Characterization of MgSO4 Hydrate for Thermochemical Seasonal Heat Storage

V.M. Essen, van, H.A. Zondag, J. Cot Gores, L.P.J. Bleijendaal, M. Bakker, R. Schuitema, W. Helden, van, Z. He, C.C.M. Rindt

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Abstract

Water vapor sorption in salt hydrates is one of the most promising means for compact, low loss, and long-term storage of solar heat in the built environment. One of the most interesting salt hydrates for compact seasonal heat storage is magnesium sulfate heptahydrate (MgSO4·7H2O). This paper describes the characterization of MgSO4·7H2O to examine its suitability for application in a seasonal heat storage system for the built environment. Both charging (dehydration) and discharging (hydration) behaviors of the material were studied using thermogravimetric differential scanning calorimetry, X-ray diffraction, particle distribution measurements, and scanning electron microscope. The experimental results show that MgSO4·7H2O can be dehydrated at temperatures below 150°C, which can be reached by a medium temperature (vacuum tube) collector. Additionally, the material was able to store 2.2 GJ/m3, almost nine times more energy than can be stored in water as sensible heat. On the other hand, the experimental results indicate that the release of the stored heat is more difficult. The amount of water taken up and the energy released by the material turned out to be strongly dependent on the water vapor pressure, temperature, and the total system pressure. The results of this study indicate that the application of MgSO4·7H2O at atmospheric pressure is problematic for a heat storage system where heat is released above 40°C using a water vapor pressure of 1.3 kPa. However, first experiments performed in a closed system at low pressure indicate that a small amount of heat can be released at 50°C and a water vapor pressure of 1.3 kPa. If a heat storage system has to operate at atmospheric pressure, then the application of MgSO4·7H2O for seasonal heat storage is possible for space heating operating at 25°C and a water vapor pressure of 2.1 kPa.
Original languageEnglish
Pages (from-to)041014-1/7
Number of pages7
JournalJournal of Solar Energy Engineering
Volume131
Issue number4
DOIs
Publication statusPublished - 2009

Fingerprint

Heat storage
Hydrates
Water vapor
Vapor pressure
Atmospheric pressure
Salts
Electron tubes
Space heating
Dehydration
Hydration
Temperature
Magnesium
Sorption
Water
Differential scanning calorimetry
Electron microscopes
Hot Temperature
Scanning
X ray diffraction
Experiments

Cite this

Essen, van, V.M. ; Zondag, H.A. ; Cot Gores, J. ; Bleijendaal, L.P.J. ; Bakker, M. ; Schuitema, R. ; Helden, van, W. ; He, Z. ; Rindt, C.C.M. / Characterization of MgSO4 Hydrate for Thermochemical Seasonal Heat Storage. In: Journal of Solar Energy Engineering. 2009 ; Vol. 131, No. 4. pp. 041014-1/7.
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abstract = "Water vapor sorption in salt hydrates is one of the most promising means for compact, low loss, and long-term storage of solar heat in the built environment. One of the most interesting salt hydrates for compact seasonal heat storage is magnesium sulfate heptahydrate (MgSO4·7H2O). This paper describes the characterization of MgSO4·7H2O to examine its suitability for application in a seasonal heat storage system for the built environment. Both charging (dehydration) and discharging (hydration) behaviors of the material were studied using thermogravimetric differential scanning calorimetry, X-ray diffraction, particle distribution measurements, and scanning electron microscope. The experimental results show that MgSO4·7H2O can be dehydrated at temperatures below 150°C, which can be reached by a medium temperature (vacuum tube) collector. Additionally, the material was able to store 2.2 GJ/m3, almost nine times more energy than can be stored in water as sensible heat. On the other hand, the experimental results indicate that the release of the stored heat is more difficult. The amount of water taken up and the energy released by the material turned out to be strongly dependent on the water vapor pressure, temperature, and the total system pressure. The results of this study indicate that the application of MgSO4·7H2O at atmospheric pressure is problematic for a heat storage system where heat is released above 40°C using a water vapor pressure of 1.3 kPa. However, first experiments performed in a closed system at low pressure indicate that a small amount of heat can be released at 50°C and a water vapor pressure of 1.3 kPa. If a heat storage system has to operate at atmospheric pressure, then the application of MgSO4·7H2O for seasonal heat storage is possible for space heating operating at 25°C and a water vapor pressure of 2.1 kPa.",
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Essen, van, VM, Zondag, HA, Cot Gores, J, Bleijendaal, LPJ, Bakker, M, Schuitema, R, Helden, van, W, He, Z & Rindt, CCM 2009, 'Characterization of MgSO4 Hydrate for Thermochemical Seasonal Heat Storage', Journal of Solar Energy Engineering, vol. 131, no. 4, pp. 041014-1/7. https://doi.org/10.1115/1.4000275

Characterization of MgSO4 Hydrate for Thermochemical Seasonal Heat Storage. / Essen, van, V.M.; Zondag, H.A.; Cot Gores, J.; Bleijendaal, L.P.J.; Bakker, M.; Schuitema, R.; Helden, van, W.; He, Z.; Rindt, C.C.M.

In: Journal of Solar Energy Engineering, Vol. 131, No. 4, 2009, p. 041014-1/7.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Characterization of MgSO4 Hydrate for Thermochemical Seasonal Heat Storage

AU - Essen, van, V.M.

AU - Zondag, H.A.

AU - Cot Gores, J.

AU - Bleijendaal, L.P.J.

AU - Bakker, M.

AU - Schuitema, R.

AU - Helden, van, W.

AU - He, Z.

AU - Rindt, C.C.M.

PY - 2009

Y1 - 2009

N2 - Water vapor sorption in salt hydrates is one of the most promising means for compact, low loss, and long-term storage of solar heat in the built environment. One of the most interesting salt hydrates for compact seasonal heat storage is magnesium sulfate heptahydrate (MgSO4·7H2O). This paper describes the characterization of MgSO4·7H2O to examine its suitability for application in a seasonal heat storage system for the built environment. Both charging (dehydration) and discharging (hydration) behaviors of the material were studied using thermogravimetric differential scanning calorimetry, X-ray diffraction, particle distribution measurements, and scanning electron microscope. The experimental results show that MgSO4·7H2O can be dehydrated at temperatures below 150°C, which can be reached by a medium temperature (vacuum tube) collector. Additionally, the material was able to store 2.2 GJ/m3, almost nine times more energy than can be stored in water as sensible heat. On the other hand, the experimental results indicate that the release of the stored heat is more difficult. The amount of water taken up and the energy released by the material turned out to be strongly dependent on the water vapor pressure, temperature, and the total system pressure. The results of this study indicate that the application of MgSO4·7H2O at atmospheric pressure is problematic for a heat storage system where heat is released above 40°C using a water vapor pressure of 1.3 kPa. However, first experiments performed in a closed system at low pressure indicate that a small amount of heat can be released at 50°C and a water vapor pressure of 1.3 kPa. If a heat storage system has to operate at atmospheric pressure, then the application of MgSO4·7H2O for seasonal heat storage is possible for space heating operating at 25°C and a water vapor pressure of 2.1 kPa.

AB - Water vapor sorption in salt hydrates is one of the most promising means for compact, low loss, and long-term storage of solar heat in the built environment. One of the most interesting salt hydrates for compact seasonal heat storage is magnesium sulfate heptahydrate (MgSO4·7H2O). This paper describes the characterization of MgSO4·7H2O to examine its suitability for application in a seasonal heat storage system for the built environment. Both charging (dehydration) and discharging (hydration) behaviors of the material were studied using thermogravimetric differential scanning calorimetry, X-ray diffraction, particle distribution measurements, and scanning electron microscope. The experimental results show that MgSO4·7H2O can be dehydrated at temperatures below 150°C, which can be reached by a medium temperature (vacuum tube) collector. Additionally, the material was able to store 2.2 GJ/m3, almost nine times more energy than can be stored in water as sensible heat. On the other hand, the experimental results indicate that the release of the stored heat is more difficult. The amount of water taken up and the energy released by the material turned out to be strongly dependent on the water vapor pressure, temperature, and the total system pressure. The results of this study indicate that the application of MgSO4·7H2O at atmospheric pressure is problematic for a heat storage system where heat is released above 40°C using a water vapor pressure of 1.3 kPa. However, first experiments performed in a closed system at low pressure indicate that a small amount of heat can be released at 50°C and a water vapor pressure of 1.3 kPa. If a heat storage system has to operate at atmospheric pressure, then the application of MgSO4·7H2O for seasonal heat storage is possible for space heating operating at 25°C and a water vapor pressure of 2.1 kPa.

U2 - 10.1115/1.4000275

DO - 10.1115/1.4000275

M3 - Article

VL - 131

SP - 041014-1/7

JO - Journal of Solar Energy Engineering

JF - Journal of Solar Energy Engineering

SN - 0199-6231

IS - 4

ER -

Essen, van VM, Zondag HA, Cot Gores J, Bleijendaal LPJ, Bakker M, Schuitema R et al. Characterization of MgSO4 Hydrate for Thermochemical Seasonal Heat Storage. Journal of Solar Energy Engineering. 2009;131(4):041014-1/7. https://doi.org/10.1115/1.4000275