Hot air balloon with solar collector and heat-engine-driven fuel cell

摘要

An example balloon system for long-duration flight can include an optically transparent envelope for solar greenhouse heating of lift gas within, a fuel cell inside a bladder within the envelope, and a solar collector beneath the bladder configured to concentrate solar energy in a focal region below the bladder. The fuel cell can include hydrogen gas, oxygen gas, and a water reservoir in a bottom portion of the bladder, and could be configured to generate electricity to run a heater to heat the lift gas during night-time hours. The example system can also include a heat engine configured with a hot side in the focal region and a cold side in the water reservoir. The heat engine could be configured to generate power by transferring heat from the hot side to the cold side, and the power could be used to recharge the fuel cell during daylight hours.

主权项

1. A balloon system comprising:
an optically transparent envelope configured for solar greenhouse heating of lift gas within the optically transparent envelope; a bladder inside the optically transparent envelope; a fuel cell system inside the bladder, wherein the fuel cell system includes a supply of hydrogen gas, a supply of oxygen gas, and a water reservoir in a bottom portion of the bladder, and wherein the fuel cell system is configured to generate electricity; a reflective solar collector beneath the bladder configured to concentrate solar energy in a focal region inside the optically transparent envelope and below the bladder; and a heat engine configured with a hot side in the focal region of the reflective solar collector and a cold side in the water reservoir, wherein the heat engine is configured to generate power by transferring heat from the hot side to the cold side, and wherein a portion of the transferred heat is used for causing at least a portion of the water in the reservoir to vaporize.