SOLAR REFRIGERATION SYSTEM

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BASIC CONCEPT

Utilisation of solar energy for cooling purpose

In this system ,solar energy is coupled with vapour absorption refrigeration system

VAPOUR ABSORPTION REFRIGERATION SYSTEM

The main parts of basic VARS are: Absorber

Pump Generator Condenser Throttling valve Evaporator

VARS PAIRS

Ammonia Water Water LiBr R22 - dimethyl ether tetraethylene glycol

(DMETEG) R21 - DMETEG R22 - dimethyl formamide (DMF) R12 - dimethyl acetamide R22 - dimethyl acetamide R21 - dimethyl ester

LAYOUT

WORKING

• Ammonia vapour produced in the generator at high pressure from strong solution of NH3 by an external heating source.

• The water vapour carried with ammonia is removed in the rectifier and only dehydrated ammonia gets enters into the condenser

• The cooled NH3 solution is passed through throttle valve and the pressure and temperature of refrigerant are reduced below the temperature to be maintain in the evaporator.

The low temperature refrigerant enters the evaporator and absorbs the required heat from evaporator and leaves the evaporator as saturated vapour

Slightly superheated low pressure NH3 vapour is absorbed by weak solution of NH3 which is sprayed in the absorber

Weak NH3 solution(aqua-ammonia) entering the absorber becomes strong solution after absorbing NH3 vapour and then it is pumped to the generator through heat exchanger

The pump increases the pressure of strong solution to generated pressure.

The strong NH3 solution coming from the absorber absorbs heat from high temperature weak NH3 solution in heat exchanger

The solution in the generator becomes weak as NH3 vapour comes out of it

The weak high temperature ammonia solution from the generator is passed to the heat exchanger from throttle valve

The pressure of the liquid is reduced to absorber pressure by the throttle valve

COMBINING VARS WITH SOLAR ENERGY

The main power consumption of VARS is generator.

So,the power is supplied by solar energy

Hence the amount of energy required to run the generator is calculated for the desired conditions.

CALCULATIONS

Calculations are performed for the ammonia water VARS based on

Condenser PressureEvaporator PressureGenerator TemperatureAbsorber Temperature

Calculations related to heat

Calculations related to radiation

MONTHS EQUIVALENT DAYS

JANUARY 17

FEBRUARY 16

MARCH 16

APRIL 15

MAY 15

JUNE 11

JULY 17

AUGUST 16

SEPTEMBER 15

OCTOBER 15

NOVEMBER 14

DECEMBER 10

EQIVALENT DAYS FOR MONTHS

MONTHS AVG. SUNSHINE HOURS

JANUARY 8.6

FEBRUARY 9.5

MARCH 9.8

APRIL 9.2

MAY 8.4

JUNE 6.5

JULY 4.8

AUGUST 5.3

SEPTEMBER 6.2

OCTOBER 6.5

NOVEMBER 6.9

DECEMBER 7.6

AVERAGE SUNSHINE HOURS FOR MONTHS

TIMELINE

REFERENCES

Refrigeration and air conditioning -

C.P.AroraSolar Energy-Principles of Thermal

Collection and Storage - S.P.

Sukhatme www.ashrae.orgwww.wikipedia.org