• Energy Research

Abstract Due to the various restrictions on the energy performance of public office buildings, it is essential to obtain occupancy information for not only evaluating but also regulating the building energy performance. There is still a lack of information and standard, however, for occupancy density due to the limitations on data collection and the lack of reliable data. Therefore, this study aimed to determine the optimal occupancy density for reducing the energy consumption in public office buildings. Towards this end, this study used various statistical methods, such as correlation analysis, decision tree, and Mann-Whitney U test, based on the actual occupancy data from public office buildings in South Korea. This study was conducted in three steps: (i) establishment of the database; (ii) determination of the optimal occupancy density using the statistical approach; and (iii) application of the proposed occupancy density using building energy policies. As a result, it was shown that buildings with an occupancy density above 31.41 m2/person could save up to 50.3% energy on average compared to those with an occupancy density below 31.41 m2/person. The analysis results showed that the proposed occupancy density could help in deciding the appropriate occupancy density for reducing the energy consumption of public office buildings.

Abstract Manufacturing operations are constantly encouraged to include energy-efficient practices into their plant operations, including through rebate programs that provide monetary rewards for firms who purchase and employ energy-efficient equipment in their facilities. This article presents a novel methodology for analyzing the cascading economic and environmental effects of an electric utility company's industrial energy-efficiency rebate programs and applies it to the case of a local utility located in the U.S. state of Ohio. It examines the utility's industrial rebate programs for lighting, motor, and heating, ventilation, and air conditioning (HVAC) systems and estimates the economic and environmental impacts of the programs using an input-output modeling framework. All three rebate programs provided a modest economic boost not only to directly involved equipment manufacturers and marketing service providers, but also to other upstream industries responding to the direct impact and the final demand augmented by the associated increase in value added in the regional economy. Emissions avoided as a result of electricity savings were found to outweigh additional emissions generated from the production of the energy-efficiency equipment in the region throughout the program years. However, if the full equipment purchase data were made available, the amount of added CO2 emissions would be larger.

Abstract Despite differences in their implementation, most carbon policies aim to have similar outcomes: effectively raising the price of carbon-intensive products relative to non-carbon-intensive products. While it is possible to predict the simple broad-scale economic impacts of raising the price of carbon-intensive products—the demand for non-carbon-intensive products will increase—understanding the economic and environmental impacts of carbon policies throughout the life cycle of both types of products is more difficult. Using the example of a carbon tax, this study proposes a methodology that integrates short-term policy-induced consumer demand changes into the input–output framework to analyze the environmental and economic repercussions of a policy. Environmental repercussions include the direct and the indirect impacts on emissions, materials flow in the economy, and the reliance on various ecosystem goods and services. The approach combines economic data with data about physical flow of fossil fuels between sectors, consumption of natural resources and emissions from each sector. It applies several input–output modeling equations sequentially and uses various levels of aggregation/disaggregation. It is illustrated with the data for the 2002 U.S. economy and physical flows. The framework provides insight into the short-term complex interactions between carbon price and its economic and environmental effects.

Abstract As interest in the distributed generation of solar power system in a building facade continues to increase, its technical performance (i.e. the amount of electricity generation) should be carefully investigated before its implementation. In this regard, this study aimed to develop the nine-node-based finite element model for estimating the technical performance of the distributed generation of solar power system in a building facade (FEM9-node), focusing on the improvement of the prediction performance. The developed model (FEM9-node) was proven to be superior to the four-node-based model (FEM4-node), which was developed in the previous study, in terms of both prediction accuracy and standard deviation. In other words, the prediction accuracy (3.55%) and standard deviation (2.93%) of the developed model (FEM9-node) was determined to be superior to those of the previous model (FEM4-node) (i.e. 4.54% and 4.39%, respectively). The practical application was carried out to enable a decision maker (e.g. construction manager, facility manager) to understand how the developed model works in a clear way. It is expected that the developed model (FEM9-node) can be used in the early design phase in an easy way within a short time. In addition, it could be extended to any other countries in a global environment.

Abstract With growing public concern over the economic, environmental, and social consequences of climate change, it is crucial for manufacturers to focus on long-term sustainable development rather than short-term gains. While many large corporations have committed to sustainable manufacturing as a core component of their business, mid-sized manufacturers often lack the resources, motivation, and expertise to make this transition. Through progressive company culture, environmental and energy management systems, net-zero carbon, zero waste manufacturing, and life cycle thinking, this paper describes the necessary steps and benefits for mid-size manufacturers on the path to sustainable manufacturing.

Abstract Successfully developing and manufacturing industrial products requires considering the economic- and environmental-factors that span multiple spatial- and temporal-scales. Here, we propose an integrated approach combining an energy-economic model with a life-cycle assessment to analyze the impacts of energy policies on the dynamic changes in the various environmental impacts of a product system. We employ the Market Allocation (MARKAL) framework to foresee the changes in several economic- and technological-parameters over specific periods for different energy policies. Furthermore, we create a dynamic life-cycle inventory database to assess the changes in the future life-cycle environmental impact of a current product/process system. Our proposed method may guide industry to proactively prepare for the possible effects of different energy policies on their current product/process system's environmental profile so that they can make strategic decisions on modifications to, and investments in their production processes thereby to enhance their environmental- and economic-performance while meeting the various emission-abatement targets.

In this research, a feasibility study of using a small wind turbine as an integrated system with a solar photovoltaic system and a diesel generator was performed using the HOMER® optimization model. For this purpose three main scenarios have been taken into account. In the first two scenarios the diesel price was considered 0.8 $/L (Scenario 1) and 1.5 $/L (Scenario 2) and no limits were assumed for emissions of diesel generator. The most efficient system in the first scenario consists of one wind turbine (15 kW), a 75 kW generator, 35 batteries, and a 15 kW converter with renewable fraction of 53%. However in the second scenario, 7 kW photovoltaic array was added to the designed optimal hybrid system and thus the renewable fraction was increased to 71%. In the third scenario the limits were specified for the different pollutants using the CAP (Ontario Clean Air Program) standard. It was revealed that the optimal configuration which contains a 75 kW diesel generator, 21 kW photovoltaic array, 75 kW wind turbines, 50 batteries, and a 20 kW converter would be the most economically feasible. Emission analysis revealed that among all of the designed hybrid systems, highest level of CO2 emissions was observed for a stand‐alone diesel system with value of 115,436 kg/yr and the lowest level was observed for the hybrid system in the third scenario with value of 991 kg/yr. Additionally it was proved that the third scenario would be the best option for connecting the system to the grid. © 2015 American Institute of Chemical Engineers Environ Prog, 34: 1521–1527, 2015