Estudio del comportamiento térmico de los edificios reutilizados. El estudio realizado pretende examinar el comportamiento térmico de este edificio mediante el registro de la temperatura y la humedad relativa en algunos puntos de su interior. Los resultados muestran que en lugar de las duras condiciones climáticas que se dan en el exterior, la temperatura interior se encuentra dentro de los límites de confort. Este estudio demuestra que la reutilización de edificaciones rurales, además de las ventajas económicas y sociales, es un sistema de reducción del consumo energético en el ciclo de vida de la edificación

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Study of the thermal behaviour of a reused rural
building.
Ignacio Cañas1
, Silvia Martin1
and Jose Maria Fuentes1
1
Departamento de Construccion y Vias Rurales.
Escuela Técnica Superior de Ingenieros Agrónomos.
Avda Complutense s/n. 28040 Madrid
ABSTRACT: In this article the thermal behaviour of a reused rural building is analyzed. Spanish rural
areas are suffering the problem of depopulation with the loss of lot of traditional buildings.
The reuse of these buildings is a system for saving the loss of rural heritage that is causing the loss
of regional identities. The particular case studied here is an old building for sheep accommodation,
this type of building was common in the interior areas of Spain due to the agrarian way of life. The
owners bought the building some years ago with the aim of constructing a rural hotel. For the
construction of the new building they followed some criterions based on the bioclimatic design. The
study carried out tries to examine the thermal behaviour of this building by means of registering the
temperature and relative humidity in some points inside it. The results show that instead of the harsh
climatic conditions happening outside, the interior temperature is inside the comfort limits. This study
shows that the reuse of rural buildings, in addition of the economic and social advantages, is a
system of reducing energy consumption in the life cycle of the building.
Conference Topic: 6, Recycled architecture (re-use, upgrading and rehabilitation of buildings)
Keywords: reuse, thermal behaviour
1. INTRODUCTION. 2. BUILDING CHARACTERISTICS.
In Spain there is a great amount of rural buildings
( rural houses, stables, agricultural machinery stores,
dovecotes, …) abandoned from the fifties due to the
rural exodus.
The studied building is placed in a small town called
Covachuelas in the province of Segovia (Castilla y
Leon). The town was uninhabited in the fifties. The
altitude is 1005 m above sea level, and it is 120 km
far away from Madrid (see figure 1).
The reuse of old buildings provide an environmental
advantage because of the reduction in energy use
and building materials compared to a new
construction. The life cycle of reusing an old building
has less steps than constructing a new one. In
addition, the reuse of old buildings has social and
cultural advantages, as maintenance of regional
texture, scale and history, and the preservation of
local identity of traditional architecture.
One of the problems about the reuse of rural buildings
is their remoteness to large population centres and
the poor quality of infrastructure in rural areas. New
leisure alternatives offer the possibility of using again
this type of buildings. Give a new use to abandoned
rural buildings involves the presence of new people
and activities in rural areas, therefore the economy
could be improved.
In this paper the results from the monitoring of a
reused rural building during summer are shown.
The building was an abandoned sheep house that
was turned into a rural hotel. The rehabilitation of the
building was made following bioclimatic criterions.
The aim of this paper is to study the hygro-thermal
conditions inside this building.
Figure 1: Map of location.

2. Plea2004 - The 21
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The area is characterized by a continental climate
with great temperature oscillations. The absolute
maximum temperature in the hottest month is 39º C,
and the absolute minimum temperature in the coldest
month is –15º C. The mean annual precipitation is
470 mm (see figure 2).
Climate in Covachuelas
0
5
10
15
20
25
30
35
January
February
March
April
May
June
July
August
September
October
November
December
T
(ºC)
0
10
20
30
40
50
60
70
P
(mm)
TM
Tm
P
Figure 4: The building after the rehabilitation.
2.1. Rehabilitation characteristics:
- All building materials used in the rehabilitation
works have low environmental impact.
Figure 2: Summary of climatic conditions in
Covachuelas. TM: monthly average of daily maximum
temperature; Tm: monthly average of daily minimum
temperature; P: monthly precipitation. Source:
National Institute of Meteorology. Weather station in
Segovia (1971 – 2000)
- Compressed earth blocks were made from local
soils. The use of this building material has two
advantages: the same colour as that found in
traditional architecture, and good thermal behaviour.
- The insulation was made of natural materials (pure
wool).
- A glazed surface was constructed in a part of the
roof oriented to South with the aim of making better
use of solar radiation in winter (greenhouse effect).
Finally, the glazed surface on the roof was larger
than that calculated in the rehabilitation project due to
several problems with the subvention for the solar
panels.
In the studied area there is plentiful use of earth as a
building material in popular architecture. This material
is very typical of some Spanish regions where the
lack of another building materials joined to the good
quality of their soils make it a suitable material as well
as ecologic.
The old sheep house was a large building constructed
of stone masonry and sun-dried bricks. When the
current owners bought the building, it was almost in
ruins. They wanted to build a rural accommodation.
The rehabilitation process aimed at keeping the
typology of regional traditional architecture as well as
incorporate some building elements from bioclimatic
design.
- The drop of the terrain was used for burying in part
the north façade, so it is less exposed to the
environment and has high thermal inertia like
underground constructions.
- The building uses renewable energy: wind power,
thermal and electric solar energy.
- The plumbing system allows to separate sewage
from washes and also to collect rainwater in a small
pond.
Figure 3: The building before the rehabilitation.
Figure 5: Elevation of the building, showing the
glazed surface on the roof oriented to South.

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3. ENERGY SAVING ON BUILDING
MATERIALS.
As indicated previously, the building materials used in
the rehabilitation works were selected following
environmental criterions. The embodied energy of the
selected materials is low, so the impact derived from
the construction phase is reduced (table 1).
Table 1: Embodied energy in various building
materials. Source: Sinha, 1997.
Material Embodied energy (MJ/kg)
Earth 0,1
Natural cement 3,8
Plaster 3,1
Aluminium 97,2
Local wood 0,72
Foreign wood 5,04
Glass 28,15
Plastic 162
In addition, the reuse of the building by itself involves
a reduction of the environmental impact due to the
elimination of some phases of the construction cycle.
In the studied case, demolition works were not
required and neither land preparation jobs previous to
the construction were done. Therefore, the energy
needed to reuse the abandoned building is less than
that needed in constructing a new building
completely.
The compressed earth block technique has the next
advantages:
- The compressed earth blocks can be made in the
same place where the building will be constructed, by
using local and plentiful material (soil), so the
transport and extraction costs are almost zero.
- The thermal behaviour of compressed earth
blocks is better than other building materials, so they
produce energy saving on insulation as well as indoor
comfort conditions (this subject is analyzed in the rest
of this paper, showing the results from the monitoring)
(table 2).
Table 2: Physical properties of adobe. Source:
Domínguez, 1998.
Property Value
Density 1200 – 1700 kg/m3
Ice resistance Low
Exposure to elements Low
Specific heat 0.85 kJ/kg
Thermal conductivity 0.46 – 0.81 W/mK
Thermal wave dampening
coefficient
(40 cm)
5 – 10 %
Daily gap (Outdoor – indoor
thermal wave)
10 – 12 h
Fire resistance Good
- The elaboration process does not need the use
of heavy machinery or working place, so the energetic
cost is also very low (table 3).
- The economic saving is helped by the low cost of
the soil/earth extracted from the local area.
- This construction system is low technological. It
does not require specialized workers, so it is suitable
for self-construction, therefore it can be another way
of economic saving. In addition, it can solve the
problem of rural depopulation because it can provide
job to rural people.
Table 3: Energy added during the manufacture
process of compressed earth blocks. Source:
Barbeta, 2000.
Concept Quantity Energy Energy/block Energy/kg
Earth 4,2 kg 0,1
MJ/kg
0,42 MJ 0,07
Natural
cement
0,65 kg 3,8
MJ/kg
2,47 MJ 0,42
Plaster 0,35 kg 3,1
MJ/kg
1,08 MJ 0,18
Water 0,87 kg 0 0 0
Energy cost
in
manufacture
0 0 0 0
TOTAL 3,97 MJ/block 0,67 MJ/kg
4. MEASUREMENT SCHEME.
In order to analyze the hygro-thermal behaviour of
this building, the monitoring of indoor and outdoor
conditions was carried out.
The measurement instruments used are:
- Data logger called Hobo H8 HR/Temp (H08-003-
02) for the measuring of temperature and relative
humidity inside the building. Its resolution is 0.4º C for
temperature and its accuracy for relative humidity is
5%.
- Data logger called Hobo Pro HR/Temp (H08-032-
08) for the measuring of the external conditions. Its
resolution is 0.02º C for temperature and its accuracy
for relative humidity is 3%.
- Data logger connected to a pyranometer for the
measuring of the global solar radiation. Its accuracy is
2%.
Inside the building the temperature was recorded in 7
points:
(i) inside the storeroom, which is placed on the
north part of the ground floor
(ii) in the kitchen, placed also in the north part on the
ground floor
(iii) in the hall on the ground floor (*)
(iv) under the glazed surface, on the ground floor
(v) inside a bedroom placed in the north part on the
first floor
(vi) in the corridor on the first floor (*)
(vii) in the south part on the first floor (*)
In the three points marked with asteriks, the relative
humidity was also recorded.
5. RESULTS.
The results from the monitoring carried out from 11 to
27 August, 2003, are showed below. Unfortunately
there have been failures in some instruments and the

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conditions in the north part on the ground floor was
not measured. Temperature comparison
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
08/18/03 08/19/03 08/20/03 08/21/03
ºC
Corridor in first floor North zone in first floor
South zone ground floor Outside
South zone in first floor
Figure 6: Comparison between indoor and outdoor
temperature (18
th
– 21
st
of August, 2003).
5.1. Outside conditions:
The maximum temperature recorded was 38.7º C at
15:00 on August , the 13th
, the minimum was 9.3º C at
7:00 on August, the 27
th
. The mean temperature was
22.9º C with an oscillation of 29.4º C.
The maximum relative humidity registered was 97%,
the minimum was 8% and the average was 48%.
The maximum value of global solar radiation recorded
was 1078 W/m2.
5.2. Indoor conditions:
- Ground floor:
On the ground floor the only recorded data are those
from the south part. This zone are affected by the
large glazed surface on the roof, whose purpose is to
be used as a solar collector during winter time when
the temperature is extremely cold.
The maximum temperature recorded was 28.7º C at
14:00 on August, the 14
th
, the minimum temperature
was 21.2º C at 8:00 on August, the 27th
. The average
temperature was 25.1º C with an oscillation of 7.5º C.
Relative humidity comparison
0.00
20.00
40.00
60.00
80.00
100.00
08/18/03 08/19/03 08/20/03 08/21/03
(%)
First Floor Ground floor Outside
Figure 7: Comparison between indoor and outdoor
relative humidity (18
th
– 21
st
of August, 2003).
The maximum relative humidity was 60%, the
minimum was 21% and the average was 39%.
- First Floor:
On the first floor there are three monitored points: the
corridor, the south zone and the bedroom oriented to
North.
In the corridor the maximum temperature registered
was 30.7º C from 18:30 to 19:30 on 13
th
of August.
The minimum temperature was 19º C at 7:30 on 27th
of August. The average temperature was 25.9º C with
an oscillation of 11.7º C. On the other hand, the
maximum relative humidity was 55%, the minimum
was 24% and the average was 35%.
In the south zone the maximum temperature
registered was 34.9º C at 15:00 on 13
th
of August.
The minimum temperature was 21.7º C. The average
temperature was 26.8º C with an oscillation of 13.2º
C.
In figures 8, 9, 10 and 11the level of cooling / heating
registered (indoor temperature – outdoor
temperature) against outdoor temperature is showed.
As it can be seen in the figures, there is a clear
overheating effect in the corridor and in the south
zone on the first floor. The poor level of natural
cooling is not able to move the points inside the
comfort band (which is around 24º C ±2º C). In the
the corridor most of points showing discomfort due to
overheating are placed between 27ºC and 30ºC. In
the south area there are some cases (10% of
measurements) near 35ºC. In the north zone the
points showing overheating are below 30º C, and
most of them are between 26ºC and 28ºC. In the
ground floor all measurements are below 29ºC, most
of them are between 26ºC and 27ºC (when the
outdoor temperature registered is in 20% of
measurements higher than 30ºC). From this analysis
we assert that the thermal behaviour of the building
can be improved. The indoor conditions registered
are much less extreme than that registered outside,
however in the corridor and the south zone on the first
floor there is an overheating effect.
In the bedroom oriented to North the maximum
temperature registered was 29.9º C from 19:30 to
00:30 on 13
th
of August. The minimum temperature
was 21.7º C at 5:30 on 21
st
of August. The average
temperature was 26.2º C with an oscillation of 8.2º C.
Figures 6 and 7 show the temperature and relative
humidity measurements during 4 days of monitoring
(18
th
– 21
st
of August, 2003).
The places where the maximum temperature is higher
are the corridor and the south area on the first floor, in
addition these two points show the higher
temperature oscillations. The North orientation and
the ground floor have the ability to control the
temperature in lower levels and more constant than
other parts of the building.

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In figure 12 the variation of indoor temperature with
regard to outdoor temperature is studied. The aim of
this analysis is to determine the influence of outdoor
conditions on the indoor ones.
Figure 8: Natural cooling/heating in the corridor on
the first floor.
From the figure the tendency lines where calculated,
where x is the outdoor temperature and y is the
indoor temperature for each point:
- in the south area on the first floor the tendency line
and the corresponding error factor are:
y= 0.3379x + 19.01 R2= 0.7408
- in the bedroom oriented to North on the first floor:
y= 0.0734x + 24.539 R2= 0.0721
The previous ecuations show that the temperature
recorded in the south area on the first floor are more
dependent on the outside temperature than that
measured in the bedroom oriented to North (first
floor). The results proves the effect of orientation as
shock absorber. In our latitudes it is better the north
orientation to achieve comfort conditions in summer.
Figure 9: Natural cooling/heating in the south zone
on the first floor.
Variation of inside temperatures according to
outside temperatures
18.00
20.00
22.00
24.00
26.00
28.00
30.00
32.00
34.00
36.00
0.00 10.00 20.00 30.00 40.00 50.00
T outside (ºC)
T
inside
(ºC) T corridor in first floor
T south area in first floor
T north area in first floor
T ground floor
Figure 12: Variation of inside temperatures according
to outside ones.
Figure 10: Natural cooling/heating in the north zone
on the first floor.
6. CONCLUSIONS.
From the data analysis and despite the lack of
measurements in most zones of ground floor, the next
conclusions were obtained:
- In this reused rural building the conservation of the
existing stone masonry walls joined to the excavation
in the north part of the ground floor below the ground
level, make the hygro-thermal conditions in this floor
comfortable. The measurements in this floor were
taken under the glazed surface. In spite of the
overheating suffered in summer due to the
greenhouse effect, the measurements recorded are
higher than the upper comfort limit only a few time.
- In spite of the existence of a small pond for the
collection of rainwater, whose main function is the
control of the relative humidity, the measurements are
in most cases below the lower relative humidity limit.
- The orientation is an important design element when
constructing a bioclimatic building, the differences
registered in zones with different orientations in the
same floor prove that conclusion.
Figure 11: Natural cooling/heating in the ground floor.

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Therefore, it is possible to dampen the external
thermal wave by means of a good orientation and
high thermal inertia envelope.
The hygro-thermal conditions on first floor could be
improved by keeping the openings on the roof opened
during the night, and by installing shading systems
during the day.
ACKNOWLEDGEMENT
The authors wish to thank the Ministry of Science and
Technology of Spain for funding the Investigation
Project PB8-0720 “Aproximación a una metodología
de reutilización de constructions rurales”.
The plans of the building were made by the architect
Gabi Barbeta, who directed the rehabilitation project.
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