Post on 22-Feb-2016
description
Engineer Fahad HasanAssociate
Yousuf Hasan Associates, Consulting engineers
District cooling
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Introduction District Cooling Components Central Plant Distribution Network Consumer System
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Pros&Cons of District Cooling More efficient due to
simultaneous production of cooling and electricity
Long term commitment More beneficial for area with
high population density
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
The Central Plant Selection Criteria
Environmental Impact Efficiency, COP, IPLV Useful life Initial cost Running cost Availability Maintainability
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Chiller efficiency rating Coefficient of performance
kW/TR for Peak Ratings
Integrated Part Load Value
Nonstandard Part Load value
Multiple Chillers
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
RefrigerantsMontreal Protocol
The 1987 Montreal Protocol, and subsequent revisions, established the following timeline for the phase-out of chlorinated fluorocarbons (CFC) and hydrochlorinated fluorocarbons (HCFC)Refrigerant Year Restrictions
CFC-11 1996 Ban on Production
CFC-12 1996 Ban on Production
HCFC-22 2010 Production Freeze and ban on use in new equipment
2020 Ban on Production
HCFC-123 2015 Production Freeze
2020 Ban on use in new equipment
2030 Ban on Production
HFC 134a - No restrictions
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Refrigerants
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Water Chiller ComparisonChiller Type Capacity
Range (tons)FirstCost
Range$/ton
COP Range
IPLV Range
COP
Reciprocating 50-230 200-250 4.2-5.5 4.6-5.8
Screw 70-400 225-275 4.9-5.8 5.4-6.1
Centrifugal 200-2000 180-300 5.8-7.1 6.5-7.9
Single effect Absorption
100-1700 300-450 0.6-0.7 0.63-0.77
Double effect Absorption
100-1700 300-550 0.92-1.2 1.04-1.30
Engine Driven 100-3000 450-600 1.5-1.9 1.8-2.3
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Reciprocating Chiller Typically uses R22 but also
available with R134a and R717
Larger machine with multiple compressors
Lower first cost but higher initial cost
Control is achieved by stepping unload and cycling compressor on/off
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Screw Chiller Positive displacement
machines
Typically uses R22, R134a, R410a & R717
Available with single screw and twin screw compressor
Having fewer moving parts
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Centrifugal Chiller Centrifugal chillers have
highest full load efficiency rating of all the chillers discussed
Uses high pressure refrigerant R22 and R134a & low pressure refrigerant R123
Air cooled & water cooled are available but due to very low COP and very high initial cost air cooled centrifugal chillers are very seldom used.
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Absorption Chiller Absorption chiller can be
single effect or double effect.
Double effect absorption chillers are more efficient than Single effect absorption chiller while Single effect is beneficial where low quality steam or hot water available
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Engine Driven Chiller Uses same vapor
compression cycle as electric chillers except it uses reciprocating engine or gas or –steam driven turbine as prime mover.
Range of refrigerants may be used including R22, R123, R134a and R717
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Combined heat & power (CHP) CHP is simultaneous production of
electricity and heat from single source fuel i.e. natural gas, biogas, biomass, coal, waste heat or oil.
Typically waste heat of gas turbine or engine via waste heat recovery boiler and heat exchangers and utilized to operate absorption chiller
Multi-energy chillers directly fed by flue exhaust of the engines
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Benefits of CHP
STANDARD RANGES OF ACHIEVABLE EFFIENCY
CHP PRIME MOVER
OVERALL EFFIENCY
Steam turbines 80 percent
Diesel Engine 70-80 percent
Natural Gas Engine
70-80 percent
Gas Turbine 70-75 percent
Micro Turbine 65-75 percent
Fuel Cell 65-75 percent
Efficiency Benefit
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Benefits of CHP Reliability Benefit
Combined heat and power (CHP) systems, when properly designed, provide critical power reliability for a variety of businesses and organizations while providing electric and thermal energy to the sites on a continuous basis, resulting in daily operating cost saving.
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Benefits of CHP Environmental Benefit
Combined heat and power (CHP) system offer considerable environmental benefits when compared with purchased electricity and onsite generated heat. By capturing and utilizing heat that would otherwise be wasted from the production of electricity, CHP systems requires less fuel than equivalent separate heat and power systems to produce the same amount of energy.
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Benefits of CHP Economic Benefit
Reduced Energy Costs
Protection of Revenue streams
Hedge against volatile energy prices
“Road to Climate Friendly Chillers - Moving Beyond CFCS and HCFCS” September 30 – October 1, 2010 – Cairo, Egypt
Conclusion Long tern commitment Requires careful design Advance flue gas cleaning Attention must be given to;
environmental impact, COP & IPLV Initial cost & Running cost Useful life & Maintainability
The benefits of CHP and/or thermal storage with district cooling system becomes more prominent as compare to decentralized small cogeneration and/or thermal energy storage plants due too larger size of plant