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energy.
1.3. Previous computational studies on reflective coatings
Other studies employedmodeling to calculate the potential ben-
efits of reflective materials. Taha et al. [21] performed simulations
and predicted a cooling load reduction of 18.9% for summer days in
California when the roof and walls reflectivity was increased from
0.30 to 0.90. The simulated ceiling and wall thermal resistances
were 5.28 and 3.35m2 K/Wrespectively. Anderson [22] found sim-
ilar reductions for a flat concrete roof of a simple single room.
Konopacki et al. [23] simulated the direct energy savings from
high reflective roofs in 11 US metropolitan areas, and computedthe annual electricity savings in old residences, new residences
and old/new office buildings to be 55%, 15% and 25% respec-
tively. A simulation study by Shariah et al. [24] for two mild and
hot climates, showed that, as the reflectance increases from 0
to 1, the total energy load decreases by 32% and 47% for non-
insulated buildings and by 26% and 32% for insulated buildings.
Wang et al. [25] developed a dynamic model and compared the
annual cooling load, heating load and electricity consumption of a
retail shed coated with solar reflective materials for six locations
around the world. Other studies also used computer simulations
to estimate the effect of reflective roofs [26–28]. Finally, Tang
and Zhou [29] analyzed the relationship between outdoor sol-air
temperature and solar radiation absorptance and investigated the
influence of wall reflectance on annual building energy consump-
tion for three Chinese cities representing hot summer and cold
winter zone. Akbari and Levinson [30] reviewed and compared the
technical development of cool-roof provisions in the ASHRAE Stan-
dards [31,32], and California Title 24 Standards and discussed the
treatment of cool roofs in other standards and energy efficiency
programs.
This paper presents an experimental study about the impact of
reflective coatings on building surface temperatures, air tempera-
ture, globe temperature, energy consumption and thermal comfort
for buildings located in Shanghai, China. This location is character-
ized by hot summers and cold winters, and the overall effects of
reflective coatings are complex considering the potential benefits
in the summer and the potential penalties during winter. In paral-
lel, another experiment with four smaller test cells was carried out
to investigate the impact of envelope material thermal properties
combined with reflective coatings.
2. Properties of selected coatings
Three types of coatings were included in this study. Their spec-
tral reflectivity was measured with a spectrophotometer over the
main solar range and it is shown in Fig. 1. Coating A is general coat-
ing and it is used as the base case; coatings B and C are reflective
coatings that have similar reflectivity over the visible spectrumbut
significant differences in the infrared spectrum. Both of these coat-
ings reflectmore at the infrared which accounts for a large portion
of solar radiation and therefore they have the potential of reduc-
ing solar heat gain and, consequently, cooling load. The integrated
average reflectivities for coatings A, B and C are 32%, 42% and 61%
respectively. Themain components of the coatings are summarized
in Table 1.3. Experimental setup and data collection
3.1. Surface temperatures and indoor environment
In order to measure the effect of reflective coatings on enve-
lope temperatures, indoor thermal conditions and energy demand,
two identical buildingswere built and placed near each other. They
have the same dimensions of 7m×7m×4m, the same envelope