Energy Savings Potential and RD&amp;D Opportunities for Non-Vapor-Compression HVAC Technologies

None, None

doi:10.2172/1220817

Cited by 18 publications

(3 citation statements)

References 19 publications

(48 reference statements)

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“…Accordingly, we should either go back to where it all started, which is using natural refrigerants, such as carbon dioxide, ammonia and hydrocarbons, and try to overcome their inherent shortcomings or move towards alternative non-vapor compression cooling technologies by redefining the notion of refrigerant. Solid-state cooling/heat pumping technologies, such as electrocalorics, magnetocalorics, barocalorics and elastocalorics are some of the alternative cooling technologies [6][7][8][9], among which elastocalorics are recognized as the most promising non-vapor-compression cooling technology according to the U.S. Department of Energy and the EU Commission [10,11].…”

Section: Introductionmentioning

confidence: 99%

From the elastocaloric effect towards an efficient thermodynamic cycle

et al. 2022

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In recent years, elastocaloric cooling technology has been considered as one of the most promising alternatives to vapor compression technology. Given that elastocaloric technology is only in the early stages of development, a uniform method for evaluating the elastocaloric effect has not yet been established, and the thermodynamics of different elastocaloric cooling cycles have not yet been studied in detail. Therefore, the main goal of this work is to investigate these two important areas. Here, multiple thermodynamic cycles were studied, focusing on the parameters of the holding period of the cycle, which is essential for heat transfer between the elastocaloric material and the heat sink/source. The cycles were applied to commercially available superelastic thin-walled NiTi tubes under compressive loading and a thin NiTi wire under tensile loading. Isostress cycles with constant stress throughout the holding period, isostrain cycles with constant strain throughout the holding period and no-hold cycles (without a holding period) were studied across multiple stress/strain ranges. Based on the experimental results, a previously developed phenomenological model was applied to better understand and further evaluate the different cycles. The results revealed that the applied thermodynamic cycle significantly affects the thermomechanical response and thus the cooling/heating efficiency of the elastocaloric material. We show that by using isostress cycles and partial transformations, a Carnot-like thermodynamic cycle with improved heating/cooling efficiency can be generated. By applying the isostress cycles, an adiabatic temperature change of 30.2 K was measured, which is among the largest directly measured reproducible adiabatic temperature changes reported for any caloric material to date. Ultimately, this study intends to serve as a basis for establishing a uniform method for evaluating the elastocaloric effect in different materials that would allow for reliable and accurate one-to-one comparison of the reported results in the rapidly growing field of elastocalorics.

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Section: Introductionmentioning

confidence: 99%

From the elastocaloric effect towards an efficient thermodynamic cycle

et al. 2022

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“…Nearly all cooling and air-conditioning devices out there, as well as heat-pumps, are based on vapour compression technology, which is over a century old. In fact, this is one of the oldest electricity-based technologies still in use, without a viable alternative [2]. Over the decades of development, vapour compression technology has increased its efficiency and specific power (and therefore its compactness) along with reducing its environmental impact.…”

Section: Introductionmentioning

confidence: 99%

“…the elastocaloric effect (eCE) in superelastic shape-memory alloys (SMAs), opens up new avenues for solid-state refrigeration. According to the great potential of eCE, the US Department of Energy in 2014 [2] and more recently also the European Commission in 2016 [10] selected the elastocaloric cooling technology as the most promising alternative to the vapour compression refrigeration in the future.…”

Section: Introductionmentioning

confidence: 99%

Elastocaloric Cooling: State-of-the-art and Future Challenges in Designing Regenerative Elastocaloric Devices

Kabirifar

Žerovnik

Ahčin

et al. 2019

SV-JME

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The elastocaloric cooling, utilizing latent heat associated with martensitic transformation in shape-memory alloys, is being considered in the recent years as one of the most promising alternatives to vapour compression cooling technology. It can be more efficient and completely harmless to the environment and people. In the first part of this work, the basics of the elastocaloric effect (eCE) and the state-of-the-art in the field of elastocaloric materials and devices are presented. In the second part, we are addressing crucial challenges in designing active elastocaloric regenerators, which are currently showing the largest potential for utilization of eCE in practical devices. Another key component of elastocaloric technology is a driver mechanism that needs to provide loading for active elastocaloric regenerators in an efficient way and recover the released energy during their unloading. Different driver mechanisms are reviewed and the work recovery potential is discussed in the third part of this work.

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Room‐Temperature Colossal Elastocaloric Effects in Three‐Dimensional Graphene Architectures: An Atomistic Study

Zhao

Guo

Zhang

2022

Adv Funct Materials

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Solid‐state cooling exploits the thermal response of caloric materials when subjected to external physical fields and represents a promising alternative to conventional refrigeration technologies. However, existing caloric materials are often limited by relatively small caloric response and hysteresis issues rooted in first‐order structural transitions. Here, colossal and reversible elastocaloric effects near room temperature in superelastic graphene architectures are predicted by thermodynamic analysis and atomistic calculations. The estimated adiabatic temperature change can reach a value of 155 K under a compressive stress of 0.7 GPa in a wide temperature range of around 300 K, yielding outstanding elastocaloric strength and efficiency. More unique is that both cooling and warming can be realized in the materials by applying tensile and compressive strains to host conventional and inverse elastocaloric effects, respectively, with almost no fatigue behavior and hysteresis effect. Such unprecedented elastocaloric performance results from a strain‐induced large change in configurational entropy in the graphene architectures. These effects are potentially extendable to other superelastic nanomaterials and hence suggest new material settings for developing high‐performance solid‐state refrigerants.

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Energy Savings Potential and RD&D Opportunities for Non-Vapor-Compression HVAC Technologies

Cited by 18 publications

References 19 publications

From the elastocaloric effect towards an efficient thermodynamic cycle

From the elastocaloric effect towards an efficient thermodynamic cycle

Elastocaloric Cooling: State-of-the-art and Future Challenges in Designing Regenerative Elastocaloric Devices

Room‐Temperature Colossal Elastocaloric Effects in Three‐Dimensional Graphene Architectures: An Atomistic Study

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