Technology-based Approach for the Impacts of Global Warming on the Energy Use of Air Conditioning in Taiwan

1. Copyright 2017 ITRI 工業技術研究院 1
Green Energy and Environment Research Laboratories
Industrial Technology Research Institute(ITRI), Taiwan
Technology-based Approach for the
Impacts of Global Warming on the
Energy Use of Air Conditioning in Taiwan
Hsin-Wei Hsu , Meng-Ying Lee, Pei-Ling Wen, Jing-Wei Kuo
IEA-ETSAP Workshop
College Park Marriott Hotel & Conference Center
July 10, 2017

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Outline
I. Introduction
II. Methodology and Evaluation Process
III. Results and Discussion
IV. Conclusions

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Outline
I. Introduction
II. Methodology and Evaluation Process
III. Results and Discussion
IV. Conclusions

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Overview of Taiwan’s Energy Consumption
Trend of electricity consumption (1996 – 2016)Total energy consumption, 2016
(116,808.9 103KLOE)
• The annual growth rate (1996-2016) for energy consumption: 2.65%
• The annual growth rate (1996-2016) for electricity consumption: 3.15%
• The share of electricity consumption for building sector is about 38%
• Fossil fuel power accounts for 82% of total electricity generated in Taiwan
Source: Energy statistics, 2016

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Contribution to the growth of electricity
Annual growth rate for electricity consumption
ResidentialServicesAgriculturalTransportationIndustrial
Energy sector
Own Use
Growth rate for electricity consumption by sectors, 2016
• The main increase in
electricity consumption
comes from the
residential sector in
2016.
• WHY?

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Electricity consumption from AC
Share of electricity consumption by building equipment
Residential School Office Hospital Discount
stores
Department
store
Hotel
Government
agencies
AC Lighting other devices
Reference: Taiwan Research Institute (2015), Taiwan Green Productivity Foundation (2015)
• Energy service demand for cooling is one of the key factor for the energy
consumption of building sector
• The share of electricity consumption for Air conditioning in the services sector
is about 46%, in the residential sector is about 22% in Taiwan.
• The share of electricity consumption in summer for AC in the services sector is
about 51%, in the residential sector is about 40% in Taiwan.

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The temperature is increasing…
The distribution of temperature in Taiwan, 2006-2015
Average of temperature, 2006-2015
• The temperature greater than 28oC in the last 10 years is about 2,000 hours
Source: Data Bank for Atmospheric & Hydrologic Research (TTFRI, 2016)

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Outline
I. Introduction
II. Methodology and Evaluation Process
III. Results and Discussion
IV. Conclusions

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Taiwan TIMES model
• Taiwan MARKAL model was established in 1993 with funding support from Bureau
of Energy. It was transformed into Taiwan TIMES model in 2010.
• Taiwan MARKAL/TIMES model has been supporting energy policy making including
nuclear debates, national energy development planning, INDC target setting, etc.

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Residential & Service Sector: ESD projection
 Cooling Energy Service Demand (ESD)
Total residential
floor space
Total cooling demand
of residential sector
Average cooling
load per area
Operation hours
(consider household
structure)
Total
population
Household
size(AR(1))
Household
Number
Floor space of
School/Retail/Accom
modation & Eating-
drinking/Hospital/Tran
sport/Other
Total cooling demand
of service sector
Average cooling load
per area
Operation hours
Total
population
GDP of
Service sector
Students
GDP per
capita
Regression Model
Regression Model

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Factors affected by temperature
Cooling Energy Service Demand
= Cooling Load × Usage Time × Floor Area
• The relation for electricity consumption of AC and cooling energy service
demand in Taiwan TIMES model can be showed as follow:
• Cooling load: 450Kcal/h each square meter in Taiwan.
• The values of usage time and floor are depend on the types of industries
– The annual usage time in Taiwan TIMES model
School Discount stores Hotel Hospital Transportation Other Residential
annual usage time
(hrs)
864 2,388 2,388 2,730 2,730 1,248 452
– Floor Area: According to the characteristics of each field, select the variables that may affect their
demand patterns (school age population, per capita income, service industry GDP, household
number, etc.) and establish the estimation formula.
infiltration load, transmission load(↑2.25%/oC) , internal load,
Electricity Consumption of AC
= Technical Efficiency × Cooling Energy Service Demand

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Infiltration and transmission load
• Air Enthalpy Formula (Wagner and Prub, 2002):
h(kJ/kg) = T × (1.01 + 0.00189X) + 2.5X, where
T = Temperature (°C); X = absolute humidity = Mixing ratio (g/kg)
• The infiltration load is one of the main factors contributes to cooling energy demand
infiltration load = 1.2 × Q × △h
(Q=Ventilation; △h=difference of outdoor and indoor enthalpy)
Source：Norbert Lechner (2014)
Internal load
positive relative to the infiltration load
Transmission load
• Transmission load: Based on the
surveys and comments from experts,
the temperature increase 1 °C, then
the impact for cooling load from
transmission is about 1.5% to 3%. We
set 2.25% in this study.

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Impact on technical efficiency of AC
• When outdoor temperature increases, the
overall technical efficiency of AC equipment
reduces.
• When outdoor temperature between 25~50°C,
the relation of temperature and technical
efficiency is approximately linear.
• The simulation for the case of Taiwan from ITRI
Model
Ambient
temperature(℃)
AC
Capacity(W)
System
power
consumption
(W)
COP
(W/W)
Outdoor/Indoor
AirFlow(CMM)
LST0931YG 30 2701.8 956.7 2.824 25.9/7.8
LST0931YG 35 2580 997.3 2.587 25.9/7.8
LST0931YG 40 2275.1 1045.9 2.175 25.9/7.8
Source：Industrial Technical Research Institute (ITRI), 2017
Outdoor temperature
Source：Wang (2006)
• For the air-cooled AC system, when the average ambient temperature increases 1
°C, the technical efficiency of AC, Coefficient of Performance (COP), reduces 2.3%.

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The structure of estimation for infiltration load

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IPCC AR5 RCP scenarios for localization
• 4 Representative Concentration Pathways (RCPs) of The Intergovernmental Panel
on Climate Change (IPCC)’s fifth Assessment Report (AR5)
– RCP 2.6: Peak in radiative forcing at ~ 3 W/m2 before 2100 and decline
– RCP 4.5: Stabilization without overshoot pathway to 4.5 W/m2 at stabilization after 2100
– RCP 6.0: Stabilization without overshoot pathway to 6 W/m2 at stabilization after 2100
– RCP 8.5: Rising radiative forcing pathway leading to 8.5 W/m2 in 2100.
• Taiwan Climate Change Projection and Information Platform Project (TCCIP) of
Ministry of Science and Technology (MOST) set up four RCP scenarios for the
four regions of Taiwan (North, Central, South and East).
Source: Taiwan Climate Projection and Information Platform Project (TCCIP), 2016. https://tccip.ncdr.nat.gov.tw/v2/index_en.aspx

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Step 1: The source of input data
Projection of temperature increase in four
regions of Taiwan between 2021 to 2040 and
1986 to 2005
• The future trends of absolute humidity for four
regions of Taiwan will be measured according to
the data from regional observation stations.
Humidity North = 0.622 ∗ Temperature North + 0.944
Humidity Central = 0.471 ∗ Temperature Central + 5.29
Humidity South = 0.690 ∗ Temperature South + 0.351
Humidity East = 1.386 ∗ Temperature(East) − 19.571
Source: Taiwan Climate Projection and Information Platform Project (TCCIP), 2016
• The average temperature in the summer (June to September) will increase
0.58~0.79℃ from 2021 to 2040, compared to that of 1986 to 2005, which
resulted in the adjustment of the temperature increasing from 2015 to 2030 to
be 0.25~0.34℃.
• The absolute humidity increase from 2015 to 2030 will be estimated as
0.12~0.45 g/kg

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Step 2: Scenario setting
Parameters
Outdoor conditions in Reference Scenario
Indoor
conditions
North
(Taipei)
Central
(Taichung)
South
(Kaohsiung)
East
(Hualien)
Temperature (℃) 29.42 28.97 29.58 28.51 26
Relative humidity (%) 72% 74% 78% 80% 60%
Absolute humidity (g/kg) 19.21 19.06 21.06 20.11 12.81
Enthalpy (kj/kg) 78.80 77.97 83.70 80.15 58.91
The setting of temperature, humidity and enthalpy in reference scenario
Parameters
Outdoor conditions in 2030
(Warming Scenario)
North
(Taipei)
Central
(Taichung)
South
(Kaohsiung)
East
(Hualien)
Temperature (℃)
RCP 2.6 29.70 29.25 29.86 28.78
RCP 4.5 29.71 29.27 29.88 28.80
RCP 6.0 29.67 29.23 29.84 28.76
RCP 8.5 29.75 29.31 29.92 28.83
Absolute humidity
(g/kg)
RCP 2.6 19.38 19.20 21.25 20.48
RCP 4.5 19.39 19.21 21.27 20.51
RCP 6.0 19.36 19.19 21.24 20.46
RCP 8.5 19.41 19.23 21.29 20.56
The setting of temperature and absolute humidity in warming scenario
Energy
conservation
Design
Benchmark
and Technical
Specification
Measured at
the regional
stations
Projection of
temperature
increase in four
regions from
TCCIP
Following the Air Enthalpy Formula

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Step 3: Estimation of different scenarios
• Following the air enthalpy formula, we can get the difference of outdoor and
indoor enthalpy in the reference and warming scenarios in 2030, and increase
ratio of enthalpy in warming scenarios can also be calculated.
Parameters
Difference of outdoor and indoor enthalpy
in 2030 (Unit: (kj/kg))
North
(Taipei)
Central
(Taichung)
South
(Kaohsiung)
East
(Hualien)
Reference Scenario 19.89 19.06 24.79 21.24
Warming
Scenario
RCP 2.6 20.62 19.70 25.59 22.48
RCP 4.5 20.66 19.74 25.64 22.57
RCP 6.0 20.54 19.65 25.52 22.39
RCP 8.5 20.75 19.83 25.74 22.73
Difference
between
Reference and
Warming
scenarios
(increase ratio)
RCP 2.6
0.73
(3.67%)
0.64
(3.36%)
0.80
(3.21%)
1.24
(5.85%)
RCP 4.5
0.77
(3.86%)
0.68
(3.57%)
0.85
(3.41%)
1.33
(6.24%)
RCP 6.0
0.65
(3.29%)
0.59
(3.08%)
0.73
(2.94%)
1.15
(5.40%)
RCP 8.5
0.86
(4.33%)
0.77
(4.02%)
0.95
(3.84%)
1.49
(7.03%)
Difference of outdoor and indoor enthalpy and increase ratio in 2030

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Step 4-1: Impacts on cooling ESD
• The contribution of infiltration gains for heat gains of AC is 33.3%.
(Architecture and Building Research Institute, 2015)
• Energy service demand for AC in summer increase 1% to 2.3% for different
regions and scenarios in 2030.
• The cooling energy service demand increase the most in East by 1.9% to 2.3% in
different warming scenarios due to the humidity. (lowest temperature)
Increase ratios of cooling ESD in four regions between June and September

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Step 4-2: Impacts on electricity consumption
Sectors
Share of electricity consumptions
in residential and service sectors
Share of electricity
consumptions for AC in
residential and service sectorsNorth Central South East
Residential
sector
25.4% 10.9% 15.6% 1.1% 21.90%
Service
sector
24.4% 9.7% 11.8% 1.1% 46.44%
Source: Taipower, 2016.
Share of electricity consumptions in different sectors and regions in the summer of 2015
Increase ratios of cooling ESD in residential and
service sectors between June and September
Increase ratios of electricity demand in residential
and service sectors

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Sensitivity analysis for infiltration load
• The most sensitive factor is absolute humidity in North region
Sensitivity analysis for the increase ratio of electricity demand in residential and service
sectors (RCP 8.5 scenario)

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Outline
I. Introduction
II. Methodology and Evaluation Process
III. Results and Discussion
IV. Conclusions

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Entire cooling ESD
Increase ratios of cooling ESD in four regions between June and September
Cooling Energy Service Demand
= Cooling Load × Usage Time × Floor Area
infiltration load, transmission load(↑2.25%/oC) , internal load,
1.8% 1.7% 1.7%
2.5%
2.0% 1.9% 1.8%
2.8%
1.7% 1.6% 1.6%
2.4%
2.1% 2.1% 2.1%
3.1%
0.00%
0.50%
1.00%
1.50%
2.00%
2.50%
3.00%
3.50%
North Central South East
RCP 2.6 RCP 4.5 RCP 6.0 RCP 8.5

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Entire electricity consumption
Electricity Consumption of AC
= Technical Efficiency × Cooling Load × Usage Time × Floor Area
• For the impacts on the entire energy system, it will based on the projection of
future energy mix and demand by Taiwan TIMES model.
Increase ratios of cooling ESD in residential and
service sectors between June and September
Increase ratios of electricity demand in residential
and service sectors
0.51% 0.54%
0.46%
0.60%
1.08%
1.15%
0.98%
1.27%
0.79% 0.84%
0.72%
0.94%
0.00%
0.20%
0.40%
0.60%
0.80%
1.00%
1.20%
1.40%
RCP 2.6 RCP 4.5 RCP 6.0 RCP 8.5
residential sector service sector residential and service sectors
1.81%
1.91%
1.64%
2.13%
1.81% 1.92%
1.65%
2.13%
0.00%
0.50%
1.00%
1.50%
2.00%
2.50%
RCP 2.6 RCP 4.5 RCP 6.0 RCP 8.5
residential sector service sector

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Evaluation of whole energy system
• RCP 8.5 scenario
• The impact of whole year is smaller than the estimation value of summer.
• Although the temperature rising may increase the needs of cooling demand and
electricity, technology progress and penetration of efficient equipment may
reduce the impact by using more efficiency equipment.
• The contribution of global warming is more significant in residential sector.
6.69%
21.14%
14.10%
BAU
Electricity consumption increase
between 2030 and 2015
residential sector
service sector
residential and service sectors
0.57%
0.19%
0.53%
0.21%
0.57%
0.53%
0.47%
0.45%
0.57%
0.36%
0.50%
0.35%
WARMING WARMING+TECHNOLOGY
PROGRESS
WARMING WARMING+TECHNOLOGY
PROGRESS
COMPARE TO 2015 COMPARE TO 2030
Increase reatios of electricity cunsumption from
warming
residential sector service sector residential and service sectors

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Impacts of whole energy system
• The impact of warming on total GHG emissions in Taiwan for air conditioning is
relative small no matter in the case of Low Carbon or BAU, but for residential and
service sectors, the impacts are higher.
0.12%
4.26%
0.08%
0.16%
0.52%
0.48%
0.36%
0.30%
0.12%
10.74%
0.06%
0.12%
0.18%
0.44%
0.32%
0.84%
0.00% 2.00% 4.00% 6.00% 8.00% 10.00% 12.00%
Total GHG emissions
GHG emissions in residentail and service sectors
Primary energy consumption
Total electricity consumption
Electricity consumption in residential sector
Electricity consumption in service sector
Electricity consumption in residential and service sector
coal-fired generation
Low Carbon BAU

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Outline
I. Introduction
II. Methodology and Evaluation Process
III. Results and Discussion
IV. Conclusions

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Conclusions
• The estimation shows that Eastern Taiwan needs to expand its cooling demand
more than that of other three regions under the warming scenarios due to the
humidity.
• Due to the high share of electricity consumption, the sensitive factors are
temperature and absolute humidity in North.
• The energy saving (using more efficiency equipment and reducing the use of air
conditioning) can reduce the impacts from warning.
• In residential and service sectors, temperature rising still influence GHG
emissions by increasing 4.26% in BAU and 10.74% in Low Carbon.
• In the case of Low Carbon, the increase of GHG emission mainly comes from the
increase of coal-fired electricity generation.
• Ongoing work: This study provided a preliminary research for the global warming
related to cooling demand. For the future works, we will research in other factors
related to the cooling energy service demand (like usage time) and the influence
of the peak load by warming.

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Thank You for Your Attention!
29
Contact information:
Hsin-Wei Hsu
E-mail: HW_Hsu@itri.org.tw