Thermofluidics’ core Non-Inertive-Feedback Thermofluidic Engine (NIFTE) is a patented heat engine technology: It converts heat at a higher temperature into mechanical work (forced motion) and heat at a lower temperature. It is well suited to a wide range of applications using solar thermal water heaters, flue gases, or other sources of waste heat as a power source. It is also suited to applications where simultaneous heating and pumping are required.
What is new and different about the NIFTE?
The NIFTE is distinguished from other heat engines in that it is capable of using relatively small temperature differences as low as 30ºC between its heat source (heat input) and heat sink (heat output), and it does this without mechanical moving parts. Instead, it has liquid pistons which move up and down in response to pressure variations, caused by boiling and condensation.
As it has liquid pistons, the NIFTE is particularly well suited to pumping and compressing fluids. It is also well suited to pumping because the pumped fluid can simultaneous provide either the heat supply, or the heat sink.
How the NIFTE works
- Two vertical cylinders (1,2) are cojoined at top (3) and bottom, via a throttle valve/restriction (4).
- Grey liquid boils in evaporator (5), pressurising the system with vapour (colourless).
- When the pressure exceeds the discharge pressure, fluid coupled to working fluid in fluidic transmission block (7) is discharged.
- A discharge check (non-return) valve (6) may be used to arrange a uni-directional flow.
- As fluid is discharged, the grey liquid in cylinder 2 descends.
- When the liquid-vapour interface in cylinder 2 is below the vapour-liquid interface in cylinder 1, grey liquid flows from cylinder 1 to cylinder 2 due to gravity, with a time delay due to speed control valve 4. It is important that the fluid’s inertia doesn’t play a significant role in generating this time delay, hence the term “Non-Inertive-Feedback”.
- When the liquid-vapour interface in cylinder 1 has descended into condenser (8), vapour condenses, de-pressurising the system.
- When the pressure falls below the suction pressure, fluid coupled to working fluid in fluidic transmission block (7) is drawn into the system.
- A suction check (non-return) valve (9) may be used to arrange a uni-directional flow.
- As fluid is drawn in, the grey liquid in cylinder 2 rises.
- When the liquid-vapour interface in cylinder 2 is above the vapour-liquid interface in cylinder 1, grey liquid flows from cylinder 2 to cylinder 1.
- This process is repeated periodically, and results in a net-pumping effect.
- In some applications, the working fluid and the pumped medium can be the same type of fluid.