Huge amount of energy is consumed by a typical telecommunication base station in order to keep the indoor climate temperature low enough to avoid any damage to IT/electronic equipment. By increasing the number telecommunication base stations applying more energy efficient cooling strategies are urgently needed. Free cooling either in direct approach (e.g. extracting fresh air), or indirect approach (e.g. thermosiphon or air to air heat exchanger) is a well-proven strategy to reduce the total power consumption for cooling telecommunication base stations. This presentatioin proposes a hybrid cooling system, which is an integrated vapour compression unit with a thermosiphon unit in a single frame. In such a hybrid system the indoor air circulates through a closed loop with minimal interaction with the outdoor air.

1. Powering the Software Defined Network
A Hybrid Cooling System for
Telecommunication Base Stations
Ehsan B. Haghighi
ehsanbh1@gmail.com
Thermal Designer

2. – 2 –
Contents
• Introduction
• Different Closed Systems
• Hybrid System
• Energy and Controlling Model
• Case Studies and Results
• Conclusion

3. – 3 –

4. – 4 –

5. – 5 –

6. – 6 –
Introduction
• Cooling traditionally counted for 25-50% of
the total energy consumption in a typical base
station.

7. – 7 –

8. – 8 –
Vapour Compression System

9. – 9 –
Thermosiphon system

10. – 10 –
Pump-driven Loop System

11. – 11 –
Hybrid System

12. – 12 –
Previous Studies
Air Conditioning
Thermosiphon

13. – 13 –
Energy Model
INFSOLENVITCOOL QQQQQ 

14. – 14 –
Controlling Model
If ΔT ≤ 5 °C=> AC
If 5 °C < ΔT ≤ ΔTTS => DU
If ΔT > ΔTTS => TS

15. – 15 –
Controlling Model

16. – 16 –
Case Studies
• A typical BTS with L=4 m, W=3 m, and H=2.8 m
• QIT = 4.4 kW (on average)
• UEnv = 1 W/m2K
• Copenhagen (Denmark), San Francisco (USA), Shanghai (China) and
Dubai (UAE)
• Weather data: ASHRAE handbook

17. – 17 –
Copenhagen, Denmark

18. – 18 –
Copenhagen, Denmark (month June)

19. – 19 –
San Francisco, USA

20. – 20 –
Shanghai, China

21. – 21 –
Dubai, UAE

22. – 22 –
Copenhagen, Denmark

23. – 23 –
San Francisco, USA

24. – 24 –
Shanghai, China

25. – 25 –
Dubai, UAE

26. – 26 –
Conclusion
• A hybrid cooling system including an air
conditioner and a thermosiphon with individual
loops is suggested to reduce total energy
consumption for a typical BTS
• This system can be operated in three modes: air
conditioning, thermosiphon, and dual
• The potential of saving energy is remarkable and
by increasing the set point temperature the share
of air conditioning mode is reduced while the
share of thermosiphon is increased