On the effect of maintaining a fixed ambient temperature in the analysis of a photovoltaic device's performance

Abstract

Abstract This article studies the consequence of shifting the point of view of photovoltaic system analysis from having a constant temperature to having a constant temperature of its ambient environment. To do so, we derive the power balance of the photovoltaic system—the rate equivalent of the first law of thermodynamics. We solve this equation in conjunction with the detailed balance photon rate equation to find the current and the temperature as a function of the cell's potential for a given bandgap, sources (sun and sky), ambient temperature, and heat conduction coefficient. We find the model to give the expected behavior of a photovoltaic system close to standard conditions. However, we find that the expected rise in efficiency for moderate concentration may flip to reduction if the cell’s ability to dissipate heat is not exquisite. Our model's applicability to any photovoltaic device is demonstrated by analyzing a thermoradiative cell—the inverse of a solar cell. We show compatibility with known models and the flexibility at which less-than-ideal systems can be analyzed in our approach. We believe that centering the analysis on a fixed ambient temperature is a more faithful representation of photovoltaic systems' experimental and real-life conditions. As such, it is essential for the development of photovoltaic technology. Also, this shift in point of view raises some fundamental questions regarding the energy carried by the electrical current that may prove vital for developing future photovoltaic concepts.