Block 1 without BTI triggers a different thermal response in
comparison with Block 2 with BTI. The differences (Block 1 minus
Block 2 data) in energy consumption are depicted in Fig. 4c. Positive
values denote Block 1 > Block 2, and vice versa for negative
values. The high solar radiation input and high ambient temperature
(Table 1) provides ample energy to warm roofs. The resulting
high roof and indoor temperatures could widen the differences in
energy consumption between the two blocks in comparison with
other weather scenarios (cf. Sections 3.4 and 3.5).
At Control, the number of compressor on–off cycles at Block 1 at
39 exceeds Block 2 at 17 (Table 2). The high electricity consumption
at Block 1 at 89.24 kW h is much higher than 67.02 kW h at Block 2.
Block 1 consumes significantly more energy than Block 2 by 24.90%
at Control, and by 19.99% at Sedum (Table 3). Such results reflect
the consequence of BTI omission at Block 1, allowing more heat
influx into indoor space at no green roof (Control) and simple green
roof (Sedum). However, Peanut displays a reverse trend with Block
1 consuming slightly less energy than Block 2 by a small margin of
4.23% (Table 3). The combination of BTI and Peanut roof at Block 2
has not brought thermal benefits above Block 1.
For Block 1 Control, an energy-consumption peak is expressed
from late afternoon to evening (Fig. 4a). The massive heat influx at
Block 1 after midday follows closely the diurnal solar-energyrhythm
with time lag. It highlights the thermal inertia in the bare roof to
impose a lingering cooling load at night. At Block 2 Control, the BTI
plays the thermal-barrier role to restrict heat intrusion into indoor
space and stifle the afternoon–evening peak (Fig. 4b). The BTI has
effectively buffered and dampened diurnal fluctuation in energy use.
For Sedum, no period registers a clear peak at both blocks
(Fig. 4a and b). The compressor on–off cycles and energy use at
Block 1 stays above Block 2 throughout the day (Tables 2 and 3).
Some 67.49 kW h is consumed at Block 1 in comparison with
54.00 kW h at Block 2. Lacking BTI at Block 1 has allowed more
downward heat flux to warm indoor space. Adding Sedum roof
has reduced energy use by 24.37% at Block 1 and 19.42% at Block
2 (Table 3). Energy saving due to Sedum roof amounts to
21.75 kW h at Block 1 but only 13.02 kW h at Block 2. In absolute
terms, BTI at Block 2 has checked downward heat passage in comparison
with Block 1. In relative terms, the added energy-conservation
value of Sedum at Block 1 is somewhat higher than Block 2.
For Peanut, electricity consumption is similar at the two blocks
(Table 3). Block 1 records 64.44 kW h versus 67.16 kW h at Block 2,
which are respectively 3.42% lower and 19.64% higher than Sedum
(Table 3). At Block 1, Peanut has brought an energy saving of
27.79% which is somewhat higher than Sedum at 24.37%. However,
at Block 2 Peanut consumes nearly the same energy as Control, and
uses 19.64% more than Sedum. Thus on hot summer sunny day,
despite BTI installation, Peanut roof with thicker substrate and
denser vegetation has poorer energy performance than Sedum.
The result signifies establishment at Block 2 of considerable GHEcum-
BHE to incur TIB (cf. Section 3.2), which has offset the thermal
resistance of BTI.
Block 1 without BTI triggers a different thermal response in
comparison with Block 2 with BTI. The differences (Block 1 minus
Block 2 data) in energy consumption are depicted in Fig. 4c. Positive
values denote Block 1 > Block 2, and vice versa for negative
values. The high solar radiation input and high ambient temperature
(Table 1) provides ample energy to warm roofs. The resulting
high roof and indoor temperatures could widen the differences in
energy consumption between the two blocks in comparison with
other weather scenarios (cf. Sections 3.4 and 3.5).
At Control, the number of compressor on–off cycles at Block 1 at
39 exceeds Block 2 at 17 (Table 2). The high electricity consumption
at Block 1 at 89.24 kW h is much higher than 67.02 kW h at Block 2.
Block 1 consumes significantly more energy than Block 2 by 24.90%
at Control, and by 19.99% at Sedum (Table 3). Such results reflect
the consequence of BTI omission at Block 1, allowing more heat
influx into indoor space at no green roof (Control) and simple green
roof (Sedum). However, Peanut displays a reverse trend with Block
1 consuming slightly less energy than Block 2 by a small margin of
4.23% (Table 3). The combination of BTI and Peanut roof at Block 2
has not brought thermal benefits above Block 1.
For Block 1 Control, an energy-consumption peak is expressed
from late afternoon to evening (Fig. 4a). The massive heat influx at
Block 1 after midday follows closely the diurnal solar-energyrhythm
with time lag. It highlights the thermal inertia in the bare roof to
impose a lingering cooling load at night. At Block 2 Control, the BTI
plays the thermal-barrier role to restrict heat intrusion into indoor
space and stifle the afternoon–evening peak (Fig. 4b). The BTI has
effectively buffered and dampened diurnal fluctuation in energy use.
For Sedum, no period registers a clear peak at both blocks
(Fig. 4a and b). The compressor on–off cycles and energy use at
Block 1 stays above Block 2 throughout the day (Tables 2 and 3).
Some 67.49 kW h is consumed at Block 1 in comparison with
54.00 kW h at Block 2. Lacking BTI at Block 1 has allowed more
downward heat flux to warm indoor space. Adding Sedum roof
has reduced energy use by 24.37% at Block 1 and 19.42% at Block
2 (Table 3). Energy saving due to Sedum roof amounts to
21.75 kW h at Block 1 but only 13.02 kW h at Block 2. In absolute
terms, BTI at Block 2 has checked downward heat passage in comparison
with Block 1. In relative terms, the added energy-conservation
value of Sedum at Block 1 is somewhat higher than Block 2.
For Peanut, electricity consumption is similar at the two blocks
(Table 3). Block 1 records 64.44 kW h versus 67.16 kW h at Block 2,
which are respectively 3.42% lower and 19.64% higher than Sedum
(Table 3). At Block 1, Peanut has brought an energy saving of
27.79% which is somewhat higher than Sedum at 24.37%. However,
at Block 2 Peanut consumes nearly the same energy as Control, and
uses 19.64% more than Sedum. Thus on hot summer sunny day,
despite BTI installation, Peanut roof with thicker substrate and
denser vegetation has poorer energy performance than Sedum.
The result signifies establishment at Block 2 of considerable GHEcum-
BHE to incur TIB (cf. Section 3.2), which has offset the thermal
resistance of BTI.
การแปล กรุณารอสักครู่..
