Arrangement and method for converting thermal energy to mechanical energy

Patent metadata

Field	Value
Publication number	US-9341087-B2
Application number	US-201113990065-A
Country	US
Kind code	B2
Filing date	Nov 22, 2011
Priority date	Dec 1, 2010
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

An arrangement and a method for converting thermal energy to mechanical energy. The arrangement has a line circuit ( 3 ), circulation device ( 4 ) for circulating a zeotropic refrigerant mixture in the line circuit ( 3 ), an evaporator ( 6 ) in which the refrigerant mixture is vaporized by a heat source ( 7 ), a turbine ( 9 ) driven by the vaporized refrigerant mixture, and a condenser ( 12 ) which cools the refrigerant mixture so that it condenses. A control unit assesses whether the refrigerant mixture does not become fully vaporized in the evaporator ( 6 ) and, leads incompletely vaporized refrigerant mixture leaving the evaporator to a separating device ( 14 ) in which a liquid portion of the refrigerant mixture is separated from the gaseous portion, after which only the gaseous portion proceeds towards the turbine ( 9 ).

First claim

The invention claimed is:

1. An arrangement for converting thermal energy to mechanical energy, the arrangement comprising:
a line circuit;
a pump configured for circulating a zeotropic refrigerant mixture in the line circuit;
the zeotropic refrigerant mixture comprises a first refrigerant and a second refrigerant, wherein the first refrigerant has a higher vaporisation temperature than the second refrigerant at a similar pressure;
an evaporator to which the refrigerant mixture is circulated and where the mixture is vaporised and a heat source for the evaporator and operative for vaporizing the refrigerant mixture;
a turbine in the line circuit and located and configured to be driven by the vaporised refrigerant mixture;
a condenser in which the refrigerant mixture is cooled so that the vaporised refrigerant mixture condenses;
an electronic control unit configured for assessing whether the refrigerant mixture does not become fully vaporised at the evaporator and, when the control unit assesses that the refrigerant mixture is not fully vaporised, the control unit is configured to put the arrangement into a low-effect state, the low-effect state comprising the arrangement leading the incompletely vaporised refrigerant mixture through a first conduit leaving the evaporator;
a gas/liquid separating device connected with the first conduit from the evaporator configured for separating a first portion of the refrigerant mixture, which is in liquid form, from a second portion of the refrigerant mixture, which is in gaseous form, wherein the separated liquid refrigerant mixture is prevented from leaving the separating device when the arrangement is in the low-effect state; and
a second conduit for transmitting the gaseous portion of the refrigerant mixture from the separating device toward the turbine in the line circuit and when a temperature of the heat source rises back to a higher temperature, the control unit being configured to put the arrangement into a high-effect state, the high-effect state comprising the arrangement leading the separated liquid refrigerant mixture back to the line circuit,
wherein the control unit is configured and operable to lead the refrigerant mixture from the evaporator towards the turbine through an ordinary line section of the line circuit bypassing the separating device when the control unit assesses that the arrangement is in the high-effect state, and through an extra line section of the line circuit which contains the separating device when the control unit assesses that the arrangement is in the low-effect state.

2. The arrangement according to claim 1 , wherein the control unit comprises at least one sensor configured to monitor a parameter, and a controller configured for receiving information about the parameter from the at least one sensor on the basis of which the controller assesses whether the refrigerant mixture does or does not become fully vaporised in the evaporator.

3. The arrangement according to claim 2 , further comprising sensors, including the at least one sensor, configured for monitoring temperature and/or pressure of the refrigerant in the evaporator or at a location in the line circuit downstream of the evaporator.

4. The arrangement according to claim 1 , wherein the control unit comprises a valve arrangement configured to lead the refrigerant mixture selectively through the ordinary line section or through the extra line section.

5. The arrangement according to claim 1 , wherein the separating device comprises a container in which the refrigerant mixture in liquid form is separated from the refrigerant mixture in gaseous form.

6. The arrangement according to claim 5 , further comprising:
a first line connected for receiving refrigerant mixture from the evaporator and for leading the refrigerant mixture from the evaporator into the container at a location above a maximum liquid level in the container and a second line connected for receiving gaseous refrigerant mixture at a location above the maximum liquid level in the container and for leading the gaseous refrigerant mixture back from the container to the line circuit.

7. The arrangement according to claim 6 , further comprising a third line extending between a bottom surface in the container and the line circuit, and a valve operable at times to lead the refrigerant mixture in liquid form which has accumulated in the container back to the line circuit.

8. The arrangement according claim 1 , wherein the heat source comprises a warm medium in a vehicle powered by a combustion engine.

9. A method for converting thermal energy to mechanical energy comprising:
providing a line circuit for circulating a zeotropic refrigerant mixture in the line circuit, wherein the mixture contains a first refrigerant and a second refrigerant and the first refrigerant has a higher vaporisation temperature than the second refrigerant at a similar pressure;
vaporizing the mixture in an evaporator via a heat source;
driving a turbine by the vaporised refrigerant mixture, and then cooling the refrigerant mixture in a condenser so that the mixture condenses; and
assessing whether the refrigerant mixture does not become fully vaporised in the evaporator and, when that occurs, leading the refrigerant mixture from the evaporator to a gas/liquid separating device and therein separating the portion of the refrigerant mixture which is in liquid form from the portion of the refrigerant mixture which is in gaseous form, then causing only the gaseous portion of the refrigerant mixture to proceed towards the turbine in the line circuit, and
when the temperature of the heat source rises back to a higher temperature, leading the separated liquid refrigerant mixture back to the line circuit and leading the refrigerant mixture from the evaporator towards the turbine by bypassing the separating device.

10. An arrangement for converting thermal energy to mechanical energy, the arrangement comprising:
a line circuit;
a pump configured for circulating in the line circuit a zeotropic refrigerant mixture comprising a first refrigerant and a second refrigerant, wherein the first refrigerant has a higher vaporisation temperature than the second refrigerant at a similar pressure;
an evaporator to which the refrigerant mixture is circulated and where the mixture is vaporised and a heat source for the evaporator;
a turbine in the line circuit and located and configured to be driven by the vaporised refrigerant mixture;
a condenser in which the refrigerant mixture is cooled so that the vaporised refrigerant mixture condenses;
an electronic control unit configured for assessing whether the refrigerant mixture does not become fully vaporised at the evaporator and, when the control unit assesses that the refrigerant mixture is not fully vaporised, the control unit is configured to put the arrangement into a low-effect state in which the arrangement leads the incompletely vaporised refrigerant mixture through a first conduit leaving the evaporator;
a gas/liquid separating device connected with the first conduit from the evaporator and configured for separating a first portion of the refrigerant mixture, which is in liquid form, from a second portion of the refrigerant mixture, which is in gaseous form, wherein the separated liquid refrigerant mixture is prevented from leaving the separating device when the arrangement is in the low-effect state; and
a second conduit for transmitting the gaseous portion of the refrigerant mixture from the separating device toward the turbine in the line circuit and when a temperature of the heat source rises back to a higher temperature, the control unit is configured to put the arrangement into a high-effect state leadin

Assignees

• Hall Ola
• Scania Cv Ab

Inventors

• Hall Ola

Classifications

• F01K25/06

  using mixtures of different fluids (plants using mixtures of steam and gas F01K21/04) · CPC title

• F01K23/101

  Regulating means specially adapted therefor (F01K23/105, F01K23/108 take precedence) · CPC title

• F01N5/02

  the devices using heat · CPC title

• F01K13/00

  General layout or general methods of operation of complete plants · CPC title

• F02G5/02

  Profiting from waste heat of exhaust gases · CPC title