ABSTRACT
Thermochemical heat storage is considered as a promising technology to enhance the utilization of energy sources due to its high energy storage density and long-term heat storage potential. However, further development of such systems depends on the development of new advanced sorption materials. In this study, a novel composite sorbent that consists of aerated porous concrete (APC) and calcium chloride (CaCl2) is investigated. Besides, vermiculite–calcium chloride (V–CaCl2) and Zeolite were also employed in the developed reactor for performance comparison. According to the testing results, energy storage density of the system operating with APC-CaCl2, V–CaCl2, and Zeolite were found 186.9, 174.2, and 182.6 kWh/m3, respectively.
Nomenclature
Cp | = | specific heat at constant pressure, J/(kg K) |
Ed | = | energy density, kJ/kg, kW h/m3 |
Ecum | = | cumulative thermal energy, Wh, kW h |
X | = | exergy, W, kW |
Xcum | = | cumulative thermal exergy, Wh, kW h |
H | = | enthalpy, kJ/s |
m | = | mass, g, kg |
= | mass flow rate of air, kg/s | |
Q | = | thermal power, W, kW |
pw | = | water vapor partial pressure, mbar |
pw, s | = | water vapor saturation pressure, mbar |
S | = | entropy, kJ/kg |
t | = | time, s, h |
T | = | temperature, °C, K |
Treg | = | regeneration temperature, °C, K |
V | = | volume, m3 |
w | = | absolute humidity, g/kg |
y | = | sorption/desorption rate, g/min |
f | = | mass uptake ratio, gwv/gabs |
Greek letters
Ø | = | relative humidity, % |
ρ | = | density, kg/m3 |
Δ | = | difference |
ƞI | = | 1st law efficiency |
ƞII | = | 2nd law efficiency |
Subscripts or superscripts
dcr | = | discharging |
cr | = | charging |
g | = | gain |
cum | = | cumulative |
ads | = | adsorbent |
a | = | air |
wv | = | water vapor |
w | = | wet |
in | = | inlet |
out | = | outlet |
d | = | dry |
avg | = | average |
h | = | heating |
l | = | lowest |
max | = | maximum |
g | = | gain |
s | = | sorption |
des | = | desorption |
aq | = | aqueous solution |
Abbreviations
APC | = | aerated porous concrete |
COP | = | coefficient of performance |
LHS | = | latent heat storage |
SHS | = | sensible heat storage |
TES | = | thermal energy storage |
THS | = | thermochemical heat storage |
Acknowledgments
Special thanks to the Eastern Mediterranean University, Department of Mechanical Engineering technicians for their technical support.
Additional information
Notes on contributors
Majid Karim Nejhad
Majid Karim Nejhad is currently a PhD student in Department of Mechanical Engineering, Eastern Mediterranean University, North Cyprus. His research interests are absorption processes and thermal energy storage systems.
Devrim Aydin
Devrim Aydin is an assistant professor in Department of Mechanical Engineering, Eastern Mediterranean University, North Cyprus. His research interests are solar energy, heat storage and refrigeration technologies.