The Solver's novel charging device for a self-contained, off-grid task light is the "Sealed Thermal Power Battery Charger".
The novel Sealed Thermal Power Battery Charger absorbs heat from sunlight and from the ambient into a fluid with low boiling point (e.g., ammonia (NH3), carbon dioxide (CO2), etc.) in a hermetically sealed reservoir under pressure. The fluid evaporates to gaseous phase, rotates an Archimedes Spiral Screw to drive an electrical generator in order to charge the rechargeable battery of the task light, and condensates back to liquid phase.
The novel Sealed Thermal Power Battery Charger is bulkier than the solar panel built onto one side of the task light, but the production cost is kept at a minimum thanks to simple construction and to a minimum number of inexpensive components. The device incurs little operating costs, and no active motion is required whatsoever to sufficiently charge the batteries. The device is durable because it is hermetically sealed in order to hold up to extended periods of usage.
Besides solar energy, the Sealed Thermal Power Battery Charger functions with any heat, e.g., hot water, in an emergency situation or when the sun does not shine. The efficiency of photovoltaic solar cells is limited to less than 20 % because the bandgap does not absorb sunlight with longer wavelengths. With a dark absorber placed inside the reservoir, the fluid of the Sealed Thermal Power Battery Charger captures energy of the sunlight in the spectrum that photovoltaic solar cells do not.
The thermodynamics of the compact Sealed Thermal Power Battery Charger is analogous to the heat pump which is a well established technology. To demonstrate the effectiveness of such a simple heat engine, the "Put Put Boat" is propelled by steam generated by a candle. In another simple example, the "Drinking Bird" is driven by ambient heat to cause perpetual motion at room temperature under pressure. Heat from the surrounding environment causes continuous boiling of a fluid which has a low boiling point. The Sealed Thermal Power Battery Charger also takes advantage of the greenhouse effect of the gas in the evaporator!
Please refer to the detailed drawings of the Sealed Thermal Power Battery Charger.
Each of the Seeker's Technical Requirements and Desirable Properties is addressed as follows.
The Sealed Thermal Power Battery Charger is a device which charges the task light batteries at a rate similar to the charge provided by the solar panel on a sunny day. The device does not employ wind-ups, cranks, dynamos or other mechanical types of generating electricity.
The Sealed Thermal Power Battery Charger is an external charging device which is connected to the batteries in the task light by a cable with ease of use.
The Sealed Thermal Power Battery Charger is very simple in design, and is inexpensive to be built.
The Sealed Thermal Power Battery Charger is rugged and durable enough for long-term use, and is also water-resistant because the system is hermetically sealed.
The Sealed Thermal Power Battery Charger is safe, and does not jeopardise the user or the environment in any way because the device is hermetically sealed. All materials used are environmentally friendly.
The Sealed Thermal Power Battery Charger has manufacturing cost similar in price or less expensive than the solar panel.
The Sealed Thermal Power Battery Charger has almost negligible cost of operation.
References and Notes
Patent application "Sealed Thermal Power Battery Charging Method and System" has been drafted by the Solver for potential exclusive licensing to the Seeker. Please find attached the partial text of the patent application for your review.
Conclusion
The Solver believes that the novel Sealed Thermal Power Battery Charger will meet all of the Seeker's Technical Requirements and Desirable Properties.
