Heat engine with cascaded cycles

Abstract

A method of converting thermal energy into another energy form using a thermodynamic cycle is disclosed, the method including the steps of: pressurizing a working fluid; supplying thermal energy to heat the working fluid from a liquid or substantially liquid state to a supercritical fluid state; in a first expander, substantially isentropically expanding the working fluid to yield energy in the other energy form; separating the expanded working fluid to form a first portion of the fluid diverted to a second expander and a second portion of the working fluid diverted to bypass the second expander; in the second expander, substantially isentropically expanding the first portion of the working fluid to yield energy in the other energy form; condensing the expanded first portion of the working fluid to a liquid or substantially liquid state; and recombining the first and second portions of the working fluid to be recirculated in the cycle.

Description

RELATED APPLICATIONS[0001]This application is related to U.S. Provisional Application Ser. No. 60 / 719,327, entitled “PIEZOELECTRIC SELECTABLY ROTATABLE BEARING,” filed on Sep. 21, 2005, Application Ser. No. 60 / 719,328, entitled “SOLAR HEAT ENGINE SYSTEM,” filed on Sep. 21, 2005, U.S. application Ser. No. 11 / 512,568, entitled “SOLAR HEAT ENGINE SYSTEM,” filed on Aug. 30, 2006, and application Ser. No. 12 / 246,127, entitled “HEAT ENGINE IMPROVEMENTS,” filed on Oct. 6, 2008 each of which are herein incorporated by reference in its entirety.BACKGROUND[0002]This disclosure relates to the conversion of heat energy to another form of energy, e.g. mechanical energy. The disclosure further relates to such conversion where the heat energy source is concentrated solar energy or a low grade or waste heat source.[0003]Several different types of heat engines have been used in practice to convert concentrated solar radiation to mechanical power, notably Stirling cycle engines and Rankine cycle engi...

AI Technical Summary

Benefits of technology

[0007]In one practical embodiment, a concentrated beam of solar radiation is directed through a high temperature resistant window, for example, of sapphire or any other suitable material, onto a thin film or droplet of water. The thin film or droplet can be sitting on or near a “target” disk or plate. The target disk or plate can be a material with high absorptivity, low emissivity in the near and far infra red range and very high surface area. The thin film or droplet of liquid is heated and subsequently expanded or exploded, to provide mechanical power.

[0037]According to another embodiment, a method of converting energy from one form to another by passing a working material through a closed liquid-vapor thermodynamic cycle, is disclosed including: expanding at least a portion of the working material from a liquid phase into a vapor phase by addition of heat; recovering heat from the working material after expanding; condensing the working material, after recovering heat, from the vapor phase into the liquid phase, in a condenser, thus restoring the working material to a state where the working material awaits expansion to start a new cycle; varying the quantity of heat recovered by varying a bypass of the working material during recovering heat from the working material, so as to vary thermodynamic efficiencies and select desired specific work output; and adding the recovered heat to working material awaiting expansion, without changing the phase thereof; whereby efficiency of the method is improved over a method lacking recovering heat.

[0048]Some embodiments include decreasing a specific power output of the engine while increasing the thermodynamic efficiency of the engine by increasing the ratio of feed liquid mass flow in the heat recovery jacket to the total feed liquid mass flow.

Problems solved by technology

Several different types of heat engines have been used in practice to convert concentrated solar radiation to mechanical power, notably Stirling cycle engines and Rankine cycle engines, however, all such known engines have had disadvantages relating to complexity, cost or low efficiency, Apparatus which convert heat energy into mechanical energy, namely the heat energy of concentrated beam of solar radiation into the movement of a piston through the explosion or expansion of a droplet of substantially uncompressed liquid targeted by the concentrated solar beam are described in patent application Ser. No. 11 / 512,568, referred to above.

Conventionally, the hot liquid vaporizes at the point of injection, with consequent loss of available energy or exergy.

Such recirculation cannot, of itself, produce a useful energy output by the system.

Images