heat pipe heat exchangers - hexag pipe heat exchangers competitive advantages for heat pipe systems...
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Heat Pipe Heat Exchangers
Dr Amir Amini
Group Heat Transfer Solution
May 2013
Heat pipe comprises : Tube filled with a working fluid, Wick Structures : Sintered, Groove and Mesh Using the latent capacity of the fluid, we can transfer large amounts of heat very rapidly from a hot point to a cold point on the tube wall. Convective heat transfer is much faster than heat transfer due to conduction
Heat in
Heat in
Heat out
Heat out
Condenser
Evaporator
Phase change
Vacuum pipe (container)
Partition
vapour
Condensate
Working fluid
Adiabatic section
The prime purpose of the wick is to generate capillary pressure to transport the working fluid from the condenser to the evaporator
Heat Pipe Basic Theory – How It Works
Up to
1000C e.g.
120C
From
-30C
Up to
350C
Primary can be hot exhaust, air,
liquid, solid surface
Secondary can be a gas, water,
thermal oil, glycol, R245fa and various others
Pipe materials chosen according
performance requirement of
fluid types and temperatures:
carbon steel, stainless steel,
aluminium, copper, etc.
Working fluid chosen according to temperatures involved - water, ammonia, acetone, Dowtherm, etc
-300
0
300
600
900
1200
1500
1800
2100
2400
Melting point , Deg.C
Boiling point Deg.C
From Deg.C
To Deg C
Heat Pipe Basic Theory – Advantages Multiple Redundancy
Each pipe operates independently so unit is
not vulnerable to a single pipe failure
• This prevents cross contamination
each heat pipe acts as an additional
buffer between the two fluids
Low Fouling
Use of smooth pipes allows exchangers
to be used in high particulate or oily
applications
Ease of Cleaning & Maintenance
Can be maintained in situ (no uninstall)
Manual/automated cleaning systems
Isothermal Operation – no hot or cold spots
Eliminates cold corners and condensation
Allows greater energy recovery
Better longevity for thermal oil
Robust Materials and Long Life
Design allows pipes to freely expand and
contract, thus no thermal stress on
structure
Thick pipe walls resist erosion/corrosion
Intermediate Pipe Working
Temperature
Allows higher exhaust temperature
limits on some applications
Suitable for high SO2 fuels
Low Pressure Drop
Low parasitic load means less capital
and running cost on fans and greater
energy recovery possibilities
Reactivity
Fast reaction time, offers different
control options and suitable for sensitive
apparatus: does not require preheating
More efficient – can be smaller and/or
lighter than conventional exchangers
Highly Scalable, Customisable & Configurable
Modular design allows on site assembly
Can be designed for future expansion,
to meet specific application or
operational needs
Heat Pipe Basic Theory – Heat Pipe Types
6
Standard Finned Hybrid
S-shape
Pulsating
Heat Exchangers
Heat Pipes Flat Panel
Heat Pipe Heat Exchangers
General Heat Exchanger
Diagram
Heat Pipe Heat Exchangers
Gas / Liquid heat exchanger diagram
Horizontal layout – Cross flow
Heat Pipe Heat Exchangers
Gas / Liquid heat exchanger diagram
Vertical layout – Through flow
Heat Pipe Heat Exchangers
Gas / Steam heat exchanger diagram
Horizontal layout – Cross flow
Heat Pipe Heat Exchangers
Gas / Air heat exchanger diagram
Horizontal layout – Cross flow
Heat Pipe Heat Exchangers
Gas / Air heat exchanger diagram
Vertical layout - Through flow
Heat Pipe Heat Exchangers
Heat exchanger details
Heat Pipe Heat Exchangers
Competitive advantages for heat pipe systems
Superior Reliability
• Multiple Redundancy
Each heat pipe operates independently; the unit can work in the event of
damage to individual heat pipe
• Isothermal operation
A unique feature of heat pipes is their Isothermal operation. This eliminates
cold corners where condensation may occur and is often the cause of
failure in conventional heat recovery equipment.
Superior Performance
• Low pressure drop
A low pressure drop can delivered relative to conventional heat recovery
equipment and subsequent decrease in electric power consumption
• Higher Recovery
The Isothermal operation of the pipes allows more heat to be extracted from
the primary flow whilst still avoiding problematic condensation in the unit.
• Lower shut-down period
Easy to clean unit through dedicated access points, and modular replacing.
Heat Pipe Heat Exchangers System
Systems - Hot Water production
Safety system:
Temperature switch
Pressure safety valve
Differential pressure switch
Temperature transmitters
Accessories:
Temperature indicator/transmitters
Pressure gauge
Manual valve for vent/drain.
Differential pressure transmitter
Electrical Cabinet :
Junction box
Electronic control board for security
management
Heat Pipe Heat Exchangers System
Systems – Steam generation (bespoke unit)