Thermodynamic limits and performance optimization of nighttime thermoradiative energy conversion systems with non-idealities

Abstract

To address the challenge of the growing global energy crisis and the greenhouse effect, employing the thermoradiative effect of photodiodes to harvest radiative energy from colder outer space is considered a promising approach for direct nighttime renewable energy generation. By considering the coupled effect of the atmosphere, ambient, and non-radiative losses, a thermodynamic model of nighttime thermoradiative diodes (NTRDs) is developed. The fundamental performance limit for the achievable electric power density and device optimal designs of NTRDs are theoretically investigated based on Shockley-Queisser analysis. The modeling predicts that an ideal (nonideal) optimized NTRD can generate a maximum power density of 1.5 (0.12) mW/cm2 when operated at room temperature with an external luminescent efficiency of 100% (10%). The calculated results indicate that the maximal electric power generation of NTRDs is strongly influenced by the semiconductor bandgap and the external luminescent efficiency of the diode, as well as the ambient temperature and humidity. This work offers insights for optimal device designs of NTRDs, thus paving the way toward designing high-performance nighttime thermoradiative power generation systems.