Thermodynamic analysis of chemical heat pumps

Obermeier, Jonas; Müller, Karsten; Arlt, Wolfgang

doi:10.1016/j.energy.2015.05.076

Cited by 22 publications

(17 citation statements)

References 9 publications

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“…This efficiency can also be found as COP in the literature [3]. However, the definition of COP may vary from an author to the other: an example is the definition of COP given by [9] which is completly different from the one given by [17].…”

Section: Thermodynamic Efficiencymentioning

confidence: 94%

“…On the other side, the theoretical COP of chemical heat pump, i.e. closed system, was studied in [17]. Calculated standard enthalpy of reaction of 34 salts were used to evaluate the influence of thermophysical properties on energy and exergy efficiency of a perfect system with recovery of condensation heat and "energy-free" heat of vaporization.…”

Section: Introductionmentioning

confidence: 99%

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Thermodynamic Efficiency of Water Vapor / Solid Chemical Sorption Heat Storage for Buildings: Theoretical Limits and Integration Considerations

Kuznik¹

2019

Preprint

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The theoretical limits of water sorbate based chemical sorption heat storage are investigated in this study. First, a classification of \textit{thermochemical heat storage} is proposed based on bonding typology. Then, thermodynamics of chemical solid/gas sorption is introduced. The analysis of the reaction enthalpy from the literature indicates that this value is only slightly varying for one mole of water. Using this observation, and with the help of thermodynamical considerations, it is possible to derive conclusions on energy efficiency of closed and open heat storage systems. Whatever the salt, the main results are 1) the energy required for evaporation of water is, at least, 65% of the available energy of reaction and 2) the maximum theoretical energy efficiency of the system is about 1.8.

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Section: Thermodynamic Efficiencymentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Thermodynamic Efficiency of Water Vapor / Solid Chemical Sorption Heat Storage for Buildings: Theoretical Limits and Integration Considerations

Kuznik¹

2019

Preprint

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“…Therefore, Coefficient of Amplification (COA) is more commonly used to represent the energy efficiency of a CHP system [82], which is defined by Eq. (18 (19) where Q syn and Q dec are heats of reaction during synthesis and decomposition reaction, respectively, Q g is the thermal energy required for heating the gaseous reactant during heat release.…”

Section: Energy and Exergy Analysismentioning

confidence: 99%

Gas–solid thermochemical heat storage reactors for high-temperature applications

Pan

Zhao

2017

Energy

106

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“…Analogously, exergetic storage density can be calculated by equation (6). This effective storage density ratio Δ eff by definition does not require the specification of the reference state in advance.…”

Section: -2 Figure 2 Duehring Plot Of the Caco 3 /Cao Reactionmentioning

confidence: 99%

“…At 1 mbar and 1 bar the resulting temperatures are 839 K and 1173 K respectively. Under real conditions, an offset of equilibrium line must be considered in order to ensure a sufficient thermodynamic driving force for the reactions [6]: in case of calcination reaction to higher and in case of carbonation reaction to lower temperatures. Thus, for the energy release reaction (carbonation) temperatures from ambient conditions up to a maximum level of 1173 K (turning temperature) at a CO 2 partial pressure of 1 bar should be considered.…”

Section: Energetic and Exergetic Storage Density Enthalpy Balance Of mentioning

confidence: 99%

A novel thermochemical energy storage and transportation concept based on concentrated solar irradiation-aided CaO-looping

Obermeier

Müller

Karagiannakis

et al. 2016

AIP Conference Proceedings

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Experimental study of compatibility of reduced metal oxides with thermal energy storage lining materials AIP Conference Proceedings 1734, 050013 (2016) Abstract. To overcome the temporal and regional gap of surplus solar energy, the concept of thermochemical heat storage is discussed. In this particular case, the application of CaO and CaCO 3 as energy carrying compounds for a trans-regional energy distribution concept is analyzed regarding the effective energetic and exergetic storage density. In a comprehensive sensitivity analysis, the influences of reaction temperature, conversion and heat recovery strategies are worked out. It can be seen that the effective storage density is strongly influenced by the preheating of reactants from ambient to reaction temperature. Thus, high conversion rates during forward and reverse reaction as well as improved heat recovery ratios are necessary to achieve a high energetic storage density. In case of effective exergetic storage density, carbonation temperature reaches an optimum. The method presented in this contribution can be applied to similar thermochemical heat storage systems and the results are of great importance for the process design and development of the suggested concept.

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Thermodynamic analysis of chemical heat pumps

Cited by 22 publications

References 9 publications

Thermodynamic Efficiency of Water Vapor / Solid Chemical Sorption Heat Storage for Buildings: Theoretical Limits and Integration Considerations

Thermodynamic Efficiency of Water Vapor / Solid Chemical Sorption Heat Storage for Buildings: Theoretical Limits and Integration Considerations

Gas–solid thermochemical heat storage reactors for high-temperature applications

A novel thermochemical energy storage and transportation concept based on concentrated solar irradiation-aided CaO-looping

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