The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Geetam Tiwari - One of the best experts on this subject based on the ideXlab platform.
-
Characteristic Equation of double slope passive solar still
Desalination, 2011Co-Authors: Rahul Dev, H.n. Singh, Geetam TiwariAbstract:Abstract In this paper, a new approach has been made to obtain the Characteristic Equation of a double slope passive solar still (DSPSS) based on experimental observations. The performance of DSPSS has been analyzed for the composite climatic condition of New Delhi, India. To obtain the Characteristic Equations under quasi-steady state condition, regression curves have been plotted for instantaneous gain and loss efficiencies with respect to a non-dimensional representative factor ({(Tw – Ta) / I(t)} / {(Tw – Ta) / I(t)}max) of climatic and operational parameters together. From the analysis, it has been concluded that non-linear Characteristic curves are more accurate for analyzing the performance, thermal testing and further design modification depending upon various parameters associated with design, climatic and operational conditions.
-
Characteristic Equation of the inverted absorber solar still
Desalination, 2010Co-Authors: Rahul Dev, Geetam TiwariAbstract:The inverted absorber solar still (IASS) is a box type solar still in which a curved reflector has been placed under the basin to heat it from both top and bottom sides. Because of this, the high water temperature can be obtained in the IASS in comparison to that of the single slope solar still (SS). In this communication, an attempt has been made to develop linear and non-linear Characteristic Equations of the IASS based on derived analytical expressions of instantaneous gain (ηi) and loss (ηiL) efficiencies by using experimental data for the climatic condition of Muscat, Oman. The results show that the behaviour of the IASS is non-linear as expected. These results have also been compared with obtained Characteristic Equations of the SS under similar operating and climatic conditions. On the basis of economic analysis of the IASS and SS, the annual costs of distilled water per kg-m2 have been found to be Rs. 0.95/- and Rs. 0.54/- respectively.
-
Characteristic Equation of a passive solar still
Desalination, 2009Co-Authors: Rahul Dev, Geetam TiwariAbstract:The Characteristic Equation has been used for experimental results of a passive solar still to generate linear and non-linear Characteristic Equations for winter and summer conditions. The different angles of inclination of condensing cover (15°, 30°, 45°) have been chosen for winter and summer conditions both. It has been observed that the passive solar still with inclination of 45° gives better performance both in winter and summer respectively. Different water depths (0.04, 0.08, 0.12, and 0.16 m) have also been taken for solar still with 30° inclination angle for summer weather condition. Comparisons of instantaneous gain and loss efficiencies at 0.01 and 0.04 m water depths for a 15° inclination angle have also been made to show the effect of water depth on the performance of solar stills. It was found that a lower water depth gives better efficiency, which is in agreement with many investigators. The instantaneous gain and loss efficiency curves have been simultaneously analyzed to give a better understanding of the performance of solar stills. The proposed method will be used to standardize the design and operational parameter of a passive solar still, i.e. angle of inclination and water depth for highest yield for a given climatic condition.
Rahul Dev - One of the best experts on this subject based on the ideXlab platform.
-
Characteristic Equation of double slope passive solar still
Desalination, 2011Co-Authors: Rahul Dev, H.n. Singh, Geetam TiwariAbstract:Abstract In this paper, a new approach has been made to obtain the Characteristic Equation of a double slope passive solar still (DSPSS) based on experimental observations. The performance of DSPSS has been analyzed for the composite climatic condition of New Delhi, India. To obtain the Characteristic Equations under quasi-steady state condition, regression curves have been plotted for instantaneous gain and loss efficiencies with respect to a non-dimensional representative factor ({(Tw – Ta) / I(t)} / {(Tw – Ta) / I(t)}max) of climatic and operational parameters together. From the analysis, it has been concluded that non-linear Characteristic curves are more accurate for analyzing the performance, thermal testing and further design modification depending upon various parameters associated with design, climatic and operational conditions.
-
Characteristic Equation of the inverted absorber solar still
Desalination, 2010Co-Authors: Rahul Dev, Geetam TiwariAbstract:The inverted absorber solar still (IASS) is a box type solar still in which a curved reflector has been placed under the basin to heat it from both top and bottom sides. Because of this, the high water temperature can be obtained in the IASS in comparison to that of the single slope solar still (SS). In this communication, an attempt has been made to develop linear and non-linear Characteristic Equations of the IASS based on derived analytical expressions of instantaneous gain (ηi) and loss (ηiL) efficiencies by using experimental data for the climatic condition of Muscat, Oman. The results show that the behaviour of the IASS is non-linear as expected. These results have also been compared with obtained Characteristic Equations of the SS under similar operating and climatic conditions. On the basis of economic analysis of the IASS and SS, the annual costs of distilled water per kg-m2 have been found to be Rs. 0.95/- and Rs. 0.54/- respectively.
-
Characteristic Equation of a hybrid (PV-T) active solar still
Desalination, 2010Co-Authors: Rahul Dev, G.n. TiwariAbstract:Abstract A hybrid (PV-T) active solar still is a combination of solar still and flat plate collector (FPC) integrated with glass–glass photovoltaic module. In this paper, two analytical methods are used to establish Characteristic Equation of hybrid (PV-T) active solar still based on annual experimental observations. In method-1, linear and non-linear curves are plotted for instantaneous gain efficiency ( η i ) with respect to x = ( T w − T a ) / I ( t ) which is a representative factor of climatic and operational parameter. In method-2, a Characteristic Equation for solar still similar to FPC i.e. η i = A + B ∙ {( T w − T a ) / I ( t )} + C ∙ {( T w − T a ) 2 / I ( t )} has been found using a matrix method. Further, both the methods are used for estimation of instantaneous loss efficiency ( η iL ). All these Equations are established by assuming steady state condition for thermal testing of solar still. The comparative performance of these two methods has also been estimated in terms of root mean square percentage (RMS) error. It has been observed that the performance of non-linear Characteristic Equation is better than linear Characteristic Equation.
-
Characteristic Equation of a passive solar still
Desalination, 2009Co-Authors: Rahul Dev, Geetam TiwariAbstract:The Characteristic Equation has been used for experimental results of a passive solar still to generate linear and non-linear Characteristic Equations for winter and summer conditions. The different angles of inclination of condensing cover (15°, 30°, 45°) have been chosen for winter and summer conditions both. It has been observed that the passive solar still with inclination of 45° gives better performance both in winter and summer respectively. Different water depths (0.04, 0.08, 0.12, and 0.16 m) have also been taken for solar still with 30° inclination angle for summer weather condition. Comparisons of instantaneous gain and loss efficiencies at 0.01 and 0.04 m water depths for a 15° inclination angle have also been made to show the effect of water depth on the performance of solar stills. It was found that a lower water depth gives better efficiency, which is in agreement with many investigators. The instantaneous gain and loss efficiency curves have been simultaneously analyzed to give a better understanding of the performance of solar stills. The proposed method will be used to standardize the design and operational parameter of a passive solar still, i.e. angle of inclination and water depth for highest yield for a given climatic condition.
G.n. Tiwari - One of the best experts on this subject based on the ideXlab platform.
-
analytical Characteristic Equation of nanofluid loaded active double slope solar still coupled with helically coiled heat exchanger
Energy Conversion and Management, 2017Co-Authors: Lovedeep Sahota, G.n. TiwariAbstract:Abstract Nanofluids are embryonic fluids and promising thermal energy carrier in solar thermal applications due to their superior thermo-physical and optical properties. In present communication, an analytical expression of the Characteristic Equation of two different systems viz. (A) active double slope solar still coupled with series connected partially covered N photovoltaic thermal flat plate collectors (N-PVT-FPC) and operating without helical heat exchanger; and (B) active double slope solar still coupled with series connected partially covered N-PVT-FPC and operating with helical heat exchanger has been developed. Analysis has been executed for 0.25 % concentration of CuO, Al 2 O 3 , TiO 2 -metallic nanoparticles; four number of collectors; 100 kg basin fluid (BF/NF) mass and 0.03 kg/s mass flow rate. The maximum values of instantaneous gain thermal energy efficiency ( CuO 80.18 % ; Al 2 O 3 71.67 % ; TiO 2 74.92 % ) and instantaneous loss thermal energy efficiency ( CuO 64.12 % ; Al 2 O 3 59.11 % ; TiO 2 64.77 % ) of the system (A) are found to be significantly higher in comparison the basefluid ( gain 66.81 % ;loss 52.42 % ) . The productivity of system (A) and system (B) are ( CuO 32 % ; Al 2 O 3 19.23 % ; TiO 2 6.47 % ) and ( CuO 31.49 % ; Al 2 O 3 26.4 % ; TiO 2 7.26 % ) respectively, higher in comparison to the case using basefluid (water). Moreover, thermal energy and exergy; and thermal exergy efficiency has been evaluated for both the systems.
-
analytical Characteristic Equation for partially covered photovoltaic thermal pvt compound parabolic concentrator cpc
Solar Energy, 2015Co-Authors: Deepali Atheaya, G.n. Tiwari, Arvind Kumar Tiwari, I M AlhelalAbstract:Abstract In this paper, an analytical expression for Characteristic Equation of a partially covered photovoltaic thermal compound parabolic concentrator (PVT-CPC) water collector system similar to Hottel–Whillier–Bliss (HWB) Equation of flat plate collector has been derived. The derivation is based on basic energy balance Equation for each component of partially covered PVT-CPC water collector system. The analytical result of proposed partially covered PVT-CPC water collectors [case (i)] has been compared with [case (ii)]: fully covered PVT-CPC water collectors; [case (iii)]: conventional CPC water collectors and [case (iv)]: partially covered PVT water collectors. It is observed that (a) an overall exergy efficiency of partially covered PVT-CPC water collector (25%PV) system is maximum and (b) an instantaneous thermal efficiency of conventional CPC water collector system [case (iii)] is maximum as compared to other cases.
-
Characteristic Equation of a hybrid (PV-T) active solar still
Desalination, 2010Co-Authors: Rahul Dev, G.n. TiwariAbstract:Abstract A hybrid (PV-T) active solar still is a combination of solar still and flat plate collector (FPC) integrated with glass–glass photovoltaic module. In this paper, two analytical methods are used to establish Characteristic Equation of hybrid (PV-T) active solar still based on annual experimental observations. In method-1, linear and non-linear curves are plotted for instantaneous gain efficiency ( η i ) with respect to x = ( T w − T a ) / I ( t ) which is a representative factor of climatic and operational parameter. In method-2, a Characteristic Equation for solar still similar to FPC i.e. η i = A + B ∙ {( T w − T a ) / I ( t )} + C ∙ {( T w − T a ) 2 / I ( t )} has been found using a matrix method. Further, both the methods are used for estimation of instantaneous loss efficiency ( η iL ). All these Equations are established by assuming steady state condition for thermal testing of solar still. The comparative performance of these two methods has also been estimated in terms of root mean square percentage (RMS) error. It has been observed that the performance of non-linear Characteristic Equation is better than linear Characteristic Equation.
Jin Liu - One of the best experts on this subject based on the ideXlab platform.
-
Measurement theory of the cavity Characteristic Equation method and experimental research on microwave permeability for ferrites
Journal of Applied Physics, 1991Co-Authors: Sheng‐chuan Zhu, Hai‐ying Chen, Fan-ping Wen, Yuan Qin, Jin LiuAbstract:The Characteristic Equation for a TE102 or TE104 rectangular cavity loaded by a ferrite slab in the middle has been derived on the basis of electromagnetic theory. This Characteristic Equation is used in a new measurement technique with improved precision, theoretical inference, and sample loading. A lot of experimental research and computational analysis have been done for the Characteristic Equation method. Microwave magnetic spectrum researches have been carried out for a series of polycrystalline microwave ferrites.
Sheng‐chuan Zhu - One of the best experts on this subject based on the ideXlab platform.
-
Measurement theory of the cavity Characteristic Equation method and experimental research on microwave permeability for ferrites
Journal of Applied Physics, 1991Co-Authors: Sheng‐chuan Zhu, Hai‐ying Chen, Fan-ping Wen, Yuan Qin, Jin LiuAbstract:The Characteristic Equation for a TE102 or TE104 rectangular cavity loaded by a ferrite slab in the middle has been derived on the basis of electromagnetic theory. This Characteristic Equation is used in a new measurement technique with improved precision, theoretical inference, and sample loading. A lot of experimental research and computational analysis have been done for the Characteristic Equation method. Microwave magnetic spectrum researches have been carried out for a series of polycrystalline microwave ferrites.
