PLEA 2018 HONG KONG Smart and Healthy within the 2-degree Limit Convenience store: The unintended large energy consumers in urban Taiwan CHEN-YU HUNG1, NEVEEN HAMZA1 1 Newcastle University, Newcastle upon Tyne, United Kingdom. 2 Abstract: In Taiwan, the average of convenient store's Energy Use Intensity (EUI) is high at a 1501 (kWh/m /year) which is 3 times higher than department stores, 7times higher than central air conditioning office buildings and 38times higher than housing due to operational hours, internal loads and a poorly designed building envelope. Unexpectedly, communities use convenience stores as thermal comfort refuges during summer. This study utilised a dataset of 251 convenience stores in Taiwan from the largest leading retailer to obtain data on the physical, construction elements, energy use and siting of convenience stores. Sample analysis results analysed the architectural features and main locations, urban setting of the convenience store for a base case design. The dynamic software IES-VE (2016) is used to simulate different envelope improvement techniques to understand cooling demand and indoor thermal performance in relation to an urban setting. The dataset energy loads were used to validate the simulation results. The simulation results show that the most efficient building envelope improvement type is an insulation roof with shading. It saves 17% of cooling load in arterial roads while saving up to 18% of cooling load in residential areas. Keywords: Convenience store, Energy consumption, Building envelopes.  1. INTRODUCTION Currently, retailers tend to construct and In Taiwan, the average of convenient store's 2 refurbish existing shops to increase the visual Energy Use Intensity (EUI) is 1501 to 2346 (kWh/m / connection between outside and the inside of shops year) [1, 2 ] which is 3 times higher than department and leading to an all glazed facade regardless of urban stores, 7 times higher than central air conditioning setting orientation (Fig. 1). However, this change of office buildings and 38 times higher than housing. building envelope influences the indoor atmosphere Taiwan is a country that possesses a significant density and energy consumption. Researchers note that the of 10,199 indoor atmosphere can change occupants’ behaviours convenience stores serving 23 million people in and energy performance. [3,4 ]. Heat loads on building Taiwan (Statistical information obtained at the end of envelopes due to the intensity of solar radiation and 2016), which means there is one store for every 2,304 less temperature fluctuations and a high level of person. This study aims to investigate the energy humidity in the Taiwanese hot humid climate consumption of stand-alone convenience stores in contributes as one of the major factors that have a Taiwan in two different urban settings. It seeks to direct impact on indoor thermal comfort. convenience stores. There were investigate and propose energy reduction strategies for new development and refurbished convenience stores. Nowadays, retailers develop their stores with more space to provide more facilities to increase consumers’ footfall. According to the retailer’s annual report (2016) the convenience stores with a designated seating plan and coffee shop incur better sales. Figure 1: Convenience store façade.  2. CONENIENCE STORE IN TAIWAN As convenience stores continued to penetrate the Taiwanese market and competition increased, the existing stores designed ways to ensure their survival. The stores offered a wide range of convenient can influence emotional responses, such as pleasure, products that met customers’ specific needs. To arousal and dominance [6]. The importance of the manage the high competition, Taiwanese convenience time spent in the shop relates to a comfortable or an stores the enjoyable experience. The significant element of retail introduction of hybrid convenience stores that environment is the ambient condition, such as lighting, provides other facilities such as neighbourhood temperature and noise [7]. However, thermal comfort meeting places, toilets and seating areas [5]. While is the condition of mind that expresses satisfaction these stores offered fast foods, they appreciated the with the thermal environment; therefore, it is strongly need for dining furniture and facilities that enabled related to psychology [8]. developed strategies that led to customers to enjoy the services and products and an  3. METHODS extended stay indoors The largest leading retailer provided a dataset of 1,416 stores. The following sources were included: 2.1 Convenience store buildings in Taiwan A new convenience store design introduced to region, address, operation type, electricity number, Taiwan’s customer in 2012. The new convenience district type, dimension of the store (total dimension, stores with a designated seating plan and coffee shop business area and storehouse), annual power expense, incur better sales. The stand-alone convenience store monthly has more space than others and has developed into equipment quantities. The obtained information was the fundamental convenience store architectural type organised into a spreadsheet database and the chief in Taiwan. It is an ongoing challenge to improve a facilities engineer was consulted. After examining the building’s energy efficiency without compromising its retailer’s database, there were 251 stand-alone indoor a convenience stores with complete data. A previous convenience store is not only a place for shopping but study was used Google Maps to determinate also a community place for the neighbourhood. convenience store building types in Taiwan [1]. This environmental quality. Nowadays, customer flow, equipment type and The light steel buildings are palpable in Taiwan study used Google Maps street view to understand and are deemed desirable due to the inexpensive convenience store’s architectural feature such as construction; the building fabric is constructed of window’s orientation, structure, urban street settings, reusable and recyclable fast to build materials. determining the road classification, adjacent and However, the light steel buildings lack insulation, surrounding building's height. Sample analysis results which causes the indoor temperature to reach 40℃ provide the architectural features and main locations, in such urban setting of convenience store for base case temperatures, air conditioning systems are used to design. The dataset analysis shows over 82% of stand- improve the indoor thermal environment, which alone convenience stores were located in the arterial leads to a heightened consumption of energy. road and residential area and 98% of 251 stand-alone the summertime [5]. To counter convenience stores 2.2 The influence of store design on user were steel roof and steel construction with single glazing buildings. The dynamic Shopping is not just about retrieving items from software (IES-VE) is used to simulate different shelves according to one’s needs; it is an experience envelope improvement techniques to understand the that one desires to enjoy. The retail store atmosphere cooling demand and indoor thermal performance in Without Store Energy Size consumption 2 (m ) (kWh) 140.7 176,618.9 One side 135.0 Two side Overhang relation to urban setting.  4. STAND-ALONE CONVENIENCE STORE ENERGY CONSUMPTION Customers EUI 2 (kWh/m /year) 346,038 1,363.9 169,945.1 318,399 1,323.9 139.2 175,784.5 321,135 1,339.9 Three side 131.1 176,442.0 355,196 1,418.8 The thermal environment of the store and Convenience stores in Taiwan tend to use the large floor to ceiling single glazing as buildings’ façade its to visually attract people and to display products. consumption of respective appliances. For instance, However, the large single glazing areas can increase during summer, the electricity consumption of air heat gain during the summertime. Table 1 shows the conditioning, and freezing and refrigeration appliances results of statistical tests of two sided and three sided increases during summer. The energy measurement window convenience store. Generally, the two sided data shows that the cooling energy consumption in window stores have marginally larger store sizes, summer is six times higher than winter. Table 3 shows which lead to lower EUI. Table 1 indicates that the the building’s envelope setting detail and Table 4 three side window convenience stores can attract shows the internal gain equipment list of the base more customers than two side window stores but it model. also increases annual store electricity consumption. Table 3: Information of simulation base case. However, the three side window stores tend to have more customers and higher EUI and energy consumption than two side window stores. Table 1: Comparison of two sided and three sided windows stores information. Number Store Annual power EUI Of size consumption Customer (kWh/m2/year) 2 windows (m ) (kWh) Two-sided 138.1 175,211 319,290 1,344.0 Three128.6 176,164 339,494 1,432.0 sided The database indicates variations of architectural shading overhangs of the convenience surrounding Built up area Entrance Window orientation Number of Storeys Floor to Floor Height External Walls Internal Walls Glazing Roof Ceiling Infiltration rate Lighting Occupancy Cooling set point largely influences the energy 2 105m East East and south 1 3.5m Tile + Brick wall+ 15 mm of timber board Brick wall + 15 mm of timer board 8 mm single glass 1mm metal cladding+ 15mm timber board 15 mm Plasterboard 3 2 4.5 m /h/m 2272w 7 26°C Table 4: Internal gain equipment list. stores. Stores varied in the provision of overhangs that Equipment Wattage Quantities provides a space for customers to rest and a smoking Microwave 1800 2 area for smokers without optimization of its Hotdog machine 900 1 dimensions to deal with the onslaught of direct solar Oden machine 900 2 Coffee machine Tea eggs cooker Water dispenser Computer and POS system ATM Copy machine and multiple media kiosk 3080 800 2800 500 2 2 1 2 4300 1 200 1 radiation. Table 2 shows that stores with three sides overhang have the highest EUI due to smaller store size. The one side overhang stores have the lowest EUI because it tend to be adjacent to other buildings, which causes less heat gain. Table 2: Energy consumption comparison of store with shading. The existing store’s roof only uses metal cladding and adds a timber panel in inner surface to reduce the noise from raining seasons. The store has a large configuration of glazing. There is no possibility of 80% of existing convenience stores condition such as opening windows at the convenience store as they are structure, store size and architectural form (two side all sealed for security, air quality and reduction of windows with veranda or shading) and can use it to outdoor sound. validate with simulation work (Fig. 4). This study During the examination of the surfaces of the simulates two urban settings: arterial road and envelope, various aspects will be signified during the residential area. The arterial road stores were process of simulation. These include internal gain, surrounded by 3.2m low rise buildings and 2.8m width occupation and equipment, and lighting. In cooling roads while the residential area stores were mode, the key focus is placed on sensible heat; the surrounded by 12m height buildings and 4.5m width impact of latent heat is so low that it is insignificant. road. All effective parameters in the assessment of the building envelope are considered in connection with the Hsinchu City climate. According to monitored data, during the summertime, the highest indoor temperature in non air cooled space can reach 46.1°C at 14:00 in the summertime. The simulation base case result shows that the highest temperature in the summertime was 48.59°C, which was over estimated the indoor temperature by 2.5°C, but creates a standard base Figure 4: Base case store floor plan. 5.1 Roof insulation improvement simulation case for comparison. The existing building simulation This section presents the simulation result of the result shows that the mean percentage of people insulated roof. as the convenience store buildings are dissatisfied is 80.89% not subject to compliance with building thermal The study simulates two most common stand- performance regulations in Taiwan, the existing alone convenience store urban settings: arterial road building roofs are; 1 mm metal cladding, 15mm timber and residential area. Each urban setting simulation board and 15 mm plasterboard without any insulation. includes four types store exposure: one side, two side, The simulation model added two types common three side and four side exposure (Fig. 3). insulation material between the metal cladding and timber board. First, insulation material is a 50 mm insulation board, and second is 30 mm of polystyrene foam (see Table 5). Those insulation materials are widely used for roof insulation on buildings in Taiwan, such as resident buildings, office buildings and schools. Table 5: The construction template of insulation roof. External Walls Figure 3: IES-VE modelled view of the building exposure.  5. STORE’S ENVELOPE IMPROVEMENT The base case is a stand-alone convenience store (in what urban setting) for simulation as it present over Internal Walls Glazing Roof Ceiling Tile + brick wall+ 15 mm of timer board Brick wall + 15 mm of timer board 8 mm single glass 1mm metal cladding + 50mm insulation board + 30mm polystyrene foam+ 15mm timer board 15 mm Plasterboard Table 6 shows that the roof insulation significantly reduced indoor temperature. In general, the mean temperature can significantly reduce from 33.51°C to 27.9°C. Moreover, the mean number of people dissatisfied also reduced from 80.89% to 52.87%. The store with insulation roof can save cooling load up to 13%. Table 6: The simulation result of insulation roof in arterial Figure 5: Shading device of convenience store. road. Exposure Mean temperature (°C) Mean people dissatisfied (%) Cooling load(kWh) Four sides Three sides Two sides One side 27.9 27.93 27.92 27.93 52.87 53.1 53.03 53.1 Table 7 shows that the insulation material adds on a residential urban setting can significantly reduce mean temperature from 33.51°C to 27.79°C. Moreover, the mean Figure 6: Louver shading device. number of people dissatisfied also reduced from 80.89% to Generally, the mean temperature in arterial road 51.75%. It save cooling energy consumption up to 15%. store can decline from 33.51°C to 25.22°C and the Table 7: The simulation result of insulation roof in residential mean people dissatisfied also reduce from 80.89% to area. 39.18% (Table 8). It save cooling load about 17%. Exposure Mean temperature (°C) Mean people dissatisfied (%) Four sides Three sides Two sides One side 27.8 27.92 27.79 27.92 51.89 53.02 51.75 53.03 5.2 Optimizing the wall sections environmental performance The shading device is an economic technique to reduce the solar gain. Most of convenience stores have the shading device. However, the designer placed the shading device too high and it cannot shade the ceiling to floor glazing properly (Fig. 5). This study simulated insulation roof with shading device. The louver shading device is placed at 2.3m above ground allows for airflow to reduce thermal stratification on the façade (Fig. 6). Table 8: The simulation result of optimizing the wall sections environment in arterial road. Four Exposure sides Mean temperature 26.84 (°C) Mean people 42.39 dissatisfied (%) Three sides Two sides One side 26.91 25.82 25.22 43.14 39.56 39.18 Table 9 presents that the mean temperature of store in residential area can decline from 33.51°C to 25.87°C and the mean people dissatisfied also reduce from 80.89% to 39.14%. The insulation roof with louver shading device can save cooling energy up to 18% in residential area. Table 9: The simulation result of optimizing the wall sections environment in residential area. Four Three Exposure sides sides Mean temperature 26.13 26.85 (°C) Mean people 40.77 42.56 dissatisfied (%) Two sides One side 25.94 25.87 39.62 39.14 5.3 Double glazing performance The large configuration of glazing makes convenience stores brighter and transparent but also increases the heat gain. According to the previous studies [9, 10] double glazing can keep the building Provision of overhangs and insulated roofs proves to transparent, but reduce the heat gain and improve the be the preferred architectural configuration to save indoor thermal environment. This study changed the energy while keeping the glazed areas. This study existing 8 mm single glass to 8 mm reflective glass however didn’t find using double glazing to provide with 10mm argon cavity between two glazing. Table substantial 10 shows the simulation result of store added double- economies of scale the single glazing is a viable option glazing on an arterial road urban setting. The mean to maintain connectedness of indoors and outdoors temperature can significantly reduce from 33.51°C to visually. 27.94°C. Table 11 shows the simulation result of  REFERENCES double glazing in an arterial road urban setting. The 1. Cho, C. (2013). Energy Consumption and Use the mean temperature can significantly reduce from Characteristics of Convenience store. Master dissertation. 33.51°C to 27.92°C. The double glazing envelope Chaoyang University of Technology. improvement can save cooling energy consumption up 2. Chou, D., Chang, C. and Hsu, Y. (2016). Investigation and to 11% in both urban settings. analysis of power consumption in convenience stores in Table 10: The simulation result of double glazing in arterial Taiwan. Energy and Buildings, 133, pp.670-687. road. 3. Kotler, P. (1973). Atmospherics as a marketing tool. Exposure Mean temperature (°C) Mean people dissatisfied (%) savings, indicating that for Four sides Three sides Two sides One side 28.03 28.07 27.94 28.07 4. Michon, R., Chebat, J. and Turley, L. (2005). Mall 54.19 54.52 53.22 54.52 atmospherics: Table 11: The simulation result of double glazing in Journal of Retailing, 49(4), pp.48–64. the interaction effects of the mall environment on shopping behaviour. Journal of Business Research, 58(5), pp.576-583. residential area. Exposure Mean temperature (°C) Mean people dissatisfied (%) energy Four sides Three sides Two sides One side 28.02 28.05 27.92 28.05 54.02 54.34 53.04 54.34 5. Hsueh, C. and Hsu, J. (2010). Taiwan Convenience Stores 2010. USDA GAIN reports. 6. Donovan, R. and Rossiter, J. (1982). Store Atmosphere: An Environmental Psychology Approach. Journal of Retailing, 58 (Spring), pp.34-57.  CONCLUSION 7. Underhill, P., (2009). Why we buy: The science of Statistical analysis shows that the three sided window stores tend to attract more customers and higher EUI and energy consumption than two sided window stores. It can be concluded that three sided window stores can increase perceptions of spaciousness by linking interior and exterior visually for customers, which results in attracting more customers. About one in six of convenience stores in Taiwan are standalone convenience store. The store’s envelope improvement can save energy up to 2,033kWh/year at a stand-alone convenience store which means saving 3,429,000 kWh per year in Taiwan. shopping. Simon and Schuster Paperbacks. 8. Chen, P., (2008). A Study on the Influence of Regulating Indoor Temperature of the Working Environment on Human Responses. Master dissertation. National Cheng Kung University. 9. Hamza, N. (2004). The performance of double skin facades in office building refurbishment in hot arid areas. PhD. Newcastle University. 10. Chan, A., Chow, T., Fong, K. and Lin, Z. (2009). Investigation on energy performance of double skin façade in Hong Kong. Energy and Buildings, 41(11), pp.1135-1142.