Evaluation and design of a solar-biomass hybrid dryer. A case ... Spin Offs-Workshop...Solar – Biomass Hybrid Drying Advantages compared to solar energy systems: • Continuous year-round

Drying process (I)

Heat Transfers Conduction conveccion amp radiation

3 main steps Pre drying processing Drying treatment Post-drying treatment

Main factors Temperature airflow velocity of drying air relative humidity material size

Phase I bull Heat up the material till the drying temperature is achievedbull The product surface is saturated with vaporbull Lasting till there is enough water in the product surface

Phase IIbull Decrease in the rate period as the surface is not vapor saturated bull Moisture diffusion controlled by the internal liquid movement

Phase IIIFalling rate drying Moisture flow from the interior to the surface decreases Lasting till an equilibrium is achieved (drying stop)

Key factor Drying rate increases with Temperature reducing dying time

Source (Bellesiottis et al 2011)

9

Drying process (II)

Drying process Transfer of heat to ensure the products get the latent heat of vaporization Extraction of water vapor from the goods Air velocity of 01 ms - adequate for drying most food products10

httpwwwprogres-cacakrsVoce_ehtml

Solar-Biomass Drier Components

Solar flat collectors

bull Absorbs the incoming solar radiationbull Convert it into heatbull Transfers the heat to a fluidbull Oriented and sloped properly

bullAbsorbing plate (aluminum cooper steel)bull Fluidbull Top transparent coverbull Edge and back insulationbull Enclosure that forms a casing

Conversion factor amp Heat loss coefficient

11www gogreenheatsolutionscoza

httpsnewenergyportalwordpresscomcategorysolar-energy

Biomass boilerSolar-Biomass Drier Components

bull Integrated with the solar drier systembull More reliable and economical systembull Solar collectors as the main heating systembull Biomass boiler as the heating backup

bull Use of different types of biomassbull Special design for olive stonesbull Reduce the costs for generating heat

12

httpwwwhergomalternativecom

Air treatment unit (ATU)Solar-Biomass Drier Components

bull Equipment designed to meet the demand forinstallations with special air requirement

bull Automatically regulate temperature amp moisture

bull Removal of excess moisture Moisture separatorunit (condensed water drained off)

bull Hot amp Cold sections to heat cold the input airwith the use of heat exchanger batteries

bull Fan to circulate the air to the drying chamber

bull Input data Masic flow water T Moisture amp T (air)

bull Output Batteries blower condenser compressor

13Source www scielobr

httpwwwarchiexpocom

Drying chamberSolar-Biomass Drier Components

bull Commercial units to dry up products(fruits vegetables fish meat plants)

bull ATU - provide the hot air

bull Control Temp amp humidity by ATU

14httpwwwtermoplinrsgallery_dryers_fruits_vegetableshtml

Project MethodologyDrier Requirements For The Process Moisture Removal and Drying Curves

Broccoli

To design the proper drying processbull Initial drying conditionsbull Drying curvesbull Optimum moisture removal ratebull Drying time

Most dry vegetables Moist content lt 20

To optimize the drying process the rightamount of moisture removal is necessary

Special aim to retain initial GLs content

Maldonado (2003) T=60ordmC amp WC=15Low GLs degradation rate

Similar conclusion (Mrkic et al 2010)

Target Drying with 60ordmC till 15 WC

Case Study

Source Maldonado (2003)

15

60ordmC

70ordmC

80ordmC

Drier Requirements For The Process Drying TimeProject Methodology

(Maldonado et al 2003) research

Drying curves at several dry bulb temperature (6070 and 80ordmC) were constructed

The moisture in fresh broccoli was 9211

When the drying temperature is higher themoisture decrease in the solid is greater

Most suitable constant-rate zones at 60 ordmC

Conclussion The equilibrium humidity level wasreached after three hours of drying at 60ordmC

(Deanna 1992) research ndash similar results (25 hrs)

Case Study

Source Maldonado (2003)

16

Time (hrs)

Energy Requirements For The Process Heat Transfer

= 782890 (3 3600 sc) = 725 KW

Project Methodology

Determination of the amount of heat required to dry up broccoli

Assumptions 907 as initial moisture content 15 as final moisture content

- 8905 gr of moisture removed per kg Cp of 401 kJkgordmC as specific heat capacity Initial temperature of the broccoli = 25degC Drying temperature = 60degC for 3 hours

Latent heat evaporation (water) = 2257 KJkg

Heat energy required for each kg of broccoli

Case Study

For 400 kg broccoli

Masic flow17

Hot water requirementsProject Methodology

The initial and final conditions of the air and water in the ATUWater Input temperature 80ordmC output temperature 50ordmC

Approximate ATU losses 20 (supplier info)Input water (T= 80ordmC) = 21525 liters per day

Hot water requirements Unit Quantity

Air heat required KW 725

Air heat required KWd 580

Air heat required KJd 20880000

Losses in ATU ‐ 20 KJd 25056000

Water temperature input ordmC 80

Water temperature output ordmC 50

Fluid specific heat glicol 20 KJkg 388

Flow ld 215258

Pipe diameter () Inches 1 14 1 14

Fluid velocity ms 24

Case Study

18

EquipmentSolar Flat Plate collector

bullViessman Vitosol 200 F

bull Highly efficient sol-titanium coated cooperabsorber with effective insulation

bull Awarded with the rating Very Good byStiftung Warentest

Case Study

19httpwwwviessmannes

EquipmentBiomass boiler

bull Hergom Oliva 100bull Local biomass (olive stones) or particles grain size lt 40 mmbull Maximum boiler output 100 kW bull Power automatically regulated Potentiometers pump control system thermostatsbull Two types of smoke flow Direct amp tangential to the walls of the combustion chamberbull High performance (up to 90 energy efficiency)bull Automatic feeding system ndash able to work for long periods of timebull Ashes removed in an easy way

1 Fuel feeding system2 Combustion chamber3 Secondary air flow4 Smoke passing area5 Secondary smoke passing area6 Third smoke passing area7 Smoke exit8 Smoke extractor9 Water flow10 Water flow return11 Cleaning system12 Thermal insulation13 Ceramic fiber insulation14 Dash recovery system15 Dash chamber16 Ventilator for combustion air

Case Study

20httpwwwhergomalternativecom

Equipment

Air treatment unit (ATU)

bullModel System Air ndash Danvent DV20

bullAutomatically control T amp moisturebullAdjustable air inflow amp outflow sectionsbullFilter sectionsbullHeat amp cold batteriesbullFan

bullUnits built in modulesbullAssembled on sitebullSoftware to determine ATU components

Case Study

21

httpwwwarchiexpocom

EquipmentDrying chamber

bullModel Progress Inzenjering VTS 3000

bullMaximum capacity of 3000 kgday

bullDesigned rate of 400 kg every 3 hours

bullMetal with double walls and heat insulated

bullGoods placed on plates within a carriage

bullLoading manually or mechanically

Case Study

22

httpwwwprogres-cacakrsVoce_ehtml

EquipmentStorage tank

bull Supplier Viessmanbull Thermal reservoirbull Heat added by the biomass boiler solar systembull Steady supply of hot water to the UTAbull Equipped with temperature sensors to be connectedto a control system that regulate the boiler operation

Case Study

23httpwwwviessmanncaenDistrict_HeatingProductsdhwStorage_Tankshtml

EquipmentHeat dissipater

Model Ferroli AE F10 ndash Up to 10 PanelsAE F20 - Up to 20 PanelsAE F30 - Up to 30 Panels

Dissipates the excess of heat producedParticularly for the summer season

Required data- The external air temperature- The temperature of the fluid- Percentage of glycol- Capacity that needs to be dissipated

Case Study

24httpinditeresproductoscatalogoaerotermos-solaresaspx

Simulation

T-Sol Simulator ResultsDetermine the optimum number of collectors required for the design of the projectTo assess the thermal performance of the solar systemInput data Geographical and climatological characteristics climate zone

global solar radiation (MJm2) horizontal radiation (KJm2d)latitude (ordmmin) altitude (m) average relative humidity()max amp Minwater temperature (ordmC) average ambient temperature (ordmC)collector characteristics collector surface (m2)

Consumption data for the energy needs and reference temperature (80ordmC)

Results of annual simulation(System with 10 flat solar collectors)

bull Installed collector power 177 kW bull Installed solar surface area (gross) 252 msup2bull Irradiation (collectors) 45 MWh 1805 kWhmsup2bull Energy delivered 15 MWh 590 kWhmsup2

Results also presented with efficiency data energy balance solar fraction fuel savings CO2 emissions wood pellet savings

Case Study

25

Economic AnalysisSystem Costs

10 Collectors system Ref

Collector costs Model size

Unit price (euro) Units Cost (euro) (I)

SupplierViessmanVitosol 200F

776 10 7760

Storage tank costs (II)

Supplier Viessman (l) 1300 4500 1 4500

Supplier Viessman (l) 2550 6000

Supplier Viessman (l) 3800 7500

Biomass boiler (III)

Supplier HergomHergom

Oliva 10020931 1 20931

Air treatmet Unit (IV)

Supplier SystemairDanvent

DV204610 1 4610

Drier Chamber (V)

Supplier Progres Inzenjering

VTS-3000 (estimated

price) 7500 1 7500

Heat exchanger (VII)Supplier Ferroli AE-F 10 765 1 765Supplier Ferroli AE-F 20 1015

Pipework amp components (VI)

Pipes supports valves insulation

150 10 1500

Labour (VI)Installation works Coll 600 10 6000

Total costs 53566

The following table shows the costs for a solar dryer with 10 collectors system + boiler

(I) Viessman pricelist (wwwcomercialgoheresTarifa5CEnergiaSolar5CViessmannpdf)(II) (wwwcalemures2009productoscalefaccionviessmanacumuladores-viessmantodos14907html) prices estimated(III) Tarifas Hergom 2012 (wwwhergomcom)(IV) See ATU quote in appendix 4(V) Supplier PROGRES INŽENJERING price estimated according to similar drier chambers in the market(V) Supplier Technisolar (wwwtechnisolares) price estimated according to supplier information(VII) httpwwwferroliestarifas2012calefaccion

Case Study

26

Operation amp Maintenance CostsEconomic Analysis

Operation and maintenance costs for the drier system with10 collectors + boiler

Case Study

10 collectors (8 hrday)

Labor costsNordm of people 2Salary for drier operator amp preparatory labour (euromonth) 1500Total labor costs (euroyear) 36000

Operating costsMaintenance 15 equipment cost (euro) 8035

Total costs (euroyear) 51077

Capital costsEquipment cost (euro) 53566Interest rate () 10Period of years 15

Total capital cost (euroyear) 7043

27

Energy CostsEconomic Analysis

Energy costs for dryer system with10 collectors + boiler

(I) Critical review on the pelletizing technology combustion technology and industrial‐scale systems 2012 European Commission under the EIE programme(II) Supplier Calor-eco (httpwwwcalor-ecoeslista-de-precioshtml)(III) Electricity consumption of the ATU is 38 kWhr See appendix 4 quote from Systemair(IV) The price of the KWh in Spain is currently 0185 eurokWh(httpwwwmineturgobesenergiaelectricidadTarifasTarifas2008Paginaspreciosaspx)

Case Study

28

Energy Costs 10 Collectorssystem

Pellets consumed by the boiler

Annual power required (MWh) 576

Calorific value (KWhkg) 5Boiler working hours (h) 800Pellets required per year (kg) 33297Unit price pellets olive stones (eurokg) 012Daily cost (euro) 1682Montly cost (euro) 36997Yearly cost (euro) 443964

Total (euroyear) 443964

Electricity consumed by the ATU

KWhd required 48704Unit price (euroKWh) 0124Daily cost (euro) 6039Montly cost (euro) 130851

Total (euroyear) 1570217

Total costs (euroyear) 2014181

Product Costs amp RevenuesEconomic Analysis

Product costs and revenues for dryer system with10 collectors + boiler

(I) Based in the two mainSpanish suppliers(wwwbiolandiaesalimentos362-polvo-de-brocoli-deshidratadohtml )(wwwcartagenaecologicacombrocoli-ecologico-deshidratado-murcia-ecologica-venta-onlinesearch=brocoli )(II) See appendix 8(wwwdpzesdiputacionareaspresidenciaz4e_observatorioproductophppr=5)

Case Study

29

DRY BROCCOLI PRODUCTION REVENUE Unit Quantity RefDrying 1500

Fresh broccoli per load kg 40000

Broccoli production per load hr 6000

Drying duration period hr 300

Load amp reload duration hr 003

Preheating duration hr 025

Duration per load hr 328

Loads per day u 244

Average market price (dry broccoli) eurokg 1150 (I)Daily revenue euro 16812

Montly revenue euro 364264

Total revenue per year euro 43711675

FRESH BROCCOLI COST

Quantity kgd 9746Quantity kgy 2534010Price eurokg 077 (II)

Purchase costs per year euro 19511878

Cash FlowEconomic Analysis

Cash Flow for dryer system with10 collectors + boiler

Case Study

30

CASH FLOW (10 collectors system)

Ref Year Year

Outcomes IncomesInital costs (No

boiler)

Biomas boiler

Operation costs Labour Capital

costs EnergyFresh

Product Cost

Pretreatment amp

cutting

Milling amp Packaging Total costs

Total income from dry products

Cash flow

0 2013 32635 20931 0 0 53566 -535661 2014 0 8035 36000 7043 20142 195119 35000 45000 346338 437117 907792 2015 0 8229 36868 7212 21745 199021 37786 48582 359443 445859 864163 2016 0 8427 37756 7386 23476 203002 40794 52449 373290 454776 814874 2017 0 8630 38666 7564 25345 207062 44041 56624 387931 463872 759405 2018 0 8838 39598 7746 27362 211203 47547 61131 403425 473149 697246 2019 0 9051 40552 7933 29540 215427 51331 65997 419832 482612 627807 2020 0 9269 41529 8124 31892 219735 55417 71251 437218 492264 550468 2021 0 9492 42530 8320 34430 224130 59829 76922 455654 502110 464569 2022 0 9721 43555 8521 37171 228613 64591 83045 475217 512152 36935

10 2023 0 9955 44605 8726 40130 233185 69732 89656 495989 522395 2640611 2024 0 10195 45680 8936 43324 237849 75283 96792 518060 532843 1478312 2025 0 10441 46781 9152 46772 242606 81276 104497 541524 543500 197513 2026 0 10693 47908 9372 50496 247458 87745 112815 566487 554370 -1211714 2027 0 10950 49063 9598 54515 252407 94730 121795 593058 565457 -2760115 2028 0 11214 50245 9829 58854 257455 102270 131490 621359 576766 -44592

Discount Rate 10 NPV 3523218

OampM (∆) 241 IRR 164

Labour Cost (∆) 241 NPV Benefits 4058878Dry productprice (∆) 2 NPV Invest 535660

Energy Cost (∆) 796 Annual Paym 533636Fresh Product(∆) 2 Payback per 10

Source Guideline VDI-Standard VDI 2067

Comparison

Case StudyEconomic Analysis

31

RESULTS ON ANNUAL SIMULATION FOR 10 20 30 AND NONE FLAT SOLAR COLLECTORS WITH THE USE OF ONE BIOMASS BOILER (8 hrd)

Numberof

collector

Area(m2)

CollectorPower

installed(KW)

Irradiation on to

collector surface (MWh)

Irradiation on to

collector surface

(KWhm2)

Power delivere

d by collector

s (MWhy)

Power delivered

by collector

s (KWhm

2)

Energy from

auxiliary heating (KW)

Wood pellets savings

(Kg)

Solar fraction

()

System efficienc

y ()NPV (euro) IRR

()

NPV Benefits

(euro)

NPV investme

nt (euro)

Annual payment

(euro)

Payback

period(years)

10 23 1764 4551 18057 1487 59018 576 34569 113 312 352322 164 405888 53566 53364 10

20 504 3528 9101 18057 2807 557 444 66252 202 300 306018 117 376594 70576 49512 14

30 756 5292 13651 18057 384 50793 341 93336 275 281 255290 87 343391 88101 45147 20

- - - - - - - 725 - - - 376435 201 421476 45041 55413 08

Considerations

Environmental ImpactbullReduction of GHEbullSustainable utilization of energyresources

(I)Review of pelletizingtechnology combustiontechnology systems2012-EuropeanCommission (EIEprogramme)(II) Supplier Calor-eco(httpwwwcalor-ecoeslista-de-precioshtml)(III) Official price inSpain on 31-11-2013(httpwwwdieselogasolinacom)(IV)The price of the KWhin Spain is currently0185 EuroskWh(httpwwwmineturgobesenergiaelectricidadTarifasTarifas2008Paginaspreciosaspx)

(I)Review of pelletizingtechnology combustiontechnology systems2012-EuropeanCommission(EIEprogramme)(II)httpwwwsunearthtoolscomestoolsCO2-emissions-calculatorphptxtCO2_9

Environmental Impact

Case Study

32

Pellets requiremets 10 Collectors system Ref

Solar power supplied (MWh) 149Boiler annual power supplied (MWh) 576Pellet calorific value (KWhkg) 47 (I)Pellets required per year (kg) 3164Unit price pellets olive stones (eurokg) 012 (II)

Pellets yearly cost (euro) 37966Petrol savingPetrol required per year (lt) 6928Unit price petrol(eurol) 1107 (III)Petrol daily cost (euro) 2905Petrol montly cost (euro) 63909Petrol yearly cost (euro) 766914

Petrol yearly savings (euro) 766914 Electricity savingUnit price (euroKWh) 0124 (IV)Daily cost (euro) 3405Montly cost (euro) 74917Yearly cost (euro) 899000

Electricity yearly savings (euro) 899000 Renewal energy generated per year (MWhy) 503 Ref

Fossil fuel savingsPetrol calorific value (KWhkg) 115 (I)Petrol required per year (lt) 48033CO2 generated per petrol (kgl) 263 (II)

Total CO2 savings (kg) 126327

Summary Conclusions

bull Viable project according (demand dried products vs costs)bull Drier with just biomass boiler has lower payback periodbull Drying process is further optimizedbull Suitable for big farmer associations amp small farmer groupsbull Increase economic development of many rural areasbull Vital to preserve agricultural surplus products

33 httpwwwtermoplinrsgallery_dryers_fruits_vegetableshtml

Considerations

Environmental ImpactbullReduction of GHEbullSustainable utilization of energyresources

(I)Review of pelletizingtechnology combustiontechnology systems2012-EuropeanCommission (EIEprogramme)(II) Supplier Calor-eco(httpwwwcalor-ecoeslista-de-precioshtml)(III) Official price inSpain on 31-11-2013(httpwwwdieselogasolinacom)(IV)The price of the KWhin Spain is currently0185 EuroskWh(httpwwwmineturgobesenergiaelectricidadTarifasTarifas2008Paginaspreciosaspx)

(I)Review of pelletizingtechnology combustiontechnology systems2012-EuropeanCommission(EIEprogramme)(II)httpwwwsunearthtoolscomestoolsCO2-emissions-calculatorphptxtCO2_9

Economic Viability amp Environmental Impact

Case Study

Economic Viabilitybull Fast Paid-Backbull Increase valuebull Generation of rural employment

Benefitsbull Enabling continuous dryingbull Enhancing quality of dried fruitsbullReducing post-harvest lostbullOpportunity to process amp store

34

Pellets requiremets 10 Collectors system Ref

Solar power supplied (MWh) 149Boiler anual power supplied (MWh) 576Pellet calorific value (KWhkg) 47 (I)Pellets required per year (kg) 3164Unit price pellets olive stones (eurokg) 012 (II)

Pellets yearly cost (euro) 37966Petrol savingPetrol required per year (lt) 6928Unit price petrol(eurol) 1107 (III)Petrol daily cost (euro) 2905Petrol montly cost (euro) 63909Petrol yearly cost (euro) 766914

Petrol yearly savings (euro) 766914 Electricity savingUnit price (euroKWh) 0124 (IV)Daily cost (euro) 3405Montly cost (euro) 74917Yearly cost (euro) 899000

Electricity yearly savings (euro) 899000 Renewal energy generated per year (MWhy) 503 Ref

Fossil fuel savingsPetrol calorific value (KWhkg) 115 (I)Petrol required per year (lt) 48033CO2 generated per petrol (kgl) 263 (II)

Total CO2 savings (kg) 126327