This paper describes a perturb-and-observe (P&O) control aiming to increase the heat exchange between solar heat stored underground and the ambient of a single conditioned room without any heat pump. This P&O control increases or decreases the water flow rate through an underground hosepipe heat exchanger. With this purpose, two power converters were used to activate, respectively, a low power water pump and a fan coil so as to keep the room within the limits of a reference temperature range (between 18 °C and 24 °C). Outside these limits, the P&O control searches for the best heat exchange between the ambient room and the underground soil and, when inside these limits, the water pump and fan coil are turned off. Two identical experimental rooms, referred in this study as “reference” and “test” rooms, had their temperatures measured every 1-min during winter and summer. For comparison purposes, the reference room was left at its natural conditions without any air conditioning. The experimental results show a remarkable improvement in the heat exchange and a considerable reduction in power demand when using the P&O control. As a result, it was obtained an energy saving of approximately 45% in one summer day and 22% in one winter day. It is important to point out that this paper refers, strictly, to the description of a P&O control for heat exchange systems involving solar heat stored underground in a single room.

References

References
1.
Stephens
,
G. L.
,
Li
,
J.
,
Wild
,
M.
,
Clayson
,
C. A.
,
Loeb
,
N.
,
Kato
,
S.
, and
Andrews
,
T.
,
2012
, “
An update on Earth's energy balance in light of the latest global observations
,”
Nature Geoscience
,
5
(
10
), pp.
691
696
.
2.
Farret
,
F. A.
, and
Simões
,
M. G.
,
2006
,
Integration of Alternative Sources of Energy
,
John Wiley & Sons, Inc.
,
Hoboken, NJ
.
3.
Florides
,
G.
, and
Kalogirou
,
S.
,
2005
, “
Annual Ground Temperature Measurements at Various Depths
,”
8th REHVA World Congress
CLIMA
, Lausanne, Switzerland, Oct. 9–12, pp.
1
6
.http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.595.5562&rep=rep1&type=pdf
4.
Sarbu
,
I.
, and
Sebarchievici
,
C.
,
2016
,
Ground-Source Heat Pumps: Fundamentals, Experiments and Applications
,
Elsevier Ltd.
,
Oxford, UK
.
5.
Eicker
,
U.
,
2014
,
Energy Efficient Buildings With Solar and Geothermal Resources
,
Wiley
,
Chichester, UK
.
6.
De Nardin
,
C. R.
,
Fernandes
,
F. T.
,
Longo
,
A.
,
Cunha
,
S.
,
Lima
,
L. P.
,
Farret
,
F. A.
, and
Ferranti
,
E. M.
,
2013
, “
Reduction of Electrical Load for Air Conditioning by Electronically Controlled Geothermal Energy
,”
39th Annual Conference of the IEEE Industrial Electronics Society
(
IECON
), Vienna, Austria, Nov. 10–13, pp.
1848
1853
.
7.
Longo
,
A. J.
,
Farret
,
F. A.
,
Fernandes
,
F. T.
, and
De Nardin
,
C. R.
,
2014
, “
Instrumentation for Surface Geothermal Data Acquisition Aiming at Sustainable Heat Exchangers
,” Industrial Electronics Society, IECON 40th Annual Conference of the
IEEE
, Dallas, TX, Oct. 29–Nov. 1, pp.
2134
2138
.
8.
Bakker
,
M.
,
Zondag
,
H. A.
,
Elswijk
,
M. J.
,
Strootman
,
K. J.
, and
Jong
,
M. J. M.
,
2005
, “
Performance and Costs of a Roof-Sized PV/Thermal Array Combined With a Ground Coupled Heat Pump
,”
Sol. Energy
,
78
(
2
), pp.
331
339
.
9.
Hepbasli
,
A.
, and
Akdemir
,
O.
,
2004
, “
Energy and Exergy Analysis of a Ground Source (Geothermal) Heat Pump System
,”
Energy Convers. Manage.
,
45
(
5
), pp.
737
753
.
10.
Wang
,
H.
, and
Qi
,
C.
,
2008
, “
Performance Study of Underground Thermal Storage in a Solar-Ground Coupled Heat Pump System for Residential Buildings
,”
Energy Build.
,
40
(
7
), pp.
1278
1286
.
11.
Bakirci
,
K.
,
2010
, “
Evaluation of the Performance of a Ground-Source Heat-Pump System With Series GHE (Ground Heat Exchanger) in the Cold Climate Region
,”
Energy
,
35
(
7
), pp.
3088
3096
.
12.
Den Braven
,
K.
, and
Nielson
,
E.
,
1998
, “
Performance Prediction of a Sub-Slab Heat Exchanger for Geothermal Heat Pumps
,”
ASME J. Sol. Energy Eng.
,
120
(
4
), pp.
282
288
.
13.
Dumas
,
A.
,
Trancossi
,
M.
,
Madonia
,
M.
, and
Coppola
,
M.
,
2014
, “
Zero Emission Temporary Habitation: A Passive Container House Acclimatized by Geothermal Water
,”
ASME J. Sol. Energy Eng.
,
136
(
4
), p.
044505
.
14.
Hong
,
Y.
,
Li
,
Y.
, and
Shi
,
J.
,
2009
, “
Geothermal Cooling Solution Research for Outdoor Cabinet
,” Therminic 2009, Leuven, Belgium, pp.
13
16
.
15.
Fernandes
,
F. T.
,
Farret
,
F. A.
,
Longo
,
A. J.
,
de Nardin
,
C. R.
, and
Trapp
,
J. G.
,
2014
, “
PV Efficiency Improvement by Underground Heat Exchanging and Heat Storage
,”
3rd Renewable Power Generation Conference
(
RPG
), Naples, Italy, pp.
1
6
.
16.
ASHRAE
,
2008
,
Handbook of Fundamentals-HVAC Systems and Equipment
,
American Society of Heating, Refrigeration and Air-Conditioning
,
New York
.
17.
Çengel
,
Y. A.
,
2009
,
Heat and Mass Transfer: A Practical Approach
,
3rd ed.
,
McGraw-Hill Education
,
São Paulo, Brazil
.
18.
Longo
,
A. J.
, et al. .,
2014
, “
Instrumentation for Surface Geothermal Data Acquisition Aiming at Sustainable Heat Exchangers
,”
Industrial Electronics Society, 40th Annual Conference of the IEEE
(
IECON
), Dallas, TX, Oct. 29–Nov. 1, pp.
2134
2138
.
You do not currently have access to this content.