Extended-range heat transfer fluid using variable composition

摘要

The present invention provides systems and methods for transferring heat using a variable composition organic heat transfer fluid that remains liquid over a wide operating temperature range useful for solar heating applications. Variable composition heat transfer fluids of the present invention comprise a miscible mixture, optionally a completely miscible mixture, of a high boiling point component selected for its beneficial high temperature physical properties, and a low freezing point component selected for its beneficial low temperature physical properties. In some embodiments, the low freezing point component is removed from the heat transfer fluid as the heat transfer fluid is heated, for example by being removed in the vapor phase, thereby selectively varying the composition and physical properties (e.g., vapor pressure, boiling point, etc.) of the heat transfer fluid as a function of temperature.

主权项

1. A heat transfer system comprising:
a heat transfer fluid comprising a high boiling point component and a low freezing point component provided as a miscible mixture, wherein said high boiling point component and said low freezing point component each comprise one or more organic compounds, wherein said high boiling point component has a boiling point temperature greater than or equal to 500° C. at a pressure of 5 atmospheres, and wherein said low freezing point component has a freezing point temperature less than or equal to 80° C.; a vessel for containing said heat transfer fluid; a heat source for heating said heat transfer fluid contained in said vessel; an outlet for removing at least a portion of said low freezing point component from said heat transfer fluid upon increasing temperature of said heat transfer fluid, wherein said low freezing point component is removed as a gas, thus allowing generation of removed low freezing point component; an inlet for adding at least a portion of said removed low freezing point component to said heat transfer fluid upon decreasing temperature of said heat transfer fluid, thereby maintaining said heat transfer fluid in a liquid state; and a condenser in fluid communication with said outlet and inlet for condensing said low freezing point component, thus generating removed liquid phase low freezing point component, wherein said inlet returns at least a portion of said removed liquid phase low freezing point component to said heat transfer fluid upon decreasing temperature of said heat transfer fluid.