Performance of Hybrid Photovoltaic/Thermal Crop Dryer in Hot Humid Nigerian Region

Abstract

This paper presents a study carried out to investigate the performance of a hybrid photovoltaic/thermal crop dryer in hot humid region of Umuagwo-Ohaji in the South-east region of Nigeria, through energy and exergy analyses, drying, electrical and thermal efficiencies, energy utilization and energy utilization ratio, sustainability indicators such as waste energy ratio (WER), sustainability index (SI) and improvement potential (IP). Drying experiments were conducted at varying inlet air temperatures (50, 60 and 70oC), airflow rates (1.14, 2.29 and 3.43 kgs-1) and slice thicknesses (10, 15 and 20 mm) on 500g batch size of red pepper slices during sunshine periods. Results obtained show that the total and specific energy consumption for drying a batch of sliced red pepper samples varied between 2.08 – 34.91kJ and 7.04 – 62.76 kJkg-1, respectively. The energy utilization and energy utilization ratio during the drying process ranged from 195.75 – 3013.21 Js-1 and 1.82 – 20.4%, respectively. The energy and exergy efficiencies varied between 15.67- 38.17% and 26% to 88%, respectively. The mean drying efficiency of the system ranged from 7.12 – 40.27%. The maximum electrical and thermal efficiencies of 23.86% and 93.03%, respectively were obtained. A waste energy ratio of 0.0827 - 0.1579 was obtained, whereas SI and IP values ranged between 1.137 ≤ SI ≤ 6.119 and 0.198 ≤ IP ≤0.583kW, respectively. There is certainly a wide range of improvement in the PV/T system as 12.1 – 18.4 % of the solar irradiance was consumed for drying. Prospects for improvement and recommendations for further studies were suggested.

Ovaj rad predstavlja studiju koja je sprovedena u cilju ispitivanja performansi hibridne fotonaponske/termičke sušare u toplo-vlažnom regionu Umuagvo-Ohaji, jugoistočni region Nigerije, kroz energetske i eks energijske analize: sušenje, električne i toplotne efikasnosti , koeficijent korišćenja energije i iskorišćenja energije, indikatori održivosti kao što su odnos energije otpada (VER), indeks održivosti (SI) i potencijal za poboljšanje (IP). Eksperimenti sušenja su sprovedeni na različitim temperaturama ulaznog vazduha (50, 60 i 70oC), brzinama protoka vazduha (1,14, 2,29 i 3,43 kg-1) i debljinama preseka (10, 15 i 20 mm) na 500g serije šarži crvenog bibera tokom perioda izlaganju sunčevoj svetlosti. Dobijeni rezultati pokazuju da ukupna i specifična potrošnja energije za sušenje serije rezanih uzoraka crvene paprike varira između 2,08 - 34,91 kJ i 7,04 - 62,76 kJkg-1, respektivno. Koeficijent korišćenja energije i iskorišćenosti energije tokom procesa sušenja kretao se od 195,75 do 3013,21 Js-1 i 1,82 do 20,4%, respektivno. Efikasnost energije i eks energije varira od 15,67 do 38,17% i 26% do 88%, respektivno. Srednja efikasnost sušenja sistema kretala se od 7,12 do 40,27%. Dobijene maksimalne električne i toplotne efikasnosti su od 23,86% i 93,03%. Dobijen je odnos energije energije od 0.0827 do 0.1579, dok su SI i IP vrijednosti u rasponu 1.137 ≤ SI ≤ 6.119 i 0.198 ≤ IP ≤ 0.583 kV, respektivno. Svakako postoji širok spektar poboljšanja u PV / T sistemu kao 12,1 do 18,4% solarnog zračenja koje je potrošeno za sušenje. Predložene su perspektive za poboljšanje i preporuke za dalje studije.