The viability of some waste as cooling pads for evaporative cooling application in South-Western Nigeria was experimentally assessed.This is to ascertain their effectiveness as a substitute for costly imported pads in...The viability of some waste as cooling pads for evaporative cooling application in South-Western Nigeria was experimentally assessed.This is to ascertain their effectiveness as a substitute for costly imported pads in a low income environment.Also presented was the feasibility of utilizing standalone evaporative coolers for storage and selling of fruits in South-Western Nigeria.Natural ambient air was forced through the various pads at three different fan speeds and constant cooling pad thickness of 30 mm.Performance characteristics were considered based on daily analysis using temperature and humidity data measured from morning to evening at location co-ordinates latitude 7°10′N and longitude 5°05′E for 6 weeks.The daily temperature T and humidity h ranged between 26℃≤T≤45℃ and 28%≤h_(2)≤80%.Temperature differenceDT and humidity differenceDh of 0.6℃≤ΔT≤18.3℃ and 1.0%≤Δh≤53%was achieved for the four cooling pad materials tested at three fan speeds.HighestDT andDh was recorded at fan speed of 4 m/s with shredded latex foam and jute sack respectively.The cooling efficiency(η)calculated for all the pads under the three speeds ranged from 17.3%≤η≤98.8%.Payback period(PBP)analysis indicated the considered EVC is economically feasible and investors will break even in 1.75 years.展开更多
Extra cooling pads on the sidewalls are needed for larger poultry houses using tunnel ventilation system.Preliminary study showed that the airflow velocity going through different aisles varies greatly when the extra ...Extra cooling pads on the sidewalls are needed for larger poultry houses using tunnel ventilation system.Preliminary study showed that the airflow velocity going through different aisles varies greatly when the extra pads are installed at the end of sidewalls,making a“[”-shape air inlet.Combined with field tests,the CFD(computational fluid dynamics)technology was used to study the uniformity of airflow distribution in a tunnel-ventilated laying-hen house.The air distribution was first monitored in a layer house to find the main reason resulting in the variations of airflows in different aisles.Then CFD simulations were carried out with different distances(D=2 m,3 m or 4 m)between the pads on end-wall and the extra pads on side walls.The field test showed that airflow streams from the different groups of cooling pads collided vertically at the house corners,mixed with each other,then flew towards the center of the house.This was the main reason that the wind speed in the middle aisle was much higher than in other aisles,leaving large zones of lower ventilation in the aisles adjacent to the sidewalls.The results of CFD simulations indicated that air distributions could be significantly improved when the extra pieces of pads were moved away for an appropriate distance from the end coolingpads.As far as conventional poultry house with a span of 12 m,the air speeds in different aisles were more uniform when this distance was about 3 m.展开更多
文摘The viability of some waste as cooling pads for evaporative cooling application in South-Western Nigeria was experimentally assessed.This is to ascertain their effectiveness as a substitute for costly imported pads in a low income environment.Also presented was the feasibility of utilizing standalone evaporative coolers for storage and selling of fruits in South-Western Nigeria.Natural ambient air was forced through the various pads at three different fan speeds and constant cooling pad thickness of 30 mm.Performance characteristics were considered based on daily analysis using temperature and humidity data measured from morning to evening at location co-ordinates latitude 7°10′N and longitude 5°05′E for 6 weeks.The daily temperature T and humidity h ranged between 26℃≤T≤45℃ and 28%≤h_(2)≤80%.Temperature differenceDT and humidity differenceDh of 0.6℃≤ΔT≤18.3℃ and 1.0%≤Δh≤53%was achieved for the four cooling pad materials tested at three fan speeds.HighestDT andDh was recorded at fan speed of 4 m/s with shredded latex foam and jute sack respectively.The cooling efficiency(η)calculated for all the pads under the three speeds ranged from 17.3%≤η≤98.8%.Payback period(PBP)analysis indicated the considered EVC is economically feasible and investors will break even in 1.75 years.
基金the China Agricultural Research System(CARS-41)and the National“Twelfth-Five Year”Research Program of China under Grant Number 2012BAD39B02.
文摘Extra cooling pads on the sidewalls are needed for larger poultry houses using tunnel ventilation system.Preliminary study showed that the airflow velocity going through different aisles varies greatly when the extra pads are installed at the end of sidewalls,making a“[”-shape air inlet.Combined with field tests,the CFD(computational fluid dynamics)technology was used to study the uniformity of airflow distribution in a tunnel-ventilated laying-hen house.The air distribution was first monitored in a layer house to find the main reason resulting in the variations of airflows in different aisles.Then CFD simulations were carried out with different distances(D=2 m,3 m or 4 m)between the pads on end-wall and the extra pads on side walls.The field test showed that airflow streams from the different groups of cooling pads collided vertically at the house corners,mixed with each other,then flew towards the center of the house.This was the main reason that the wind speed in the middle aisle was much higher than in other aisles,leaving large zones of lower ventilation in the aisles adjacent to the sidewalls.The results of CFD simulations indicated that air distributions could be significantly improved when the extra pieces of pads were moved away for an appropriate distance from the end coolingpads.As far as conventional poultry house with a span of 12 m,the air speeds in different aisles were more uniform when this distance was about 3 m.
