Chilling Adsorption Refrigeration Technologies Research Topics

8/10/2019 Chilling Adsorption Refrigeration Technologies Research Topics

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CHEMICAL ENGINEER

University of Valladolid

Ana Celina Gondim Santos

Sara Prez Nieto

(Group B - 22)

Valladolid, 20 de Octubre de 2011

Chemical Engineering Laboratory II

CHILLING ADSORPTION


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1. INTRODUCTION

Cooling adsorption systems

Advantages:environmentally friendly refrigerants

can recover waste heat at low temperature levelslow operation costs

Evaluation of an Adsorption cooling system:

coefficient of performance (COP)specific cooling power (SCP)

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Oil crisis (1970)Ecological problems (1990)


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2. ADSORPTION REFRIGERATOR

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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


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2.1 System configuration and operation

Figure 2. Photograph of the silica gel-water adsorption chiller.


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2.2 Parameters of work

Parameters that influence in the performance of

the system:Temperature of cooling waterAdsorption temperature

Heating source temperature

Desorption temperature

Cycle time

to get more cooling.

load control toolTand madsorbed(Pconst)

Tand P(madsorbed-const)


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2.3 Key issues for the development of adsorption

systems

The hight cost of production is a drawback foradsorption systems.

To become more commercially attractive, it isnecessary 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.


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systems

The main technologies to enhance the externalheat transfer are related to:

extended surfaces: to increase of the heat

exchange area;

coated adsorbers: to increase the wall heat transfercoefficient;

heat pipe technology: to have a high heat flux densityand less intermediate elements.


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systems

The main technologies to enhance the internalheat transfer are related to:

consolidated adsorbents: because consolidatedadsorbents have lower mass transfer properties than

granular adsorbents, which could lead to very lowadsorption rates.


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3. RESEARCHS

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3.1 Researches tendency

Increase in adsorption cooling systemsperformance compete with electric compressionmachines.

R&D develop performing

Harmonization of the adsorbent with thethermodynamic cycle.

Adsorbents

Components

Sistems


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3. RESEARCHS

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Investigation in adsorbing materials:

silica gel/water

zeolite/water

activated carbon

activated carbon fibres/ammonia

Methanol

R134a


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3. RESEARCHS

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Simulation constant values:

Overall heat transfer coefficient for adsorbentbeds;

Evaporator;

Condenser.


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3. RESEARCHS

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Figura 5. Design drawing and a frontal view of theadsorption chiler test facility.

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3. RESEARCHS

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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.


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3. RESEARCHS

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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 theperformance of an adsorption cooling system.

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3. RESEARCHS

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3.2 Read Researches

Design and performance prediction of a newgeneration adsorption chiller:

(Mathematical model)

Describe the heat and mass transfer process

Adsorbent bedthe composite adsorbentthe metal of the tubethe working fluids

Condensercooling waterthe metal of the tuberefrigerant

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3. RESEARCHS

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3.2 Read Researches

Optimization the operation strategy :

Different temperatures of hot water inlet, cooling waterinlet and chilling water inlet different COP and coolingcapacity;

Conventional chiller;

Composite adsorbenthigher cooling capacityCOP slightly higher

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4 . APLICATIONS

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Jiagsu Province, China

cool a grain depot during hot summers ;

silica-gel adsorption chiller driven by a lowtemperature heat source .

Shanghai Research Institute of Building Science

chillers being used in the air conditioning system of agreen building.

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4 . APLICATIONS

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Figure 6. (a) Shanghai Green Building; (b) equipment room.

(a) (b)

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4 . APLICATIONS

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European project Climasol

examples of buildings that already use solar-poweredsorption air conditioners

System located in the cosmetic company

adsorption chillers powered by hot water in thesummer

Chinese policy for energy exploitation

small power adsorption chillerssuitable for combined cooling, heating and power

systems or heating and power system

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5 . CONCLUSIONS

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We tried to synthesize the four articles, taking the best thateach had. It was observed that:

Adsorption cooling systems are becoming increasinglyconsidered for applications where cooling is required and

low grade heat is available. Adsorption refrigerating machines consist essentially of anevaporator, a condenser, valves, and an adsorber-reactorcontaining a porous medium as adsorbent.

Some parameters influence in the performance of the system

and there are drawbacks in these systems that dont makethem 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.

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Thank you!

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CHEMICAL ENGINEER

University of Valladolid

Ana Celina Gondim Santos

Sara Prez Nieto

(Group B - 22)

Valladolid, 20 de Octubre de 2011

Chemical Engineering Laboratory II

CHILLING ADSORPTION

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Chilling Adsorption Refrigeration Technologies Research Topics

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