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CHEMICAL ENGINEER University of Valladolid Ana Celina Gondim Santos Sara Pérez Nieto (Group B - 22) Valladolid, 20 de Octubre de 2011 Chemical Engineering.

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Presentation on theme: "CHEMICAL ENGINEER University of Valladolid Ana Celina Gondim Santos Sara Pérez Nieto (Group B - 22) Valladolid, 20 de Octubre de 2011 Chemical Engineering."— Presentation transcript:

1 CHEMICAL ENGINEER University of Valladolid Ana Celina Gondim Santos Sara Pérez Nieto (Group B - 22) Valladolid, 20 de Octubre de 2011 Chemical Engineering Laboratory II CHILLING ADSORPTION

2 1.INTRODUCTION 2.ADSORPTION REFRIGERATOR 3.RESEARCHS 4.APLICATIONS 5.CONCLUSIONS 2/27

3 1. INTRODUCTION Cooling adsorption systems Advantages: environmentally friendly refrigerants can recover waste heat at low temperature levels low operation costs Evaluation of an Adsorption cooling system: coefficient of performance (COP) specific cooling power (SCP) 3/27 Oil crisis (1970) Ecological problems (1990)

4 2. ADSORPTION REFRIGERATOR 4/27 2.1 System configuration and operation Figure 1. General basis system layout of the adsorption chiller. ADSORBENT ADSORBATE Adsorbent cooling: adsorption process + refrigerant evaporation Adsorbent heating: desorption process + refrigerant condensation

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

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

7 2. ADSORPTION REFRIGERATOR 7/27 2.2 Parameters of work Parameters that influence in the performance of the system: Temperature of cooling water Adsorption temperature Heating source temperature Desorption temperature Cycle time to get more cooling. load control tool T and m adsorbed (P const ) T and P (m adsorbed-const )

8 2. ADSORPTION REFRIGERATOR 8/27 2.3 Key issues for the development of adsorption systems The hight cost of production is 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 2. ADSORPTION REFRIGERATOR 9/27 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 2. ADSORPTION REFRIGERATOR 10/27 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 3. RESEARCHS 11/27 3.1 Researches tendency Increase in adsorption cooling systems performance compete with electric compression machines. R&D develop performing Harmonization of the adsorbent with the thermodynamic cycle. Adsorbents Components Sistems

12 3. RESEARCHS 12/27 3.1 Researches tendency Investigation in adsorbing materials: silica gel/water zeolite/water activated carbon activated carbon fibres/ammonia Methanol R134a

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

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

15 3. RESEARCHS 15/27 3.1 Researches tendency 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 3. RESEARCHS 16/27 3.1 Researches tendency Figura 5. Design drawing and a frontal view of the adsorption chiler test facility.

17 3. RESEARCHS 17/27 3.2 Read Researches Development and test of two heat regenerative adsorption systems: ice making and air conditioning; activated carbon-methanol adsorption pair; cycle time was short good heat transfer.

18 3. RESEARCHS 18/27 3.2 Read Researches 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 3. RESEARCHS 19/27 3.2 Read Researches Testing of the lab scale adsorption chiller: Study the influence of the cycle time; Study the relative duration of the isobaric steps; Relative duration of the isobaric steps on the performance of an adsorption cooling system.

20 3. RESEARCHS 20/27 3.2 Read Researches 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 3. RESEARCHS 21/27 3.2 Read Researches 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 higher cooling capacity COP slightly higher

22 4. APLICATIONS 22/27 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 chillers being used in the air conditioning system of a green building.

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

24 4. APLICATIONS 24/27 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 5. CONCLUSIONS 25/27 We tried to synthesize the four articles, taking the best that each had. It was observed that: Adsorption cooling systems are becoming increasingly considered 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 dont 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 Thank you! 26/27

27 CHEMICAL ENGINEER University of Valladolid Ana Celina Gondim Santos Sara Pérez Nieto (Group B - 22) Valladolid, 20 de Octubre de 2011 Chemical Engineering Laboratory II CHILLING ADSORPTION


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