paccar Inc. Dual cycle rankine waste heat recovery cycle
US20130186087A1 (en) * 2010-07-14 2013-07-25 Mack Trucks, Inc. Waste heat recovery system with partial recuperation
WO2014060761A2 (en) * 2012-10-17 2014-04-24 Norgren Limited Vehicle waste heat recovery system
WO2015082975A1 (en) * 2013-12-05 2015-06-11 Toyota Jidosha Kabushiki Kaisha Waste heat recovery apparatus
WO2016069707A1 (en) * 2014-10-31 2016-05-06 Modine Manufacturing Company Cooling module and rankine cycle waste heat recovery system
DE102015016783A1 (en) * 2015-12-23 2016-08-11 Daimler Ag Device for recovering energy from waste heat of an internal combustion engine of a motor vehicle
WO2016156800A1 (en) * 2015-03-27 2016-10-06 Norgren Limited Heat energy recovery

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005103453A1 (en) * 2004-04-09 2005-11-03 Armines System for recovering heat energy from a heat engine vehicle
EP2397659A2 (en) * 2010-06-21 2011-12-21 Paccar Inc. Dual cycle rankine waste heat recovery cycle
US20130186087A1 (en) * 2010-07-14 2013-07-25 Mack Trucks, Inc. Waste heat recovery system with partial recuperation
CN201837261U (en) * 2010-10-12 2011-05-18 无锡市广运环保机械有限公司 Special device for power generation by using high-temperature high-dust-content flue gas waste heat in metallurgical furnace
WO2014060761A2 (en) * 2012-10-17 2014-04-24 Norgren Limited Vehicle waste heat recovery system
WO2015082975A1 (en) * 2013-12-05 2015-06-11 Toyota Jidosha Kabushiki Kaisha Waste heat recovery apparatus
WO2016069707A1 (en) * 2014-10-31 2016-05-06 Modine Manufacturing Company Cooling module and rankine cycle waste heat recovery system
WO2016156800A1 (en) * 2015-03-27 2016-10-06 Norgren Limited Heat energy recovery
DE102015016783A1 (en) * 2015-12-23 2016-08-11 Daimler Ag Device for recovering energy from waste heat of an internal combustion engine of a motor vehicle

Also Published As

Publication number Publication date
DE112017005170B4 (en) 2023-03-02
DE112017005170T5 (en) 2019-07-11
SE540641C2 (en) 2018-10-09
SE1651544A1 (en) 2018-05-26

Similar Documents

Publication Publication Date Title
US10787935B2 (en) Cooling arrangement for a WHR-system
US9932862B2 (en) Method and apparatus for heating an expansion machine of a waste heat recovery apparatus
EP3227536B1 (en) A cooling arrangement for a whr-system
CN104066936B (en) Waste heat recovery plant and primemover system
CN105042952B (en) Apparatus for controlling a closed loop operating on a Rankine cycle and method of using the same
EP3093456B1 (en) Heat energy recovery system
CN103237961A (en) Emissions-critical charge cooling using an organic Rankine cycle
JP2011231636A (en) Exhaust heat recovery power generator and ship provided with exhaust heat recovery power generator
WO2016069455A1 (en) System and method of low grade heat utilization for a waste heat recovery system
KR102220071B1 (en) Boiler system
JP2014501874A (en) Apparatus and method for converting thermal energy into mechanical energy
EP3532715B1 (en) A cooling system for cooling of a combustion engine and a whr system
EP3768953B1 (en) An arrangement and a method for controlling a shutdown phase of a whr-system
JP2011074897A (en) Fluid machine driving system
EP3402964B1 (en) A cooling system for a combustion engine and a WHR system
CN114846222A (en) Energy recovery device
WO2018097780A1 (en) A whr system including an aluminium condenser
EP3074613B1 (en) Supplemental heating in waste heat recovery
WO2019147179A1 (en) An arrangement and a method for controlling of a whr system
AU2011201220A1 (en) A heat engine and reciprocating engine arrangement
SE540362C2 (en) An arrangement for recovering heat energy in exhaust gases from a combustion engine
JP2023093168A (en) Marine power generation system
SE540385C2 (en) A WHR system for recovering heat energy from a combustion engine

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17873909

Country of ref document: EP

Kind code of ref document: A1

122 Ep: pct application non-entry in european phase

Ref document number: 17873909

Country of ref document: EP

Kind code of ref document: A1