Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Mathematical Modelling and Experimental Validation of a Flat Plate Solar Collector for Crop Dryer

M Ayub Hossain
Farm Machinery and Postharvest Process Engineering DivisionBangladesh Agricultural Research Institute, Gazipur-1701

Abstract/ Executive Summary:

A flat plate concentrating solar collector was designed and constructed for agricultural product drying. The collector was tested in different weather and operating conditions such as day time heating using solar radiation and night time heating - without external heater, night time heating with hot water flow from the storage tank without water heater and night time heating with hot water flow using water heater. Day time average temperature rose at the outlet air of the collector was about 30°C over ambient air temperature and collector efficiency varied from 25 to 60%. Collector efficiency was increased by 10% using solar collector. A mathematical model was developed for a concentrative flat plate solar collector. One set of equations was developed to predict cover temperature, receiver (absorber) temperature and air temperature in the collector. These equations were solved iteratively. The simulated cover, air and receiver temperatures in the collector agreed well with the measured temperatures. This model can be used for providing design data of a solar drier.

Keywords: Collector, Concentrating, Efficiency, Flat plate, Crop dryer

Location: Gazipur

Start Date: 01-07-2005

End Date: 30-06-2007

Program Area: Farm Mechanization

Commodity: Farm machineries

Objectives:

To develop a flat plate concentrating solar collector for crop dryer
To develop a mathematical model for solar collector
To validate the model with experimental data.

Methodology:

The dimensions of the horizontal solar collector were 2.5 m long, 1.8 m wide and 0.18 m high. The transparent cover of the collector was 4 mm thick glass. About 200 mm below the glass cover, 1.5 mm black painted corrugated iron sheet was used as an absorber plate. To increase the efficiency of the solar collector, flat type reflector made of brilliant aluminium was built on top of the collector. The dimensions of the reflector were the same as the solar collector so that it was used as a reflector in day time and a cover in night time. Six legs with 150 mm wheel were used to turn and move the solar collector horizontally and change its direction according to the change of the sun’s angle during the day. A 0.75 kW centrifugal fan was connected in one side of the collector to draw the atmospheric air in the collector and to push out the heated air to the drier with a desired air velocity. There was an automatic air controlling system using three air dampers- inlet, mixing and outlet. Analysis of Collector Performance Flat plate collector is designed for applications requiring moderate temperature not exceeding 100?C. It is relatively cheap and can be easily constructed. It uses both beam and diffuse solar radiation and is well suited for the drying of agricultural crops. The collector in this study is a concentrator type with a flat plate reflector. It may be termed as concentrator type flat plate air heater. Because air is the heating fluid to transfer heat energy from collector to drier by forced convection. Total incident radiation flux on the collector cover is the sum of global radiation (directly falls on the cover) and reflected radiation (reflection from the reflector)

Source of Information: Research Report, BARI

Article Link (Online Journal):

Funding Source:

1.

Budget:

Total Budget (Tk.) :

Achievement/Findings:

Day time average temperature rose at the outlet air of the collector was about 30°C over ambient air temperature and collector efficiency varied from 25 to 60%. Collector efficiency increased by 10% using reflector. Collector cover, air and receiver temperatures and collector thermal efficiency were predicted along the length of the collector and their highest values were found at the end of the collector length. The predicted cover temperature, air temperature and relative humidity at outlet of the collector were validated with measured data and found to be agreed well with the measured data. This model can be used for providing design data of a solar drier.

Knowledge Management: Report/Proceedings