A novel heat pump system using a multi-stage Knudsen compressor

Kugimoto, K.; Hirota, Yasuo; Yamauchi, Tomofusa; Yamaguchi, Hiroki; Niimi, Tomohide

doi:10.1016/j.ijheatmasstransfer.2018.06.072

Cited by 16 publications

(5 citation statements)

References 23 publications

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“…Kerpicci et al investigated the effects of the oil viscosity on the performance of a reciprocating compressor, and they found that the low viscosity values affected the mass flow rates in particular. Kugimoto et al adopted a one‐dimensional analytical model to predict the performance of a novel heat pump system that used a multistage Knudsen compressor, and they found that a heat pump system with a 30‐stage Knudsen compressor can yield an output power of 1.27 kW . Torregrosa et al observed the velocity field and identified the reversed flow in a turbocharger compressor by using particle image velocimetry (PIV), and they pointed out that the results agreed well with existing numerical predictions.…”

Section: Introductionmentioning

confidence: 82%

“…Kugimoto et al adopted a one-dimensional analytical model to predict the performance of a novel heat pump system that used a multistage Knudsen compressor, and they found that a heat pump system with a 30-stage Knudsen compressor can yield an output power of 1.27 kW. 10 Torregrosa et al 11 observed the velocity field and identified the reversed flow in a turbocharger compressor by using particle image velocimetry (PIV), and they pointed out that the results agreed well with existing numerical predictions. Gancedo et al 12 described the compressor stability and surge line of a turbocharger centrifugal compressor, and they emphasized that the surge limit criterion definition is significant for the actual surge margin improvement.…”

Section: Introductionmentioning

confidence: 99%

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The energy performance of a single‐screw compressor for natural gas liquefaction process: Effects of the lubricating oil flow rate

et al. 2019

Int J Energy Res

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Summary An experimental test system including the oil circulation system and the gas circuit system has been designed and built to explore the effects of the lubricating oil flow rate on the performance of a single‐screw compressor, used in a portable natural gas liquefaction process. Outlet pressure, outlet volumetric flow rate, volumetric efficiency, and specific power rate are the parameters for evaluation of the energy performance of the single‐screw compressor. The experimental results indicate that the outlet pressure and outlet volumetric flow rate can be effectively increased by increasing the flow rate of the lubricating oil at different rotational frequencies and that a certain amount of lubricant oil is helpful to improve the volumetric efficiency. In terms of the specific power rate, the optimum oil‐gas ratios are 0.7%, 0.93%, and 1.79%, and the corresponding outlet pressures are 0.45, 0.45, and 0.48 MPa at the conditions of 50, 40, and 30 Hz, respectively.

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Section: Introductionmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

The energy performance of a single‐screw compressor for natural gas liquefaction process: Effects of the lubricating oil flow rate

et al. 2019

Int J Energy Res

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“…The energy consumption is decreased substantially compared to traditional refrigeration systems. Moreover, KPs have also been used to design a new low energy consumption heat pump system [223][224][225][226] . Using a single-stage KP, the demonstrated output power of the system is 3.09 W 226 .…”

Section: Fluid Deliverymentioning

confidence: 99%

“…Using a single-stage KP, the demonstrated output power of the system is 3.09 W 226 . A system containing a 30-stage KP produces an output power of 1.27 kW (theoretical prediction) at a temperature difference of 6 K 225 . Compared to energy conservation and consumption reduction, the development of renewable energy sources seems to have attracted more attention.…”

Section: Fluid Deliverymentioning

confidence: 99%

Knudsen pumps: a review

Wang

Zhang

et al. 2020

Microsyst Nanoeng

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The Knudsen pump (KP) is a kind of micro-pump that can form thermally induced flows induced by temperature fields in rarefied gas environments. It has the advantages of having no moving parts, simple structure, easy construction and extension, a wide range of energy sources, and low energy consumption. With the development of Micro/Nano Electro Mechanical Systems (MEMS/NEMS), extensive studies have been conducted on KPs, and the applications of KPs have widened. In order to obtain efficient flow fields in KPs, it is necessary to adopt modern computational methods for simulation and analysis. In many circumstances, the simulation and experimental results have good agreement. However, there seems to be no comprehensive review on KPs at present. In this paper, KPs are first defined and classified according to the flow mechanisms of the thermally induced flows. Then, the three aspects of configurations, performance, and applications of KPs in the current state of research are reviewed and analyzed. Finally, the current problems of KP are discussed, and some suggestions are provided for future research and applications.

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“…The reason for this is that the linear nature of a rectangular Knudsen pump does not require a gross change in mean flow direction [18]. For Knudsen pumps in rectangular layouts, in practice [12,13,[25][26][27][28][29], with the help of micro-machining technologies, heaters are placed on one side of the narrow channels. On the other side of the narrow channels, however, the temperature is decreased by placing a heat sink or the natural convection of the ambient air.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation into the Flow Characteristics of Gas Mixtures in Knudsen Pump with Variable Soft Sphere Model

Wang

Han

et al. 2020

Micromachines

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In Knudsen pumps with geometric configuration of rectangle, gas flows are induced by temperature gradients along channel walls. In this paper, the direct simulation Monte Carlo (DSMC) method is used to investigate numerically the flow characteristics of H2–N2 mixtures in the Knudsen pump. The variable soft sphere (VSS) model is applied to depict molecular diffusion in the gas mixtures, and the results obtained are compared with those calculated from a variable hard sphere (VHS) model. It is demonstrated that pressure is crucial to affecting the variation of gas flow pattern, but the gas concentration in H2–N2 mixtures and the collision model do not change the flow pattern significantly. On the other hand, the velocity of H2 is larger than that of N2. The velocities of H2 and N2 increase if the concentration of H2 rises in the gas mixtures. The results of velocity and mass flow rate obtained from VSS and VHS models are different. Finally, a linear relation between the decrease of mass flow rate and the increase of H2 concentration is proposed to predict the mass flow rate in H2–N2 mixtures.

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A novel heat pump system using a multi-stage Knudsen compressor

Cited by 16 publications

References 23 publications

The energy performance of a single‐screw compressor for natural gas liquefaction process: Effects of the lubricating oil flow rate

The energy performance of a single‐screw compressor for natural gas liquefaction process: Effects of the lubricating oil flow rate

Knudsen pumps: a review

Numerical Investigation into the Flow Characteristics of Gas Mixtures in Knudsen Pump with Variable Soft Sphere Model

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