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components and are equipped with the same HVAC system. One
building was painted with coating A (Building A) and the other
was painted with coating C (Building C). As this study is focused
on envelope and indoor temperature improvement and envelope
heat gain reduction with reflective coatings, the buildings have
no windows. Building surface temperatures, indoor air tempera-
ture at different heights, indoor globe temperature and electricity
consumptionweremeasured and recorded every 10min. Themete-
orological conditions, including environmental air temperature,
global solar radiation and direct normal radiation, were recorded
with the same frequency using aweather station installed near the
buildings. The measuring points are shown in Fig. 2(a) and (b). Ten
thermo recorder TR-71Wsensors (one recorder has two channels)
were used to measure and monitor temperatures. Each of them
was assigned a number as shown in Fig. 2. Recorders numbered
1–5 measured surface temperatures of the roof and the vertical
walls (channel 1 for interior surface temperatures; channel 2 for
exterior surface temperatures).Recordersnumbered 6–9measured
indoor air temperatures from floor to roof height at 0.5m inter-
vals.3.2. Effect of envelope properties and reflective coatings
In parallel with the main experimental measurements, another
secondary study was carried out in order to investigate the impact
of envelope material thermal properties combined with reflective
coatings. Four test cells with roof dimensions 0.5m×0.5m were
built and used for measuring the resulting surface temperatures
and heat flow through the roof section using the four different
materials presented in Table 2. For eachmaterial, the three selected
coatings were tested. Surface temperatures were measured with
thermo Recorder TR-52, and heat flux through samples was mea-
sured with Heat Flow Meter HFM-215. Fig. 3 shows a schematic of
the testing configuration and sample pictures.
4. Experimental results and discussion
This study includes three separate experiments. The two main
experiments were carried out fromAugust 2008 toMarch 2009, to
compare indoor thermal conditions in building A and building C
under real weather conditions. The first case considered free float-
ing conditions in the rooms, while in the second case the spaces
were conditioned and electricity consumption for air conditioning
wasmeasured. The third experiment took place in September 2008,
comparing coating effects applied on different envelope surface
materials. In the following sections, representative experimental
results are presented for all cases.
4.1. Results and discussion for free floating case
The measurement period included summer, winter and shoul-
der season conditions to evaluate the effect of reflective coatings
on indoor thermal environment for buildings A and C. During the
measurement period, data was collected from 9:00 am to 6:00 pm.
Representative weather data for a 3-day period during winter and
summer is shown in Fig. 4. Average daily total solar radiation is
13.6MJ/m2 in summer and 10.7MJ/m2 in winter. Average dailyFig. 4. Representative weather data for (a) summer and (b) winter.
mean ambient temperature is 28.6 ◦C in summer and 11.3 ◦C inwin-
ter. The results showthat reflective coatingshave a significant effect
on surface temperatures. Since the roof has a different construction
from walls, and buildings are usually multi storied, only wall sur-
face temperatures were compared to identify the most applicableorientation.Maximumand average surface temperature reductions
for every wall are shown in Fig. 5.
In the summer, the greatest exterior surface temperature reduc-