Impact of Low-E Window Films on Energy Consumption and CO2 Emissions of an Existing UK Hotel Building
2. Materials and Methods
3.1. Validating the Simulation Results Against the Actual Data
3.1.1. Baseline Model Energy Simulation
3.1.2. Actual Annual Consumption
3.1.3. Choosing the Representative Data
3.2. Model with Window Films
- Baseline model: Hotel building in its existing state.
- Model with Thinsulate film: Model with Thinsulate film applied as a retrofitting measure on the internal surface of the inner windowpane.
- Model with Low-E double glazed unit (DGU): Model with a newly installed Low-E coated double glazed window unit.
- The reduction in total energy consumption is 4% for the model with Low-E DGU, and 2.7% for the model with Thinsulate, compared to the baseline model.
- Heating and cooling consumptions are both reduced in the retrofitted models. Therefore, in this aspect, Low-E films can demonstrate a better performance (although not significantly) compared to sun control films.
- The maximum reductions in different end use consumptions occur in auxiliary consumption, 14.9% for the model with Thinsulate and 16.7% for the model with Low-E DGU, which is due to a reduced usage of fans and pumps, as both heating and cooling energy consumptions are decreased.
- The main difference between the two retrofitted models comes with their impact on reducing heating energy consumptions. The 17% reduction in heating energy consumption achieved in the model with Low-E DGU outweighs the 3% reduction received in the model with Thinsulate. This is consistent with the literature, where it states the maximum function of Low-E glazing/films is achieved when they are applied on the external layer. The two models show similar reductions in cooling energy consumption, around 20%.
- The Low-E coating (regardless of its position) reduces the light transmittance—in the case of this study, the reduction is 20%. However, the lighting energy consumption is unaffected, which can be justified as below:
- The NCM profile for hotels considers areas such as guestrooms to be vacant during the day (from 09:00 to 21:00) and occupied in the late afternoon/evening when there is already the need for using artificial lighting. Therefore, a reduced light transmittance will not increase the need for lighting in the guestrooms.
- Areas with constant use such as the restaurant, lobby, and gym keep their lights on during their active time as part of the hospitality policy. Therefore, a reduced light transmittance will not increase the need for lighting in these areas, as well.
- Electricity: 11.53 Pence/kWh
- Natural gas: 2.371 Pence/kWh
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|Type of Window Film||Visible Light||G-Value||Light to Solar Gain (LSG)||UV Block||Heat Gain Reduction %||Heat Loss Reduction %|
|Reflected % (Interior)||Reflected % (Exterior)||Transmitted %|
|Thinsulate CC 75||12||16||74||0.53||1.4||99.9||35||40|
|PR 70 EXT||7||7||71||0.48||1.5||99.9||41||-|
|PR 40 EXT||5||6||42||0.39||1.6||99.9||53||-|
|Type of Window Film||Visible Light||G-Value||Light to Solar Gain (LSG)||UV Block %||Heat Gain Reduction %||Heat Loss Reduction %||Emissivity|
|Reflected % (Interior)||Reflected % (Exterior)||Transmitted %|
|Thinsulate CC 75||17||21||66||0.51||1.3||99.9||27||40||0.15|
|PR 70 EXT||14||12||63||0.39||1.6||99.9||45||-||0.84|
|PR 40 EXT||13||7||37||0.29||1.3||99.9||59||-||0.84|
|Number of Observations||Multiple R||R Squared||p-Value|
|Number of Observations||Multiple R||R Squared||p-Value|
|Measure Taken||Heating Energy Consumption %||Cooling Energy Consumption %||Total Energy Consumption %||CO2 Emissions from Gas %||CO2 Emissions from Electricity %||Total CO2 Emissions %||Gas Costs %||Electricity Costs %||Total Energy Costs %|
|PR 70 EXT||−0.2||28||2.1||−0.5||5||3||N/A||5||3|
|PR 40 EXT||−1.3||32||1.9||−1||6||3||N/A||6||3|
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Amirkhani, S.; Bahadori-Jahromi, A.; Mylona, A.; Godfrey, P.; Cook, D. Impact of Low-E Window Films on Energy Consumption and CO2 Emissions of an Existing UK Hotel Building. Sustainability 2019, 11, 4265. https://doi.org/10.3390/su11164265
Amirkhani S, Bahadori-Jahromi A, Mylona A, Godfrey P, Cook D. Impact of Low-E Window Films on Energy Consumption and CO2 Emissions of an Existing UK Hotel Building. Sustainability. 2019; 11(16):4265. https://doi.org/10.3390/su11164265Chicago/Turabian Style
Amirkhani, Shiva, Ali Bahadori-Jahromi, Anastasia Mylona, Paulina Godfrey, and Darren Cook. 2019. "Impact of Low-E Window Films on Energy Consumption and CO2 Emissions of an Existing UK Hotel Building" Sustainability 11, no. 16: 4265. https://doi.org/10.3390/su11164265