adsorption refrigeration system new slide

7/30/2019 Adsorption Refrigeration System New Slide

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Adsorption Refrigeration

System

Presented by

BEJOY S

M-103

TKMCE


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INTRODUCTION

Adsorption refrigeration system uses adsorbent beds to

adsorb and desorb a refrigerant to obtain cooling effect.

Adsorption systems mainly use a natural working fluidwhich have zero ozone depletion potential.

However, the adsorption cooling machines still havesome disadvantages that hinder their wide application.

Inventors propose technologies to improve adsorptionsystem and make it become a realistic alternative.

An assessment is made about current development ofadsorption refrigeration technologies.


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One bed adsorption system by

Monma and Mizotain 2005


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Disadvantages ofOne Bed adsorption system

Intermittent cooling effect

Low Coefficient of Performance (COP)

Long Cycle Time

Low Specific Cooling Power (SCP)


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SILICA GEL/WATER ADSORPTION CHILLER INTEGRATED

IN SOLAR COOLING SYSTEM by Dr. Uli Jakob in 2008

Step 1: Desorpt io n Drying of the adsorbent

The adsorbent is dried by heat input. Water

vapour is set free, flows in the condenser and is liquefied there under heat

emission. When the material is dry, the heat input in the adsorber is stopped andthe upper check valve closes.


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Step 2: Adsorption

water vapour is adsorbed at the surface of

the adsorbent. After a cool down phase the reverse reaction and the evaporation

of the liquid refrigerant starts. The lower check valve to the evaporator opens and

the dry adsorbent aspirates water vapour. In the evaporator, water evaporatesand generates cold.


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Step 3: Return o f con densate

In a final step, the liquid condensate is returned

to the evaporator and the circuit is closed.


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Fig. Internal construction of the adsorption chiller.


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Technical data ACS 08

Cooling Capacity 7.5 kW

Thermal COP 0.56

Electricity Consumption 9 W

Chilled Water Circuit 18/15 C at 2.0 m/h

Heat Rejection Circuit 27/32 C at 3.7 m/h

Heat Supply Circuit 72/67 C at 1.6 m/h


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A Hybrid Solar powered water Heater and Refrigerator

by R.Z. Wang in 2000


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The working principle is just a combination of a solar water heater and adsorption

refrigeration.

Heating of the water tank is started in the morning through vacuum tube type solar

collector. With the increasing of the water temperature, the temperature in theadsorbent bed rises.

When the adsorbent temperature rises up desorption of the water vapour is get

started from the bed at constant pressure. The desorbed vapor is condensed in the

condenser and collected in the receiver.

The liquid flows to the evaporator via an flow rate regulating valve.

A maximum temperature of 80100C could be achieved at the end of the process

hot water in the tank could be drained out and moved into another tank thus hot water

can be used very flexibly.

With the refilling of the water tank with cold water, the temperature of the adsorbent

bed is reduced rapidly and the pressure in the adsorber drops to a value below

evaporation pressure .

Evaporation could happen if the connecting valve is open, Refrigeration will

continue for the whole night until the next morning.


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Rotary thermal regenerative adsorption device

by R.E. Critoph in 2001

A refrigeration/heat-pump system based on a number of

simple tubular adsorption modules.

A single module is comprised of a generator and

a receiver/condenser/evaporator


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Fig 1Rotary thermal regenerative adsorption device


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Fig. 2 Section through the generators.


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Sixteen modules are shown, arranged in a cylindrical shell. All rotateabout the central axis.

Air is blown over the tubes, counterflow to their direction of motion

and exchanging heat with them. The carbon is at its coldest, perhaps 50C and has maximum

concentration at position 1 in fig 2.

As it moves clockwise through the annular duct it is heated by airflowing in the opposite direction.

The carbon is heated it desorbs ammonia which condenses in the

receiver section of the module.The module reaches the end of thedesorption section it is perhaps at 200 C.

A similar process occurs in the adsorbing section, but withevaporation occurring in the receiver, which cools the airstreampassing over it.

All rotate about the central axis typically completing one revolution in

10 min


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Heat recovery adsorption refrigeration cycles by R.Z.

Wang in 2000


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A two beds continuous adsorption refrigeration system with

heat recovery is shown in Fig. 1

When adsorber 1 is cooled and connected to theevaporator to get adsorption refrigeration in the evaporator.

Adsorber 2 is heated and is connected to the condenser to

get heatingdesorptioncondensation.

The condensed refrigerant liquid flows into evaporator via aflow control valve.

The operation phase can be changed, and the go-between

will be a short time heat recovery process in which the two

pumps drive the thermal fluid in the circuit between two

adsorbers. (the connection to the heater and cooler are

blocked during this process).

Heat recovery is important to increase the cycle COP.


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Solar-Powered Rotary Solid Adsorption

Refrigerator by Aiping Zheng Juan Gu in 2004


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The low-pressure refrigerant vapor with low temperature from evaporator is

introduced to the 3/5 area of the nether part of the rotary adsorbent bed by

the gas circulation pump.

it will be adsorbed by the activated carbon fibre, adsorption heat released

from the adsorbing course will be taken away by the refrigerant vapor notadsorbed and then enters the solar energy heater.

The refrigerant vapor will be heated by the solar energy heater and its

temperature will rise gradually, and it will enter the 2/5 area of the upper

part of the rotary adsorbent bed.

The refrigerant will desorbed from the activated carbon fibre when it isheated by the high temperature vapour refrigerant.

the refrigerant is condensed in the condenser by the cooled water.

After being throttled its pressure is reduced, the liquid refrigerant will enters

the evaporator.

In the evaporator, the low-pressure refrigerant liquid will adsorb the heatfrom the cooled medium, and then it will be gasified into refrigerant vapor.

Then the low-pressure low temperature refrigerant vapor will be channeled

into the 3/5 area of the under part of the rotary adsorbing bed by the gas

pump again and the cycle repeats.


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Conclusion

For adsorption refrigeration system, significant

achievements have been obtained on the use of varioustechnologies to reduce the complexity of systemstructure, initial cost, to increase the system operationreliability as well as energy performance.

However, intensive research is still needed to:

i) enhance the amount of recovered thermal energy,without adding complexity into the design and operationof system

ii) optimize the recovered mass rate to achieve thebest effect.

Applied material research could produce new combinedmaterial in order to achieve a higher SCP for adsorptionrefrigeration system.


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adsorption refrigeration system new slide

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