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

Tokarev, M. M.

doi:10.3390/en12214037

Cited by 13 publications

(17 citation statements)

References 18 publications

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“…Compared with state‐of‐the‐start absorption heat transformers, [ 14,15 ] the efficiency COP of our AdHT also achieves the values up to 0.5. Compared with the AdHT in a two‐bed configuration working at very low temperatures, [ 24 ] the efficiency COP exergetic of our AdHT also achieves the values greater than 0.5. Although we compare our simulative results with experimental data of actual prototypes, the comparison shows that the performance of an AdHT operating around 100 °C is very promising, encouraging to perform further analyzes in the future.…”

Section: Resultsmentioning

confidence: 96%

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Upgrading Waste Heat from 90 to 110 °C: The Potential of Adsorption Heat Transformation

et al. 2020

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Globally, heat demand accounts for 71% of industrial energy consumption. [1] For example, the industry in the US requires 3416 PJ heat between 40 and 260 C, with 1755 PJ already in the temperature range between 120 and 160 C, and the industry in the European Union requires 626 PJ heat for temperatures below 150 C, with 116 PJ in the temperature range between 100 and 150 C. [2] Examples of such industrial processes and their process temperatures were summarized by Arpagaus et al. or Brückner et al. (Table 1). [2,3] Simultaneously, the global industry releases 31902 PJ of waste heat, with 42% occurring below 100 C as low-grade heat. [4] Transforming this low-grade waste heat from temperatures below to above 100 C could enhance industrial energy efficiency. Thereby, heat transformation has the potential to reduce both primary energy consumption and greenhouse gas emissions. [5] The low-grade waste heat can be transformed into useful heat with higher temperatures by mechanically driven vapor compression heat pumps or thermally driven heat transformers. However, classical heat pumps currently available are restricted to a maximum gross temperature lift of 50 K and a maximum condensing temperature of 130 C. [2,6] Vapor compression heat pumps for higher temperatures suffer from the lack of suitable working fluids. [2,6] Designs are often challenging for both the cycles (e.g., multi-stage cycles) and components (e.g., multi-stage compressors) due to high discharge pressures and temperatures. [2,6-8] To overcome these limitations, many researchers screen working fluids or improve the thermodynamic cycle design. For example, Mikielewicz and Wajs screened working fluids with low global warming potential for upgrading heat from 50 to 130 C. [6] Ethanol was identified as a promising working fluid in a singlestage cycle design, whereas multi-stage cycles generally seemed

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Section: Resultsmentioning

confidence: 96%

“…[ 23 ] For example, Tokarev reported a COP of 0.44, a COP exergetic of 0.51, and a specific heating power (SHP) of 350 W kg −1 for a closed AdHT in a two‐bed configuration that upgrades heat from 20 to 30 °C releasing waste heat at −30 °C. [ 24 ]…”

Section: Introductionmentioning

confidence: 99%

Upgrading Waste Heat from 90 to 110 °C: The Potential of Adsorption Heat Transformation

et al. 2020

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“…A plate-tube finned heat exchanger (Yamaha Aerox) made of aluminium with the dimensions 190 × 200 × 30 mm 3 is used as a reference HEx as it was tested for the HeCol prototype in refs. [ 14 , 15 ]. The mass of carbon loaded into the HEx m a = 0.15 kg and the HEx mass M Al = 0.50 kg.…”

Section: Effect Of the Working Fluid On The Useful Heat Per Cyclementioning

confidence: 99%

“…[ 16 , 21 , 22 , 23 ] ( Table 3 ). To be specific in calculating the sensible heat, the analysis is made for a typical HeCol cycle with T L = −20 °C, T M = 20 °C, and T H = 40 °C [ 14 ].…”

Section: Effect Of the Working Fluid On The Useful Heat Per Cyclementioning

confidence: 99%

Thermodynamic Analysis of Working Fluids for a New “Heat from Cold” Cycle

Girnik

Tokarev

Aristov

2020

Entropy

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Adsorptive Heat Transformation systems are at the interface between thermal and chemical engineering. Their study and development need a thorough thermodynamic analysis aimed at the smart choice of adsorbent-adsorptive pair and its fitting with a particular heat transformation cycle. This paper addresses such an analysis for a new “Heat from Cold” cycle proposed for amplification of the ambient heat in cold countries. A comparison of four working fluids is made in terms of the useful heat per cycle and the temperature lift. The useful heat increases in the row water > ammonia ≥ methanol > hydrofluorocarbon R32. A threshold mass of exchanged adsorbate, below which the useful heat equals zero, raises in the same sequence. The most promising adsorbents for this cycle are activated carbons Maxsorb III and SRD 1352/2. For all the adsorptives studied, a linear relationship F = A·ΔT is found between the Dubinin adsorption potential and the driving temperature difference ΔT between the two natural thermal baths. It allows the maximum temperature lift during the heat generation stage to be assessed. Thus, a larger ΔT-value promotes the removal of the more strongly bound adsorbate.

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“…Recently, researchers focused on the development of new adsorptive transformation devices. A new cycle for the heat transformation of ambient air at negative temperatures was presented by Aristov [9] and tested by Tokarev [10]. Freni et al [11] report advanced sorbent materials such as new zeolite-like materials (AIPO and SAPO) and composite adsorbents like LiBr-silica and CaCl 2 -silica as very promising for conventional adsorptive heat pumps and chillers.…”

Section: Introductionmentioning

confidence: 99%

Development and Testing of Novel Applications for Adsorption Heat Pumps and Chillers

et al. 2020

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This work aims at the development and the experimental characterization of new applications for adsorption heat pumps and chillers driven by industrial waste heat or renewable sources that can provide heating and/or cooling. Adsorption technologies offer the advantage of providing heating and cooling from low temperature sources below 100 °C without using refrigerant with high Global Warming Potential and with very low electricity consumption. Therefore, the technology enables the use of large untapped heat sources, increasing the energy efficiency of the heating and cooling sector with very limited impact on the environment. Several applications were investigated numerically for Switzerland using a simplified model of an adsorption heat pump. Four scenarios were identified as interesting: (1) the valorization of low-grade industrial waste heat in district heating networks, (2) energy efficiency improvement of district heating substations, (3) an autonomous adsorption heat pump with a wood pellets burner and (4) cooling applications. These scenarios were experimentally validated with a laboratory test of a commercial silica gel/water machine. Results show that there is a gap of up to 40% between the prediction of the simplified model and the experimental results. Therefore, there is huge potential to improve the performances of this commercial unit for these applications.

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

Cited by 13 publications

References 18 publications

Upgrading Waste Heat from 90 to 110 °C: The Potential of Adsorption Heat Transformation

Upgrading Waste Heat from 90 to 110 °C: The Potential of Adsorption Heat Transformation

Thermodynamic Analysis of Working Fluids for a New “Heat from Cold” Cycle

Development and Testing of Novel Applications for Adsorption Heat Pumps and Chillers

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