130301- dx system vs ammonia absorption (2)

DX REFRIGERATION SYSTEMVS. AMMONIA ABSORPTION REFRIGERATION SYSTEMFahim I. SiddiquiCEO/Principal Mechanical EngineerFahim, Nanji & deSouza (Pvt.) LtdConsulting EngineersFAHIM I. SIDDIQUI*

FAHIM I. SIDDIQUI

DX Refrigeration vs. Ammonia Absorption RefrigerationA Case StudyFAHIM I. SIDDIQUI*FND designed the refrigeration plant for an abattoir for Tata Best Foods at Landhi, Karachi within the precincts of Salfi Textile Mills.

The facility includes a PEN (cattle storage) area, slaughtering halls and meat chilling rooms.

The abattoir has a capacity to handle 540 Beef (6 chill rooms) and 3,000 lamb (6 chill rooms) carcasses per day.The carcasses are chilled to 2C in 16 hours and then shipped out. Preferred chill period 24 hours.

FAHIM I. SIDDIQUI

DX Refrigeration vs. Ammonia Absorption RefrigerationFAHIM I. SIDDIQUI*Project initially designed on Central DX Refrigeration system with 4 x 75 TR (one stand by) Compressors. Cost-Rs 73.5 million

Due to budgetary constraints, individual DX Refrigeration system adopted. Cost Rs 64.5 million

Salfi Textile has own power generation plant with Gas Engines

No waste heat recovery

Connected load of 5.8 MW

Maximum demand of 4.3 MW.

FAHIM I. SIDDIQUI

DX Refrigeration vs. Ammonia Absorption RefrigerationFAHIM I. SIDDIQUI*A feasibility study was carried out to produce steam from waste genset heat and operate Ammonia Absorption Refrigeration System.

Steam generated through WHR Boilers calculated at approx. 3.7 TPH.

Total refrigeration using Ammonia Absorption Refrigeration System and 3 TPH steam was calculated at 260 TR.

FAHIM I. SIDDIQUI

DX Refrigeration vs. Ammonia Absorption RefrigerationProject: Abattoir for Tata Best Foods Limited

Location: Landhi, Karachi

Product: Chilled beef & lamb carcasses

Capacity: 540 beef/day (6 chill rooms) & 3000 lambs/ day ( 6 chill rooms)

FAHIM I. SIDDIQUI*

FAHIM I. SIDDIQUI

DX Refrigeration vs. Ammonia Absorption RefrigerationRefrigeration load of the carcasses:

FAHIM I. SIDDIQUI*Beef156 TRLamb-114 TRTotal270 TR (Connected)215 TR (Max. Demand)

FAHIM I. SIDDIQUI

DX Refrigeration vs. Ammonia Absorption RefrigerationRefrigeration System: Individual air-cooled condensing units with DX Evaporators ( Refrigerant 404A)

No. of Condensing Units: 30

Refrigeration capacity: 270 TR

FAHIM I. SIDDIQUI*

FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUI*

FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUI*View of chill room lobby

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FAHIM I. SIDDIQUI*View inside the chill roomTemperature controllers

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FAHIM I. SIDDIQUI*

FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUI3rd Option studied was ammonia refrigeration system using steam produced from WHR boilers on the gensets.

Use Ammonia Absorption Refrigeration Plant and produce low temperature refrigeration at -10C.

Ammonia absorption chiller operates on steam at 4 bars.

Brine produced by the chillers at -10C is pumped to fan coil units in the storage areas.

*Ammonia Absorption Refrigeration

FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUIOldest known refrigeration technology invented in 19th century.Overshadowed by electric operated vapor compression technology due to:

development of CFC refrigerants,cheap availability of electric power, low initial cost due to mass production and simple controls.

Applications primarily limited to large scale plants:

PetrochemicalFertilizerFood Processing Industry.*Ammonia Absorption Refrigeration

FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUIAdvantages of Ammonia Absorption Refrigeration

Potential for waste heat utilization Low temperature range (+5C to -60C) Ammonia is an environment friendly refrigerant Readily available No specialized materials requiredLow maintenance costNo specialist required for operation & maintenanceFully automatic operation of the plant


FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUIAdvantages of Ammonia Absorption Refrigeration

Excellent part load behavior-automatically modulatingSimple back-up of all moving components possibleLong life-more than 25 to 30 yearsOnly small electricity consumptionEquipment produces no noise other than pumpsNo oil required in the systemIf waste heat is available, running costs are very low.Plant rooms not necessary- chillers are designed for outdoor installationSteam can be produced by alternate fuels


FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUIAmmonia, as refrigerant and water, as absorbent, has following advantages:

High affinity High stability Moderate operating pressure. No vacuum up to -30C Absence of solid phase Non-corrosive to carbon steel Zero ozone depletion potential


FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUIDisadvantages of Ammonia Refrigeration Plant

More complex refrigeration system Capital cost higher than mechanical vapor compression plant More space requiredHigh grade heat requiredPerception that it is out-dated technology


FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUI*Ammonia Absorption Refrigeration

FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUIApplication Range Single stage heat source temperature from 95C to 180C,evaporation temperature from -5C to 40C,30C to 35C cooling water for absorber and de-sorber,for temperatures lower than -40C (up to 60C), chilled water at 10-15C is preferred coolant.*Ammonia Absorption Refrigeration

FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUITwo refrigeration options are possible

Option-1 To directly pump the liquid ammonia into the cold storage using a liquid overfeed system.


FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUIOption-2:To run a separate glycol circuit which is cooled down to minus 10C at the AARP.


FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUI*Ammonia Absorption Refrigeration

FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUI*Central Rack Refrigeration System: (life 20 years)Cost of Central Refrigeration System =Rs. 73,500,000/-Power Consumption per day = 2,160 kWhOperating Cost =Rs. 21,605 (1kWh = Rs.10/-)Individual Units for Each Chill Refrigeration System: (life 10 years)Cost of Individual Units for Each Chill =Rs. 64,500,000/-Power Consumption per day = 2,996 kWhOperating Cost =Rs. 29,964 (1kWh = Rs.10/-)

Operational Saving per year @ 200 days =Rs. 1,671,000/Year

Difference of Central Rack System & Individual Units =Rs 9,000,000Simple payback period =5.4YearsFinancials

FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUI*Ammonia Absorption Refrigeration System: (life 20 years)Cost of Central Refrigeration + WHR System =Rs 85,000,000/=Power Consumption per day = 900 kWhWater Consumption per day=380 Gals/dayOperating Cost =Rs. 9200/-Central Rack Refrigeration System: (life 18 years)Cost of Central Refrigeration System =Rs. 73,500,000/-Power Consumption per day =2,160 kWhOperating Cost =Rs. 21,605 (1kWh = Rs.10/-)

Operational Saving per year =Rs. 2,480,000/Year

Difference of Central Rack System & Individual Units for Each Chiller Refrigeration System =Rs 11,500,000Simple payback period =4.6 YearsFinancials

FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUI*Ammonia Absorption Refrigeration System: (life 20 years)Cost of Central Refrigeration + WHR System =Rs 85,000,000/=Power Consumption per day = 900 kWhWater Consumption per day=380 Gals/dayOperating Cost =Rs. 9200/-Individual Units for Each Chill Refrigeration System: (life 10 years)Cost of Individual Units for Each Chill =Rs. 64,500,000/-Power Consumption per day =2,996 kWhOperating Cost =Rs. 29,964 (1kWh = Rs.10/-)

Operational Saving per year =Rs. 4,150,000/Year

Difference of Ammonia system & Individual Units =Rs 20,500,000Simple payback period =4.9 YearsFinancials

FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUIConclusion

great potential to offer economical and innovative solutions

Appropriate application engineering is a key to success

can provide a major boost to food processing, food storage and food preservation.


FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUIReferences:Literature of Transparent Energy Systems Pvt. Ltd.Erickson, Extending the Boundaries of Ammonia Absorption Chillers; ASHRAE Journal, April 2007AARP Article by Gordon Brothers Industries Private LimitedColibri-Reliability of AARP in Chemical & Food Industries


FAHIM I. SIDDIQUI

FAHIM I. SIDDIQUIThank You& Questions Please

FAHIM I. SIDDIQUI

130301- dx system vs ammonia absorption (2)

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