DECISION-MAKING IN LOW-INCOME HOME RENOVATION THROUGH OPTIMIZATION BY BALANCING SUSTAINABILITY AND AFFORDABILITY

S team systems are a ubiquitous element in nearly every type of manufacturing plant. In the United States, steam systems are the single largest consumer of energy in the industrial sector, where they account for 37% of annual onsite energy use. Steam use is particularly prominent in the chemicals, paper, petroleum refining, and food and beverage industries, where it is used in a wide range of processes, including reforming, distillation, concentration, cooking, and drying. Together, these four industries comprise nearly 90% of U.S. industrial steam demand, with chemicals manufacturing (30%) and paper manufacturing (30%) holding the largest shares. At the national level, industrial steam systems account for around 6% of U.S. total primary energy use, or 5,900 trillion British thermal units (TBtu). As such, much attention has been paid to steam system energy efficiency improvements as part of corporate, utility, and government energy and air pollution initiatives. Key incentives include local utility rebates, tax incentives, and lowor no-cost steam system energy efficiency audits. Steam system energy efficiency not only makes sense from an environmental perspective, but also from an economic perspective. As of 2006, U.S. manufacturers spent $21 billion on externally purchased boiler fuels. The actual price tag of industrial steam is likely much higher; nearly one-half of U.S. boiler fuels are self-generated within plants in the form of waste gas, black liquor, wood wastes, and other byproducts. These byproduct fuels are not free, as they are generated from purchased materials and typically require further processing for efficient combustion. Reducing demand for boiler fuels can, therefore, help reduce operating costs and improve profit margins. While clearly justified, the historical focus on reducing energy use has overlooked an increasingly compelling benefit of steam system efficiency: namely, reduced water use. Compared to the many public and private incentives for industrial energy efficiency, there are surprisingly few external incentives for industrial water efficiency. One key barrier to such incentives is the lack of credible data on industrial water use, which, unlike data on energy use, are not compiled at the manufacturing industry or process level in regular national surveys. This dearth of data contributes to a general lack of awareness of the sources and scale of industrial water use within the engineering and policy communities, which limits broader attention to water efficiency beyond the plant floor. Another barrier to steam system water efficiency is that the cost of boiler water—and the associated chemicals required for its treatment—typically only represents a small fraction of boiler operating costs, which are dominated by the costs of fuel. However, as we discuss in this Perspective, U.S. industrial steam systems consume copious amount of water. It follows that steam systems are worth a closer look as a manufacturing water efficiency target. Several current trends suggest that water efficiency will play an increasingly prominent role in the financial and sustainability plans of U.S. manufacturers. Recent water stress due to droughts and rising water infrastructure costs have led to increased public water rates around the country. These conditions may worsen with a changing climate. An increasing number of manufacturers are reporting water use as an important environmental indicator in annual corporate sustainability reports, which raises both public awareness of and accountability for water efficiency. Many manufacturers are also being asked by their corporate customers for environmental “footprint” data as part of large-scale sustainable Correspondence concerning this article should be addressed to E. Masanet at eric.masanet@northwestern.edu; M.E. Walker at mwalker9@hawk.iit.edu.

We are faced with chronic water and energy vulnerabilities. Some argue that we will face two crises in the 21st century: a water crisis and an energy crisis (Brown 1998, 2003, Flavin 1999, Feffer 2008). Water will become increasingly scarce as water tables drop due to over-consumption and water quality will continue to deteriorate as a result of excessive contamination. Further, the present energy regime’s dependence on non-renewable sources has added considerable stress to the environment, including the prospect of climate change (Intergovernmental Panel on Climate Change 2007). We are amidst a situation where we could be easily blamed for compromising the ability of future generations to meet their needs. This paper first briefly describes a need for understanding the integrated considerations of water and energy in resource planning, especially during droughts. After introducing a conceptual framework of the water-energy integration, this paper reviews the results of a national survey of energy and water departments to see how these synergic benefits are explored at the state level. Lessons learned from our case studies serve as useful guidelines for state water-energy planning and program development. Finally, as an example case of the water-energy nexus, the concept of desalination is introduced with its implication on energy demand.

Energy savings and emission reduction benefits of China's aluminum use paths in transport sector.

Exploring the nexus between water saving and energy conservation: Insights from industry sector during the 12th Five-Year Plan period in China

Author(s): Meyers, Stephen; Williams, Alison; Chan, Peter; Price, Sarah | Abstract: This paper presents estimates of the key impacts of Federal energy and water conservation standards adopted from 1987 through 2015. The standards for consumer products and commercial and industrial equipment include those set by legislation as well as standards adopted by DOE through rulemaking. In 2015, the standards saved an estimated 4.49 quads of primary energy, which is equivalent to 5% of total U.S. energy consumption. The savings in operating costs for households and businesses totaled $63.4 billion. The average household saved $320 in operating costs as a result of residential appliance standards. The estimated reduction in CO2 emissions associated with the standards in 2015 was 238 million metric tons, which is equivalent to 4.3% of total U.S. CO2 emissions. The estimated cumulative energy savings over the period 1990-2090 amount to 216.9 quads. Accounting for the increased upfront costs of more-efficient products and the operating cost (energy and water) savings over the products’ lifetime, the standards have a cumulative net present value (NPV) of consumer benefit of between $1,627 billion and $1,887 billion, using 7 percent and 3 percent discount rates, respectively. The water conservation standards, together with energy conservation standards that also save water, reduced water use by 1.9 trillion gallons in 2015 and estimated cumulative water savings by 2090 amount to 55 trillion gallons. The estimated consumer savings in 2015 from reduced water use amounted to $12 billon.

This paper presents estimates of the key impacts of Federal energy and water conservation standards adopted from 1987 through 2012. The standards for consumer products and commercial and industrial equipment include those set by legislation as well as standards adopted by DOE through rulemaking. In 2012, the standards saved an estimated 3.6 quads of primary energy, which is equivalent to 3% of total U.S. energy consumption. The savings in operating costs for households and businesses totaled $51.4 billion. The average household saved $347 in operating costs as a result of residential and plumbing product standards. The estimated reduction in CO2 emissions associated with the standards in 2012 was 198 million metric tons, which is equivalent to 3% of total U.S. CO2 emissions. The estimated cumulative energy savings over the period 1990-2070 amount to 179 quads. Accounting for the increased upfront costs of more-efficient products and the operating cost (energy and water) savings over the products’ lifetime, the standards have a past and projected cumulative net present value (NPV) of consumer benefit of between $1,104 billion and $1,390 billion, using 7 percent and 3 percent discount rates, respectively. The water conservation standards, together with energy conservation standards that also save water, reduced water use by 1.8 trillion gallons in 2012, and will achieve cumulative water savings by 2040 of 54 trillion gallons. The estimated consumer savings in 2012 from reduced water use amounted to $13 billon.

<p>Water resources planning at the basin scale is the keystone to adaptation of water resources systems to socio-economic and climate changes. Simulation and optimization models can provide a useful support to the planning process. Besides including all significant processes, they need to incorporate the contribution of the relevant stakeholders from the early stages of their development, particularly in areas where multiple concurring uses of water resources occur and where surface water-groundwater interactions are important.  This is the case of the plain of the Lombardy Region, Italy, where an ancient system of irrigation canals has been successfully used for centuries to supply huge amounts of water to a large irrigated area, which is also one of the most industrialized in Europe (Lombardy is one of the “Four Motors for Europe”, a transnational network of highly industrialized regions including Rhône-Alpes, Baden-Württemberg and Catalonia). Indeed, the Lombardy water resources have suffered recurrent crisis in the last years and a huge pressure has been raising on irrigation water use, which is by far the main consumptive use. We illustrate here an integrated approach to the analysis of different strategies of adaptation of irrigation systems to changing conditions, which accounts for the links between water use, crop production, energy consumption and hydrological conditions (as a proxy of the ecosystems quality).  We will consider the case study of the Adda river basin, an 8,000 km<sup>2</sup> basin including lake Como, where the requirements of hydropower production and irrigation supply need to strike a balance with lake tourism, flood protection and environment conservation.</p><p>The approach is based on a combination of simulation models (of upstream sub-basin, lake and downstream sub-basin) and optimization model (of lake regulation policy) that allow assessing the effects of different climate and technological scenarios. The former scenarios were obtained downscaling the regional climate projections provided by the CORDEX project till 2100, while for the latter we focused on measures to increase the efficiency of irrigation systems, that emerged as priority from the discussions with the stakeholders. Specifically, we considered different degrees of reconversion of irrigation methods from surface irrigation to more efficient methods (sprinkler or drip). The effects of the reconversion, under different climate projections, were assessed by running simulations with the IdrAgra spatially distributed agro-hydrological model, which provided the estimated values of crop water use, groundwater recharge, return flows, as well as of crop production and energy consumption.  The comparison of different reconversion intensities was carried out considering indicators for the satisfaction of crop water requirements, the energy consumption, the groundwater recharge, and the river hydrological regime. A number of remarks can be made from the analysis of the results, among which it clearly emerged that under the current trend of increasing temperature already at the mid of the century irrigation deficits and impacts on the river hydrological regime will be intolerable unless the irrigation system efficiency will increase significantly in vast portions of the study area. Finally, a preliminary estimate of the cost of interventions is provided.</p>

Local government decision-making competition and regional carbon emissions: Experience evidence and emission reduction measures

7 - Analysis of water consumption and potential savings in a cotton textile dye house in Denizli, Turkey

Urban residential water uses entail energy consumption and associated carbon emissions. Reducing residential water uses thus can simultaneously save water and energy and help reduce carbon emissions. However, residential water uses are strongly affected by the choices of household appliances and fixtures, and water use behaviors. In this study, we first conducted a household water use survey in Shanghai, the largest city in China, to understand residential water use behaviors in different seasons. A two-stage stochastic optimization model is developed to optimize water and energy conservation decisions so as to minimize the expected total cost of water and water-related energy uses and maximize carbon emission reduction. Data collected through questionnaire surveys are used to parameterize the optimization model. Water and energy conservation choices are categorized into long- and short-term decisions. The results show that in Shanghai residential water uses has a strong impact on urban carbon emission reduction. Typical temperature range in different seasons strongly affects the effectiveness of short-term conservation actions. The results support a subsidy policy for water-saving appliances that can incentivize citizens in water-saving. Model results are useful for exploring the water-energy-carbon nexus of urban households considering seasonal factors

Waterlogging and secondary salinization have become a serious problem in the canal irrigated areas of arid and semi–arid regions worldwide. In this study, a unique and simple technique was evolved in which a linear programming (LP) optimization model was first developed that allocates available land and water resources in order to maximize net annual returns by mitigating the waterlogging problems. A finite–difference two–dimensional simulation model was then used to evaluate the long–term impacts of various water management strategies on the groundwater table with the optimal land and water use parameters which were obtained through the optimization model. The model was used to combat the waterlogging and salinity problem of an area located in Haryana State of India. The calibration, validation, sensitivity analysis, and error analysis of the model was performed before it was used to study the impact of various water management scenarios on the long-term groundwater level. Based on the model results a change in cropping pattern with reduced rice area is suggested. Groundwater withdrawal should be increased by 1–7 % in the various nodes. It is concluded from the analysis of various scenarios that implementing multiple approaches simultaneously are more effective in controlling waterlogging problems as compared to individual interventions.

본 연구에서는 댐군을 연계운영할 경우 발생하는 효과를 이수측면에서 평가할 수 있는 방법을 개발하여 한강수계 댐군 운영 실적의 평가에 적용하였다. 개발된 평가방법에서는 용수공급과 유황개선 부분에서 연계운영의 효과를 평가하기 위하여 평가지점에서 필요수량에 대한 충족률과 유황안정도를 평가지표로 사용하였다 발전 부분에서 연계운영의 효과는 댐군에 의해 생산된 총발전량을 평가지표로 사용하였다. 실제 운영실적은 공칭공급량을 공급하는 단독운영과 최적화 모형에 의한 평가지표들과 비교하여 평가되었다. 한강수계의 2001년부터 2004년까지의 실제 연계운영 실적을 단독운영과 최적화 모형의 결과와 각 연도별로 비교해 보면, 용수공급 측면에서 필요수량 충족률은 단독운영은 <TEX>$94.36{\sim}99.68%$</TEX>, 실제운영은 <TEX>$97.16{\sim}99.90%$</TEX>, 최적화 모형은 4개년 모두 100.0 %를 나타냈다. 댐 운영 방법별로 하상계수와 유황계수를 사용하여 유황안정도를 평가해 보면, 유황이 단독운영 보다 실제운영과 최적화 모형이 더 안정적인 결과를 나타냈다. 실제 총발전량을 다른 운영방법의 결과와 비교해 보면, 최적화 모형은 실제 총발전량 보다 <TEX>$-3.47{\sim}6.54%$</TEX> 증가된 결과를 나타냈으며, 단독운영은 실제 총발전량 보다 <TEX>$12.68{\sim}38.94%$</TEX> 감소된 결과를 나타냈다. In this study, a methodology was developed to evaluate the effects produced in the event of joint-operation of dams from the viewpoint of water use. It was applied to evaluating the actual results of dam operation in the Han River basin. In order to evaluate the effects of real joint-operation in terms of water supply and flow conditions, the methodology used the satisfaction rate of water requirement and the stability of flow conditions at the evaluation site as indicator. In order to evaluate the effects of joint-operation in terms of power generation, the total power generation produced by dams was used as evaluation indicator. Actual operation results were evaluated by comparison of evaluation indicators relating to single dam operation by which the notified mont of water was supplied, as well as to optimization models. Results of actual joint-operation of the Han River basin, from 2001 to 2004, were compared yearly with results from single operation and optimization model; in terms of water supply, the satisfaction ratio of water requirement stood at <TEX>$94.36{\sim}99.68%$</TEX> for single operation, <TEX>$97.16{\sim}99.90%$</TEX> for actual joint-operation, and 100.0 % for optimization model for all four years. The stability of flow condition was evaluated by the coefficient of river regime and coefficient of flow conditions definitely, indicating that flow conditions were more stable in case of actual operation and optimization models than in case of single operation. The actual total power generation was compared with that generated by other operation rules, indicating that the optimization model increased the power generation by <TEX>$-3.47{\sim}6.54%$</TEX> compared with the actual total power generation, and that the single operation decreased the power generation amount by <TEX>$12.68{\sim}38.94%$</TEX> compared with the actual total power generation.

The Mathematics of Optimization

This paper explores and analyzes the methods for predictive maintenance and deterministic maintenance scheduling for continuous process industry rotary equipments. This paper consists of a brief introduction of various types of predictive maintenance techniques, maintenance schedules and the methodology to develop the optimization models. The paper also considers a turbine as a case example for an equipment type, analysis of results using the optimization model and conclusion from the analysis and future scope related to the optimization model. In the overall end-end flow, this paper outlines the use of analytical modeling techniques to first predict for example, the likelihood of a component of an equipment failing, the recommendations that can be generated based on the predictive model scores, and then use an optimization model to generate the maintenance schedule. The predictive model and the optimization model are modular and can also be used together or in isolation to provide different set of capabilities and advantages to the end customer. Binary integer programming model is used to generate the maintenance schedule considering the deterministic part life, pulling back of events, non maintenance period of equipment and minimum number of outage. There are mainly two decisions in the optimization model which are occurrence of event for each part and outage for the equipment. Few of the business constraints are as part life for repair and replace, non maintenance period due to business requirement. The objective of the optimization model is to minimize total maintenance cost over time horizon. The generated maintenance schedule using the optimization model reduces the wastage of part life and number of outage for equipment. This also increases the utilization of the equipment. This also reduces the downtime of equipment due to unscheduled and unnecessary maintenance. Over and above this minimize the total maintenance cost of the equipment. This model can be extended to stochastic model considering stochastic failure time of parts life. Net present value can also be included to calculate the maintenance cost for long term. Production reduction is a major issue due to unscheduled maintenance. This optimization model gives an unique idea to generate the maintenance schedule for very complex machine such as turbine which has many sections, each section has many part-kit, each part-kit consist of many parts with various failure time for each type of event in a very efficient and effective way. This idea can be used for any industry which has very large and complex machine to get the maintenance schedule. Dragline in opencast mine, turbine, manufacturing industry, production industry are the suitable place to use this type of maintenance schedule.

Over the past decade, rising water and energy consumption in educational institutions has become a topic of increasing attention among the scientific and policy communities. This work assesses the potential for water and energy savings in 100 public schools in southern Brazil. There was great variation in the water consumption (0.81–35.43 l/student/day) and also great variation in the energy consumption (0.31–66.47 kWh/student/month). Two schools were selected for assessing the implementation of a rainwater harvesting system and improvements in the artificial lighting system. One of the schools has high water and energy consumption, while the other has low consumption. In the school with high consumption, the potential for potable water savings by using rainwater varied from 2996 to 5431 l/day; and the payback period ranged from 20 to 36 months. The potential for energy savings by improving the artificial lighting system was 62%; and the payback period was just five months. In the school with low consumption, the potential for potable water savings by using rainwater ranged from 542 to 1574 l/day; and the payback period ranged from 46 to 83 months. As for the improvements in the artificial lighting system, there was an increase of 13% in the monthly energy consumption due to the current low illuminance levels in the classrooms. The results show the importance of choosing strategies for decreasing water and energy consumption in schools. Such strategies are usually economically and environmentally feasible, bringing significant reduction to the consumption of water and energy.