Cooling Systems - Chiller Technologies
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Transcript of Cooling Systems - Chiller Technologies
Cooling System – Chiller TechnologiesBy Husain Baqer – Engineering (Tahleeq)
Outside Design Conditions
Dry Bulb 46
Wet Bulb 30.9
Based on the heat load, the chilled water temperatures shall be as follows:
Chilled Water Temperatures
Leaving Temperature 5.5
Return Temperature 14.5
Design Criteria
The selected Chiller System shall satisfy the Design Criteria.
Husain Baqer – Engineering
What do we want from an air-conditioning system?
Production of chiller water
Durability
Reliability
Efficiency
Controllability
Power
Maintenance
Network
Allocation of Space
Initial cost
Equipment (Accessories)
Husain Baqer – Engineering
What do we want from a Chiller System?
Husain Baqer – Engineering
Main Types of Chiller Systems1) Air-Cooled Chiller
Condenser
Fan
Evaporator
Compressor
Expansion Valve
What do we want from a Chiller System?
Husain Baqer – Engineering
Main Types of Chiller Systems1) Air-Cooled Chiller
Air cooled chillers
Primary pumpCHWR CHWS
Main Types of Chiller Systems
2) Water-Cooled Chiller
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Main Types of Chiller Systems
3) Absorption Chiller
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1) Air-Cooled VS Water-Cooled Chillers (Pros and Cons)
Husain Baqer – Engineering
Air-Cooled Water-Cooled• Lower installation cost• Less maintenance (depending on
application)• Cooling tower not needed• Condenser pump not required• Require less space
• Usually have a longer life• Higher efficiency• Indoor placement • Larger tonnage capabilities • Refrigeration containment• LEED points
• Generally less efficient• Life span is not as long• Noisy• No LEED points
• Additional maintenance costs• Water treatment cost• Mechanical room needed• Large consumption of water• Require larger space• 3 storey CUC in lieu of 2
Central Utility Complex-Chillers Layout (Original Design)
Air-Cooled Chillers(on the roof)
24 Air-cooled chillers capacity 435 TR.
Husain Baqer – Engineering
Husain Baqer – Engineering
1A) Closed Loop Dry Cooling System (Similar to BIA current cooling system):
Water-Cooled Chiller Types
• Is similar to the radiator in your car.• The system uses an air-cooled fluid cooler to transfer
the heat from the closed-loop coolant fluid pumped through rows of finned tubes that have ambient air blown/drawn across them
Description
Basic Components
• Fluid Cooler (Contains air-to-liquid heat exchanger with the fan(s).
• Pump• Control Skid• Coolant• Piping
Strengths
Very simple and relatively easy to install.
Energy requirement are relatively low and it’s easily controlled.
Maintenance is normally low requiring and periodic inspection, lubrication, and testing of the fluid.
Weaknesses
Dependent on the atmospheric dry bulb temperature.
1A) Closed Loop Dry Cooling System
Husain Baqer – Engineering
The fluid cooler must be placed in a location that is not affected by the prevailing winds, not too close to a building that will allow the warm exhaust air from the fluid cooler to be recirculated back to the fluid cooler, and finally not in a location that has heavy concentration of dust, dirt, leaves or seeds.
Husain Baqer – Engineering
1A) Closed Loop Dry Cooling System
Requirements:
• The system requires free clear air to work efficiently. Why?
same as the closed-loop dry system but adds a supplemental fluid cooler.
This system is typically used in a location that has too high temperature of a dry bulb in the summer to provide the proper coolant temperature to the load.
With an added liquid-to-liquid trim cooler the customer can use a water source to trim the temperature to the desired set point.
Many times closed-loop dry system with a trim cooler are used to reduce the reliance on city water as a coolant.
Husain Baqer – Engineering
1B) Closed-loop Dry System with Trim Cooling
Description:
• Uses the design Wet Bulb (i.e. 30.9) as the basis of the outlet temperature of the cooling water.
• During the evaporation, the remaining water is cooled to as close as 7F or higher above the wet bulb temperature
• The evaporated water is replaced with some type of make-up water system like a float valve
Husain Baqer – Engineering
2A) Open-loop Evaporative Cooling System
Description
Components• Chiller (Evaporator & Condenser)• Condenser Pump• Cooling Tower• Piping
Strengths
Equipment is typically inexpensive
Simple to employ in warmer climates
Maintenance is normally low requiring and periodic inspection, lubrication, and testing of the fluid.
2A) Open-loop Evaporative Cooling System
Husain Baqer – Engineering
RequirementsA drain will be required for blow-down of the water to
keep the conductivity in check from the constant evaporating and concentrating of the dissolved solids.
Make-up water is continually required from external source such as city water or treated well water, etc. Biological control of bacteria, slime, and mold are major concerns for proper operation of an open evaporative tower system.
2A) Open-loop Evaporative Cooling System
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2A) Open-loop Evaporative Cooling System (Highlights)
Husain Baqer – Engineering
• Typical open loop cooling towers have been called “air scrubbers,” because airborne dust and other contaminants inevitably end up in the process water loop.
• In addition, they also suffer from algae, bacterial/legionella, and microbiological build-up, as well as scale accumulation
• This results in the need for constant testing of the water and injection of replacement chemicals.
To achieve one ton of cooling, a tower must evaporate around 0.03 gallon (3.8 Liter) of process water each minute.
The following example of evaporative loss is based on 8,760 operating hours per year (24 hours per day, 365 days per year) with tower operating at full capacity:
2A) Open-loop Evaporative Cooling System
100 Ton Tower 3 GPM 1,576,800 GPY (5,968,837 LPY)
Highlights
Husain Baqer – Engineering
Is a hybrid system with an open tower and a closed-loop heat exchanger built into the tower. The tower water stays outside in the tower and does not circulate through the coolant
piping. The coolant piping is a closed loop, with a glycol/water solution flowing from the tower to
the load and back
Husain Baqer – Engineering
2B) Closed-loop Evaporative Cooling System
Description:
Refrigerant vapor in
Refrigerant liquid out
Strengths
it can deliver closed loop coolant to the load at approximately 7 to 10 F above the wet bulb temperature
The closed-loop coolant remains free of contaminates and allows the equipment heat exchanger and piping to remain clean
Any contaminates from the atmosphere will stay outside with the tower
Fewer water treatment chemicals will be used because they are only treating the open water in the tower and not the coolant in the piping and system heat exchangers
2B) Closed-loop Evaporative Cooling System
Husain Baqer – Engineering
New Technology (Eco-friendly, closed-loop dry-cooling system
Husain Baqer – Engineering
• Eco-friendly, closed-loop, dry-cooling system. This intelligent process cooling system provides economic and environmental advantages that are particularly important to industry today.
• These closed-loop systems are designed to dramatically reduce water use and keep water clean while minimizing costly chemicals.
Description
Components
• Fluid Cooler (Contains air-to-liquid heat exchanger with the fan(s).
• Pump• Control Skid• Coolant• Piping
Closed-loop design ensures that the process water is never exposed to outside elements and never disposed of into ground water.
Water returning from a process is pumped into a heat exchanger and cooled with ambient air, providing clean water at the right temperature year-round.
Intelligent control systems maintain the desired water temperatures, even during extreme hot and cold weather conditions.
Eco-friendly, closed-loop dry-cooling system
Husain Baqer – Engineering
Highlights
• closed-loop systems are designed to dramatically reduce water use and keep water clean while minimizing costly chemicals.
• these systems save up to 95 percent of water consumption typically associated with conventional tower/central chiller systems.
• In the quest for greater efficiency, sustainability and competitiveness, such potential results should not be overlooked by any processor.
Conclusion
Energy Saving Cost Effective Efficient Sustainable Adaptable
Husain Baqer – Engineering
Questions and Answers
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