A case study for influence of building thermal insulation on cooling load
and air-conditioning system in the hot and humid regions
Received 20 February 2009
Received in revised form 8 April 2009
Accepted 6 May 2009
Available online 26 May 2009
Reducing cooling load,
Building energy performance
Ensuring the effective thermal insulation in regions, where the cooling requirement of building with
respect to heating requirement is dominant, is very important from the aspect of energy economy. In this
study, the influence of thermal insulation on the building cooling load and the cooling system in case of
air-conditioning by an all-air central air-conditioning system was evaluated for a sample building located
in Adana, based on the results of three different types of insulation (A, B and C-type buildings) according
to the energy efficiency index defined in the Thermal Insulation Regulation used in Turkey. The operating
costs of the air-conditioning system were calculated using cooling bin numbers. Life-cycle cost analysis
was carried out utilizing the present-worth cost method. Results showed that both the initial and the
operating costs of the air-conditioning system were reduced considerably for all three insulation thick-
nesses. However, the optimum results in view of economic measurements were obtained for a C-type
building. The thickness of thermal insulation for the buildings in the southern Turkey should be deter-
mined according to the guidelines for a C-type building.
Air-conditioning system (ACS) is responsible for a significant
part of total energy consumption in building. Capacity of ACS is
determined according to total cooling load of building. Building
cooling loads consist of heat gains through opaque external sur-
faces and fenestration areas of the building and internal heat gains.
Architectural and physical properties of building, such as thermal
mass, structural material and its shape, are the most important
parameters, which influence the space-cooling load. Another
parameter is local climate. As reported in literature, different effec-
tive techniques such as free cooling, natural ventilation, thermal
mass and night cooling can used in order to reduce the cooling
load. Therefore, a significant energy saving (more than 50% as com-
pared to an existing building) can be achieved [1–7]. On the other
hand, thermal insulation is applied for reducing of heat loss or/and
gain in buildings through the envelope. Yearly building cooling
load and the peak cooling demand of building can be reduced sig-
nificantly in the thermally insulated buildings located in hot dry
and hot humid regions [7–13]. Therefore, reducing energy use for
space cooling in buildings is a key measure to energy conservation
and environmental protection. The main objective of this study is
to reveal the influence of the building thermal insulation on the
annual energy consumption of the cooling system in hot and hu-
mid regions, especially in the southern Turkey.
2. Application of thermal insulation in building
In Turkey, the thickness of thermal insulation material that
should be applied to buildings is determined according to Turkish
Standard 825 (TS 825) ‘‘thermal insulation in building” . TS
825 is an application of ‘‘ISO 9164-Thermal insulation calculation
of space heating requirements for residential buildings” in every
respect and basically similar to EN 832-Thermal performance of
buildings calculation of energy use for heating residential buildings.
It is adapted to climatic conditions of Turkey [14,15]. In TS 825, the
thickness of thermal insulation material can be determined accord-
ing to the annual requirement of heating energy of the building
which based on heat losses calculation. Turkey is classified into four
climatic zones considering only heating energy requirement by
using degree-day concept in TS 825. However, in the standard, cool-
ing load of the building is not taken into consideration and the heat
storage capacity of the building envelope is neglected. While heat-
ing is required in a region, cooling is needed in another region of
Turkey. Because Turkey has a wide geographical area and different
climatic regions. Bulut  showed that Turkey should be divided
into five different heating degree-day and three different cooling
degree-day regions. Aktacir and Büyükalaca  emphasized in
result of study that the cooling-degree days for the main provinces
Sanlıurfa (South-eastern Anatolia Region), Antalya (Mediterranean Region), Istanbul (Marmara Region) and Zonguldak (Black Sea Re-
gion) at 22 C base temperature are 933 h, 550 h, 104 h and 6 h,
respectively, although all these cities are listed in the second region
in TS 825. But, these provinces were positioned into the different re-
gions according to their cooling-degree day values by Bulut .
Similarly, Yılmaz  investigated thermal performance of the same
typical residential building in Istanbul and Mardin. Istanbul and
Mardin are considered in the second region in TS 825, however
those are in temperate-humid and hot-dry climatic zones, respec-
tively. The study showed that cooling load in the same building in
Mardin is bigger than that of Istanbul.
It is stated in TS825 that insulation should be applied according
to PrEN ISO 13791 ‘‘Thermal performance of buildings – Internal
temperatures in summer of a room without mechanical cooling –
General criteria and calculation procedures” for cooling if neces-
sary. However, this approach is not followed in Turkey even in
the buildings for which cooling is more important than heating.
Bolattürk  studied the optimum insulation thicknesses for
external walls of buildings using cooling and heating degree-hours
in the warmest regions of Turkey. Results of his study showed that
use of cooling degree-hours is more suitable in these regions.
Ensuring the effective thermal insulation in regions, where the
cooling requirement of building with respect to heating require-
ment is dominant, is very important from the aspect of energy
economy. In some provinces of Turkey, such as the South-eastern
Anatolia Region and in the coastal provinces located in the Medi-
terranean and Aegean Regions, which have a hot dry or hot humid
climate and a longer cooling season (about 7 month) than heating
season [17,19], the thermal insulation applied considering only
heating energy consumption using degree-day concept may be
insufficient during summer. Parallel to the economic growth of
the country, package air-conditioners are used more and more fre-
quently for thermal comfort in these regions. This can be seen
clearly from Table 1 that shows the number of the split type and
variable refrigerant flow (VRF) type package air-conditioners sold
in Turkey during 1998–2006 .
In some countries, special procedures are followed for the re-
gions having hot and longer summers and warm winters. The local
energy conservation design standards used for residential buildings
in Shanqai of China and the Single Family Housing Programs used in
Colorado only at locations exceeding 600 cooling degree-day at
18.3 C base temperature may be given as examples [21,22] to these
procedures. Furthermore, AS2627.1–1993, ‘‘Thermal insulation of
roof/ceilings and walls in dwellings” is uniquely and specifically
Australian in that it deals with heating and cooling aspects with
equal emphasis. It nominates the optimum amount of thermal
resistance for 760 climate locations throughout Australia .
3. Sample building and thermal insulation
3.1. Building characteristics
In this study, an office center with three floors and 27 offices lo-
cated in Adana, Turkey (36 590 latitude, 35 180 longitude and
20 m altitude; in Mediterranean region) was considered. Adana
has hot and humid summer and warm winter, and is in the first de-
gree-day region according to TS 825. To benefit from solar energy
and light, typical window areas of building in Mediterranean re-
gion are generally designed larger than that of the standard. Total
gross area of the building is 1628 m2 and total fenestration area
and external wall surface area are 299 m2 and 668 m2
Therefore, in this study, fenestration area is 45% of the external
surface area of the building. Two people in each office and three
laborers in each floor of the office center work between 09:00
and 20:00 h.
The height of each floor of the office center is 3 m. Fig. 1 shows
the architectural plan of the ground floor of the sample building.
Features of the opaque construction materials of the sample build-
ing are given in detail in Table 2.
3.2. Calculation of insulation thickness
In this study, it was assumed that thermal insulation with three
different thicknesses is applied to opaque external components of
the sample building (Building A, Building B and Building C). Thick-
ness of the thermal insulation for each building was determined so
that Buildings A, B and C are, respectively type A, B and C buildings
according to the building classes defined in thermal insulation
regulation . In the regulation, the buildings are classified as
‘‘A-type”, ‘‘B-type” or ‘‘C-type” according to the ratio of the annual
energy requirement of building Q (kW h/m2
) to the maximum al-
lowed annual energy requirement of building QI (kW h/m2). Table
3 presents classification of the energy efficiency index of the build-
ings according to the regulation. If Q/QI is higher than 0.99, insula-
tion should be applied to reduce annual energy required for
The thermal insulation thickness (L) and the overall heat trans-
fer coefficient (U) of opaque constructions of the sample building
given in Table 4 were obtained by equalizing Q/QI to 0.79, 0.89
and 0.99 for Buildings A, B and C, respectively. The overall heat
transfer coefficient of fenestration for all cases was 3 W/m2 K.
In this study, architectural and physical properties of building
are the same for all calculations, but not insulation thickness as gi-
3.3. Thermal insulation cost
The extruded polystyrene foam with thermal conductivity of
0.031 W/m K was used as thermal insulation material. The amount
and cost of the thermal insulation material required for the build-
ing components for all three types of buildings considered in this
study are given in Table 5.
4. Air-conditioning system
4.1. System design
All-air systems have been widely used in air-conditioning appli-
cations. The sample building is conditioned by an all-air central air
handling unit (AHU) as shown in Fig. 2. As can be seen from the fig-
ure, the air-conditioning system consists of AHU, duct, air-cooled
chiller system and control units. The indoor air conditions are
26 C dry bulb temperature and 50% relative humidity. In the sys-
tem, air is supplied to the air-conditioned volumes by mixing the
minimum amount of the outdoor air (fresh) required for ventila-
tion with the return air. Two main air distribution systems associ-
ated with all-air air-conditioning systems are constant-air-volume
(CAV) and variable-air-volume systems (VAV). CAV systems have
been used since the introduction of air-conditioning while VAV
systems have been utilized since the 1960s. Energy saving is one
of primary reasons that VAV systems are very popular design
choices today for some commercial buildings and many industrial
In this study, both CAV and VAV air distribution systems were
investigated. In the VAV system, the mixing air supplied to con-
ditioned space is constant at a temperature of 15 C, but the mix-
ing air flow rate is varied by the combined action of the closing
of the zonal VAV box dampers and the fan speed controller to
meet the building cooling load. In the CAV system, supply air
flow rate is constant, but supply air temperature (minimum
15 C) is varied to remove the heat gain from inside of condi-
tioned space. Outdoor air requirement of the sample building
was obtained to be 1596 m3/h for minimum ventilation level in
accordance with ASHRAE Standard 62 ventilation rate procedure.
Building cooling load was calculated according to the Radiant
Time Series (RTS) method suggested by ASHRAE [26,27]. Hourly
distribution of the design-cooling load calculated for all types of
buildings considered are shown in Fig. 3. In the calculation, out-
door design conditions for Adana were taken to be 38 C dry bulb
temperature and 26 C wet bulb temperature. As shown in Fig. 3,
design-cooling load of the no insulation building is 145.14 kW
and sensible heat ratio (SHR) is 0.98. Design cooling loads of Build-
ings A, B and C are 92.15 kW, 94.19 kW and 97.11 kW, respectively,
and their SHRs are all 0.97. Design cooling load of the sample
building is decreased maximum 33% due to thermal insulation. In-
crease of the thickness of the insulation material does not reduce
significantly cooling load of the building. Design cooling load of
Building A, which has the best insulation, is only 2% and 5% less
than that of Building B and Building C, respectively. Hourly distri-
butions of parts of the design-cooling load for building without
insulation are presented in Fig. 4. As it can be seen in Fig. 4, the
cooling load due to opaque external components (external wall,
roof, and floor) surface areas of the building without insulation is
about 40% of the maximum total cooling load. For this reason, ther-
mal insulation was applied to the building’s opaque surfaces for
reducing of heat gain in buildings through the envelope. Moreover,
space-cooling load can be reduced because of the low solar heat
gains, when fenestration surface area (openings) is decreased. Sim-
ilarly, cooling load is influenced by thermal mass of opaque ele-
ments [1,2,7]. In this study, the ratio of the building’s openings
to the opaque areas is 0.45. Construction materials of sample build-
ing were the same for all calculations.
Variation of the ratio of cooling load due to insulation applied
opaque external components to the total cooling load of the building during occupation period is shown in Fig. 5. The ratio obtained
for the no insulation building is also shown in the figure. As can be
seen from the figure, the opaque external components of the no
insulation building constitute approximately 50% of the total load,
while this percentage is between 2% and 20% for the insulated
buildings (Buildings A, B and C).
Using the design conditions given above (design-cooling load,
sensible heat ratio, minimum fresh air ventilation requirement
and supply air temperature), the maximum (design) cooling coil
capacity and the maximum (design) total mass flow rates of supply
and return fans were determined with an iterative approach (Table
6). Therefore, a computer program was written for the calculations.
Capacities of the supply and return fans for CAV and VAV systems
are the same.
Equipment of the air-conditioning system was selected from a
local supplier (Alarko-Carrier). Net cooling capacity and electricity
consumption of the chiller unit selected are 111 kW and 47.4 kW
for Buildings A, B and C, 152 kW and 67 kW for the no insulation
building under nominal operating conditions (38 C condenser
temperature, 12 C evaporator inlet and 7 C outlet water temper-
ature), respectively. Total mass flow rates of the supply and return
fans in AHU for the no insulation building is 45,438 m3
/h. The sup-
ply and return fans have 22 kW and 18.5 kW power consumptions,
respectively. Total mass flow rates and power consumptions of the
supply and return fans for Buildings A, B and C are 30,000 m3
/h,15 kW and 11 kW, respectively.
4.2. Initial cost
Total initial costs of the air-conditioning system including the
chiller unit, AHU, duct and automation equipment costs are given
in Table 7. When building envelopes were insulated (Buildings A, B
and C), the initial cost of ACS for CAV and VAV systems were about
22% less than those of buildings without insulation.
4.3. Operating cost
The Bin method was used for calculation of energy consumption
of the chiller unit. This method is based on the calculation of the
energy consumption for different values of the outdoor tempera-
ture (Tout) and multiplying it by the corresponding number of
hours (Nbin) in the temperature bin centered on that temperature
. The bin method, which has different forms today, has been
developed from the various degree-day methods available. For
many applications, the degree-day method should not be used,
even with the variable-base method, because the heat loss coeffi-
cient, the efficiency of the HVAC system, or the balance point tem-
perature may not be sufficiently constant. The efficiency of the
HVAC equipment, for example, varies strongly with outdoor tem-
perature. In such cases, a steady-state calculation can yield good
results for the annual energy consumption if different temperature
intervals and time periods are evaluated separately .
Monthly bin data with 3 C increments in 4-h periods between
9:00–20:00 h during cooling season for Adana are given in Table 8
. The cooling period for Adana, which has a hot and humid cli-
mate during summers, covers 184 days between May and October
Operating costs of the air-conditioning systems during cooling
season for 9:00–12:00 h, 13:00–16:00 h and 17:00–20:00 h were
obtained using bin number. The minimum reducing ratio of the
variable-speed drive (VSD) used in VAV system in order to adjust
the operating speed of the fan was taken to be 30%.
Free cooling systems use outdoor air to reduce the cooling
requirement when outdoor air is cool enough to be used as a cool-
ing medium. In this study, the sample building is conditioned by
free cooling (outdoor air is directly supplied to the air-conditioned
space) when outdoor air temperature is least 8 C lower than in-
door temperature (Tout 6 18 C) . By doing this, operating hours
of the chiller unit in ACS is reduced. Therefore, both electricity con-
sumption and environmental impact are reduced as well.
Total operating hours of the mechanic and free cooling systems
during cooling season for Adana are presented in Table 9. Free cool-
ing is possible only in May and October with the conditions
Tout 6 18. As shown in Table 9, the potential of free cooling is not
enough for the occupation period considered in this study (9:00–
20:00). However, an increase in the potential of free cooling for
Adana is noticeably observed in night time (20:00–08:00).
The main electricity-consuming units in the air-conditioning
systems are the fans and the chiller unit. In this study, the energy
consumption of the ACS was determined by the following proce-
dure. Firstly, part load ratio of the chiller unit (PLRchil) was found
PLRchil 1⁄4 Qcoil part=Qcoil full (1)
where Qcoil_full indicates the full load of the chiller unit and is ob-
tained from the manufacturer’s data for all bin data (time shift
and interval temperature). Qcoil_part indicates the instantaneous load
removed by the ACS from interior of building. It was obtained using
psychometric analysis for all bin data. Qcoil_part is the sum of the
cooling load of the building and the fresh air load due to the mixing
air supplied to room.
Secondly, coefficient of performance at part load (COPpart) was
calculated by the following equation :
COPpart 1⁄4 ðCOPfull PLRchilÞ=ð0:16 þ 0:32PLRchil þ 0:52PLR2
in which, COPfull indicates the coefficient of performance of the chil-
ler at full load. It was obtained from the manufacturer’s data for all
Thirdly, the power consumption of the compressor in the chiller
unit for part load (Wchil_part) was determined using:
For determining the power consumption of the fan, the part load ra-
tio of the fan (PLRfan) was found by the following equation:
where Mfan_full represents the design (maximum) capacity of the
fan. Mfan_part indicates the quantity of the mixing air supplied to
room. For the CAV system, mass-flow rate is constant through the
operation of the system; therefore even for the part-load conditions
the fans consume the maximum power. Under peak-cooling condi-
tions, the VAV system operates identically to a CAV system with
AHU operating at maximum flow (Mfan_full) and maximum cooling
coil capacity (Qcoil_full). However, at reduced cooling load, the air-
flow is reduced by the combined action of the closing of the zonal
VAV box dampers and the fan speed controller. The power con-
sumption of the fan under the real operating conditions (Wfan_part)
was calculated by the following equation :
Wfan part 1⁄4 Wfan fullPLR3
in which, Wfan_full indicates the power consumption of the fan at full
Finally, total energy consumption of the compressor in the chil-
ler unit and the fans under real operating conditions (Epart) was ob-
tained multiplying BIN data (Nbin) with the power consumption of
the chiller unit and the fans:
Epart 1⁄4 NbinðWchil part þ Wfan partÞ ð6Þ
Energy cost of the system (Ocost), can be determined using the en-
ergy consumption of the system (Epart) and price of electricity (T),
which is currently about 0.11 $/kW h in Turkey:
Ocost 1⁄4 EpartT ð7Þ
Using the procedure given above, operating costs of the chiller, the
fans and the total operating cost were calculated and the results are
given in Table 10 for a cooling season.
Seasonal operating cost of the ACS with VAV was determined to
be $6967 for the no insulation building. In the case of Buildings A, B
and C, seasonal operating cost is about 25% less than that of the no
insulation building. Similar results were obtained with CAV air dis-
tribution system. In this case, seasonal operating cost for Buildings
A, B and C is about 33% less than that of the no insulation building.
5. Economic analyses
An economic analysis was carried out in order to determine
influence of the thermal insulation on the initial and operating
costs of the ACS. Present-worth cost (PWC) method, which is one
of the analyses methods of the life-cycle cost, was used for evalu-
ating the ACS in case of different thermal insulations [19,27,31,32].
Results of the LCC analysis are directly affected by the economic
measures. Therefore, in the analyses, an annual interest rate of
14% and inflation rate of 8% were selected considering the present
economic conditions of Turkey. The system life of the ACS was ta-
ken as 15 years. Total initial cost consists of the initial cost of the
ACS and the cost of the building insulation.
The initial and operating costs of the ACS and the insulation cost
of the building are given in Table 11 for all building types consid-
ered in this study.
Results of the economic analyses are given in Table 12. From the
table it is seen that at the end of the lifetime (15 years), the pres-
ent-worth cost of the no insulation building is $302,873 for the
CAV air distribution system. There is almost no difference between
the insulated buildings (<2.8%). The present-worth cost for the
insulated buildings is approximately 26% smaller than that for
the no insulation building.
In the case of the VAV air distribution system, the trend is sim-
ilar to that for the CAV. While the present-worth cost of the no
insulation building at the end of the lifetime is $223,634, its value
for Buildings A, B and C are, respectively, 17.5%, 19.6% and 20.6%
less than for the no insulation building.
Annual variation of the overall present-worth cost of the ACS for
all building types are presented in Figs. 6 and 7 for VAV and CAV
systems, respectively. From the figures it is seen that the pres-
ent-worth cost of the no insulation building is always higher than
that of Buildings A, B and C even from the initial installation of the
system. The difference between the no insulation building and the
insulated buildings continually increases during lifetime. These re-
sults show that the insulation applied to the building envelope for
all thicknesses considered in this study is feasible.
In this study, Building C, which has the least thermal insulation
among the insulated building types, was compared with Buildings
A and B to determine the optimum thermal insulation thickness
from economy point of view. Extra investment needed for Build-
ings A and B with respect to Building C is $7990 and $2908, respec-
tively. Compared with these extra investments needed, the savings
due to thicker insulations (Buildings A and B) are not significant.
Yearly savings in operating cost of ACS with VAV for Buildings A
and B were found to be, respectively, $117 and $72 with respect
to Building C (Table 13). In the case of the CAV system, the savings
are even smaller ($63 for Building A and $45 for Building B).
Payback times of applying extra insulation with respect to
Building C vary between 40 and 125 years. These results clearly
show that the insulation thickness applied to Building C is enough.
Thicker insulations do not offer extra savings.
In this study, a sample building located in Adana in Mediterra-
nean Region (hot and humid summer and warm winter) was con-
sidered for studying the influence of different thicknesses of
insulation applied to the opaque external components on cooling
load and energy consumption of air-conditioning system. Energy
performance of the building for cooling period was investigated
with life-cycle cost analysis. The thicknesses of the insulation
material were determined according to A, B and C-type buildings
defined in the ‘‘energy efficiency index” in TS 825.
Design cooling load of the sample building decreased maximum
33% due to thermal insulation. The capacities of the equipment
used in the air-conditioning system for the insulated buildings
were lower than that of the no insulation building. Therefore, both
the initial and the operating costs of the ACS were reduced consid-
erably. For Buildings A, B and C;
initial cost of the ACS for CAV and VAV systems are about 22%
operating cost of the ACS is 25% less for VAV and 33% less for
with respect to the no insulation building.
Results of economic analyses show that the insulation invest-
ments for Buildings A, B and C are feasible due to reduced operat-
ing and initial costs of the ACS. However, when the different
insulation thicknesses considered in this study are compared with
each other, it is clearly seen that C-type insulation applied to build-
ings is satisfactory from economic aspect. Therefore, if a building
located in hot regions of Turkey is constructed according to C-type
building in ‘‘energy efficiency index” both the operating and initial
costs of the ACS are significantly reduced.
As a result, it is suggested that the thickness of thermal insula-
tion material for buildings in the coastal provinces located in the
Mediterranean countries (such as Turkey, Italy, Spain and Greece),
which have hot and longer summers and warm winters, should be
determined according to the cooling-degree day. Otherwise, the
thermal insulation applied considering only heating degree-day
concept may be insufficient during cooling period.
 Lina Y, Yuguo L. Cooling load reduction by using thermal mass and night
ventilation. Energy Build 2008;40(11):2052–8.
 Spindler HC, Leslie KN. Naturally ventilated and mixed-mode buildings. Part II:
optimal control. Build Environ 2009;44:750–61.
 Papadopoulos AM. State of the art in thermal insulation materials and aims for
future developments. Energy Build 2005;37(1):77–86.
 Perez YV, Capeluto IG. Climatic considerations in school building design in the
hot-humid climate for reducing energy consumption. Appl Energy
 Kolokotroni M, Aronis A. Cooling-energy reduction in air-conditioned offices
by using night ventilation. Appl Energy 1999;63:241–53.
 Balaras CA. The role of thermal mass on the cooling load of buildings: an
overview of computational methods. Energy Build 1996;24:1–10.
 Yılmaz Z. Evaluation of energy efficient design strategies for different climatic
zones: comparison of thermal performance of buildings in temperate-humid
and hot-dry climate. Energy Build 2007;39:306–16.
 Bojic M, Yik F. Cooling energy evaluation for high-rise residential buildings in
Hong Kong. Energy Build 2005;37:345–51.
 Bojic M, Yik F, Leung W. Thermal insulation of cooled spaces in high
rise residential buildings in Hong Kong. Energy Convers Manage
 Danny Harvey LD. Net climatic impact of solid foam insulation produced with
halocarbon and non-halocarbon blowing agents. Build Environ
 Florides GA, Tassou SA, Kalogirou SA, Wrobel LC. Measures used to lower
building energy consumption and their cost effectiveness. Appl Energy
 Safarzadeh H, Bahadori MN. Passive cooling effects of courtyards. Build
 Bojic M, Yik F, Sat P. Influence of thermal insulation position in building
envelope on the space cooling of high rise residential buildings in Hong Kong.
Energy Build 2001;33:569–81.
 Turkish Standard 825 (TS 825). Thermal insulation in buildings. Ankara:
Official Gazette (23725); 14 June 1999.
 Dilmac S, Kesen N. A comparison of new Turkish thermal insulation Standard
(TS 825), ISO 9164, EN 832 and German regulation. Energy Build
 Bulut H. Determination of weather data for Turkey for heating and cooling
systems. Çukurova University Institute of Natural and Applied Sciences,
 Aktacir MA, Büyükalaca O. Influence of TS 825 thermal insulation standard in
the warm climate. In: Proceedings of the eighth international symposium on
HVAC+R technology, _
Istanbul, 12–14 Mayis; 2008. p. 98–108.
 Bolattürk A. Optimum insulation thicknesses for building walls with respect to
cooling and heating degree-hours in the warmest zone of Turkey. Build
 Aktacir MA, Büyükalaca O, Yılmaz T. Life-cycle cost analysis for constant-air-
volume and variable-air-volume air-conditioning systems. Appl Energy
 Turkish Air-Conditioning & Refrigeration Manufacturers0 Association (_
2006 Statistic data. <http://www.iskid.org.tr/karsilastirmali.htm>.
 Architectural Technical Guide 0016. Thermal Performance Construction
Standards and Eligible Locations for Air-Conditioning for New and Existing
Construction Financed by the USDA/Rural Housing Service’s Single Family
Housing (SFH) Programs; 10 March 2006.
 Ogawa Y, Gao W, Zhou N, Watanabe T, Yoshino H, Ojima T. Investigation on
standard for energy and environmental design of residential house in China. J
Asian Architect Build Eng 2005;4(1):253–8.
 Australian Standard (AS2627.1). Thermal insulation of roof/ceilings and walls
in dwellings; 1993. <http://www.ais-group.com.au/homeinsulation/
 Thermal Insulation Regulation in Buildings. Ankara: Official Gazette (24043); 8
 ANSI/ASHRAE Standard 62. Ventilation for acceptable air-quality. Atlanta (GA):
American Society of Heating, Refrigerating and Air-Conditioning Engineers,
 Spitler JD, Fisher DE, Pedersen CO. The radiant time series cooling load
calculation procedure. ASHRAE Trans 1997;103(2):503–15.
 ASHRAE handbook-fundamentals. Atlanta (GA): American Society of Heating,
Refrigerating and Air-Conditioning Engineers Inc.; 2001.
 Bulut H, Büyükalaca O, Yılmaz T. Bin weather data for Turkey. Appl Energy
 Aktacir MA. Free cooling potentials of all-air air conditioning system in
different climatic region (in Turkish). Chamber of mechanical engineers. J Sanit
 Kreider JF, Rabl A. Heating and cooling of buildings design for
efficiency. McGraw-Hill, Inc.; 1994.
 Elsafty A, Al-Daini AJ. Economical comparison between a solar powered vapor
absorption air-conditioning system and a vapor compression system in the
Middle East. Renew Energy 2002;25:569–83.
 Hasan A. Optimizing insulation thickness for buildings using life cycle cost.
Appl Energy 1999;63:115–24.