Open AccessApplication of an Energy Efficient Hot Air Recirculation Controlled Closed System Environment for Parchment Coffee Dehydration in Puerto Rico
Author(s) -
Francisco RodrÃguez Robles,
Francisco M. Monroig-Saltar,
David Serrano- Acevedo
Publication year - 2017
Publication title -
american journal of agricultural science, engineering, and technology
Language(s) - English
Resource type - Journals
eISSN - 2164-0920
pISSN - 2158-8104
DOI - 10.54536/ajaset.v2i5.30
Subject(s) - environmental science , parchment , ripeness , air conditioning , heat exchanger , waste management , environmental engineering , process engineering , pulp and paper industry , engineering , mechanical engineering , geography , horticulture , archaeology , ripening , biology
The high and increasing costs associated with propane gas, diesel and electricity used by mechanicaldryers have negatively affected the coffee processors in Puerto Rico. In 1991 the cost to process onehundred pounds of parchment coffee was $14.13, while in 2011 was over $35.00. From all the sectorswithin the coffee industry in Puerto Rico, the processors are the ones that have experience the largestincreases in operational cost, over 145% in the past years, mainly due to post harvesting drying. Toaddress this specific challenge, the Department of Agriculture of Puerto Rico (DAPR) assigned funds toresearch coffee dehydration energy efficient alternatives that would reduce the costs to the coffeeprocessors of the island. As part of this effort, a hot air recirculation controlled closed-system(HARC2S) was designed and constructed at the University of Puerto Rico at Mayagüez. The basicconcept of the HARC2S is to condition the hot air that has already passed through the coffee bean massand direct it back to the mechanical dryer. The hot air conditioning consist in removing part of themoisture from the recirculation air with a heat exchanger that uses water at ambient temperature, toincrease the moisture absorbing capacity of the air before it re-enters the mechanical dryer.Experimental results of the HARC2S, under various operational configurations, provided substantialdrying energy savings ranging from 12% to 59%. The range variation in energy savings is due to thesystem operational configurations and possible variations of the parchment coffee bean ripeness statefrom the various batch experiments. Investing in the development and implementation of thistechnology will provide not only sustainable operation of the coffee processors facilities, but will alsosustain close to 20,000 jobs with potential employment growth representing over a $41 million annualincome to the local economy.