A combined infrared/heat pump drying technology applied to a rotary dryer

The short drying time and low product temperature makes it suitable for drying such heat-sensitive materials as herbs and vegetables. The purpose of this work was to develop a small-scale dryer for herbs and vegetables. A prototype rotary dryer combining infrared radiation with a so-called heat pump...

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Main Author: K. PÄÄKKÖNEN
Format: Article
Language:English
Published: Scientific Agricultural Society of Finland 2008-12-01
Series:Agricultural and Food Science
Online Access:https://journal.fi/afs/article/view/5726
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spelling doaj-b33698dc109648cf884df0d33aa219002020-11-24T23:21:12ZengScientific Agricultural Society of FinlandAgricultural and Food Science1459-60671795-18952008-12-01113 A combined infrared/heat pump drying technology applied to a rotary dryerK. PÄÄKKÖNENThe short drying time and low product temperature makes it suitable for drying such heat-sensitive materials as herbs and vegetables. The purpose of this work was to develop a small-scale dryer for herbs and vegetables. A prototype rotary dryer combining infrared radiation with a so-called heat pump drying method was applied in drying experiments for several herbs and vegetables. The drying experiments were performed under actual crop production conditions. The drying curves for leaves of birch (Betula spp.), rosebay willowherb (Epilobium angustifolium) and dandelion (Taraxacum spp.) as well as slices of red beet (Beta vulgaris) and carrot (Daucus carota) are presented. During the drying operation, temperature and humidity of the drying air were recorded, as well as the energy consumed in drying. The quality parameters measured were water content, colour and rehydration ratio. In the present rotary dryer design, intermittent irradiation and mixing of the product enable to avoid overheating, which is particularly important for maintaining product quality. In this dryer design the drying drum slowly rotates and simultaneously mixes the product. The infrared heaters are attached to a panel, allowing the product to receive infrared radiation periodically.https://journal.fi/afs/article/view/5726
collection DOAJ
language English
format Article
sources DOAJ
author K. PÄÄKKÖNEN
spellingShingle K. PÄÄKKÖNEN
A combined infrared/heat pump drying technology applied to a rotary dryer
Agricultural and Food Science
author_facet K. PÄÄKKÖNEN
author_sort K. PÄÄKKÖNEN
title A combined infrared/heat pump drying technology applied to a rotary dryer
title_short A combined infrared/heat pump drying technology applied to a rotary dryer
title_full A combined infrared/heat pump drying technology applied to a rotary dryer
title_fullStr A combined infrared/heat pump drying technology applied to a rotary dryer
title_full_unstemmed A combined infrared/heat pump drying technology applied to a rotary dryer
title_sort combined infrared/heat pump drying technology applied to a rotary dryer
publisher Scientific Agricultural Society of Finland
series Agricultural and Food Science
issn 1459-6067
1795-1895
publishDate 2008-12-01
description The short drying time and low product temperature makes it suitable for drying such heat-sensitive materials as herbs and vegetables. The purpose of this work was to develop a small-scale dryer for herbs and vegetables. A prototype rotary dryer combining infrared radiation with a so-called heat pump drying method was applied in drying experiments for several herbs and vegetables. The drying experiments were performed under actual crop production conditions. The drying curves for leaves of birch (Betula spp.), rosebay willowherb (Epilobium angustifolium) and dandelion (Taraxacum spp.) as well as slices of red beet (Beta vulgaris) and carrot (Daucus carota) are presented. During the drying operation, temperature and humidity of the drying air were recorded, as well as the energy consumed in drying. The quality parameters measured were water content, colour and rehydration ratio. In the present rotary dryer design, intermittent irradiation and mixing of the product enable to avoid overheating, which is particularly important for maintaining product quality. In this dryer design the drying drum slowly rotates and simultaneously mixes the product. The infrared heaters are attached to a panel, allowing the product to receive infrared radiation periodically.
url https://journal.fi/afs/article/view/5726
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