Suppose I power a Peltier device to heat up/cool down some water. Then I later use the same Peltier device, in reverse, to convert the separated heat energy back into electricity.
I have read somewhere that a Peltier device can realistically achieve about 10% efficiency. Since the device is used twice, will I only recover about 1% of my input energy?
I am building a machine and considering the operation mentioned above. If only 1% would be recovered, I should explore other means; If so, then what heat-pumping/electricity-generating options should I consider if I am concerned about efficiency?