Saving energy in German greenhouses - D. Ludolph - PCS

Saving energy in German greenhouses - D. Ludolph - PCS

Saving energy in Germangreenhouses• Situation• Measures• ProjectsGreenGrowing, Destelbergen, 23.10.2013Dr. Dirk Ludolph

Horticulture in Germany –Concentration of companies rises!Ornamentals 2012:3.496 companies > 0,1 ha2.000 companies < 0,1 ha1.840 ha protectedProtected vegetables 2012:≈ 1.000 companies≈ 1.000 hain Gartenbau Report 4-5/2013

Greenhouse production in Germany:‣ many old greenhouses‣ high demand for investments in facilities‣ increasing areas per company‣ uniform crops‣ increasing specialization on one or two crops‣ less companies with individual demands for specialcrops‣ increasing production costs (cost pressure)‣…

Saving energy…• Reducing consumption and/or costs ofheat energy– real energy saving measures– changing crops (low temperature crops)!!– no cultivation during winter time!–…• Rising own production (efficiency)– higher areal productivity– higher prices–…

Heizölpreis Price of oilin €/Liter (€/liter)0,700,60Pot Topfpflanzenbetriebe, plant producer indirekter Absatz >75%Quelle: Orientierungsdaten Baden-WürttembergEfficiency of heat energyEnergieeffizienz- amount of oil (liter) per EUR of product -Last third1. Drittel First third of 3. Drittel Heizölpreis Price of oilof companiesincompanies€/liter€/LiterEnergieeffizienz (liter oil per inLiter Heizöl/€ EigenproduktionEUR ofproduct) 1,401,200,500,961,000,400,800,600,300,600,200,400,100,170,090,200,00198119831985198719891991199319951997199920012003200520070,00JahryearHeise, Technik im GartenbauQuelle: hortigate, energieportal

What have german growers done to reduceenergy consumption or energy costs?1. Changing the heat source:

Coal(anthracite)1,7-1,9 ct/kWhWoodwood chips:1,5 – 1,7 ct/kWhwood pellets:3,0 ct/kWh

Waste heat from biogas plantsPrice strongly depends oncontract details (quantity ofheat, price for alternatives,investments, …)More than 1500 biogasplants in Lower saxony

What have german growers done to reduceenergy consumption or energy costs?1. Changing the heat source-coal- wood (chips or pellets)- waste heat from biogas plants or other industries- CHPs with plant oil (palm oil) or gas-…2. Installing- heat storage tanks (water)- and increasingly heat pumps

What have german growers done to reduceenergy consumption or energy costs?3. Covering materials:- anti-reflex coating- double-layer polyacrylic sheets (Alltop)- double-layer films ETFE…

Kultursysteme: Gewächshaus / FreilandInflatable double filmcovering systems

What have german growers done to reduceenergy consumption or energy costs?4. Multiple energy screens- two or three layers

double layer energy screensdaylight energy screendaylight energy screenblackout screenthermal/shading screen

Savings with the use of adaylight screenBlackout:45 %Energy screendaylight screennight dayTotal (day andnight)Domke, 2012

What have german growers done to reduceenergy consumption or energy costs?1. Changing the heat source2. Installing heat buffers and heat pumps3. New covering materials4. Multiple energy screens5. Optimizing greenhouse climate (fans, heating strategies, …)

Energy saving with new temperature controldynamic heating strategies =adaption of setpoints (heating temperature, venting, …)to other climatic factors (light, outside temperature,wind speed, …)

Energy saving with new temperature controlFor example:dynamic adaption to outside temperatureAdaptation of setpoints to the difference between the actual outsidetemperature and the longterm mean temperature at the specificlocation of the nursery

Energy saving potential: 5 to 20 %(Wartenberg, 2009)

Ideas for the future (actual projects)1. Storage2. Covering materials3. New greenhouse systems

Latent heat storage systemphase change material (PCM)substance with a high heat of fusion which, melting and solidifying at acertain temperature, is capable of storing and releasing large amountsof energy.Heat is absorbed or released when the material changesfrom solid to liquid and vice versa at a certaintemperature.Paraffin 18 HC inFolienkissen (Ketten)zu je 25 gPCM (latent storage)T p : temperature of phase changeGrafik: BINE Informationsdienst

Geothermal energy (storage system)Project LVG Heidelberg: Near surface geothermie for the heating ofgreenhouses• U-tube heat exchanger (water-trimethylglycin-mix)• Heating system: heat baseload with low-temperature system,peak load with gas heater• heat pumps (70 kW)• storage of heat in tanks (2 x 30 m³ watertank)• screens: daylight screen, thermal screen, blackoutPhotoquelle: GIG GerberLVG Heidelberg,Diebsweg 2,69123

New covering materialsDouble layer systems, for example:- low-e-glass (low thermal emissivity)- Glass-film-combination, inflatable:Double: glass-filmTriple: film-glass-film• high PAR-transmissivity• high thermal insulation• high stability• inflation on demand!• problem: price!

Ideas for the future (actual projects)1. Storage2. Covering materials3. New (greenhouse) systems

ZINEG The low energy greenhouseJoint research project (May 2009 – April 2014)Main objective: reducing the consumption of fossil energy and CO 2 emissions by 90%→ combination of horticultural arrangements and technical innovations

ZINEGBerlin Hannover OsnabrückMünchen/Neustadtcrops tomato pot plants pot plants vegetables (bio)roof coveringsingle-glassdouble-glass,Ar-coatedlowemissivityglassdouble-filmPE, ETFE (F-Clean)energy screen 1 screen 3 screens 1 screen double screenalternativeenergymode ofoperation (CO 2)storage solarenergysolarsolarwood pellet heaterwith buffersemi-closed semi-closed ventilation ventilationrain water tankwarm / coldwater bufferpassivpassiv

ZINEG greenhouse HanoverGreenhouse with maximum thermal insulation for pot plants

greenhouse concept for ornamental plant production960 m 2 greenhouse area, 2 sections insulation double glazed roof, AR coated acrylic multi-layer sidewalls 3 thermal screens using solar energy in a day-night storageheat pump, heat exchangers and water puffer tanks semi closed ventilation supplement CO 2

Effects of thermal insulation measuresEnergy savings (during night) in comparison with single glazing and single glazing +thermal screenthermal insulationmeasured saving savingU CS -valueinsulation glassU CS = 4,0single glassU CS = 7,6single glass +thermal screenU CS = 4,6W m -2 K -1 % % %insulation glass 4,0 0 48 14insulation glass +thermal screen3,0 27 62 38insulation glass +2 thermal screens2,1 47 72 54insulation glass +3 thermal screens1,2 70 84 74(nach Tantau, 2012)

Thermal insulation- very good (U cs = 1,2)- semi closed ventilation- very low heat demandusing solar energy- 4 - 6 weeks in spring andautumn- 30 – 100% substitution offossile heating energy- 5 - 25% electric energyfor solar heat storageplant quality- No differences toconventionalgreenhouses- high air humidity but noincrease in plant diseases-lowCO 2 concentration(< 200 vpm)- modification in cultivationhigh energy saving in ornamental crop production

Pioneers in praxisNursery Kern (Bavaria)young plant and finished productsmain crops: bedding plants, chrysanthemum, poinsettianew greenhouse for ornamentalsbuilt April 2013thermal insulation• Alltop (Co. Evonik) in roof• two-layer thermal screenheating systems• 450 KW wood chip heater• solar heating system• heat pump (100 KW, 50°C flow temperature, COPcontrolled)• 12 x heat exchangers• 2 x 70 m 3 heat storage water tanks (above ground)2 x 430 m 3 water buffer tanks, subsurface

Outlook on the future• Back to the roots:different greenhouses for different demands:low temperature, high temperature greenhouses, …• Energy management in greenhouses:Combinations of different heating systems with intelligentenergy (heat and electricity) management systems• Many good ideas and energy efficient systems!• Problem: prices for the systems are too high!!!!

Thank you!GreenGrowing, Destelbergen, 23.10.2013Dr. Dirk Ludolph

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