Research Project Simulation Wäschepflege Recommendations for Improving Resource Efficiency in the Laundry Washing Process in Households in Germany

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1 Research Project Simulation Wäschepflege Recommendations for Improving Resource Efficiency in the Laundry Washing Process in Households in Germany K. Ellmer 1,2, M. Fuchs 1, U. Bauer 1, T. Schneider 1, P.-U. Thamsen 2, T. Morgenthal 2,4, J. Villwock 3, A. Hanau 4, 1 HTW Berlin, Clothing Technology/Fabric Processing, Germany. 2 Technical University Berlin, Fluid System Dynamics, Germany. 3 Beuth Hochschule für Technik Berlin, Mechanical Engineering, Germany. 4 BSH Bosch und Siemens Hausgeräte GmbH Berlin, Germany. Abstract The resource consumption of energy, water and detergents during the washing process of laundry in private households in Germany is remarkably high, with over 5.5 billion kilowatt hours of electricity (kwh) and 380 million cubic meters of water used every year. To address this situation researchers from three different universities (Technical University Berlin, HTW Berlin, Beuth Hochschule Berlin) together with their industrial partner (BSH Bosch und Siemens Hausgeräte GmbH) are working in an interdisciplinary team to solve this resource dilemma. The main objectives of the research program Simulation Wäschepflege are to identify ways to: Improve the resource efficiency in private washing Reduce the water pollution during the washing process, while sustaining high level laundry care at the same time The work of the research team includes (1) an analysis of basic principles of the mechanical action in washing machines by using Design of Experiments, FEM simulations and physical textile testing of various textiles in the laboratory. In addition (2) a consumer survey has been conducted to gain understanding of the education level of consumers on washing principles. In this paper the excerpts from the results of the interdisciplinary research program Simulation Wäschepflege will be presented together with the survey results, also giving an insight into endconsumer behavior. Furthermore, ideas for the future of washing will be discussed in reference to increased sustainability and resource efficiency of the washing process. 1 Introduction Washing clothes is a frequent process in each household. In Germany 4 kg laundry per person and week are washed and 20 million tons of laundry are obtained yearly. 1 The resource consumption of energy, water and detergents during the washing process of laundry in private households is remarkably high. In the laundry process in private households in Germany 5.5 billion kilowatt hours of electricity (kwh) and 380 million cubic meters of water as well as tons of detergent are used. 2 Not only in Germany but also in most industrialized countries, washing machines and tumble dryers are the two highest energy-using appliances in the average home, after refrigerators. 3 Clothes washing needs 12 % of the total water consumption 1 Vgl. N.N. (2011):Textilien richtig waschen - Werte erhalten!; Forum Waschen c/o Industrieverband Köperpflege- und Waschmittel e.v. (Hrsg.), Frankfurt a. M., S Vgl. Pakula, C.; Stamminger, R. (2010): Electricity and water consumption for laundry washing by washing machine worldwide; In: Energy Efficiency, November 2010, Springer, S ACEEE (2011): American Council for an Energy-Efficient Economy, Washington, D.C (Accessed: 09/2014)

2 of drinking water in private households in Germany and is therefore the third biggest item. Dishwashing in comparison requires 6 % of the water consumption. 4 Due to this data and the high impact laundry has on a sustainable future, research into the washing process, the behavior of the consumer, and their role in the process is needed. The main influence on resource consumption and on good cleaning performance is described in Sinner s Circle for Laundry and Cleaning (Figure 1) and listed below: mechanical action, time, chemistry and temperature. As the circle underlines, the segments can be changed in their size, but by reducing the size of one segment another segment size is consequently increased. For example, if temperature is reduced in order to save energy the amount of time required to complete the washing process will be increased, or more chemistry has to be used. However, two extremely relevant aspects are missing in this view: Both 1) Textiles and 2) consumer behavior in laundry care. Both have an enormous influence on resource efficiency and on cleaning performance. Figure 1: Sinner s Circle for Laundry and Cleaning Researchers from three different universities (Technical University Berlin, HTW Berlin, Beuth Hochschule Berlin) and their industrial partner (BSH Bosch und Siemens Hausgeräte GmbH) currently work in an interdisciplinary research program called Simulation Wäschepflege. The main objective of this program is to improve resource efficiency during the washing process while achieving high-level gentle laundry care. With the interdisciplinary team the entire washing process with all aspects involved can be researched. Different fields of the washing and drying process that influence the development of more resource and energy efficient washing machines have been identified. The research focuses on the following fields: The analysis and the simulation of the washing process The behavior of the textiles and garments in the washing process The impact of the consumer on the washing process The focus areas, the current state of the teams research and its results are described in the research steps. 4 Vgl. Erhebung des Bundesverbandes der Energie- und Wasserwirtschaft zum Thema Verwendung von Trinkwasser in deutschen Haushalten im Jahr 2013 nach Verwendungsart; URL: (Accessed: 09/2014). 2

3 2 Research Program The research program was funded by an interdisciplinary team in The idea is to work with an interdisciplinary structure to find new answers to the complex process of washing. The research network includes the Technical University Berlin Department of Fluid System Dynamics (Prof. Dr.-Ing. Paul Uwe Thamsen), the Hochschule für Technik und Wirtschaft (HTW) Berlin Clothing Technology/Fabric Processing (Prof. Monika Fuchs, Prof. Ulrich Bauer, Prof. Dr.-Ing. Thomas Schneider), the Beuth Hochschule für Technik Berlin Mechanical Engineering (Prof. Dr.-Ing. Joachim Villwock) and BSH Bosch und Siemens Hausgeräte GmbH Berlin (Dr. Andreas Hanau). Approved research projects within the program are: DynTexTro Ansätze zur Vorhersage der Dynamik der Wäsche in der bewegten Trommel (time period 04/ /2013), the prediction of the dynamic of laundry in the moved drum and OptWaTro - Reduktion des Ressourcenverbrauchs durch Optimierung der Waschmechanik in der Trommel (time period: 10/ /2016). The focus is on the reduction of the resource consumption by optimizing the washing mechanics in the drum. 3 Research Steps The work of the research program include an analysis of basic principles of the mechanical action in washing machines by using Design of Experiments, FEM simulations and physical textile testing of various textiles in the lab. In addition a consumer survey was conducted. The washing behavior of 840 consumers in Germany was analyzed in The consumers were asked questions about themselves and their households, washing machines and practices, laundry sorting and ideas for future washing. A detailed description of each research step is listed below. Analysis of basic principles of the mechanical action in washing machines by using Design of Experiments An important part of the interdisciplinary research program focuses on the simulation of the entire washing process by computer to enable the development of environmentally friendly washing machines. Those should need less water while reaching the same hygienic washing results with very low temperature. Figure 2: Transparent washing machine So far the development of washing machines depends primarily on prior physical testing. The process prediction on the basis of valid results from simulation is a new approach. The mathematical modeling and the simulation of the laundry movement in the rotating drum is a first 3

4 step in that direction. A transparent washing machine was designed and developed in 2012 for this purpose. Figure 2 shows the transparent washing machine. The transparent washing machine is used for detecting the three-dimensional movement of the laundry items and the water in the drum as well as for validating the simulation. The movement can be recorded with video cameras and the mode of motion can be evaluated by analyzing the videos. During the proceedings of the project the transparent machine will be developed further and a sensor-based method for tracking the motion of the laundry items will be added and evaluated. The results show that the rotation of the laundry items is not evenly spread across the drum. The irregular stops of the laundry have an impact on the washing performance. The knowledge of the combination of mechanical washing action and washing performance by statistical methods (Design of Experiments) means that the mathematical model is able to predict the results of the washing process, which is relevant for the development of new washing machines. Physical textile testing of various textiles in the lab To develop a mathematical model and a simulation of the laundry movement in the rotating drum the material parameters of the laundry must be clearly described. In a first step it was tested which parameters have an impact on the rheological behavior. The physical textile testing of various textiles in the lab results in parameters or dimensions of the material, such as the type of fiber, the thread constructions, the construction of the fabrics, the design of the garment or the type of seams. Referring to DIN EN 60456, woven cotton towels and bed sheets were mainly tested. The tests include e.g. mass, thickness, water absorption capacity and textile friction (Figure 3). Figure 3: Testing textile friction Depending on the test equipment and the technical realization the tests were made in three clearly defined textile conditions: dry, damp and wet. Because of adhesive forces that occur while testing damp and wet textiles the tests had to be modified or sometimes even cancelled. All material parameters are collected in a textile database and provided for the use in the simulation models. 4

5 Analysis of consumer behavior by an online-survey As the figure (Figure 4: Consumer activities of Laundry Care) implies, the consumer has a high impact on the whole process of washing. Laundry care is not an automated process in which the washing machine operates independently. The consumer decides based on their personal understanding of cleanliness which garments should be washed in which combination (laundry load). The process of combining garments is of high interest, as laundry load should match with the washing program. After filling the machine the consumer chooses the type and the amount of detergent, the temperature, the program, the water level and the washing time. All decisions can be based on the textile material and the processing of the garment. After the laundry is sorted and put into the washing machine, the type and amount of detergent and the washing program are decided by the user, laundry washing is done automatically by the washing machines, as used in industrialized countries. wearing storing collecting folding sorting ironing pretreatment drying preparing and filling in the laundry washing process selection of the washing program selection and dosing of detergent Figure 4: Consumer activities of Laundry Care The development, implementation and evaluation of the online based consumer survey was carried out in The survey focused on how the consumer organizes the whole process, comes to decisions and which knowledge is relevant to them. Furthermore, ideas for future washing were collected. It is important to analyze consumer behavior as the improvement of the washing machine and the laundry process is based on the exact knowledge of the usage of the person who is in charge of washing in a household. One aspect of particular importance in this paper is therefore the results of the online-based consumer survey. Online surveys are advantageous in that they offer cost-efficient and quick access to possible respondents combined with digital collection of data, which has a positive effect for further processing of the data. The main disadvantage of online surveys is that results are restricted in their representation through self-selection of respondents and the missing information on the 5

6 population of Internet users and washing households in Germany. Although self-selection is considered to be a methodical weakness, it can also have a positive effect on the quality of the answers because the respondents that take part in the survey are highly motivated to answer and take interest in the survey topic. The development of the survey consisted of the conception of the questions based on the results from secondary research, of the construction of the questionnaire layout in consultation with a marketing expert and of the implementation of the questionnaire with professional software and evaluation with pretests. The link to the survey was mailed to friends, family and colleagues and spread via networks of the cooperation partners. The respondents were also asked to invite more people to the survey. The evaluation of the survey included a check for completeness. Unfinished questionnaires were deleted while missing values were replaced by using multiple imputation techniques. The survey consisted of 42 questions in total. Both question types (open and closed questions) were used. Closed questions were used as multiple-choice-questions with single or multiple options to answer or as matrix questions. The questions focused on the following fields: person, washing machine, washing programs, laundry and future ideas. Concerning to the given answer the respondents had to answer between 8 and 38 questions. A detailed description of the results is listed below. In total, 840 people from all over Germany took part in the survey. Only the small number of 8,4 % left the questionnaire unfinished. The reduced sample size relates to 770 respondents. The average age is 31 and three-quarters are female. The household sizes of the respondents, specifically the frequency of single-person-households, two-person-households, three-personhouseholds and more-person-households coincide with data from the Central Statistical Office in Germany. More than the half of the sample are employed, the others are mainly students. The equipment level with washing machines of the households also coincides with data from the Central Statistical Office in Germany and is around 97 %. The equipment level with dryers is 29 % in the survey sample, which is 12 % lower than the data from the Central Statistical Office in Germany. This might be interpreted by the young average age of the sample. In general the equipment level of washing machines and dryers increases with the household size. The most frequently used washing programs have been Koch-/Buntwäsche (Cotton), followed by Pflegeleicht (easy care) and Kurzwäsche (short program). Special programs are only available for one third and mainly seldom used. The most frequently used washing temperature is 40 degrees Celsius, followed by 60 degrees Celsius and 30 degrees Celsius. Only 10 % wash cold or at 90/95 degrees Celsius. Based on filter questions, the survey sample can be clustered into different types of persons. One detected type is the person who is not responsible for laundry washing at home. This type mainly consists of men. The other type consists of persons who mainly or sometimes do the laundry. This type is mainly made up of women. This finding clearly shows that women mainly do the laundry in German households. More types of persons can be clustered as people who sort the laundry before the washing process and people who do not sort the laundry before the washing process. A remarkable 10 % of the survey sample does not sort the laundry at all. Of the 90 % who sort the laundry, two thirds sort by type of the textile, which means that they wash clothes and household items such as towels and bed sheets separately. The frequency of washing loads in the households depends on the household size, the individual sorting process and the composition of the washing loads. As household size increases, as does the number of washing loads. The more exactly the laundry is sorted the more washing loads are washed per week. More than three-quarters sort by color, half separate clothing from household items, and half use the care symbols in the textile garments, which is remarkably few. Only one quarter of the survey sample pays attention to the material composition of the textile garments, the used fibers or the degree of soiling. 6

7 More than two thirds of the respondents in the survey sample wash specific garments inside out. To those garments belong mainly jeans, T-shirts and printed clothing. Zippers are closed before the washing process by half of the respondents and buttons are closed by a quarter. Half of the respondents use laundry nets for special garments like bras, tights and lingerie. More than half wash special garments in separate washing loads. To those garments mainly belong towels and bed linen. On the basis of these results two washing loads for further textile testing in the lab can be identified: One washing load consisting of towels, the other of bed linen. Low energy and water consumption, energy-saving-washing programs and long durability are very important criteria for the respondents when thinking about buying a new washing machine. 60 % of the survey sample think that in the year 2030 the washing will change and be different from today. The ideas of the consumer vary from sharing the washing machines to digitized and communicating washing machines and laundry items to garments that will not require washing anymore. 4 Results and Discussion Laundry washing and tasks related to laundry washing such as sorting and drying belong to daily tasks in households in Germany and raise many questions regarding the consumers. The results of the questionnaire clearly indicate that in particular, the sorting process of the laundry and the preparation of the laundry items before the washing process are time consuming and not done optimally concerning energy and water consumption or the gentle care of the garments. Some consumers sort their laundry in a very detailed and exact manner. Because of the detailed sorting, a higher number of washing loads results and therefore a higher number of wash loads per household and week. This is counterproductive concerning a sustainable washing process because energy and water consumption is higher. The analysis clearly underlines the significance of the consumer and their influence on the process. Research results show that consumers have to undertake several tasks and come to numerous decisions concerning the washing process. Examples of which are: collecting, preparing and sorting the laundry, compose the laundry loads, decide on the type and dosing of washing detergent, temperature and washing program, line or tumble drying, ironing, folding and storing. This leads to the insight that consumers are mainly responsible for resource consumption of energy, water and detergent during the washing process. A second insight is the finding that consumers are very interested in laundry washing. The selfselection of the survey sample was an advantage concerning the high amount of respondents who were highly motivated and answered the open questions with a lot of detail. The respondents detailed many problems and wishes about laundry washing. Furthermore consumers were asked to imagine living and washing in the year Collected ideas vary from very sustainable to high-resource demanding visions. 5 Conclusion Finally two recommendations can be derived from the results when thinking of a sustainable future: 1) The research on consumer behavior in the laundry process needs to be improved to make an effort in influencing consumer behavior towards a sustainable lifestyle. 2) It is important that consumers learn more about textiles and the washing process so that they can act in a more sustainable manner. As an alternative, the responsibility of the consumer towards resource consumption during the washing process could be minimized. One of the next main tasks for future research for the project team will be to intensify research on consumer behavior. Another result of the work shows the necessity to extend the research on the washing process from analyzing the mechanics and process inside the washing machine itself towards the whole washing process including upstream and downstream process phases. This will be one of the next main tasks for the research program Simulation Wäschepflege for its future research. 7