1. CAPRI Cables Private Limited
Manufacturers of:
HEAT PIPE
based
Thermal Devices

2. The Company
Has a full fledged manufacturing set-up to produce 130,000 Nos. of Heat pipes per annum. and is Located in the outskirts of Hyderabad.
Project started in Commercialization achieved in 2007.
Infrastructure expansion underway - to be completed by Dec’11.
From a turnover of 4Cr in the previous financial year, the company is set to achieve a turnover of 9Cr in the current financial year.

3. Products
CAPRI has developed and manufactures following products based on Heat pipe technology:
Heat pipe based heat sinks (forced & natural cooled) in 10W to 5kW capacity.
Heat pipe stacks for heat recovery and de-humidification.
Heat pipe based heat exchangers as Panel & Cabinet coolers

4. What is a Heat Pipe ?
A heat pipe is an extremely efficient conductor of heat. It comprises two basic components :
1) - A sealed container
2) - A working fluid
By using the latent capacity of the fluid the heat pipe can transfer large amounts of heat, very quickly.

5. Basic principle of operation
A simple heat pipe comprises a hollow tube partly filled with a working fluid
Heat
out
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.
Within the heat pipe, the fluid will be part vapour, part liquid and at a uniform temperature.
If the temperature of the top of the container wall falls below that of the fluid, the fluid vapour will tend to condense at this point and the liquid will then fall to the bottom of the tube where it will evaporate again. This process will continue until the temperature of the container is the same as that of the fluid. In this way, heat will be transferred very rapidly to the cold end of the container.
The heat pipe can operate across a wide range of temperatures as the pressure within the container will vary with changes in the fluid temperature, so continuously modifying the boiling point of the fluid.
Heat in

6. Basic principle of operation . . . . .

7. Summary of characteristics
Heat is transferred by latent means giving a heat transfer rate of around 1000 times that of a solid copper rod
Vaporisation and condensation take place at the same temperature allowing high heat transfer at low temperature differences
Heat pipes without wicks (Thermosyphons) rely on gravity to return the condensed liquid.

8. Heat Pipe Heatsinks
Applying the principle of heat pipes to heat sinks, a far superior dissipation of heat can be achieved.
CAPRI manufactures following Heat Pipe based heatsinks.
Natural Convection – in range of 10W to 4.5kW and,
Forced Convection – in range of 100W to 5kW.
The Perkins tube was developed around the turn of the century and several patents were granted. The commonest uses were in boilers and baking ovens.
The space programme saw a huge investment in the wick heat pipe, primarily as a temperature stabilising device.
While the first patent for an extended surface, air to air, heat exchanger was granted in 1929, it was not until the energy crisis that there use became more prevalent.
The ability of the heat pipe to transfer heat at low temperature differences makes it ideal for this application.
4kW FC Heat sink for Railway locomotives
1kW FC Heat sink for BHEL

9. Characteristics of Heat pipe heatsinks
High thermal conductance - higher wattage removed.
Capability to control thermal flux.
20 to 40% reduction in weight and volume.
Very long life (>10-20 years).
Cost comparable to conventional extruded heat sinks.
No maintenance – No moving parts.
No restriction on orientation of heat sink.
Comparison of conventional sinks with Heatpipe heatsinks

10. Heat pipes & Heat recovery
For heat transfer between supply & Exhaust air
Best suitable when high volumes of air is involved and when there is large temp difference between exhaust & supply air
Heat pipe stack is inserted in duct in either horizontal or vertical orientation in a counter flowing air stream

11. Heat pipes & Heat recovery. . . . .
Requires no energy to run
No maintenance
No cross contamination
Can be sized to suit the ductwork or AHU
Small footprint
Easy condensation removal
Significant Energy Savings.

12. Dehumidifying with coils
Generally the air is overcooled
11°C
Drier, overcooled
air, 11°C
Comfortable air,
16°C
Warm humid
air, 28°C
When using cooling coils to dehumidify, the air must be cooled until it can no longer hold its original quantity of water vapour.
This usually requires that it is cooled down below what would be considered a comfortable supply temperature and it becomes necessary to reheat the air before supplying to the room.
Energy is therefore being used to cool the air and condense the water vapour and also to reheat the air after cooling.
Condensation

13. Adding a Heat Pipe
The heat pipe improves the efficiency of the system.
16°C
By positioning a heat pipe such that the evaporator end is held within the warm incoming air and the condenser end is held within the cooled air, we can remove some of the sensible heat from the air and bypass this around the cooling coil before putting it back into the airstream prior to the reheat coil.
The heat pipe will then reduce the cooling load and the reheat load.
28°C
23°C
11°C

14. Heat Pipe In Practice 16 / 12.9oC 11 / 10.8oC 23 / 18.3oC 28 / 20oC
Airflow

15. Summary Requires no energy to run, “driven” by the cooling coil
Nett energy savings of around 33% compared to standard cooling and reheat
Lower cooling load = smaller chiller/compressor
Simple to specify
Easy installation
Controlled by the cooling coil.

16. Enclosure cooling
The Heat Pipe transfers unwanted heat generated within the enclosure to the outside environment.
The Heat Pipe is mounted such that warm internal air is circulated over one side and cooler outside air is blown over the other side
Cools without the ingress of external air and its associated contaminants.

17. Cooling an electrical enclosure
Heat Pipe Q
Equipment generating unwanted heat

18. Cooling an electrical enclosure & cabinet
CAPRI Panel coolers are available as:
Slide-in type – for smaller heat loads – up to 500W
Clamp-on type – for medium heat loads – up to 1kW
Air-to-Air Heat exchangers for high heat loads – up to 5kW

19. Conclusion Heat Pipes are extremely efficient heat transfer devices.
Does not require external energy for operation other than the energy it transfers.
A typical, optimised, heat pipe system can be manufactured for required heat loads.
Heat pipe heatsinks, as compared to extruded heatsinks, can provide unmatched characteristics in Thermal resistance, weight and volume for a comparable cost.

20. Conclusion
By installing across supply and exhaust ducts we can recover energy that would otherwise be lost to atmosphere Typical efficiencies - 50 to 60 %
By wrapping The Heat Pipe around a cooling coil we can bypass a certain amount of heat so saving on the cooling load and giving the same amount of free reheat Nett energy savings - around 33 %
Enclosure cooling is possible without any ingress of external contaminants and without any active cooling.

21. THANK YOU