Clothes Dryer Research Articles

Performance Improvement of a Domestic Condenser Tumble Clothes Dryer by Using a Heat Pipe Heat Exchanger

An air-to-air heat pipe heat exchanger was built and tested for a domestic condenser tumble clothes dryer in this study, which can achieve better drying performance than a water-cooled type condenser tumble clothes dryer. The heat pipe heat exchanger was made asymmetrical, which can make full use of the irregular internal space without changing the original structure of the dryer. Under the same test conditions, the condenser tumble clothes dryer with the asymmetric heat pipe heat exchanger had lower final moisture content and a faster average drying rate than the water-cooled type condenser tumble clothes dryer. The average drying rate increased by 10.032% compared with the water-cooled type dryer. At the same time, it can achieve the objective of drying clothes without using water. This can save 2600–13,000 L of water for one year and reduce the cost of drying clothes. Besides, the energy consumption was investigated. More energy consumption and drying time can reach better dry results. With the increase in the hot fluid flow rate, the energy efficiency of the dryer has a decreasing trend. As the drying process progresses, the average drying rate decreases. These conclusions are helpful in optimizing domestic condenser tumble clothes dryers.

Blade shape optimization of centrifugal fan for improving performance and reducing aerodynamic noise of clothes dryer

Blade shape optimization of centrifugal fan for improving performance and reducing aerodynamic noise of clothes dryer

Dimensional change of wool fabrics in the process of a tumble-drying cycle

Currently domestic tumble dryers are popularly used for drying garments; however, excessive drying and the inappropriate way of tumble agitation could waste energy and cause damage to or the dimensional change of garments. Shrinkage of wool fabrics during tumble drying causes a serious problem for wool garments. The current study investigated the shrinkage of untreated and Chlorine-Hercosett–finished wool fabrics at different drying times. Temperature of air in the tumble dryer, temperature of fabric, moisture content of fabric, and dimensional change at different drying times were measured. For the duration of the tumble drying, the rise of fabric temperature and the reduction of moisture content on the wool fabric were investigated to explore their relationship to the shrinkage of wool fabrics in the tumble-drying cycle. It was found that the tumble-drying process can be divided into different stages according to the temperature change trend of wool fabrics. The shrinkage mechanisms of the untreated and the treated fabrics were different. The dimensional change of untreated wool fabric was caused mainly by felting shrinkage during tumble drying. Chlorine-Hercosett–finished wool fabric can withstand the tumble-drying process without noticeable felting shrinkage due to the surface modification and resin coating of surface scales of wool fibers. The finding from the current research provides further understanding of the shrinkage behavior of wool fabrics during the tumble-drying process, leading to optimizing operational parameters at specific stages of a tumble-drying cycle.

Propose design of smart clothesline with the tree diagram approach analysis and quality function deployment method for indonesia weather

Tropical countries such as Indonesia have uncertain rainfall levels every year. This requires an innovation in technology. One example is innovation in design of clothesline in accordance with the conditions of society and the seasons that exist in Indonesia. During the rainy season, the majority of people feel anxious when hanging clothes. This is because they are afraid that if they are not at home and it rains their clothes will get wet. People, therefore, are unwilling to hang their clothes in an exposed place. Whilst, current electric clothesline are a solution, they need more power and therefore cost a lot to operate. This has an impact on the household economy. The aim of this research is to understand consumer desire for a model or design of a clothesline that will be developed with tree diagram analysis and a QFD Method (Quality Function Deployment).The outcome of this research is priority and attribute of product that will be used to design based on customer demand, among other precentage of feature “additional rain sensor on clothesline” is 21.518 %, attribute “structure of material not easy bend and break” is 12.971 %, and main priority is “Clothes dryer are easily removed and can be folded “with a value of 8.544%.

A Heuristic Home Electric Energy Management System Considering Renewable Energy Availability

This paper presents the development of a heuristic-based algorithm for a Home Electric Energy Management System (HEEMS). The novelty of the proposal resides in the fact that solutions of the Pareto front, minimizing both the energy consumption and cost, are obtained by a Genetic Algorithm (GA) considering the renewable energy availability as well as the user activity level (AL) inside the house. The extensive solutions search characteristic of the GAs is seized to avoid the calculation of the full set of Pareto front solutions, i.e., from a reduced set of non-dominated solutions in the Pareto sense, an optimal solution with the best fitness is obtained, reducing considerably the computational time. The HEEMS considers models of the air conditioner, clothes dryer, dishwasher, electric stove, pool pump, and washing machine. Models of the wind turbine and solar PV modules are also included. The wind turbine model is written in terms of the generated active power exclusively dependent on the incoming wind profiles. The solar PV modules model accounts for environmental factors such as ambient temperature changes and irradiance profiles. The effect of the energy storage unit on the energy consumption and costs is evaluated adapting a model of the device considering its charge and discharge ramp rates. The proposed algorithm is implemented in the Matlab® platform and its validation is performed by comparing its results to those obtained by a freeware tool developed for the energy management of smart residential loads. Also, the evaluation of the performance of the proposed HEEMS is carried out by comparing its results to those obtained when the multi-objective optimization problem is solved considering weights assigned to each objective function. Results showed that considerable savings are obtained at reduced computational times. Furthermore, with the calculation of only one solution, the end-user interaction is reduced making the HEEMS even more manageable than previously proposed approaches.

An efficient correlation for heat and mass transfer effectiveness in tumble-type clothes dryer drums

A heat and mass transfer effectiveness definition relevant to clothes dryers is developed in this work. A correlation is presented for determining the effectiveness of heat and mass transfer in a horizontal-axis, tumble-type clothes dryer drum with axial airflow. The correlation is a function of four measurable quantities: air mass flow rate, cloth mass, air mass in the drum, and the fall time experienced by a cloth falling the full height (i.e. diameter) of the drum. The Buckingham Pi Theorem is applied to the problem in order to derive dimensionless terms upon which the effectiveness depends. Empirical data from several dryers are used to derive an empirical correlation as a function of the dimensionless variables. Three cloth types were investigated, and a separate empirical correlation is proposed for each. Together, the drum effectiveness concept and the correlation presented provide a new, more accurate, computationally efficient, and readily implemented framework for modeling and simulating clothes dryers. It is relevant to conventional gas and electric clothes drying appliances, vapor compression heat pump dryers, and thermoelectric heat pump clothes dryers. With appropriate empirical inputs, the framework is extensible to any thermal-evaporative cloth drying systems, including radial-flow horizontal axis tumble drying drums.

Two-Stream Numerical Simulation of a New Type Drum Dryer

In recent years, the new type of tumble waste dryer has been promoted and developed. Heat generation through phase transition is an environmental, friendly and efficient heat transfer drying method. In order to know under what conditions the water vapor has higher heat transfer efficiency in the semi-circular cylinder and more sufficient liquid phase transition, and under what conditions the quantity of heat transferred can be exactly controlled, we carried out relevant work. Based on the analysis of two-phase heat transfer of rotating body, a three-dimension model of garbage dryer is established. Then, the commercial CFD software ANSYS Fluent is used to simulate the two-phase flow in the semi-circular cylinder, and the simulation calculation is carried out. Finally, the theoretical calculation results are verified by experiments. Calculated by the simulation results analysis: according to the industrial use of setting conditions, simulation calculation results can achieve convergence, namely water vapor through the pipe wall heat conduction. Finally condense into liquid water, and to ensure that the liquid cavity in the body has a higher volume fraction, water vapor phase change rate is of more than 90%, the Nusselt number of the heat transfer surface is 60 to 300.

Energetic and exergetic investigation of a novel refrigeration system utilizing ejector integrated subcooling using different refrigerants

Increase in coefficient of performance of refrigeration systems is eminently important for various applications such as household refrigerator, tumble dryer, and more in practical applications. A new ejector subcooling system is described and investigated numerically without using an extra pump or compressor. After condenser, some part of the liquid (by-pass refrigerant) is expanded so that its temperature could be lower than the intended subcooling temperature. By using this by-pass refrigerant, the main flow of the refrigerant is subcooled. After evaporation, the by-pass refrigerant is expanded using an ejector. Seven different refrigerants are considered as working fluids (namely; R32, R1234yf, R290, R134a, R717, R600a and R245fa). R1234yf, R290, R600a and R717 are considered as low global warming potential refrigerants in European Union regulation. For each refrigerant, the values of coefficient of performance, relative increment in coefficient of performance and exergy efficiencies are calculated and demonstrated graphically for different condenser temperatures between 30°C/70°C and evaporator temperatures between −20°C/10°C. Results show that the best performance is obtained for R1234yf with an increment of about 20% in coefficient of performance and 18% in exergy efficiency. These efficiencies can be higher or lower approximately by 3% using ejector with higher or lower component efficiencies.

RANCANG BANGUN SISTEM KONTROL LEMARI PENGERING PAKAIAN BERBASIS MIKROKONTROLER ATMEGA8535

Design and manufacture of this thesis aims to apply microcontroller-based technology for drying clothes automatically without relying on erratic weather conditions. The closet dryer uses a drying method forced convection, by utilizing the flow of hot fluid to reduce moisture in damp clothing. The closet dryer uses a microcontroller ATMEGA8535 as a controller of heater, fan, and UV lamps based temperature and humidity readings by sensors SHT11. The closet clothes dryer is working until the end of the moisture conditions were legible on the sensor SHT11 is <19% RH. The results of sensor readings and status of clothing displayed on the LCD 16x2. After the clothes was dried then closet dryer will informing status of clothes through a voice module ISD1820. From the results of tests and experiments, closet dryer can dry clothes with a maximum capacity of 3 kg within a period of 1 hour to 3 hours, with the value of the first moisture drying legible and on the sensor SHT11 is 70-80% RH and 17-19% RH in the end. Keywords: Type of clothing,Microcontroller ATMEGA8535,heater, fan, UV lamp, sensor SHT11, LCD16x2, ISD1820.

Causes, consequences and prevention of refrigeration fires in residential dwellings

There are around 300 residential dwelling fires in Great Britain each year where a fridge or freezer is cited as the cause. A number of these incidents have resulted in injuries/fatalities and produced significant levels of property damage. This paper examines the causes and consequences of refrigeration fires in residential dwelling fires in Great Britain (London and England) and the evidence collected via fire investigation of residential dwelling fires involving fridges or freezers. Analysis of the data collected from these fires suggests that, once ignition occurs, fires started by faults in fridge/freezers are more likely to spread beyond both the appliance and the room of origin, and tend to cause more damage than fires started by the other types of white goods appliance (washing machine, dishwasher or tumble dryer). A number of common failure modes leading to ignition in domestic refrigeration fires, along with specific fire escalation and spread mechanism are identified. Based upon the information obtained from fire investigations and a comparison between the design and construction of refrigeration appliances used in Great Britain and USA, a number of recommendations are suggested which could be used to help reduce the risk of domestic refrigeration fires.

Modeling of heat pump tumble dryer energy consumption and drying time

The use of heat pump tumble dryers is nowadays more common because they offer huge energy savings compared to conventional tumble dryers. Earlier studies made on conventional tumble dryers have shown that parameters such as heater power, fan speed, drum speed, weight and initial moisture content of textiles and air leakage have a huge impact on the energy efficiency and drying time. In the present study, a modified commercial heat pump tumble dryer was evaluated for energy consumption and drying time by changing operating parameters including fan speed, drum speed, and mass load. The total energy consumption and drying time were measured and corrected for the initial and final moisture content in the textiles. The experimental results based on 27 drying tests were evaluated to develop linear regression models for energy consumption and drying time, which show a good agreement with the experimental data. The results show that a large mass load, a high drum speed, and a low fan speed give the highest energy efficiency, i.e. the lowest energy consumption per kg of drying load. Larger loads extend the length of the drying cycle while higher fan and drum speeds result in shorter drying time.

Influence of drum inlet air conditions on drying process in a domestic tumble dryer

This study examines how the inlet air temperature, relative humidity, and flow rate influence the textile drying process in an open cycle tumble dryer. An experimental setup was prepared by connecting a domestic tumble dryer to an external system for controlled heating, humidification, and transport of air. Experiments were conducted by drying cotton textiles (8 kg dry mass) at different air inlet conditions. On the basis of measured data, correlations for determination of the total drying time, the moisture evaporation rate during the constant drying rate, and the area-mass transfer coefficient were developed. The process in the drum was modeled by using an established moisture evaporation model, based on sorption isotherms. A commonly used and a recently reported sorption isotherm for cotton were used with the model. Agreement between calculated and measured drying curves was better in case of the commonly used sorption isotherm, but final moisture content was better predicted by the recently reported sorption isotherm.

A rationally based model applicable for heat pump tumble dryer

The present study proposes a rationally based heat pump clothes dryer model which is capable of handling transient behaviors of both air-side and refrigerant side. The model can take into account the geometrical variation of the heat exchangers. Yet the proposed model is free from extra constraints that were normally imposed by previous studies. The simulation shows that there exist three stages in a typical drying process, including a preheat stage, followed by a constant evaporation stage, and finally a falling drying rate period. The calculation indicates that the variation of the clothes temperature and the system suction/discharge pressure show an appreciable rise in the first stage, remain nearly unchanged at the second stage, and increase again at the final stage of drying process. Also, the corresponding maximum specific moisture extraction rate (SMER) peaks at the end of the second stage while the corresponding coefficient of performance (COP) drops continuously. The simulation also indicates that increasing the air volumetric flowrate yields a lower discharge/suction pressure, a higher COP value, and a shorter drying time. The results also suggested that a good strategy to maximize COP is initiated by a low volumetric rate during the preheat stage, increasing it during the second stage and lowering it to an intermediate flowrate at the end of the drying period. Increasing heat exchanger size, either by increasing heat exchanger width or the number of tube row, results in a lower suction/discharge pressure and a shorter drying time. Although both approaches adopt larger surface area to promote overall performance, it is found that increasing the width of heat exchanger yields more effective results.

Utilization of waste heat for energy conservation in domestic dryers

A physical means of dehumidification was used in this study to recover and reuse waste heat emitted from tumble dryers to increase drying efficiency and decrease power consumption. An experiment was conducted; waste heat from a dryer was dehumidified in a heat exchanger, and some heat was reclaimed to preheat external air. After the optimal mixture ratio of external and re-circulated air had been determined, that optimal air mixture was introduced into the dryer through the recirculation air ducts designed in this study.Experimental results showed that the improved dryer, operated at a 60% recirculation ratio produced the highest energy efficiency, resulting in 18% less power consumption than a standard dryer. In addition, this configuration produced the lowest specific moisture extraction rate (1.099) and the highest drying efficiency (60.6%). This efficiency was higher than that of the dryer (50%) and the proposed heat exchange system was thus more energy efficient than was the dryer. The theoretical mathematical model derived in this study matched experimental results. The average error values between the theoretical and experimental values for the drying efficiency and the specific moisture extraction rate were 0.7% and 0.6%; the largest error values were only 1.5% and 1.2%.

Contributions of partial noise sources to overall noise of domestic appliance

This article describes a method to identify partial sources of noise and their respective effects on the overall noise level of a clothes dryer. The focus is on the major sources of noise and options to control their noise levels so that the resulting declaration program produces as effective as possible acoustic improvement, while maintaining the desired drying performance, as indicated by the manufacturer in the rating plate. A rating plate is the main informative indicator allowing a consumer to compare performances of various competitor products.

Biomechanical Study on the Convenience of Loading and Unloading Laundry in Clothes Dryer

Recently, household appliance designs have been emphasizing ergonomics and reducing the risk of musculoskeletal disorders for users. When laundry is taken out of a washing machine and put into a clothes dryer with the inlet in the front, a great deal of force is applied to users’ shoulders, waist, and knees. This study proposes a new door system for clothes dryer that can be used more conveniently. The characteristics of the human body when moving laundry were first analyzed. For this purpose, experiments were carried out to determine the important biomechanical and design factors. We used Rapid Entire Body Assessment (REBA) to evaluate the postures of the body. Motion data were then obtained from subjects using a three-dimensional motion analysis system. A biomechanical analysis of the internal organs in the human body was then performed using three-dimensional virtual human modeling.

The improvement on efficiency and drying performance of a domestic venting tumble clothes dryer by using a heat pipe heat recovery heat exchanger

The domestic venting tumble clothes dryer consumes a lot of energy during the drying process, which has drawn more and more attention. This article reports a method to reduce its energy consumption by using heat recovery. A self-made heat pipe heat exchanger was used for a domestic venting tumble clothes dryer as a heat recovery unit. The performance of the clothes dryer in the case of heat recovery and no heat recovery was tested under the same conditions, including weighing before drying, drying and weighing after drying. Compared with the case of without heat recovery, it can be found that the exergy efficiency of the venting tumble clothes dryer with heat recovery is increased from 10.122% to 12.292%, and the energy efficiency is increased from 47.211% to 57.335%. The increase of the temperature of the moist air entering the drum increases the temperature difference between the hot dry air and the moisture in the clothes. This enhances the evaporation of moisture. So it takes less energy to evaporate the same amount of moisture. The electricity consumption can reduce 17.606%. The effect of heat pipe heat recovery on the dryer can be a guide to the optimization of clothes dryers.

Experimental evaluation and thermodynamic system modeling of thermoelectric heat pump clothes dryer

Electric clothes dryers consume about 6% of US residential electricity consumption. Using a solid-state technology without refrigerant, thermoelectric (TE) heat pump dryers have the potential to be more efficient than units based on electric resistance and less expensive than units based on vapor compression. This paper presents a steady state TE dryer model, and validates the model against results from an experimental prototype. The system model is composed of a TE heat pump element model coupled with a psychrometric dryer sub-model. Experimental results had energy factors (EFs) of up to 2.95 kg of dry cloth per kWh (6.51 lbc/kWh), with a dry time of 159 min. A faster dry time of 96 min was also achieved at an EF of 2.54 kgc/kWh (5.60 lbc/kWh). The model was able to replicate the experimental results within 5% of EF and 5% of dry time values. The results are used to identify important parameters that affect dryer performance, such as relative humidity of air leaving the drum.

Forensic Engineering Investigations of Residential Clothes Dryer Fires

Residential clothes dryers are common in the United States, and thousands of residential fires involving clothes dryers occur each year. Forensic engineers are called upon to conduct scientific analyses of the causative factors in these fires. Forensic engineering investigations of clothes dryer fires consider design, installation, use, and maintenance of clothes dryers as well as evaluate ignition sources, first fuel ignited, fire containment and fire spread. A forensic engineering methodology for investigation of clothes dryers will bepresented in this paper, drawing on experience from hundreds of residential clothes dryer fire investigations.

Rapid-Control-Prototyping as part of Model-Based Development of Heat Pump Dryers

Today’s products are characterized by a highly interdisciplinary level. Likewise, household appliances are affected to this evolution. Mechanical structures, actuators, sensors and distributed control units can be found in modern tumble dryers, as well as in other mechatronic systems. The main challenge in the development process of such systems is to ensure the functionality which contains the proper interaction within the components of the tumble dryer. Mechanical knowledge, thermodynamical expertise, control-engineering competence and knowledge in software have to be managed and brought together. Apart from the interdisciplinary challenge, the rising functionality of modern tumble dryers leads to a further challenge, which appears in the development. Intelligent processes within their components have to be tested intensively, to ensure the benefit they promise. Time-consuming iterations during the development are inacceptable, to guarantee a specified start of production.To face the mentioned challenges in the development process, Miele already applies model-based systems engineering in its development [1]. Using simulation models enables Miele to analyze a lot of different and complex concepts of tumble dryers, to consider innovative and novel ways to dry clothes. As part of these Model-in-the-Loop simulations in early phases of the development, holistic system simulation-models are established. These models basically contain physical and control behavior. Immediately after different concepts are analyzed by the virtual systems, the concepts have to be validated.This work focusses the Rapid-Control-Prototyping (RCP) technology to validate novel innovative heating concepts for tumble dryers. Evaluation different concepts and the integration into home appliance processes is a formidable challenge, accepted in this paper. The RCP technology enables to test first component setups of heating systems, which are controlled by the simulation model of the controller. To set up the Rapid-Control-Prototyping scenario, a testing bench is built up, including equally the software-environment. The controller models are elaborated and simulated within the MathWorks® environment, in detailSimulink®/Stateflow®. This model contains the logical procedure and several safety aspects of a drying process. The simulation model is subsequent integrated into the software environment of National Instruments, to connect the virtual controller with existing and prototypical hardware components of a prototypically heat pump dryer. Within the test bench and the software periphery, the integration of the approach into the development process of Miele is described in this work.