| abstract |
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. |