| 摘要 | ABSTRACT
1. The Purpose of Study
The Paris Agreement, an agreement on new climate regime, was adopted at the 21st Conference of the Parties to the United Nations Framework Convention on Climate Change(UNFCCC) in December 2015. Accordingly, most of the UNFCCC Parties, including Korea, submitted their voluntary greenhouse gas emission reduction targets to the UN in late 2015. For its part, Korea set out its 2030 target of reducing greenhouse gas emissions by 37% from business-as-usual(BAU) levels.
To join such global efforts to reduce greenhouse gas emissions (GHGs) as well as an active response to the evolving paradigm in the global energy market, the Korean government unveiled its ��2030 New Energy Industry Dissemination Strategy�� in November 2015. New energy industries represent business models built on key policies, of existing ones on energy demand side management and GHGs reduction, that can serve as new drivers of economic growth. New energy industries consist of 8 business models – electric vehicles, the demand response market, self-sufficient energy islands, energy storage systems (ESS), eco-friendly energy towns, zero energy buildings, utilization of hot waste water at power plants, and solar power rentals. By encouraging participation from the private sector, the government is seeking to create markets for these models.
This study covers zero energy buildings as a business model related to buildings. This model represents a policy that is not new but one that the government has consistently stayed with as a key measure to reducing GHG emissions of buildings. The 2nd Energy Master Plan set out in January 2014 stated that the government would tighten energy-saving design standards that apply to new buildings, with the goal of making all new buildings zero energy by 2025. A zero energy building is one that produces the total amount of energy used by the building with renewable energy created in the building.
In order to reduce such GHG emissions (in the household, commercial, and public sectors), which account for roughly 19% of the nation��s total final energy consumption based on 2015 estimates, it is significant not only to make new buildings zero energy, but also to steadily improve efficiency of energy use for existing buildings, amounting to as many as approximately 6.5 million complexes.
To reduce building energy demand and GHG emissions, figuring out the architectural features and energy use patterns of the nation��s buildings is paramount. This would include building shape, materials, and insulation of a building envelope and windows, which materially affect building energy demand. Specific information on energy use patterns would include which energy sources are used, for what purpose, through which facilities and equipment, and how much. Only when such basic information has been obtained, can an evaluation of the effects of building energy saving policies be conducted.
A survey of commercial and public buildings has been ongoing for three years to provide basic data for establishment and evaluation of energy policies for buildings, with a total of 599 buildings selected as survey samples. Sample designs and the survey system were set up in the first year. Then, analyses of energy consumption characteristics, including estimation of building energy demand functions, were performed in the second. During this, the third year, survey data on the sampled buildings has been compiled. Key data include architectural features (such as building shape, outer wall and window materials, and insulation), current status of energy facilities and equipment in buildings (facility types and capacities, and utilized energy sources), activity data (such as hours of building use and facility operation), and monthly consumption by energy sources.
The core purpose of this study is to apply the survey data to the energy modeling technique using an engineering-based simulation model to estimate the amount of energy consumed by building sector (sales, offices, education and research, and broadcasting and communication), building size, and end-use. Another key purpose of this study is to suggest the implications of the case study on the effects of energy saving policies.
2. Summary
This study first of all involves an in-depth analysis of overseas cases of the most advanced building energy survey systems in operation, and found that the most realistic alternative for the estimation of energy consumption by end-use is to interconnect the survey data and a separate analysis method. This study used ��eQUEST�� as the analysis tool for estimation of energy consumption by end-use. Taking into account the constraints (including budget and time) and purpose of this study, eQUEST was deemed the optimal analysis tool.
This study identified additional survey items needed to operate eQUEST, and completed improvements to the questionnaire before going ahead with the 2016 sample survey. The Korea Energy Engineers Association (KEEA) was responsible for conducting this survey. For network energy, such as electricity and city gas, the KEEA conducted a survey of suppliers only on buildings that consented to provide this information. It ultimately collected questionnaires from 580 of the 599 sampled buildings, with the remaining 19, or about 3% of the total, declining to participate in the 2016 survey.
Analysis of a building energy modeling first requires establishment of standard building models. This study did so in 4 building sectors – sales, offices, education and research, and broadcasting and communication. Since the characteristics of energy use differ according to building size, this study reclassified the standard building models by building sector into 5 building sizes (medium 1, medium 2, large 1, large 2, and large 3), and conducted simulation analysis.
The outcome of this analysis of the energy model for standard models for 4 building sectors is as follows. Regarding electricity consumption, the gap between standard consumption defined by standard models and predicted consumption through simulation (the sum of consumption by end-use) was within the established error range. That is, with respect to electricity consumption, the sum of consumption by end-use derived from the model showed little difference from actual numbers, demonstrating high reliability of the model. On the other hand, when it comes to gas consumption, simulation figures for all standard building models exceeded the allowable error range. This is probably attributable to gas consumption of the buildings actually surveyed, rather than a reflection of problems with the model. A precise review of the gas consumption of these buildings is required.
Analysis shows that sales buildings, lighting and electric devices make up 40-50% of total final energy consumption, while air conditioning, heating, and ventilation make up 50-60%. Air conditioning energy differs depending on the type of equipment used in standard buildings, but is the sum of energy used by freezers, electronic heat pumps (EHPs), cooling towers, and other pumps during the air conditioning period. Heating energy is the amount of energy used by boilers, EHPs, and other pumps during the heating period. Ventilation energy includes energy used for fans related to air conditioning, heating, and air intake and exhaust systems.
For a case study of policy effects based on a simulation model, this study selected a policy of replacing double pane transparent windows of existing standard office buildings with double pane low-E windows. Since windows have a higher heat transmission rate than outer walls, they have a high heat loss. In office buildings, windows make up about 50% of the area of a building envelope on average, making it crucial to bring down the heat transmission rate of windows in office buildings in order to improve energy efficiency. Assuming that the energy efficiency policy (introduction of double pane low-E windows) is implemented on all sample office buildings, annual electricity consumption is estimated to decrease by 41.1GWh, or 5.1% and gas by 2.2 million �� or 8.6%.
In addition, this study selected another policy of replacing the fluorescent lamps of existing standard office buildings with LED (Light Emitting Diode) lamps for the second case study. Assuming the second energy efficiency policy is implemented on all sample office buildings, annual electricity consumption is estimated to decrease by 26.0GWh, or 3.3%, while, gas consumption is estimated to increase by 0.7 million �� or 2.8%.
Finally, extrapolating above estimation results to all office building in Seoul, annual greenhouse gas emissions from electricity are expected to fall by 141,155t of CO2 (��5.1%) and those from gas by 33,009 of CO2 (��8.6%) by introduction of double pane low-E windows.
This study is the first research in the nation that associates a building energy survey project with an energy modeling technique. Taking into account cases both at home and abroad, this method is believed to be the most effective for classification of building energy consumption by end-use. However, this study has several weaknesses including the problem of survey data quality due to limited budget and project period, and fundamental limitations of an engineering-based model.
In order to boost efficiency of energy policies for buildings, it is recommended that investment be expanded to conduct a micro-survey on buildings. At the same time, a data construction systems and analytic methodologies should be developed consistently. |
