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Abstract

Abstract

As a drying system, heat pump drying with appropriate configuration is potential to safe energy. The objective of this research was to develop vapor compression heat pump system for rough rice drying and to obtain low energy consumption from several system configurations. Therefore, the model of vapor compression heat pump system was designed in which its configuration was modifiable. The result showed that the ratio of specific moisture extraction rate which calculated mechanic and thermal consumption (SMERTot) upon resistive heating dryer for those several configurations was 159 – 329%. The open cycle heat pump drying method with intermittent operation produced the highest specific moisture extraction rate which only calculated thermal energy (SMERT) and SMERTot at 7.06 and 5.06 kg/kWh, respectively. Intermittent operation did not much influence drying rate but significantly reduced energy consumption. Ambient air inlet which placed before evaporator and condenser on a closed cycle could produce different SMERTot i.e. 4.01 dan 3.07 kg/kWh respectively. The utilization of ambient air through forced convection in heat exchanger could increase SMERTot, while the utilization of air flow the dryer from outlet could reduce SMERTot.

Abstrak

Pengeringan heat pump merupakan sistem pengeringan yang berpotensi menghemat energi terutama apabila konfigurasinya sesuai. Tujuan dari penelitian ini adalah mengembangkan sistem heat pump kompresi uap (HPKU) untuk pengeringan gabah dan mendapatkan konsumsi energi yang rendah dari
berbagai konfigurasi sistem. Untuk itu pada penelitian ini didesain sebuah model sistem pengering heat pump yang konfigurasinya dapat diubah-ubah untuk  pengeringan gabah. Hasil percobaan memperlihatkan bahwa rasio peningkatan specific moisture extraction rate yang memperhitungkan konsumsi energi mekanik dan termal (SMERTot) terhadap pengering pemanas resistif untuk berbagai konfigurasi tersebut
adalah 159 – 329%. Metode pengeringan heat pump siklus terbuka dengan pengoperasian HPKU yang intermittent memberikan specific moisture extraction rate yang hanya memperhitungkan konsumsi energi termal (SMERT) dan SMERTot yang paling tinggi yaitu masing-masing 7.06 dan 5.06 kg/kWh. Pengoperasian intermittent tidak banyak mempengaruhi laju pengeringan, tetapi secara nyata menurunkan konsumsi energi. Penempatan inlet udara lingkungan sebelum evaporator dan sebelum kondensor pada siklus tertutup memberikan SMERTot yang berbeda yaitu 4.01 dan 3.07 kg/kWh. Penggunaan udara lingkungan dengan menggunakan konveksi paksa melalui penukar panas dapat meningkatkan SMERTot, sedangkan penggunaan aliran udara dari keluaran pengering dapat menurunkan nilai SMERTot.

Keywords

rough rice drying vapor compression heat pump system specific moisture extraction rate (SMER)

Article Details

References

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