latest trends of earth air tunnel heat exchanger

1. EARTH AIR TUNNEL HEAT
EXCHANGER
Submitted to
Dr. Vashimanth Sharma
Submitted by
Sumitabh Tiwari
Sai Goutham Golive
4/22/20151

2. 4/22/20152
Table of Contents
1. Earth Air Tunnel Heat Exchanger coupled with a solar
air heating duct
2. Hybrid Earth Air Tunnel Heat Exchanger
3. Coupled Cooling system with EATHE Exchanger and
Solar Chimney
4. Integrated EATH-Evaporative Cooling system in Hot
and Dry Climate

3. EARTH AIR TUNNEL HEAT EXCHANGER
COUPLED WITH A SOLAR AIR HEATING
DUCT During winter, fresh cold air needs to be warm up before supplying to the
buildings, thus consuming more energy.
 To reduce high grade energy consumption of conventional active heating
systems, earth air tunnel heat exchanger (EATHE)system is used as
alternative.
 Soil temperature, at a depth of about 10 feet or more, stays fairly constant
throughout the year and is approximately equal to the average annual
ambient air temperature.
 The ground can, therefore, be used as a heat source for heating in winter.
 Cold outdoor air is sent into the earth air tunnel heat exchanger. When air
flows in the earth air tunnel, heat is transferred from the earth to the air. As a
result, the air temperature at the outlet of the earth air tunnel heat exchanger
is much higher than that of the ambient. 4/22/20153

4.  The outlet air from the earth air tunnel can be directly used for space heating
if its temperature is high enough.
 Alternatively, the outlet air may be heated further by associating air
conditioning machines and solar air heating duct. Both of the above uses of
earth air tunnel heat exchanger can contribute to reduction in energy
consumption.
 The main advantages of the system are its simplicity, high preheating
potential, low operational and maintenance costs, saving of fossil fuels and
related emissions.
4/22/20154

5. 4/22/20155

6.  The EATHE coupled with a solar air heating duct.
 A U-shaped made of galvanized iron has been used as a solar air heating
duct having top and lateral wall exposed to solar energy.
 Inlet of duct was connected to the outlet pipe of EATHE by means of T-
socket and outlet of duct was also connected at the exit of EATHE pipe at
suitable position.
 The exterior surface of the entire duct was painted black so as to absorb
most of the solar radiation falling on it.
 Dampers were provided at the inlet and exit of solar air heating duct as well
as at the exit of EATHE pipe, to regulate the flow of air.
 Heated air coming out of EATHE pipe can be made to flow through solar air
heating duct for further heating.
4/22/20156

7. HYBRID EARTH AIR TUNNEL HEAT
EXCHANGER
 In the area with very hot weather temperature in summer like Ajmer the
condenser temperature and pressure are increased considerably which
consequently increases the power consumption of the air conditioner due to
the increase in the pressure ratio.
 Increasing condenser temperature also decreases cooling capacity.
 In order to increase the performance of air conditioner in this situation, one of
the best solutions is decreasing the condenser temperature.
 Reducing the condenser temperature reduces the pressure ratio across the
compressor which results into reduction in power consumption.
 The temperature of the condenser tubes can be reduced by cooling them
down with the help of cold air form the EATHE.
4/22/20157

8. 4/22/20158

9.  It comprises of long horizontal cylindrical PVC pipe buried at a depth in a flat
land with dry soil.
 Inlet of EATHE is connected to a single phase, variable speed motorized
blower having maximum speed of 2800 rpm and maximum flow rate of
0.0945 m3/s through a vertical pipe.
 The air from the ambient was forced to move through the earth air pipe
system with the help of blower.
 Velocity of air through the pipe can be varied by changing the speed (rpm) of
the blower with the help of an auto transformer.
 window air conditioner has been used as an active cooling system.
 Air from the EATHE was supplied to the condenser coils of the air conditioner
using well insulated wooden boxes provided on the outer casing of the air
conditioner.
 To reduce peak power, as well as save energy we use hybrid earth air tunnel
heat exchanger. 4/22/20159

10. EATHE Exchanger and Solar
Chimney [2]
4/22/201510

11. Coupled Cooling system with
EATH Exchanger and Solar
Chimney(contd.)
4/22/201511
 The air inside the solar collector is heated up as the
solar radiation strikes the solar collector
 Hence, the hot air migrates from the solar collector to
chimney bottom and rises to the top of the chimney.
 As the system components are tightly connected, the
hot air migration creates a pressure difference and
draws the ambient air through the EAHE.
 As the warm ambient air travels through the EAHE
tube, it cools down due to the heat exchange process
that occurs with the underground soil, providing a
fresh cool air draft to the test facility building.

12. Integrated EATH-Evaporative
Cooling system in Hot and Dry
Climate [1]
4/22/201512

13. Integrated EATHE and cooler(contd.)
4/22/201513

14. Integrated EATHE and cooler(contd.)
4/22/201514

15. REFERENCES
1. Sanjeev Jakhara, Rohit Misrab, Vikas Bansalc, M.S. Soni
Thermal performance investigation of earth air tunnel heat exchanger
coupled with a solar air heating duct for northwestern India.
2. Rohit Misraa, Vikas Bansala, Ghanshyam Das Agarwala, Jyotirmay
Mathur, Tarun Aseri , Thermal performance investigation of hybrid earth air
tunnel heat exchanger
3. Vikas Bansal, Rohit Mishra, Ghanshyam Das Agarwal performance analysis of
integrated earth–air-tunnel-evaporative cooling system in hot and dry climate
Energy and Buildings 47 (2012) 525–532
4.Haorong Li, Yuebin Yu, Fuxin Niu, Michel Shafik, Bing Chen, performance
of a coupled cooling system with earth to air heat exchanger and solar
chimney. Renewable Energy, Volume 62, February 2014, Pages 468-477
4/22/201515