Modelling of a solar wood dryer with glazed walls

This work present a study of a solar wood dryer in a Moroccan climate. The wood drying process is investigated theoretically by a mathematical model based on actual climate data. The model constantly gives dryer humidity and temperatures (air and walls) as well as wood temperature and moisture contents. For verification, the present drying model is executed within the simulation program with experimental data of wood drying experiments conducted in two dryers located in two different sites. The computational results show a reasonable agreement between the predicted and measured wood moisture content.Este trabajo presenta un estudio de un secador solar de madera en un clima marroquí. El proceso de secado de madera es investigado teóricamente desarrollando un modelo matemático basado en datos climáticos reales. El modelo da a cada momento, la humedad y la temperatura  del secador (aire y paredes) así como la temperatura y la humedad de la madera. Para la verificación experimental, este modelo de secado es introducido en el programa de simulación con datos experimentales de secado de madera de los experimentos realizados en dos secaderos situados en dos lugares diferentes. Los resultados muestran un acuerdo razonable entre la humedad de la madera predicha y medida experimentalmente. 

Using a parametric study to analyse the performance of wood solar dryers with glazed walls

Parameters characterizing wood and air were studied in order to analyze the performance of a wood solar dryer functioning under Moroccan climate. A mathematical model based on the climate data of Rabat city was used to investigate theoretically the wood drying process. Two wood speciesthuya (Tetraclinis articulate) and pine (Pinus pinaster)-were examined in the present study. The results obtained by computer simulations are in good agreement with the experimental values. Furthermore, our findings indicate that the use of a global mass transfer coefficient for low temperature convective and homogenous drying conditions allows the influence of the principal operating parameters (wood thickness, wood density, air temperature, air velocity and ventilation mode) on the drying time to be estimated with great accuracy. Analyses pertaining to the two studied wood species revealed that(1) pine dries more quickly than thuya, (2) the drying process is faster in the summer relative to other seasons, (3) increasing the air velocity by 100% results in a 20% reduction in the drying time, and (4) continued ventilation reduces the drying time by 43%.   PDF XM

Solar drying of pine lumber: Verification of a mathematical model

This work presents verification of a mathematical model for drying of a wood stack in a greenhouse type solar dryer. A simplified heat and mass transfer numerical model has been developed with input parameters based on the actual metrological data of a Moroccan climate. For its validation, a comparative study is performed in this work; the present model is solved to simulate the solar drying of pine wood using experimental data of previous wood drying experiments. The average relative discrepancies between the model predicted and experimental data are 1,2% for wood moisture content, 1% for drying air temperature and 5% for the air relative humidity. The close agreement between the predicted and experimental results shows the ability of the model to reproduce experimental drying data for wood

Using a parametric study to analyse the performance of wood solar dryers with glazed walls

Parameters characterizing wood and air were studied in order to analyze the performance of a wood solar dryer functioning under Moroccan climate. A mathematical model based on the climate data of Rabat city was used to investigate theoretically the wood drying process. Two wood speciesthuya(Tetraclinis articulate) and pine (Pinus pinaster)-were examined in the present study. The results obtained by computer simulations are in good agreement with the experimental values. Furthermore, our findings indicate that the use of a global mass transfer coefficient for low temperature convectiveand homogenous drying conditions allows the influence of the principal operating parameters (wood thickness, wood density, air temperature, air velocity and ventilation mode) on the drying time to be estimated with great accuracy. Analyses pertaining to the two studied wood species revealed that(1)pine dries more quickly than thuya, (2) the drying process is faster in the summer relative to other seasons, (3) increasing the air velocity by 100% results in a 20% reduction in the drying time, and (4) continued ventilation reduces the drying time by 43%

Solar drying of pine lumber: Verification of a mathematical model

This work presents verification of a mathematical model for drying of a wood stack in a greenhouse type solar dryer. A simplified heat and mass transfer numerical model has been developed with input parameters based on the actual metrological data of a Moroccan climate. For its validation, a comparative study is performed in this work; the present model is solved to simulate the solar drying of pine wood using experimental data of previous wood drying experiments. The average relative discrepancies between the model predicted and experimental data are 1,2% for wood moisture content, 1% for drying air temperature and 5% for the air relative humidity. The close agreement between the predicted and experimental results shows the ability of the model to reproduce experimental drying data for wood

Modelling of a solar wood dryer with glazed walls

Este trabajo presenta un estudio de un secador solar de madera en un clima marroquí. El proceso de secado de madera es investigado teóricamente desarrollando un modelo matemático basado en datos climáticos reales. El modelo da a cada momento, la humedad y la temperatura del secador (aire y paredes) así como la temperatura y la humedad de la madera. Para la verificación experimental, este modelo de secado es introducido en el programa de simulación con datos experimentales de secado de madera de los experimentos realizados en dos secaderos situados en dos lugares diferentes. Los resultados muestran un acuerdo razonable entre la humedad de la madera predicha y medida experimentalmente

Solar frying of pine lumber: verification of a mathematical model

This work presents verification of a mathematical model for drying of a wood stack in a greenhousetype solar dryer. A simplified heat and mass transfer numerical model has been developed with inputparameters based on the actual metrological data of a Moroccan climate. For its validation, a comparativestudy is performed in this work; the present model is solved to simulate the solar drying of pine woodusing experimental data of previous wood drying experiments. The average relative discrepanciesbetween the model predicted and experimental data are 1,2% for wood moisture content, 1% for dryingair temperature and 5% for the air relative humidity. The close agreement between the predicted andexperimental results shows the ability of the model to reproduce experimental drying data for wood

Energy and exergy analysis of solar dryer with triple air passage direction collector powered by wind generator

© 2022 Springer Nature Switzerland AG. Part of Springer Nature. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1007/s40095-022-00502-8The objective of this study is to thermodynamically investigate the performance of solar dryers by delaying the airflow in the collector. For this reason, a triple air path on a single pass collector with the fan powered by a wind generator was developed and evaluated in a very humid climate. The evaluation parameters were drying efficiency, energy and exergy analysis, sustainability assessment, CO2 mitigation ability and effective moisture diffusivity of dried product. The results showed that the collector efficiency of triple air passage path collector designs improved the direct passage collector by 119 %. The overall collector and drying efficiencies were 8.43 % and 2.6 % higher than the direct flow path collector. The specific energy consumption was 1.1033 kWh/kg while the specific moisture extraction rate was obtained as 0.273 kg/kW, respectively. The average exergy efficiency ranged between 38.09 % and 63.81 % while the waste exergy ratio, improvement potential and sustainability index for the three dryers ranged from 0.00 to 1.13, 7.54 x 10-7 to 2.003 kW and 0.00 to 11.47, respectively. Using the solar dryers instead of the coal-powered dryer will mitigate more CO2 into the atmosphere in the range of 9741.334 to 21481. 476 tons of CO2 per year while using grid-based electricity will limit the least amount of CO2 in the range of 12.981 to 14.153351.50 tons of CO2 per year.Peer reviewe