Comparison of different hay drying techniquesAlfred PöllingerInstitute for Animal Husbandry and Animal Health

AgEng 2014 Zürich 6.-10. JulyInternational Conference of Agricultural Engineering

Agricultural Researchand Education Centre (AREC)

Content

1. Hay drying – background of the project2. Field working chain3. Hay drying equipment

Heat pump dehumidifier with solar collector and cold air ventilation

4. Methods and measurement technology5. Results6. Summary

BackgroundA lot of research was done in feed quality and preservation of silage – worlde wide

Since the begin of 2000 – closer attention of hay drying and feed quality in Austria

2009: planing of a comprehensiv projekt at the AREC regarding new hay drying techniques (new regulations) – less energy consumption and how to get a high feed and milk quality

Installation of a heat pump dehumidifier for hay drying combined with a solar collector!

Hay should look like this !

Green colourHigh rates of leavesGood smell of hayNo fungal odour

1. cut, 2012, Stainacher Wiese, permanent meadow - drying with dehumidifiers

Field working chain

Cut – since 2011 with conditionerTedding – rotational speed 350 – 500!First time 470-500 r.p.m. „Effect of conditioner“from 50 % TM < 430 r.p.m. driving speed – ca. 6-8 km/hRaking – double-rotor central rakeSelf-loading trailer – with cutting system –we used only 4 knifesDetermination of harvested product – weighing

Mowing with conditioner: - front - rear combination of Krone and Pöttinger – 5.5 und 5.7 m AB- ca. 3 kW bigger power consumption/m WW) + 15 bis 20 kWh/box-filling- ca. 2-4 hours shorter drying process in the haybox – 60 – 120 kWh- = 45 bis 100 kWh savings potential (12.000 kg TM = ca. 5 ha DW)

Zetten mit geringer Drehzahl!?Tedding with adjusted PTO speed!?

Field dried hay Cold air ventilation dehumidifierNumber ofturning operations

4 (3-6) 3 (2-5) 2 (1-4)

PTO Speed: 350 to 500 r.p.m. …. dependet on dry matter condition of feedDriving speed: ca. 6 km/h

Raking with double-rotor central rakeHarvesting with self-loading trailer

PTO speef: 450 r.p.m. at rakingKnife configuration of self-loading trailer: 4 (0-33)

Determination of crumb losseswith suckling method

Heat pump dehumidifier combined with a solar collector

Ansaugbereich stirnseitig von Ost und/oder West zur Mitte

Süden NordenZubau-Dach

Klappe 1 Umluft

Tor 2 FrischluftWärmebildkamera - Oberflächentempertur möglich

Klappe 3 offen=reiner Solarbetrieb

offen Aufstieg u.Tür Abstieg

Bodenrost

1

2 2 2 2

Firstkappe

1/1Sammelkanal

1/5

1/6

4/2

4/1 4/3

3/1

5

4/4

4/5

2 2 2 2

3/2

6

78/1,2 8/3,4

2 2 2 2

Combination with solar based air heating

and air dehumidification

southroof

north

grate

door

thermographic camera – temp. of surface area

flap 3 open = just solar operation

gate 2 fresh air possible

way up and down

flap 1 circulating air

collection channel

suction zone from east and/or west to centre

Dehumidifier WP - data

Vaporizer(4 m2

cross-sectional area)

Heat pump dehumidifierType SR 60 N MJRBuilt in 2011Refrigerant R 407cAmount of refrigerant 45 kgVoltage 400 VConnection power 16 kW

Fan – SR 1000FanType SR 1000/22/6/RD 270Built in: 2011Air volume capacity 55000 m³/hPAst 603Drive motorConnection power PA 22 kWCurrent rating In, 400V 44.5 AV/Hz 400V/50HzCos 0.83Rated speed 980 r.p.m.

Box dimension– drying with dehumidifier

Base area: 96 m²Height: 6,0 mGrate level 60 cmSupports: 50 x 150 mmDistance round logs 60 cmConstruction steel grid CQS 100Side cover 60 cm

Filling height: 2 m (0.75 bis 3.5 m)

Blow into direction

Cold air ventilation (CAV)71 m² base areaHeight of the box: 3.90 mGrate level: 45 cm5.5 kW fan28 200 m³/h – 490 Pa(0.11m³/sec.m² base area)Intake on the south side

Field retention timeHourly data

You can harvest about 20 h earlier with thermal ventilation Field drying all over the year is no option!

Silage HPD CAV FDH1. Cut 10.2 18.8 26.4 37.32. Cut 3.2 16.5 25.1 34.53. Cut 6.2 20.0 28.8 51.34. Cut 23.2 41.9 49.9 58.6 1)

1) Hourly data not realisitic, beause the feed was spread below the roof

Crumb losses

Durchschnitt2010-2012 1. Schnitt 2. Schnitt 3. Schnitt 4. Schnitt MW

Differenz zu

Silage 160 169 127 162 154 0

Luftentf.Tr. 234 204 155 191 196 42

Kaltbel. 292 264 258 273 272 118

Bodentrockg. 383 383 n.a. 392 386 232

n.a. = nicht auswertenbar

Werte in kg TM/ha, Dauerwiese 2012

Differenz zwischen Bodentrocknung und Luftentfeuchtertrocknung kann mehr als 1.500 l milk/ha.a betragen(190 kg x 2 l / kg x 4 Schnitte)

Volume flow – 1. cut 2011

max. 0.13 m3/sec and m2 base area

at least 0.07 m3/sec.m2

Dehumidificaton – 1. cut 2011

0.5-1.0 liters/minute water separation!

Energy consumption/costs 2012

note: no 3. cut in 2012 because of flood

1. Cut 2. Cut 4. CutHPD CAV HPD HPD CAV HPD CAV

Date harvesting 19.05. 19.05. 26.05. 29.06. 29.06. 17.09. 18.09.FM kg 13 230 4 145 38 830 18 805 9 850 14 120 6 080Dry matter % 56.6 66.1 60.2 62.4 75.9 65.2 72.8d.m in box kg 7 491 2 739 23 358 11 727 7 475 9 208 4 427Hay weight in box kg 8 465 3 095 26 395 13 251 8 447 10 405 5 002Water loss kg 4 765 997 12 435 5 554 1 258 3 715 992Energy consumption1)

per tonne dry matter kWh 87 66 146 140 25 306 111per tonne hay kWh 77 57 129 124 22 271 97spec. energy cons. W/kg 137 180 275 297 149 758 497Costs of energy (18 Cent/kWh)

per kg dry matter cent 1.6 1.2 2.6 2.5 0.5 5.5 2.0per kg hay cent 1.4 1.0 2.3 2.2 0.4 4.9 1.7

Costsinvestments Heat pump

dehumidifierCold air

ventilationNotes

fan € 10 000,-- 7 000,-- Heating ventilation mit FU; ND: 15Jhaybox, grate, channels € 15 000,-- 15 000,-- 100 m2, self made; ND 30 years

collector € 10 000,-- 250 m2, self made; ND 30 J

dehumidifier € 30 000,-- including control system ND 30 years

Total fixed costs/a € 6 317,-- 1 607,--

consumption of hay/a kg 146 900 146 900 20 ha, harvest: 6.500 kg drymatter/ha.a

drying amount /a kg 96 954 96 954 2/3 feedfixed costs/kg hay Cent 5.54 1.66energy consumption kWh 12 8 per 100 kg hayvariable costs/kg hay Cent 2.16 1.44 18 Cent/kWh

total costs /kg hay Cent 7.70 3.10 per kg hay

Calculated without haystorage and crane mechanization

SummaryTo dry hay successfully, the whole process is very important:mowing – tedding/raking – harvesting –distribution in box and process managingValidated resulats just in the years (2011 to) 2012 (13) – technical and operational interferences100 m2 base area – 20 ha farm– possible to run with a electricity demand of 50 A

Summary

Soil drying method is loosing 760 kg dry matter/ha - in comparison to thermal ventilationSavings potential in transport and numbers of teddings (silage) (0,8 Cent/kg hay and tedding process)Cold air drying is in energy consumption superior to dehumidifier drying – only unther good harvesting conditions

Summary

A hay plant with medium to higher achievement levels needs a heating system. Drying with dehumidifiers is in comination with a good controle and regulation technology a good solution

Available field working dayscountry‘s border

district border

rivers

lakes

Available field working dayscountry‘s border

district border

rivers

lakes