Apparatus and method for detecting low charge of working fluid in a waste heat recovery system
First Claim
1. A method of detecting a low charge of working fluid in a waste heat recovery system having in serial flow relationship an evaporator, a superheat controller, a condenser and a pump that is driven by a variable speed motor, comprising the steps of:
- establishing a reference trajectory for the superheat controller;
determining an actual operational trajectory for the superheat controller at a time of operation of the waste heat recovery system;
comparing said reference trajectory with said actual operational trajectory to determine the deviation therebetween; and
on the basis said deviation, determining whether there is a indication of a low charge in the system.
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Accused Products
Abstract
In a waste heat recovery system having a superheat controller, a reference superheat controller operating trajectory is established and compared with operational superheat controller trajectories from time to time and measuring the deviation therebetween to determine whether a low charge condition exists. If such a condition does exist, warning steps and possibly shut down steps can be taken. As a verification of a low charge condition, the absence or presence of oscillations in the pressure and/or pump power conditions can be observed.
66 Citations
14 Claims
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1. A method of detecting a low charge of working fluid in a waste heat recovery system having in serial flow relationship an evaporator, a superheat controller, a condenser and a pump that is driven by a variable speed motor, comprising the steps of:
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establishing a reference trajectory for the superheat controller; determining an actual operational trajectory for the superheat controller at a time of operation of the waste heat recovery system; comparing said reference trajectory with said actual operational trajectory to determine the deviation therebetween; and on the basis said deviation, determining whether there is a indication of a low charge in the system. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for monitoring and detecting a low charge condition in a waste heat recovery system having an evaporator, a superheat controller, a turbine, a condenser and a pump driven by a variable speed motor comprising:
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means for generating a reference trajectory for the superheat controller; means for determining an actual operating trajectory for the superheat controller at a time of operation of the waste heat recovery system; means for comparing said reference trajectory with said actual operating trajectory to determine the variation therebetween as an indication of a low charge condition of the system. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A method of determining the adequacy of the charge of working fluid in a waste heat recovery system having an evaporator, a condenser and a pump that is driven by a variable speed motor, comprising the steps of:
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providing a superheat controller which controls the degree of superheat to the turbine by varying the speed of the variable speed motor; establishing a reference trajectory for the superheat controller; determining an actual operational trajectory for the superheat controller at a time of operation of the waste heat recovery system; comparing said reference trajectory with said actual operation trajectory to determine the deviation therebetween; and on the basis of said deviation, determining whether there is an indication of a low charge of working fluid for this system.
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Specification