Ultra-low district heating (ULTDH) networks are operated at temperatures below 30 °C. However, the temperatures supplied are still too low for direct heating of the consumers. Heat pumps use the ...heating network as a source and can supply the consumers with space heating and domestic hot water as needed. Although individual manufacturers provide performance figures for the source temperature of 20 °C, these are usually derived from extrapolation from standard conditions with source temperatures of 0 °C and 10 °C. Up to now practical measurements are missing how efficiently heat pumps work in an ULTDH network environment and how the network temperature spread affects the performance. In this paper test rigs are used to investigate heat pumps under the conditions in ULTDH networks at a network supply temperature of 20 °C. It is shown that heat pumps can operate up to twice as efficient as with a geothermal probe. Furthermore, the network temperature spread has a significant influence on the performance of the heat pump. Heat pumps operate significantly better with a low source temperature spread.
•Test rig measurements for heat pump efficiency in an ULTDH network environment.•Network supply temperature of 20 °C.•Impact of the network temperature spread on the heat pump performance.•COP maximum COP of 10 at a source outlet temperature of 17 °C in the ULTDH network.•Heat pumps compressor limitations must be considered in ULTDH networks.
The piston/cylinder pair is the critical lubricating interface of axial piston pumps. It suffers from excessive wear, especially under high output pressure. The performance degradation of the ...piston/cylinder pair is significant to be clarified. In this paper, a wear prediction method of the piston/cylinder pair is established by coupling the load-bearing and lubrication parameters calculation model and the wear calculation model. The models are validated through experiments. The experimental and simulated results show that the wear of two ends of the cylinder bore is severe in the specific ranges of circumferential angle. The time-varying wear process of the piston/cylinder pair can be obtained by using this method; therefore, the maintenance time can be predicted.
•A wear prediction method which can obtain the time-varying wear process of the piston/cylinder pair is established.•The interaction between load-bearing and lubrication parameters and surface wear is taken into account.•The simulation and experimental results show that the wear of two ends of the cylinder bore is relatively serious.•The wear process can be divided into two wear stages according to the wear rate and the wear depth.
Electrification and hybridization of off-highway vehicles have the potential to yield significant fuel savings and air emissions improvements. However, developing the required components to electrify ...these systems is an extremely challenging task due to high force and power density requirements and highly variable drive cycles. This article investigates a new approach to off-highway vehicle electrification based around a linear piston pump integrated into a linear actuator. The article first reviews linear actuator machine topologies within the context of the charge pump application requirements. A tubular machine topology is optimized for integration with a hydraulic pump and experimentally validated using a prototype machine. A multiphysics simulation framework is developed to simulate the entire charge pump design with a position regulator. An optimized design is proposed with an oscillation frequency of 132 Hz and a total system efficiency (pump and motor) calculated to be 81.3% at full load.
Idiopathic pulmonary fibrosis (IPF) is a pathological condition of unknown etiology that results from injury to the lung and an ensuing fibrotic response that leads to the thickening of the alveolar ...walls and obliteration of the alveolar space. The pathogenesis is not clear, and there are currently no effective therapies for IPF. Small airway disease and mucus accumulation are prominent features in IPF lungs, similar to cystic fibrosis lung disease. The
gene encodes the α-subunit of the nongastric H
, K
-ATPase, which functions to acidify the airway surface fluid and impairs mucociliary transport function in patients with cystic fibrosis. It is hypothesized that the ATP12A protein may play a role in the pathogenesis of IPF. The authors' studies demonstrate that ATP12A protein is overexpressed in distal small airways from the lungs of patients with IPF compared with normal human lungs. In addition, overexpression of the ATP12A protein in mouse lungs worsened bleomycin induced experimental pulmonary fibrosis. This was prevented by a potassium competitive proton pump blocker, vonoprazan. These data support the concept that the ATP12A protein plays an important role in the pathogenesis of lung fibrosis. Inhibition of the ATP12A protein has potential as a novel therapeutic strategy in IPF treatment.
In order to limit global warming of 1.5 °C before 2050, the heat pump with waste heat recovery has been acknowledged as an effective technical solution. In this paper, a new kind of centrifugal heat ...pump system is applied to recover the waste heat from a steel plant for district heating. Two centrifugal compressors with vapor injection and two-cycle parallel connected system configuration are adopted to achieve higher energy efficiency and larger heating capacity. From simulation, the COP is expected to be more than 6 with a temperature rise of above 30 °C. To validate the calculation results, a 10 MW scale (9.5 MW) centrifugal heat pump was installed and tested in Angang Lingshan steel plant of China. With the waste water inlet temperature of 32.5 °C and hot water outlet temperature of 62.5 °C, the tested COP and heating capacity were 6.67 and 9.67 MW, respectively. The heating capacity of the system was greater than the heating load under severe conditions. Environmental and economic analyses of the waste heat recovery system are presented, showing advantages compared to the conventional heating methods. The PER of megawatt compression heat pump is as high as 2.53 and the payback period of this waste heat recovery system is 1.66 years.
•Ten megawatt compression heat pump is developed for waste heat recovery.•PSF centrifugal compressor and two cycle parallel connected system is adopted.•Theoretical analysis and on-site test of waste heat recovery system are carried out.•COP of 6.67 and heat capacity of 9.5 MW are achieved.•PER of megawatt compression heat pump is up to 2.53 for district heating.
A pseudo-3D regulated dc-dc boost converter, based on a modified Dickson charge pump (DCP) topology, is presented as an effective solution to achieve optimized current conversion efficiency. In this ...solution, currents of the clock generator are directly conveyed to the DCP, with the result of reducing the power wasted by drivers and oscillator. The whole converter implements two concurrent feedback loops: the external one, constituted by the output voltage divider and the error amplifier, serving to set the output voltage; the internal one, included in the DCP core, automatically tunes the clock frequency and makes the system efficient in terms of current conversion. A prototype of the design was implemented in a standard 130-nm CMOS process and its operation was tested and compared to the previous arts.
This study reviews gas engine-driven heat pump (GEHP) systems for residential and industrial applications in terms of energetic and exergetic aspects for the first time to the best of the authors’ ...knowledge. These systems are novel heat pump systems (one of today's promising new technologies). Although the first investigations had been performed at late 1970s, the first merchandized GEHP was produced and introduced in the market in 1985. Gradually, it has become widespread all over the world for various purposes. Main application of GEHPs are for space and water heating/cooling purposes. However, they can be integrated to industrial applications, especially to drying processes.
In this study, historical development of GEHP systems was briefly given first. Next, the operation of these systems was described, while studies conducted on them were reviewed and presented in tabulated forms. GEHPs were then modeled for performance evaluation purposes by using energy and exergy analysis methods. Finally, an illustrative example was given, while the results obtained were discussed. In addition, a new project on integration of GEHP systems to food drying processes in Turkey initiated by the authors was introduced. It is expected that this comprehensive study will be very beneficial to everyone involved or interested in the energetic and exergetic design, simulation, analysis and performance of assessment of GEHP systems.
Deep learning has made remarkable achievements in fault diagnosis. However, the working conditions of the axial piston pump are diverse, and the distribution of the data is not the same, which causes ...most of the deep learning models to invalid. A deep multi-signal fusion adversarial model based transfer learning (MFAN) is presented to solve this problem. A multi-signal fusion module is designed to assigns weights to vibration signals and acoustic signals, which improves the dynamic adjustment ability of the method. Moreover, the residual network is embedded in the shared feature generation module to obtain abundant feature information. According to the different working loads of the axial piston pump, nine transfer scenarios are designed, and the proposed method is compared with five typical diagnosis methods. The average accuracy of MFAN on all scenarios reaches 98.5%, indicating this method has excellent performance in cross-domain fault detection of axial piston pumps.
Fault diagnosis is vital in manufacturing system, since early detections on the emerging problem can save invaluable time and cost. With the development of smart manufacturing, the data-driven fault ...diagnosis becomes a hot topic. However, the traditional data-driven fault diagnosis methods rely on the features extracted by experts. The feature extraction process is an exhausted work and greatly impacts the final result. Deep learning (DL) provides an effective way to extract the features of raw data automatically. Convolutional neural network (CNN) is an effective DL method. In this study, a new CNN based on LeNet-5 is proposed for fault diagnosis. Through a conversion method converting signals into two-dimensional (2-D) images, the proposed method can extract the features of the converted 2-D images and eliminate the effect of handcrafted features. The proposed method which is tested on three famous datasets, including motor bearing dataset, self-priming centrifugal pump dataset, and axial piston hydraulic pump dataset, has achieved prediction accuracy of 99.79%, 99.481%, and 100%, respectively. The results have been compared with other DL and traditional methods, including adaptive deep CNN, sparse filter, deep belief network, and support vector machine. The comparisons show that the proposed CNN-based data-driven fault diagnosis method has achieved significant improvements.
Abstract In order to analyze the effect of different tongue type on large volute pump, this paper takes a large volute pump as the research object, and analyzes the calculation results of three ...different types of volute models. The commercial modeling software UG is used to construct the small tongue angle, partitioned and large tongue angle volute based on the volute of the model pump. The ANSYS CFX is used to complete the numerical calculations. Comparative analysis of the hydraulic performance and pressure pulsation near the tongue of the three large volute pumps with different types of volutes are carried out. The results show that the efficiency of the partitioned volute plan decreases significantly under the over-load condition, and the pressure pulsation near the tongue is melted under the design condition. The small tongue angle plan is more suitable for large volute pumps.
