Polyurethane–urea elastomers as working substances in rubber heat engines

Lyon, Richard E.; Wang, D. X.; Farris, Richard J.; MacKnight, W. J.

doi:10.1002/app.1984.070290916

Cited by 11 publications

(6 citation statements)

References 20 publications

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“…Work is maximized with the requirement of positive torque in the strain range of 300–330% giving engine outputs of 65 mJ g −1 per total mass of elastomer. This predicted work output per cycle is somewhat smaller than reported experimentally for polyurethane fiber powered heat engines of 200–250 mJ g −1 , [ 8,9 ] although engine designs and types of elastomer were different in the experimental studies.…”

Section: Comparing Thermally Stimulated Actuator Materials In Heat En...contrasting

confidence: 54%

“…Work is maximized with the requirement of positive torque in the strain range of 300-330% giving engine outputs of 65 mJ g −1 per total mass of elastomer. This predicted work output per cycle is somewhat smaller than reported experimentally for polyurethane fiber powered heat engines of 200-250 mJ g −1 , [8,9] [17] and [19]. For each material, the stress-strain curves measured at two temperatures are shown: room temperature (blue) and after heating (red): 85 °C in (a) and (b) and 70 °C in (c).…”

Section: Comparing Thermally Stimulated Actuator Materials In Heat En...mentioning

confidence: 75%

“…The maximum work per engine cycle normalized to rubber mass was 257 mJ g −1 . In another demonstration from Lyon et al [9] a similar engine was fitted with 100 g polyurethane rubber fibers and generated 27 W from a temperature difference of 77 °C at 80 rpm. These performances demonstrate the potential for ordinary rubber to harness low grade heat but their practical utility has been limited by poor cycle lifetimes.…”

Section: Introductionmentioning

confidence: 99%

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Actuator Materials for Environmentally Powered Engines

Spinks

Abbasi

Gautam

et al. 2023

Adv Materials Technologies

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The first solid‐state engine that converted heat into continuous mechanical motion using a thermally responsive actuating material was introduced almost a century ago. These engines used vulcanized rubber where the cyclically heating and cooling of the rubber generate continuous mechanical power in pendulum or wheel type engines. The development of solid‐state heat engines has seen several waves of activity with interest stimulated by the introduction of new actuating materials capable of responding to different environmental stimuli. Opportunities for improved engine outputs are afforded by recently developed artificial muscle materials. A theoretical connection between engine output and the characteristics of the actuator material is developed to compare the performances of vulcanized rubber, shape memory alloys (SMAs), and twisted and coiled polymer (TCP) fiber artificial muscles. It is shown that with an engine designed to suit the actuation performance of TCPs engines powered by the tensile actuation of such materials would exceed the output of SMA heat engines. The properties needed in actuator materials to further enhance engine output are identified and polymer structures that may produce such properties are described.

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Section: Comparing Thermally Stimulated Actuator Materials In Heat En...contrasting

confidence: 54%

Section: Comparing Thermally Stimulated Actuator Materials In Heat En...mentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

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Actuator Materials for Environmentally Powered Engines

Spinks

Abbasi

Gautam

et al. 2023

Adv Materials Technologies

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“…Constructing an elastomer heat pump that enables cooling is challenging, and attempts to build one are rare. The elastocaloric effect of NR was explored to build elastomer heat engines for classroom purposes early on [24][25][26] , with theoretical description following later 27,28 . NASA patented a design for a manually operated device for use in space emergencies 29 .…”

Section: Introductionmentioning

confidence: 99%

Elastocaloric heat pump with specific cooling power of 20.9 W g–1 exploiting snap-through instability and strain-induced crystallization

et al. 2021

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Conventional refrigeration relies on hazardous agents, contributing to global warming. Soft, cheap, biodegradable solid-state elastocaloric cooling based on natural rubber offers an environmental friendly alternative. However, no such practical cooler has been developed, as conventional soft elastocaloric designs are not fast enough to ensure adiabaticity.In this work, we combine snap-through instability with strain-induced crystallization and achieve a sub-100 ms quasi-adiabatic cycling which is 30 times faster than previous design.Negligible heat exchange in expansion/contraction stages combined with the latent heat of phase transitions result in a giant elastocaloric crystallization effect. The rubber-based all-soft heat pump enables a specific cooling power of 20.9 W/g, a heat-flux of 256 mW/cm 2 , a coefficient of performance of 4.7 and a single-stage temperature span between hot and cold reservoirs of 7.9 K (full adiabatic temperature change of rubber membrane exceeding 23 K).The pump permits a compact all-soft voltage-actuated setup, opening up the opportunity of a viable plug-in-ready cooling device.

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“…These technologies include the most matured and commercialized thermoelectric cooling (Sharp et al, 2006), the rapidly developing magnetic cooling (Sarlah et al, 2006, Zimm et al, 2006, Jacobs et al, 2014, Bahl et al, 2014, electrocaloric cooling (Gu et al, 2013, Jia andYu, 2012), and the most recently proposed thermoelastic cooling (Cui et al, 2012). Although similar concepts have been applied to rubber bands with the same terminology (Fischer et al, 1994, Lyon et al, 1984, Gerlach, 2009, M A N U S C R I P T…”

Section: Introductionmentioning

confidence: 99%

Performance enhancement of a compressive thermoelastic cooling system using multi-objective optimization and novel designs

Qian

Alabdulkarem

Ling

et al. 2015

International Journal of Refrigeration

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Thermoelastic cooling is a recently proposed, novel solid-state cooling technology. It has the benefit of not using high global warming potential (GWP) refrigerants which are used in vapor compression cycles (VCCs). Performance enhancements on a thermoelastic cooling prototype were investigated. A few novel design options aiming to reduce the cyclic loss were proposed. It was found that the maximum temperature lift increased from 6.6 K to 27.8 K when applying the proposed novel designs, corresponding to 0 to 152 W cooling capacity enhancement evaluated under 10 K water-water system temperature lift. In addition, a multi-objective optimization problem was formulated and solved using the genetic algorithm to maximize the system capacityACCEPTED MANUSCRIPT 2 and coefficient of performance (COP). With all the novel designs, the optimization could further enhance 31% COP, or 21% cooling capacity, corresponding to COP of 4.1 or 184 W maximum cooling capacity. Nomenclature Symbols A area [m 2 ] COP coefficient of performance [-] c p specific heat [J·g -1 ·K -1 ] D diameter [m] GWP global warming potential HR heat recovery HTF heat transfer fluid h heat transfer coefficient [W·m -2 ·K -1 ] ID internal diameter [m] k thermal conductivity [W·m -1 ·K -1 ] L length [m] N quantity [-] OD outside diameter [m] PEEK polyether-ether-ketone ra nitinol heat transfer area to volume ratio [m -1 ] SMAs shape memory alloys sec second T temperature [K] M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 3 t time, or duration [sec] t* heat recovery duration coefficient [-] u fluid mean velocity [m·s -1 ] VCC vapor compression cycle α thermal diffusivity [m 2 ·s -1 ] β tubes holder contact area ratio [-] δ equivalent thickness [m] κ thermal mass factor ρ density [kg·m -3 ]

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Polyurethane–urea elastomers as working substances in rubber heat engines

Cited by 11 publications

References 20 publications

Actuator Materials for Environmentally Powered Engines

Actuator Materials for Environmentally Powered Engines

Elastocaloric heat pump with specific cooling power of 20.9 W g–1 exploiting snap-through instability and strain-induced crystallization

Performance enhancement of a compressive thermoelastic cooling system using multi-objective optimization and novel designs

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