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Evaluation of building retrofit strategies in different climate zones.

INTRODUCTION

Buildings account for 32% of total energy consumption in the world (IEA 2015). In developed countries like the United Kingdom, heating and cooling systems account for 31% of the total energy consumption (DECC 2014), and in China, 25% of total energy used is in buildings (Li and Yao 2009). With its economy prosperous and rapid urbanization (National Bureau of Statistics of China 2014), Chinese people are expecting a more healthy and comfortable indoor environment. This has resulted in tensions between three different priorities: i) energy and resource demand, ii) the environment, and iii) climate change mitigation. Due to sustainable development strategies, the Chinese government is paying great attention to building energy savings and has launched a series of policies for building retrofitting during its 12th five-year plan (MOHURD 2012). At the same time, the UK Climate Change Act 2008 legislates for an 80% reduction in carbon emissions by 2050 against the 1990 baseline (Parliament of the United Kingdom 2008).

Building retrofitting is one of the potential approaches to improve a building's energy performance and the associated carbon dioxide (C[O.sub.2]) emissions. Apart from the energy savings and carbon emission reduction, building retrofitting can also improve the indoor air quality and the level of thermal comfort. Moreover, building retrofitting helps reduce the risk of asset depreciation (The Economist Intelligence Unit 2013). Review of the open literature revealed several studies that address the energy-saving potential associated with building retrofit strategies (Hall et al. 2013; Wang et al. 2014). The aim of this study is to achieve better understanding about the potential energy savings of a variety of retrofit methods and to provide information to policy makers so that they can choose the most appropriate building retrofitting strategies.

METHODOLOGY

In this study, to evaluate the potential energy savings associated with building retrofit strategies, four scenarios were set up:

* Scenario 1: Baseline. The baseline scenario uses 1980s standards to describe the building envelope and systems. The information used for Scenario 1 regarding building use, systems operation schedules, and appliances and their use were fixed for all scenarios, even though in actual conditions it is likely that such scenario elements would be improved or reduced over time.

* Scenario 2: Base Case. This business-as-usual scenario describes a major renovation with energy-related measures included in the scope of work that meet the minimum current standards. Building use schedules and plug loads remain the same as in Scenario 1.

* Scenario 3: Deep Retrofit Plan. In this scenario, the characteristics of the core technology bundle are improved to achieve about 50% of energy use reduction against the baseline (S1). The core technology bundle includes the building fabric; lighting and daylight systems; and heading, cooling, and ventilation systems and their associated control mechanisms.

* Scenario 4: Ideal Retrofit Plan. This scenario optimizes the characteristics of the core technology bundle and uses additional energy efficiency measures.

Options considered in the core technology bundle to improve the energy efficiency of the building include the following:

* Improvement of building insulation (roof, external wall, ceiling, floor, windows) and air infiltration level

* Improvement of the electrical efficiency of indoor lighting systems and equipment

* Improvement of HVAC system efficiency (fan efficiency, boiler and chillier efficiency)

* Additional controls (occupancy profile control for lighting and equipment use, external shading, cooperative daylight control)

* Additional energy-saving strategies (mechanical ventilation, heat recovery)

[FIGURE 1 OMITTED]

From a variety of simulation packages, EnergyPlus version 8.1 (DOE 2015a) was adopted mainly due to its abilities in thermal and airflow modeling. In addition, EnergyPlus has been successfully used in several building thermal energy performance assessment and building-energy-related studies (Li and Wu 2010; Eisenhower et al. 2012; Koronaki 2013; Rodrigues and Gomes 2014). The following subsections provide further information about the simulation of the prototype buildings under different climate conditions and building retrofit plans.

Climate Conditions

According to the Chinese national standard (MOHURD 1993), climate conditions in China are categorized into five climate zones: very cold, cold, hot summer and cold winter, mild, and hot summer and warm winter. This categorization is based on maximum, minimum, and average ambient temperatures of the regions. In this study, Harbin, Beijing, Shanghai, Kunming, and Guangzhou are the cities selected to represent the broad climate conditions in China (see Figure 1). Table 1 provides both the local and international climate zone classifications for these regions. Considering different weather conditions in these areas, International Weather for Energy Calculations (IWEC) data files are used in the simulation of the prototype buildings and numerical modeling of the energy performance of building retrofit plans (DOE 2015b).

[FIGURE 2 OMITTED]

Building Model

A prototypical office building with a deep plan layout was selected to form a basis for the energy performance evaluation of building retrofit plans. The Chinese prototype building is an eight-story, naturally ventilated building with a total floor area of 13200 [m.sup.2] (142097 [ft.sup.2]). Central heating systems apply for Harbin and Beijing. The UK prototype building is a three-story, naturally ventilated cellular office called a Type 1 typical office building according to the UK's Energy Consumption Guide 19 (EEBPp 2000). It has a total floor area of 4950 [m.sup.2] (53287 [ft.sup.2]). The building aspect ratio for both Chinese and UK buildings is 1.5, and the window-to-wall ratios are 0.33 and 0.5 in China and the UK, respectively (see Figure 2). Tables 2 and 3 provide the indoor design parameters and the daily occupancy and lighting equipment load profiles considered in the simulations.

Building services operation schedules are provided in Table 4 according to the local office operation period. The selection of heating and cooling seasons are based on the local normal situation to reflect actual practice. For Harbin (China), London (UK), and Aberdeen (UK), heating supply starts in October and ends at the end of April; the remaining four Chinese cities' heating periods are from November to March, excluding Kunming and Guangzhou, which have no heating supply. The cooling supply periods for all the cities are from May to September, except for Scenario 4 in Kunming (China) and Scenario 1 in both UK cities, which have no cooling supply. For lighting operation, Chinese Scenario 1 uses the Chinese lighting profile shown in Table 3 from 7:00 to 20:00, while the other three Chinese scenarios use the profile from 11:00 to 20:00; UK Scenarios 1 and 2 use the UK lighting profile from 8:00 to 18:00 and Scenarios 3 and 4 use the occupancy profile from 8:00 to 18:00. Scenario 4 for both China and the UK uses cooperative daylight as a lighting control strategy. For Scenarios 3 and 4 for Shanghai, Kunming, Guangzhou, London, and Aberdeen, the external shading with a 0.5 shading coefficient is used in the cooling supply season (except for Shanghai and Guangzhou, Scenario 4, which have a shading coefficient of 0.8). Finally, for some cold-winter areas, namely Harbin, Beijing, and Aberdeen, heating recovery systems with 0.7 recovery rates are used during the heating supply seasons.

Building Envelope Assumption

Two base scenarios represent the typical 1980s building envelope construction (S1) and the current standard envelope construction (S2). The 1980s building envelope construction (S1) was set as the baseline for the energy usage before any measures are taken. In the business-as-usual scenario (S2), the thermal and physical characteristics of the building envelope comply with the current national standards in China and the UK. Apart from those two scenarios, the deep retrofit scenario (S3) and deeper retrofit scenario (S4) were proposed. The building envelope characteristics and HVAC system information are shown in Tables 5 and 6, respectively, for each scenario.

RESULTS AND DISCUSSION

The outcomes of the simulations are categorized to site and source energy consumption of the prototype buildings in Table 7. In general terms, site energy refers to the amount of energy used in buildings that is reflected in utility bills and source energy is the raw fuel that is used to generate the required site energy, such as electricity.

Comparing the energy performance of the prototype buildings under different retrofit scenarios (Table 8) reveals that in China, implementing the deep retrofit plan (S3) could reduce the total site and source energy consumption of the buildings in the ranges of 46.51% to 52.63% and 38.39% to 50.83%, respectively, compared with the base scenario (S1). The highest site and source energy savings were achieved in Beijing and Shanghai, respectively, and the lowest site and source energy savings were achieved in Kunming (46.51%) and Harbin (38.39%), respectively. In the UK, the deep retrofit plan (S3) contributed to savings in total site and source energy consumption up to 51.45% and 31.96%, respectively, in London (climate zone 4A) and 60.05% and 42.15%, respectively, in Aberdeen (climate zone 5A). The simulation outcomes (Tables 7 and 8) indicate that the deeper retrofit scenario (S4) can further improve the total source energy efficiency of the prototype buildings up to 22.52% and 10.28% higher than the deep retrofit scenario (S3) in China and the UK, respectively.

In China, implementation of the deep retrofit plan (S3) can achieve up to 66.54% and 60.90% savings (in the Beijing case) in the site and source energy consumption associated with heating and cooling systems (Table 8). In addition, the deep retrofit scenario (S3) can save up to 79.45% (in the Aberdeen case) and 70.85% (in the London case) of site and source energy consumption of heating and cooling systems in the UK. Moreover, the deeper retrofit scenario (S4) can improve the level of savings in source energy consumption associated with heating and cooling systems in the range of 54.92% (Guangzhou) to 100% (Kunming) in China and 60.14% (London) to 78.91% (Aberdeen) in the UK.

CONCLUSION

This paper presents strategic studies about the feasibility of retrofit plans applying the core technology bundle to mitigate the energy consumption in existing Chinese and UK buildings by 50% based on 1980s construction (baseline scenario, S1). Simulation results demonstrate that the target of 50% reduction in energy consumption cannot be achieved through the retrofit plan in Scenario 2 that only complies with the minimum requirements of the current building regulations and standards in China and the UK. However, this target is achievable through the deep retrofit plan (S3) and ideal retrofit plan (S4) in different climate zones in China and in the UK.

The baseline (S1) complies with 1980s building regulations and standards for naturally ventilated buildings. In this scenario, the central heating period is fixed from October to the end of February in Harbin and Beijing. The external walls and windows in China were poorly insulated in pre-1980s buildings, and there is no central heating system in Shanghai, Kunming, or Guangzhou. The insulation levels of the baseline (S1) in China were worse than those in the UK. Therefore, the improvement of the insulation level in China is more significant than in the UK to reach 50% reduction in energy consumption. In addition, in China, there will be a greater potential for energy reduction if a renovation level similar to that in the UK cases is adopted. However, the economic cost analysis should be considered. Government measures play an important role in China's progress towards a resource-conservation and environmentally friendly society. Stricter compliance and verification systems should be established in order to implement energy-efficiency codes and standards in actual practice.

The limitation of this research is that the energy simulations are based on typical naturally ventilated office buildings.

Further studies are needed for different building types and energy systems associated with office buildings.

REFERENCES

ASHRAE. 2013. ANSI/ASHRAE Standard 169-2013, Climatic data for building design standards. Atlanta: ASHRAE.

DECC. 2014. Official statistics: Energy consumption in the UK. London: Department of Energy & Climate Change. https://www.gov.uk/government/statistics/energy-consumption-in-the-uk.

DOE. 2015a. EnergyPlus Energy Simulation Software, ver. 8.1. Washington, DC: U.S. Department of Energy Building Technologies Office and National Renewable Energy Laboratory. http://apps1.eere.energy.gov/buildings /energyplus/?utm_source=EnergyPlus&utm_medium =redirect&utm_campaign=EnergyPlus%2Bredirect%2B1.

DOE. 2015b. EnergyPlus Energy Simulation Software: Weather Data Sources. Washington, DC: U.S. Department of Energy Building Technologies Office and National Renewable Energy Laboratory. http://apps1.eere.energy.gov/buildings/energyplus/weatherdata_sources.cfm.

EEBPp. 2000. Energy consumption guide 19: Energy use in offices. London: Energy Efficiency Best Practice Programme. www.targ.co.uk/other/guide19.pdf.

Eisenhower, B., Z. O'Neill, S. Narayanan, V.A. Fonoberov, and I. Mezi. 2012. A methodology for meta-model based optimization in building energy models. Energy and Buildings 47(0):292-301.

Hall, M.R., S.P. Casey, D.L. Loveday, and M. Gillott. 2013. Analysis of UK domestic building retrofit scenarios based on the E.ON Retrofit Research House using energetic hygrothermics simulation--Energy efficiency, indoor air quality, occupant comfort, and mould growth potential. Building and Environment 70(0):48-59.

IEA. 2015. Energy efficiency. Paris: International Energy Agency. http://www.iea.org/aboutus/faqs/energy efficiency/.

Koronaki, I.P. 2013. The impact of configuration and orientation of solar thermosyphonic systems on night ventilation and fan energy savings. Energy and Buildings 57(0):119-31.

Li, B., and R. Yao. 2009. Urbanisation and its impact on building energy consumption and efficiency in China. Renewable Energy 34(9):1994-98.

Li, Y.M., and J.Y. Wu. 2010. Energy simulation and analysis of the heat recovery variable refrigerant flow system in winter. Energy and Buildings 42(7):1093-99.

MOHURD. 1993. GB50176-93, Thermal design code for civil building. People's Republic of China: Ministry of Housing and Urban-Rural Development.

MOHURD. 2012. The 12th five year plan--Building energy saving special planning [in Chinese]. People's Republic of China: Ministry of Housing and Urban-Rural Development. http://www.mohurd.gov.cn/zcfg/jsbwj_0/jsbwjjskj /201205/W020120531015852.doc.

National Bureau of Statistics of China. 2014. China statistical yearbook. Beijing: China Statistic Press.

Parliament of the United Kingdom. 2008. Climate Change Act 2008. London, UK. http://www.legislation.gov.ukZu kpga/2008/27/pdfs/ukpga_20080027_en.pdf.

Rodrigues, A.M., and M.G. Gomes. 2014. Natural ventilation of a room with an atmospheric-vent water heater in both on- and off-states. Energy and Buildings 74(0):53-60.

The Economist Intelligence Unit. 2013. Investing in energy efficiency in Europe's buildings: A view from the construction and real estate sectors. London: The Economist Intelligence Unit Ltd. http://www.gbpn.org/s ites/default/files/06.EIU_EUROPE_CaseStudy.pdf.

Wang, P., G. Gong, Y. Wang, and L. Li. 2014. Thermodynamic investigation of building integrated energy efficiency for building retrofit. Energy and Buildings 77(0): 139-48.

Runming Yao, PhD, CEng Member ASHRAE

Mehdi Shahrestani, PhD Associate Member ASHRAE

Shiyu Han

Baizhan Li, PhD Member ASHRAE

Xinyi Li

Runming Yao is a global expert professor at Chongqing University, Chongqing, China, and a professor at the School of the Built Environment, University of Reading, Reading, UK. Shiyu Han is a master's student and Mehdi Shahrestani is a research fellow at the School of the Built Environment, University of Reading. Xinyi Li is a PhD researcher at the Key Laboratory of Three Gorges Reservoir Regions' Eco-Environment, MoE, Chongqing University. Baizhan Li is a professor at the Key Laboratory of Three Gorges Reservoir Regions' Eco-Environment and a director of the National Centre for International Research of Low Carbon and Green Buildings, funded by the MOST, Chongqing University.
Table 1. Climate Zones Categorization of the Studied Regions

                           Climate Zones Categorization

City/Country       Thermal Design Code for      Climatic Data for
                        Civil Building               Building
                        (MOHURD 1993)             (ASHRAE 2013)

Harbin/China              Very cold             Zone 7--Very cold
Beijing/China                Cold              Zone 4A--Mixed humid
Shanghai/China    Hot summer and cold winter   Zone 3A--Warm humid
Kunming/China                Mild              Zone 3C--Warm marine
Guangzhou/China   Hot summer and warm winter    Zone 2A--Hot humid
London/UK                     --               Zone 4A--Mixed humid
Aberdeen/ UK                  --               Zone 5A--Cool humid

Table 2. Indoor Design Parameters

Country   Scenario   Metabolic Rate,        Occupancy
                        W/person            Density,
                     (Btu/h/person)     person/[m.sup.2]
                                       (person/[ft.sup.2])

China        S1         108 (368)         0.150 (0.014)
             S2                           0.075 (0.007)
             S3                           0.075 (0.007)
             S4                           0.075 (0.007)
UK           S1         140 (478)         0.041 (0.004)
             S2                           0.059 (0.005)
             S3                           0.059 (0.005)
             S4                           0.059 (0.005)

Table 2. Indoor Design Parameters

Country      Power Density,         Power Density         Fresh Air
              W/[m.sup.2]            W/[m.sup.2]           Supply,
          (Btu/h x [ft.sup.2])   (Btu/h x [ft.sup.2])    L/s/person
           / Radiant Fraction     / Radiant Fraction    (ftVs/person)
              for Lighting          for Equipment

China       10.8 (3.4)/0.42         7.8 (2.5)/0.2        8.33 (0.29)
             7.8 (2.5)/0.42         6.6 (2.1)/0.2        8.33 (0.29)
             6.6 (2.1)/0.37         6.6 (2.1)/0.2        8.33 (0.29)
             5.4 (1.7)/0.37         6.6 (2.1)/0.2        8.33 (0.29)
UK           9.75 (3.1)/0.5        11.9 (3.8)/0.25        10 (0.35)
             5.20 (1.6)/0.5        11.9 (3.8)/0.25        10 (0.35)
             4.55 (1.4)/0.3        10.6 (3.4)/0.25        10 (0.35)
             4.55 (1.4)/0.3         9.3 (3.0)/0.25        10 (0.35)

* Occupancy density, lighting, equipment power density have been
multiplied with utilization rate, as 0.6 for China and 0.65 for
UK cases.

Table 3. Daily Occupancy Lighting and Equipment Load Profiles

Profile     Location   Location               Hour
            Acronym
                                  1-6   7-8   8-9    9-11   12-13

Occupancy    O-CHN      China      0    10%   50%    95%     80%
              O-UK        UK       0     0    10%    100%    75%
Lighting     L-CHN      China      0    10%   50%    95%     80%
              L-UK        UK       0     0    100%   100%   100%
Equipment    E-CHN      China      0    10%   50%    95%     80%
load          E-UK        UK      5%    5%    100%   100%   100%

Profile                     Hour

            14-16   17-18   18-19   19-20   20-24

Occupancy    95%     95%     30%     30%      0
            100%     50%      0       0       0
Lighting     95%     95%     30%     30%      0
            100%    100%      0       0       0
Equipment    95%     95%     30%     30%      0
load        100%    100%     5%      5%      5%

Table 4. Schedule of Operation for Building Services

Representative     Scenario     Heating      Cooling    Lighting *
City/Country

Harbin/ China         S1       Oct to Apr    May-Sept   7-20 L-CHN
                      S2       Oct to Apr    May-Sept   11-20 L-CHN
                      S3       Oct to Apr    May-Sept   11-20 L-CHN
                      S4       Oct to Apr    May-Sept   11-20 L-CHN
Beijing/ China        S1       Nov to Mar    May-Sept   7-20 L-CHN
                      S2       Nov to Mar    May-Sept   11-20 L-CHN
                      S3       Nov to Mar    May-Sept   11-20 L-CHN
                      S4       Nov to Mar    May-Sept   11-20 L-CHN
Shanghai/ China       S1       Nov to Mar    May-Sept   7-20 L-CHN
                      S2       Nov to Mar    May-Sept   11-20 L-CHN
                      S3       Nov to Mar    May-Sept   11-20 L-CHN
                      S4       Nov to Mar    May-Sept   11-20 L-CHN
Kunming/ China        S1       Nov to Mar    May-Sept   7-20 L-CHN
                      S2       Nov to Mar    May-Sept   11-20 L-CHN
                      S3       Nov to Mar    May-Sept   11-20 L-CHN
                      S4           --           --      11-20 L-CHN
Guangzhou/ China      S1       Nov to Mar    May-Sept   7-20 L-CHN
                      S2       Nov to Mar    May-Sept   11-20 L-CHN
                      S3       Nov to Mar    May-Sept   11-20 L-CHN
                      S4           --        May-Sept   11-20 L-CHN
London/UK             S1      Oct to April      --       8-18 L-UK
                      S2      Oct to April   May-Sept    8-18 L-UK
                      S3      Oct to April   May-Sept    8-18 O-UK
                      S4      Oct to April   May-Sept    8-18 O-UK
Aberdeen/UK           S1      Oct to April      --       8-18 L-UK
                      S2      Oct to April   May-Sept    8-18 L-UK
                      S3      Oct to April   May-Sept    8-18 O-UK
                      S4      Oct to April   May-Sept    8-18 O-UK

Representative       Lighting        External          Heat
City/Country         Control         Shading       Recovery ***
                    (Daylight     Coefficient **       Rate
                   Cooperative)

Harbin/ China           --              --              --
                        --              --              --
                        --              --              --
                        On              --             0.7
Beijing/ China          --              --              --
                        --              --              --
                        --              --              --
                        On              --             0.7
Shanghai/ China         --              --              --
                        --              --              --
                        --             0.5              --
                        On             0.8              --
Kunming/ China          --              --              --
                        --              --              --
                        --             0.5              -
                        On             0.5              --
Guangzhou/ China        --              --              --
                        --              --              --
                        --             0.5              --
                        On             0.8              --
London/UK               --              --              --
                        --              --              --
                        --             0.5              --
                        On             0.5              --
Aberdeen/UK             --              --              --
                        --              --              --
                        --             0.5              --
                        On             0.5             0.7

* Lighting schedule 7-20 L-CHN means lights are operating following
L-CHN schedule during hours 7-20 and are off at other times.

** Shading control is only applied during the cooling supply season.

*** Heating recovery is only applied during the heating supply season.

Table 5. Building Envelope Information

Representative    Scenario   Building Envelope U-factor, W/[m.sup.2]
City/Country                  x K (Btu/h x [ft.sup.2] x [degrees]F)

                              External     External    Ceiling/Floor
                                Wall         Roof

Harbin/China         S1      0.93(0.16)   0.77(0.14)    1.60(0.28)
                     S2      0.48(0.08)   0.38(0.07)    1.56(0.27)
                     S3      0.31(0.05)   0.30(0.05)    0.60(0.11)
                     S4      0.14(0.02)   0.26(0.05)    0.38(0.07)
Beijing/China        S1      0.96(0.17)   1.00(0.18)    1.60(0.28)
                     S2      0.60(0.11)   0.53(0.09)    1.56(0.27)
                     S3      0.48(0.08)   0.38(0.07)    0.60(0.11)
                     S4      0.38(0.07)   0.17(0.03)    0.53(0.09)
Shanghai/China       S1      1.53(0.27)   1.00(0.18)    1.60(0.28)
                     S2      0.96(0.17)   0.77(0.14)    1.56(0.27)
                     S3      0.60(0.11)   0.53(0.09)    0.60(0.11)
                     S4      0.48(0.08)   0.38(0.07)    0.53(0.09)
Kunming/China        S1      1.60(0.28)   1.00(0.18)    1.60(0.28)
                     S2      1.53(0.27)   0.77(0.14)    1.56(0.27)
                     S3      0.96(0.17)   0.53(0.09)    0.60(0.11)
                     S4      0.60(0.11)   0.38(0.07)    0.53(0.09)
Guangzhou/China      S1      1.60(0.28)   1.00(0.18)    1.60(0.28)
                     S2      1.53(0.27)   0.77(0.14)    1.56(0.27)
                     S3      0.96(0.17)   0.53(0.09)    0.60(0.11)
                     S4      0.60(0.11)   0.38(0.07)    0.53(0.09)
London/UK            S1      0.96(0.17)   0.53(0.09)    1.53(0.27)
                     S2      0.28(0.05)   0.18(0.03)    0.22(0.04)
                     S3      0.22(0.04)   0.13(0.03)    0.19(0.02)
                     S4      0.15(0.03)   0.12(0.02)    0.14(0.02)
Aberdeen/UK          S1      0.96(0.17)   0.53(0.09)    1.53(0.27)
                     S2      0.27(0.05)   0.20(0.03)    0.22(0.04)
                     S3      0.22(0.04)   0.13(0.03)    0.19(0.02)
                     S4      0.15(0.03)   0.12(0.02)    0.14(0.02)

Representative       Building Envelope            Air
City/Country       U-factor, W/[m.sup.2]     Infiltration,
                        x K (Btu/h x         ach (per hour)
                  [ft.sup.2] x [degrees]F)

                          External
                           Window

Harbin/China             3.30(0.58)               1.5
                         2.50(0.44)                1
                         1.79(0.32)               0.5
                         0.78(0.14)               0.25
Beijing/China            6.40(1.13)               1.5
                         2.50(0.44)                1
                         1.79(0.32)               0.5
                         1.20(0.21)               0.25
Shanghai/China           6.40(1.13)               1.5
                         3.10(0.55)                1
                         2.55(0.45)               0.5
                         1.77(0.31)               0.25
Kunming/China            6.40(1.13)               1.5
                         3.10(0.55)                1
                         2.70(0.48)               0.5
                         2.55(0.45)               0.25
Guangzhou/China          6.40(1.13)               1.5
                         3.10(0.55)                1
                         2.55(0.45)               0.5
                         1.77(0.31)               0.25
London/UK                4.80(0.85)               1.5
                         1.80(0.32)               1.0
                         1.32(0.23)               0.5
                         0.78(0.14)               0.3
Aberdeen/UK              4.80(0.85)               1.5
                         2.00(0.35)               1.0
                         1.79(0.32)               0.5
                         0.78(0.14)               0.3

Table 6. HVAC System Information

Representative    Scenario       Heating System/         Boiler
City/Country                        Setpoint           Efficiency/
                                  Temperature,          Heating
                             [degrees]C ([degrees]F)   System COP

Harbin/China         S1            CH/20 (68)           0.67/0.8
                     S2            CH/20 (68)           0.78/0.8
                     S3            CH/20 (68)           0.89/0.8
                     S4            CH/20 (68)           0.95/0.9
Beijing/China        S1            CH/20 (68)           0.67/0.8
                     S2            CH/20 (68)           0.78/0.8
                     S3            CH/20 (68)           0.89/0.8
                     S4            CH/20 (68)           0.95/0.9
Shanghai/China       S1           SAC/18 (64.4)          --/2.6
                     S2           SAC/18 (64.4)          --/2.8
                     S3           SAC/18 (64.4)          --/3.4
                     S4           SAC/18 (64.4)          --/3.6
Kunming/China        S1           SAC/18 (64.4)          --/2.6
                     S2           SAC/18 (64.4)          --/2.8
                     S3           SAC/18 (64.4)          --/3.4
                     S4                --                  --
Guangzhou/China      S1           SAC/18 (64.4)          --/2.6
                     S2           SAC/18 (64.4)          --/2.8
                     S3           SAC/18 (64.4)          --/3.4
                     S4                --                  --
London/UK            S1           CH/22 (71.6)          0.75/0.8
                     S2           CH/22 (71.6)          0.82/0.8
                     S3           VAV/22 (71.6)          0.9/0.8
                     S4           VAV/22 (71.6)         0.95/0.9
Aberdeen/UK          S1           CH/22 (71.6)          0.75/0.8
                     S2           CH/22 (71.6)          0.82/0.8
                     S3           VAV/22 (71.6)          0.9/0.8
                     S4           VAV/22 (71.6)         0.95/0.9

Representative    Cooling System/   Cooling    Ventilation
City/Country         Setpoint       System       Type/Fan
                   Temperature,       COP       Efficiency
                    [degrees]C
                   ([degrees]F)

Harbin/China       SAC/26 (78.8)      2.6        Natural
                   SAC/26 (78.8)      2.8        Natural
                   SAC/26 (78.8)      3.4     Mechanical/0.7
                   SAC/26 (78.8)      3.6     Mechanical/0.8
Beijing/China      SAC/26 (78.8)      2.6        Natural
                   SAC/26 (78.8)      2.8        Natural
                   SAC/26 (78.8)      3.4     Mechanical/0.7
                   SAC/26 (78.8)      3.6     Mechanical/0.8
Shanghai/China     SAC/26 (78.8)      2.6        Natural
                   SAC/26 (78.8)      2.8        Natural
                   SAC/26 (78.8)      3.4        Natural
                   SAC/26 (78.8)      3.6        Natural
Kunming/China      SAC/26 (78.8)      2.6        Natural
                   SAC/26 (78.8)      2.8        Natural
                   SAC/26 (78.8)      3.4        Natural
                        --            --         Natural
Guangzhou/China    SAC/26 (78.8)      2.6        Natural
                   SAC/26 (78.8)      2.8        Natural
                   SAC/26 (78.8)      3.4        Natural
                   SAC/26 (78.8)      3.6        Natural
London/UK               --            --         Natural
                   SAC/23 (73.4)     2.55        Natural
                   VAV/23 (73.4)      2.8     Mechanical/0.7
                   VAV/23 (73.4)       3      Mechanical/0.8
Aberdeen/UK             --            --         Natural
                   SAC/23 (73.4)     2.55        Natural
                   VAV/23 (73.4)      2.8     Mechanical/0.7
                   VAV/23 (73.4)       3      Mechanical/0.8

CH = central heating system with boiler and hot water radiator

SAC = split air-conditioning unit

VAV = variable-air-volume system connected to a central heating and
cooling system with boiler and chiller

Table 7. Annual Energy Consumption and Annual Energy Costs of
Prototype Buildings in Different Scenarios and Regions

City        Scenario            Annual Energy Consumption,
                              kWh/[m.sup.2] (kBtu/[ft.sup.2])
                          Heating          Cooling        Lighting

Harbin         S1      238.65 (75.69)   12.12 (3.84)    35.26 (11.18)
               S2      165.39 (52.45)    9.03 (2.86)    17.61 (5.59)
               S3      91.40 (28.99)    12.01 (3.84)    14.45 (4.58)
               S4      57.75 (18.32)     9.03 (2.86)     6.68 (2.12)
Beijing        S1      116.82 (37.05)   26.56 (8.42)    35.11 (11.14)
               S2      53.25 (16.89)    19.29 (6.12)    17.57 (5.57)
               S3      33.85 (10.74)    14.12 (4.48)    14.85 (4.71)
               S4       30.65 (9.72)     9.70 (3.08)    10.01 (3.17)
Shanghai       S1       24.90 (7.90)    34.00 (10.78)   35.30 (11.20)
               S2       15.00 (4.76)    21.47 (6.81)    17.54 (5.56)
               S3       9.53 (3.02)     16.35 (5.19)    15.46 (4.90)
               S4       5.06 (1.60)      9.98 (3.17)     8.48 (2.69)
Kunming        S1       8.44 (2.68)     11.35 (3.60)    35.27 (11.19)
               S2       6.34 (2.01)      7.16 (2.27)    17.63 (5.59)
               S3       3.01 (0.95)      5.96 (1.89)    14.84 (4.71)
               S4            0                0          8.12 (2.58)
Guangzhou      S1       2.59 (0.82)     42.97 (13.63)   35.58 (11.28)
               S2       2.16 (0.69)     27.16 (8.61)    17.79 (5.64)
               S3       1.14 (0.36)     21.06 (6.68)    14.97 (4.75)
               S4            0          20.54 (6.51)     9.58 (3.04)
London         SI      88.98 (28.22)          0         25.13 (7.97)
               S2      61.98 (19.66)     3.74 (1.19)    13.28 (4.21)
               S3       14.63 (4.64)     7.97 (2.53)    10.01 (3.17)
               S4       13.74 (4.36)     6.86 (2.18)     7.05 (2.24)
Aberdeen       S1      135.30 (42.91)         0         25.13 (7.97)
               S2      96.87 (30.72)     0.51 (0.16)    13.28 (4.21)
               S3       22.43 (7.11)     5.37 (1.70)    10.01 (3.17)
               S4       17.67 (5.60)     3.43 (1.09)     7.20 (2.28)

City                  Annual Energy Consumption,
                   kWh/[m.sup.2] (kBtu/[ft.sup.2])
              Equipment     Fans, Pumps,     Total Site
                            and Controls      Energy *

Harbin      18.36 (5.82)    1.03 (0.33)    306.47 (97.20)
            15.52 (4.92)    0.63 (0.20)    209.16 (66.34)
            15.05 (4.77)    15.81 (5.01)   154.05 (48.86)
            14.85 (4.71)    10.06 (3.19)   100.87 (31.99)
Beijing     18.29 (5.80)    0.90 (0.29)    201.21 (63.82)
            15.49 (4.91)    0.62 (0.20)    106.44 (33.76)
            15.47 (4.91)    16.28 (5.16)   95.31 (30.23)
            15.28 (4.85)    9.49 (3.01)    76.64 (24.31)
Shanghai    18.38 (5.83)    6.34 (2.01)    119.20 (37.81)
            15.46 (4.90)    4.38 (1.39)    74.47 (23.62)
            15.46 (4.90)    1.31 (0.42)    58.62 (18.59)
            15.44 (4.90)    2.01 (0.64)    41.38 (13.12)
Kunming     18.37 (5.83)    3.11 (0.99)    76.78 (24.35)
            15.54 (4.93)    2.14 (0.68)    48.98 (15.53)
            15.46 (4.90)    1.45 (0.46)    41.07 (13.03)
            15.45 (4.90)         0          23.78 (7.54)
Guangzhou   18.53 (5.88)    5.42 (1.72)    104.51 (33.15)
            15.68 (4.97)    3.76 (1.19)    66.17 (20.99)
            15.59 (4.94)    2.90 (0.92)    55.66 (17.65)
            15.59 (4.94)    2.59 (0.82)    48.32 (15.33)
London      34.38 (10.90)        0         154.83 (49.11)
            34.13 (10.82)   1.18 (0.37)    123.73 (39.24)
            30.34 (9.62)    5.61 (1.78)    75.17 (23.84)
            26.47 (8.40)    4.58 (1.45)    65.49 (20.77)
Aberdeen    34.38 (10.90)        0         200.94 (63.73)
            34.13 (10.82)   0.73 (0.23)    155.61 (49.35)
            30.34 (9.62)    5.33 (1.69)    80.28 (25.46)
            26.47 (8.40)    4.49 (1.42)    66.08 (20.96)

City          Annual Energy Consumption,         Annual Cost of
            kWh/[m.sup.2] (kBtu/[ft.sup.2])        Energy per
                 Total Source Energy *              [m.sup.2]

Harbin              471.78 (149.63)                [yen]121.7
                    316.26 (100.30)                 [yen]82.5
                    290.67 (92.19)                  [yen]64.7
                    193.19 (61.27)                  [yen]42.0
Beijing             392.92 (124.62)                 [yen]85.7
                    226.19 (71.74)                  [yen]46.8
                    230.79 (73.20)                  [yen]43.9
                    177.59 (56.32)                  [yen]34.3
Shanghai            377.52 (119.73)                 [yen]61.7
                    235.85 (74.80)                  [yen]38.3
                    185.64 (58.88)                  [yen]30.2
                    131.05 (41.56)                  [yen]21.3
Kunming             243.17 (77.12)                  [yen]39.7
                    155.12 (49.20)                  [yen]25.4
                    130.08 (41.26)                  [yen]21.1
                     75.32 (23.89)                  [yen]12.2
Guangzhou           330.98 (104.97)                 [yen]54.1
                    209.57 (66.47)                  [yen]34.2
                    176.27 (55.91)                  [yen]28.6
                    153.02 (48.53)                  [yen]24.9
London              290.65 (92.18)            [pounds sterling]9.3
                    244.85 (77.66)            [pounds sterling]8.1
                    197.77 (62.72)            [pounds sterling]6.7
                    168.75 (53.52)            [pounds sterling]5.7
Aberdeen            340.64 (108.04)           [pounds sterling]10.5
                    271.58 (86.13)            [pounds sterling]8.8
                    197.06 (62.50)            [pounds sterling]6.6
                    162.04 (51.39)            [pounds sterling]5.5

* For London and Aberdeen, the total energy usage include DHW
consumption.

Table 8. Site and Source Energy Saving Associated with Each
Building Retrofit Scenario in Different Regions

City        ASHRAE Climate Zone       Chinese Climate Zone

Harbin       Zone 7, very cold             Very cold

Beijing     Zone 4A, mixed humid              Cold

Shanghai    Zone 3A, warm humid    Hot summer and cold winter

Kunming     Zone 3C, warm marine              Mild

Guangzhou    Zone 2A, hot humid    Hot summer and warm winter

London      Zone 4A, mixed humid               --

Aberdeen    Zone 5A, cool humid                --

City        Scenario                 Site

                        Energy Savings    Total Energy
                       Associated with       Savings
                         Heating and      Compared with
                       Cooling Compared        S1
                           with S1

Harbin         S1             --               --
               S2           30.45%           31.75%
               S3           58.76%           49.73%
               S4           74.28%           67.09%
Beijing        S1             --               --
               S2           49.41%           47.10%
               S3           66.54%           52.63%
               S4           71.86%           61.91%
Shanghai       S1             --               --
               S2           38.08%           37.53%
               S3           56.06%           50.82%
               S4           74.47%           65.29%
Kunming        S1             --               --
               S2           31.78%           36.21%
               S3           54.67%           46.51%
               S4          100.00%           69.03%
Guangzhou      S1             --               --
               S2           35.65%           36.69%
               S3           51.27%           46.74%
               S4           54.92%           53.77%
London         S1
               S2           26.14%           20.09%
               S3           74.60%           51.45%
               S4           76.85%           57.70%
Aberdeen       S1             --               --
               S2           28.03%           22.56%
               S3           79.45%           60.05%
               S4           84.41%           67.11%

City                        Source

             Energy Savings      Total Energy
            Associated with    Savings Compared
              Heating and          with S1
            Cooling Compared
                with S1

Harbin             --                 --
                 29.98%             32.96%
                 53.28%             38.39%
                 71.44%             59.05%
Beijing            --                 --
                 43.10%             42.43%
                 60.90%             41.26%
                 69.46%             54.80%
Shanghai           --                 --
                 38.08%             37.53%
                 56.06%             50.83%
                 74.47%             65.29%
Kunming            --                 --
                 31.78%             36.21%
                 54.67%             46.51%
                100.00%             69.03%
Guangzhou          --                 --
                 35.65%             36.69%
                 51.27%             46.74%
                 54.92%             53.77%
London
                 17.03%             15.76%
                 55.19%             31.96%
                 60.14%             41.94%
Aberdeen           --                 --
                 27.21%             20.27%
                 70.85%             42.15%
                 78.91%             52.43%
COPYRIGHT 2016 American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
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Article Details
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Author:Yao, Runming; Shahrestani, Mehdi; Han, Shiyu; Li, Baizhan; Li, Xinyi
Publication:ASHRAE Transactions
Article Type:Report
Date:Jan 1, 2016
Words:5747
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