“Heat from Cold” – A new cycle for upgrading the ambient heat: Adsorbent optimal from the dynamic point of view

Aristov, Yu. I.

doi:10.1016/j.applthermaleng.2017.06.107

Cited by 9 publications

(5 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As was mentioned above, a part of the adsorption heat produced at T H is utilized for isosteric heating Q(−), whereas heat Q(+) released during isosteric cooling remains in a circuit connected with the source of low potential heat at T M . Evidently, proper organization of internal heat recuperation could result in mutual compensation of Q(+) and Q(−), giving a formal thermal efficiency η ads = Q ads /(Q des + Q ev ) = 0.51 (10) that is close to the formal cycle efficiency previously reported for a single-bed HeCol prototype [11].…”

Section: Heat Balance and Performance Evaluationsupporting

confidence: 79%

See 1 more Smart Citation

A Double-Bed Adsorptive Heat Transformer for Upgrading Ambient Heat: Design and First Tests

Tokarev

2019

Energies

View full text Add to dashboard Cite

A full scale lab prototype of an adsorptive heat transformer (AHT), consisting of two adsorbers, an evaporator, and a condenser, was designed and tested in subsequent cycles of heat upgrading. The composite LiCl/SiO 2 was used as an adsorbent with methanol as an adsorbtive substance under boundary temperatures of T L /T M /T H = −30/20/30 • C. Preliminary experiments demonstrated the feasibility of the tested AHT in continuous heat generation, with specific power output of 520 W/kg over 1-1.5 h steady-state cycling. The formal and experimental thermal efficiency of the tested rig were found to be 0.5 and 0.44, respectively. Although the low potential heat to be upgraded was available for free from a natural source, the electric efficiency of the prototype was found to be as high as 4.4, which demonstrates the promising potential of the "heat from cold" concept. Recommendations for further improvements are also outlined and discussed in this paper.

show abstract

Section: Heat Balance and Performance Evaluationsupporting

confidence: 79%

“…Recently, a novel adsorption cycle called "heat from cold" (HeCol) was suggested for upgrading ambient heat [10]. The HeCol cycle consists of two isosteres (1)(2)(3)(4) and two isotherms (2)(3), and operates between three thermostats at low (T L ), middle (T M ), and high (T H ) temperatures ( Figure 1).…”

Section: Introductionmentioning

confidence: 99%

A Double-Bed Adsorptive Heat Transformer for Upgrading Ambient Heat: Design and First Tests

Tokarev

2019

Energies

View full text Add to dashboard Cite

show abstract

“…[ 12,23 ] Aristov and co‐workers have comprehensively studied the optimal working pair both theoretically and experimentally to increase useful heat generation and, thus, the cycle performance. [ 24 ] Important progress has been made, e.g., the theoretical derivation showing that the optimal working pair requires a convex/concave sorption isotherm for adsorption/desorption [ 25 ] or the experimental demonstration of pressure‐initiated desorption at very low vapor pressures. [ 26 ] Moreover, different prototypes of closed‐loop cycles have been studied experimentally at low temperatures, finding the following: 1) the cycle is experimentally feasible with a one‐bed prototype and ACM35.4 and methanol as working pair, [ 27 ] 2) composite adsorbents generate more useful heat than conventional adsorbents for the studied operating conditions, [ 28 ] and 3) a two‐bed prototype can generate useful heat quasicontinuously.…”

Section: Introductionmentioning

confidence: 99%

Closed‐Loop Adsorption‐Based Upgrading of Heat from 90 to 110 °C: Experimental Demonstration and Insights for Future Development

et al. 2022

View full text Add to dashboard Cite

Industrial energy efficiency can be increased by recovering waste heat, mainly available below 100 °C. This low‐temperature waste heat can drive adsorption heat transformers (AdHTs) to upgrade waste heat to industrially relevant temperatures above 100 °C. Flexible process integration can be achieved by decoupling adsorptive and heat transfer fluid in closed‐loop cycles. However, the experimental feasibility of closed‐loop AdHTs has not been shown yet. Hence, this work studies an experimental one‐bed setup of an AdHT based on a closed‐loop cycle using silica gel 123 and water as the working pair. Experimental feasibility is demonstrated for heat transformation from 90 to 110 °C with waste heat released at 25 °C. The highest coefficient of performance (COP) is 0.183 J J−1 (23% of the maximum Carnot efficiency), and the highest specific heating power (SHP) is 168 W kg−1. A systematic variation of the operating conditions shows that efficiency COP and power density SHP strongly depend on the operating temperatures, volume flows, and phase times. Furthermore, avoiding condensation inside the adsorber casing and heat losses are identified to be crucial for the design of AdHTs. In summary, AdHTs based on a closed‐loop cycle show a promising performance to recover low‐temperature waste heat.

show abstract

“…To the best of the authors' knowledge, so far, no experimental results were reported in the literature about AdHT technology for industrial waste heat applications. Recently, the AdHT cycle was proposed to exploit extremely low ambient temperatures under specific climatic conditions, for instance in Siberia (Russia), to upgrade waste heat in residential applications for space heating purposes [16]. The authors performed a deep development activity, starting from thermodynamic analysis [16,17] up to the experimental characterization of small-scale dynamics of the process [18].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, the AdHT cycle was proposed to exploit extremely low ambient temperatures under specific climatic conditions, for instance in Siberia (Russia), to upgrade waste heat in residential applications for space heating purposes [16]. The authors performed a deep development activity, starting from thermodynamic analysis [16,17] up to the experimental characterization of small-scale dynamics of the process [18]. They were then able to design, realize, and test a lab-scale prototype, based on the working pair silica gel-LiCl/methanol, which was tested under controlled operating conditions [19].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Performance of Adsorption Working Pairs for Low-Temperature Waste Heat Upgrading in Industrial Applications

2021

View full text Add to dashboard Cite

The present work aims at the thermodynamic analysis of different working pairs in adsorption heat transformers (AdHT) for low-temperature waste heat upgrade in industrial processes. Two different AdHT configurations have been simulated, namely with and without heat recovery between the adsorbent beds. Ten working pairs, employing different adsorbent materials and four different refrigerants, have been compared at varying working boundary conditions. The effects of heat recovery and the presence of a temperature gradient for heat transfer between sinks/sources and the AdHT components have been analyzed. The achieved results demonstrate the possibility of increasing the overall performance when internal heat recovery is implemented. They also highlight the relevant role played by the existing temperature gradient between heat transfer fluids and components, that strongly affect the real operating cycle of the AdHT and thus its expected performance. Both extremely low, i.e., 40–50 °C, and low (i.e., 80 °C) waste heat source temperatures were investigated at variable ambient temperatures, evaluating the achievable COP and specific energy. The main results demonstrate that optimal performance can be achieved when 40–50 K of temperature difference between waste heat source and ambient temperature are guaranteed. Furthermore, composite sorbents demonstrated to be the most promising adsorbent materials for this application, given their high sorption capacity compared to pure adsorbents, which is reflected in much higher achievable specific energy.

show abstract

“Heat from Cold” – A new cycle for upgrading the ambient heat: Adsorbent optimal from the dynamic point of view

Cited by 9 publications

References 19 publications

A Double-Bed Adsorptive Heat Transformer for Upgrading Ambient Heat: Design and First Tests

A Double-Bed Adsorptive Heat Transformer for Upgrading Ambient Heat: Design and First Tests

Closed‐Loop Adsorption‐Based Upgrading of Heat from 90 to 110 °C: Experimental Demonstration and Insights for Future Development

Thermodynamic Performance of Adsorption Working Pairs for Low-Temperature Waste Heat Upgrading in Industrial Applications

Contact Info

Product

Resources

About