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Industrial-Scale Heat Pump Drying

Name: ฐานิตย์ เมธิยานนท์

Organization : มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

keyword: drying

; papaya glace

; heat pump

; Energy consumption

; Industrial scale drying

Abstract: An industrial-scale prototype of heat pump dryer (HPD) was designed, constructedand tested. The drying chamber contains four trolleys with product capacity of 600-700 kg. In theexperiments, papaya glace’ was dried in close system at an average temperature of 55?C specificair flow rates of 25-32 kg dry air/h-kg dry papaya glace’ and the evaporator by-pass air of 81%.The papaya glace’ with initial moisture content of 83-86% dry basis was dried in three stages tofinal moisture content of 12-14% dry basis within approximately 32 hours. No significant finalmoisture gradient along the vertical and horizontal directions of the dryer was observed due touniform air distribution within the drying chamber and high enough air flow rate respectively.The experimental results indicate that drying rate decreases rapidly with time, while total powerconsumption remains nearly constant. At high initial moisture content, the moisture removal ishigher than that at low initial moisture content. The maximum average drying rate (DR) andspecific moisture extraction rate (SMER) are 9.34 kg water evap./h and 0.732kg water evap.ikWh respectively. The maximum average moisture extraction rate (MER) is 8.59kg water cond./h and the relative lowest average specific energy consumption (SEC) is about4.92 MJ/kg water evap. The coefficient of performance of heat pump (COP,, )SyS varies fromabout 4.1 to 4.7 which is higher than ( COP;,, )used obtained by the internal condenser load whichvaries from 3.0 to 3.8. This attributes to the excess heat rejected to atmosphere through theexternal condenser. The quality of dried papaya glace’ in terms of colour is acceptable due tolow drying temperature. Cost evaluation found that cost of papaya glace’ drying was 6.43was fured cost (US$ 1 = 40 Baht). In conclusion, HPD achieves high energy effkiency, and it isfeasible to be commercialized, particularly in food drying industry.

มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

Address: กรุงเทพมหานคร

Email: info.lib@mail.kmutt.ac.th

Name: สมชาติ โสภณรณฤทธิ์

Role: อาจารย์ที่ปรึกษา

Created: 2541

Issued: 2005-09-01

Modified: 2554-02-06

ISBN: 9746242652

CallNumber: ET352

tha

DegreeName: วิศวกรรมศาสตรมหาบัณฑิต

Level: ปริญญาโท

Descipline: เทคโนโลยีพลังงาน

Grantor: มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

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