Novel Electrothermodynamic Power Generation

Abstract

The electrothermodynamic cycle is described by the loop of the electric displacement, D , versus the electric fi eld, E ( D-E loop). In Figure 1 a, a schematic of the theoretical Olsen cycle is presented as ABCD. The cycle begins at a low temperature ( T low ) with no electric fi eld (point A). When the electric fi eld ( E 1 ) is applied, the state moves to point B (path AB), corresponding to the hysteresis loop section of the material obtained at T low (see Figure S1b, Supporting Information), denoting an increase in electric displacement. The temperature is increased to the value T high (path BC). Then, electric displacement corresponds to another hysteresis loop, obtained at T high (point C). Removing the external electric fi eld, the state moves to point D along the hysteresis loop at T high (path CD). Finally, the temperature is decreased to T low , and the state moves to point A (path DA). The produced loop area is considered as an energy density ( N D , the area of the D -E loop); the power density ( P D , = N D f ) is also evaluated from the area. [7][8][9][10][11][12][13][14] To the best of our knowledge, there is no application that satisfi es a true energy breakeven because of the diffi culties associated with fi nding a suitable energy source that can simultaneously give alternative heat and an electric fi eld. [7][8][9][10][11][12][13][14] In this study, a novel electrothermodynamic cycle is presented based on temporal temperature variation to obtain practical net energy from exhaust heat of automobile. Another representative heat electric conversion cycle, the Stirling cycle, is modifi ed, and this cycle has a higher potential than the Olsen cycle. [ 6,7 ] The most representative pyro and piezoelectric material, PZT (C-6, Curie temperature T C : 305 °C), is employed. The temperature variation is considered as a simple pseudo-sinusoidal wave based on the imaging of the temperature fl uctuation of the exhaust gas. An external electric fi eld is applied to the material corresponding to the temperature variation (see details in the Supporting Information). The general Sawyer-Tower (ST) circuit is redesigned by inductions of a Diode and a SWitch (named as DSW circuit, see Figure S2b, Supporting Information) to evaluate the D-E loop and simultaneously harvest the net energy.In Figure 1 a, a schematic of our cycle (ABC 1 D) is shown. The AB path is the same as the Olsen cycle. The material is then isolated and the electric displacement D is kept constant while the temperature is increased to T high . The voltage is increased to the E 2 value (path BC 1 ) based on the electrothermodynamic equation: [ 15,16 ] and p are the electric displacement, electric fi eld, temperature, dielectric permittivity, time, and pyroelectric coeffi cient, respectively (see details in the Supporting Information). Then, the material is reconnected to the circuit, and the state moves to point D (path C 1 D). Finally, temperature is decreased back to T low , and the D-E loop is closed. The triangular area BC 1 C is the additional ...

Relationship Between the Material Properties and Pyroelectric‐Generating Performance of PZTs

“…As a result, the D-E loop of the new cycle resulted in a 1.9-fold larger area and 1.3-fold larger practical net energy than that produced by the Olsen cycle with the same input energy. [1] Furthermore, a net generated energy of 0.1 mW cm −3 was obtained for the duration of the official standard test for light-duty vehicles in Japan (JC08) with a real engine. [1] The proposed new cycle indicated the possibility for real-world applications.…”

“…[1] Furthermore, a net generated energy of 0.1 mW cm −3 was obtained for the duration of the official standard test for light-duty vehicles in Japan (JC08) with a real engine. [1] The proposed new cycle indicated the possibility for real-world applications.…”

“…This is 13 times greater than the generated energy reported in a previous study of C-6 (0.1 mW cm −3 ). [1] How much wasted heat exists, and how can we utilize it as renewable energy? These questions have been explored in automotive applications.…”

“…[13][14][15][16][17][18][19][20] In a previous study, we presented a novel electro-thermodynamic cycle based on a temporal temperature variation to obtain a practical net energy from the exhaust gas of an automobile. [1] The most representative pyroelectric and piezoelectric material, Pb(Zr x , Ti 1−x )O 3 (PZT, Fuji ceramics), was used. The temperature variation was considered as a simple pseudosinusoidal wave based on imaging of the temperature fluctuation of the exhaust gas ( Figure S1, Supporting Information).…”

“…The samples were divided into three groups according to the investigation of their material properties and the generating performance; C-9, C-91, C-82, and C-3 formed group A, C-6 and C-2 were group B, and C-213 was group C. a) basis sample used (C-6) from a previous study. [1] summarized in Table 1. As a representative of the samples, the data for the C-91 sample is shown in Figure 1 (all other data is compiled in Figure S2 of the Supporting Information).…”