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CHEMICAL ENGINEER University of Valladolid

CHEMICAL ENGINEER University of Valladolid. Chemical Engineering Laboratory II. CHILLING ADSORPTION. Ana Celina Gondim Santos Sara Pérez Nieto (Group B - 22) Valladolid, 20 de Octubre de 2011. 2/27. INTRODUCTION ADSORPTION REFRIGERATOR RESEARCHS APLICATIONS CONCLUSIONS. 3/27.

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CHEMICAL ENGINEER University of Valladolid

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  1. CHEMICAL ENGINEERUniversity of Valladolid ChemicalEngineeringLaboratory II CHILLING ADSORPTION Ana Celina Gondim Santos Sara Pérez Nieto (Group B - 22) Valladolid, 20 de Octubre de 2011

  2. 2/27 • INTRODUCTION • ADSORPTION REFRIGERATOR • RESEARCHS • APLICATIONS • CONCLUSIONS

  3. 3/27 1. INTRODUCTION Oil crisis (1970) Ecological problems (1990) Coolingadsorptionsystems Advantages: ●environmentally friendly refrigerants ● can recover waste heat at low temperature levels ● lowoperationcosts Evaluation of an Adsorptioncoolingsystem: ●coefficient of performance (COP) ● specific cooling power (SCP)

  4. 4/27 2. ADSORPTION REFRIGERATOR 2.1 Systemconfiguration and operation ADSORBENT ADSORBATE Figure 1. General basis system layout of the adsorption chiller. Adsorbentheating: desorptionprocess + refrigerantcondensation Adsorbentcooling: adsorptionprocess + refrigerantevaporation

  5. 5/27 2. ADSORPTION REFRIGERATOR 2.1 Systemconfiguration and operation Figure 2. Photograph of the silica gel-water adsorption chiller.

  6. 6/27 2. ADSORPTION REFRIGERATOR 2.1 Systemconfiguration and operation Figure 3. The adsorption icemaker during ice production. Figure 4. Solar-powered icemaker without valves.

  7. 7/27 2. ADSORPTION REFRIGERATOR 2.2 Parametersofwork Parameters that influence in the performance of the system: ●Temperatureofcoolingwater ● Adsorptiontemperature ● Heatingsourcetemperature ● Desorptiontemperature ● Cycle time load control tool T↑ and madsorbed↓ (Pconst) T↑ and P↑ (madsorbed-const) toget more cooling.

  8. 8/27 2. ADSORPTION REFRIGERATOR 2.3 Key issues for the development of adsorption systems ● The hightcostofproductionis a drawback for adsorption systems. ● To become more commercially attractive, it is necessary to make a cost and size reduction: ●Increasing the SCP throught enhancement of the internal and external heat transfer of the adsorber; ● Increasing the COP throught the improvement of the heat management.

  9. 9/27 2. ADSORPTION REFRIGERATOR 2.3 Key issues for the development of adsorption systems The main technologies to enhance the external heat transfer are related to: ●extended surfaces: to increase of the heat exchange area; ●coated adsorbers: to increase the wall heat transfer coefficient; ●heat pipe technology: to have a high heat flux density and less intermediate elements.

  10. 10/27 2. ADSORPTION REFRIGERATOR 2.3 Key issues for the development of adsorption systems The main technologies to enhance the internal heat transfer are related to: ●consolidated adsorbents: because consolidated adsorbents have lower mass transfer properties than granular adsorbents, which could lead to very low adsorption rates.

  11. 11/27 3. RESEARCHS 3.1 Researchestendency ●Increase in adsorption cooling systems performance → compete with electric compression machines. ● R&D developperforming ● Harmonization of the adsorbent with the thermodynamic cycle. • Adsorbents • Components • Sistems

  12. 12/27 3. RESEARCHS 3.1 Researchestendency Investigationin adsorbingmaterials: ●silicagel/water ●zeolite/water ●activatedcarbon ●activatedcarbonfibres/ammonia ●Methanol ●R134a

  13. 13/27 3. RESEARCHS 3.1 Researchestendency Adsorption refrigeration systems modelling: ●Many modelling techniques; ●Simulate the adsorption refrigeration systems; ●Simulation techniques: ●lumped-parameter ; ●lumped analytical ; ●dynamic ; ●distributed .

  14. 14/27 3. RESEARCHS 3.1 Researchestendency Simulation constant values: ●Overall heat transfer coefficient for adsorbent beds; ●Evaporator; ●Condenser.

  15. 15/27 3. RESEARCHS 3.1 Researchestendency Researches about adsorption cooling: ●evaluation of adsorption and physical-chemical properties of the working-pairs; ●development of predictive models of their behaviour in different working conditions. ●study of the different kinds of cycles. • Divided into some specifics ways to improve adsorption cooling systems.

  16. 16/27 3. RESEARCHS 3.1 Researchestendency Figura 5. Designdrawing and a frontal view of theadsorptionchiler test facility.

  17. 17/27 3. RESEARCHS 3.2 ReadResearches Development and test of twoheatregenerativeadsorptionsystems: ●ice making and air conditioning; ●activatedcarbon-methanoladsorptionpair; ●cycle time was short →goodheat transfer.

  18. 18/27 3. RESEARCHS 3.2 ReadResearches Synthesis and characterization of a new composite sorbent: ●Improve the adsorbent; ●Make the isobars of ads-/desorption steeper; ●Increase the mass of water exchanged at the same boundary conditions; ●Improve the hydrothermal stability.

  19. 19/27 3. RESEARCHS 3.2 ReadResearches Testing of the lab scale adsorption chiller: ●Study the influence of the cycle time; ●Studythe relative duration of the isobaric steps; ●Relative duration of the isobaric steps on the performance of an adsorption cooling system.

  20. 20/27 3. RESEARCHS 3.2 ReadResearches Design and performance prediction of a new generation adsorption chiller: (Mathematical model) ● Describe the heat and mass transfer process ●Adsorbent bed ●the composite adsorbent ●the metal of the tube ●the working fluids ●Condenser ●cooling water ●the metal of the tube ●refrigerant

  21. 21/27 3. RESEARCHS 3.2 ReadResearches Optimization the operation strategy : ● Different temperatures of hot water inlet, cooling water inlet and chilling water inlet →different COP and cooling capacity; ● Conventional chiller; ● Composite adsorbent • highercooling capacity • COP slightly higher

  22. 22/27 4 . APLICATIONS ●Jiagsu Province, China ●cool a grain depot during hot summers ; ●silica-gel adsorption chiller driven by a low temperature heat source . ●Shanghai Research Institute of Building Science ●chillersbeing used in the air conditioning system of a “green” building.

  23. 23/27 4 . APLICATIONS (a) (b) Figure 6. (a) Shanghai ‘‘Green’’ Building; (b) equipment room.

  24. 24/27 4 . APLICATIONS ●European project Climasol ●examples of buildings that already use solar-powered sorption air conditioners ●System located in the cosmetic company ●adsorption chillers powered by hot water in the summer ●Chinese policy for energy exploitation ● small power adsorption chillers ●suitable for combined cooling, heating and power systems or heating and power system

  25. 25/27 5 . CONCLUSIONS We tried to synthesize the four articles, taking the best that each had. It was observed that: • Adsorptioncoolingsystems are becomingincreasinglyconsidered for applications where cooling is required and low grade heat is available. • Adsorption refrigerating machines consist essentially of an evaporator, a condenser, valves, and an adsorber-reactor containing a porous medium as adsorbent. • Some parameters influence in the performance of the system and there are drawbacks in these systems that don’t make them so commercially attractive. • Researches about adsorption cooling are divided into some specifics ways to improve adsorption cooling systems. • Looking for real application for the cooling adsorption, some buildings and grain depot were found in Asia and Europe.

  26. 26/27 Thank you!

  27. CHEMICAL ENGINEERUniversity of Valladolid ChemicalEngineeringLaboratory II CHILLING ADSORPTION Ana Celina Gondim Santos Sara Pérez Nieto (Group B - 22) Valladolid, 20 de Octubre de 2011

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