Energy Harvesting Using Thermocouple and Compressed Air

Abstract

In this paper, we describe the possibility of using the energy of a compressed air flow, where cryogenic temperatures are achieved within the flow behind the nozzle, when reaching a critical flow in order to maximize the energy gained. Compared to the energy of compressed air, the energy obtained thermoelectrically is negligible, but not zero. We are therefore primarily aiming to maximize the use of available energy sources. Behind the aperture separating regions with a pressure difference of several atmospheres, a supersonic flow with a large temperature drop develops. Based on the Seebeck effect, a thermocouple is placed in these low temperatures to create a thermoelectric voltage. This paper contains a mathematical-physical analysis for proper nozzle design, controlled gas expansion and ideal placement of a thermocouple within the flow for best utilization of the low temperature before a shockwave formation. If the gas flow passes through a perpendicular shockwave, the velocity drops sharply and the gas pressure rises, thereby increasing the temperature. In contrast, with a conical shockwave, such dramatic changes do not occur and the cooling effect is not impaired. This article also contains analyses for proper forming of the head shape of the thermocouple to avoid the formation of a detached shockwave, which causes temperature stagnation resulting in lower thermocouple cooling efficiency.

Mathematical and physical analysis of the character and position of shock waves during pumping of vacuum chambers

“…These equations are valid in the region of Knudsen number up to 10 -3 as seen in Figure 2. Previous analyses have been performed confirming that in the simulations we are dealing with we are still in the region where the Stock Navier equations are valid [20,21]. Comparative analyses have also been performed with published results of Dr. Danilatos, who used the Monte Carlo method for the case of differentially pumped chamber analysis, proving the agreement [3].…”

Mathematical-Physics Analyses of the Nozzle Shaping at the Aperture Gas Outlet into Free Space under ESEM Pressure Conditions

“…The results presented in this paper will be the basis for the upcoming experiments. All of the research team is using a modern technique of a combination of experimental measurements with mathematical-physics analyses [ 42 , 43 ].…”

Impact of Supersonic Flow in Scintillator Detector Apertures on the Resulting Pumping Effect of the Vacuum Chambers

“…The very same applies to mass flow over time, meaning that under no circumstances will the amount of gas passing through the aperture at 1 Mach be surpassed. With another increase in pressure difference, a supersonic flow occurs behind the aperture, in the area of lower pressure, since matter cannot pass anymore due to the critical flow [ 27 , 28 ].…”