Autocascade system with superheat control
AssigneeTrane International Inc.
InventorsDaniel Gorman, Stephen A. Kujak, Logan Stephenson
Life of this patent
Estimating the term…
Abstract
An autocascade heat transfer fluid circuit includes one or more concentration sensors. The concentration sensors allow the determination of a current composition of a blended working fluid containing multiple components that separate during operation of the autocascade heat transfer fluid circuit. The current composition allows determination of a dew point for the current composition, and a superheat can be calculated based on the determined dew point and pressure and temperature readings. The determined superheat can in turn be used to control operations of the autocascade heat transfer fluid circuit by control of an expander thereof.
Claims16
A heat transfer fluid circuit, comprising:
- a compressor configured to compress a working fluid, the working fluid including a plurality of components;
- a condenser;
- a liquid-vapor separator, downstream of the condenser;
- a cascade heat exchanger, the cascade heat exchanger having a first side configured to receive a first portion C1 of the working fluid from the liquid-vapor separator and a second side configured to receive a liquid phase of the working fluid;
- a subcooler disposed directly downstream of the cascade heat exchanger to receive the first portion C1 from the cascade heat exchanger;
- an evaporator configured to receive the first portion C1 from the subcooler, wherein at the subcooler, the first portion C1 from the evaporator exchanges heat with the first portion C1 from the cascade heat exchanger, and wherein at the cascade heat exchanger, a second portion C2 of the working fluid from the liquid-vapor separator combined with the first portion C1 from the subcooler exchanges heat with the first portion C1 from the liquid-vapor separator;
- an expander located between the subcooler and the evaporator;
- a temperature sensor;
- a pressure sensor;
- one or more concentration sensors;
- and
- a controller, configured to:
- receive concentrations from a sensor of the one or more concentration sensors;
- determine a composition of the working fluid therefrom;
- obtain a dew point of the working fluid based on the composition determined;
- determine a superheat based on the dew point, a temperature from the temperature sensor, and a pressure from the pressure sensor;
- and
- control the heat transfer fluid circuit based on the superheat.
Dependencies are inferred from the claim text.