Combined heat and power plant integrated with mobilized thermal energy storage (M-TES) system

Abstract

Energy consumption for space and tap water heating in residential and service sectors accounts for one third of the total energy utilization in Sweden. District heating (DH) is used to supply heat to areas with high energy demand. However, there are still detached houses and sparse areas that are not connected to a DH network. In such areas, electrical heating or oil/pellet boilers are used to meet the heat demand. Extending the existing DH network to those spare areas is not economically feasible because of the small heat demand and the large investment required for the expansion. The mobilized thermal energy storage (M-TES) system is an alternative source of heat for detached buildings or sparse areas using industrial heat. In this paper, the integration of a combined heat and power (CHP) plant and an M-TES system is analyzed. Furthermore, the impacts of four options of the integrated system are discussed, including the power and heat output in the CHP plant. The performance of the M-TES system is likewise discussed.

Key words： Mobilized thermal energy system; district heating; thermal energy storage; combined heat and power; detached houses

Acknowledgments

This work was supported by the Ångpanneföreningens Forskningsstiftelse (ÅF), Sweden. The scholarship to Weilong from the Chinese Academy of Engineering (CAE)-Royal Swedish Academy of Engineering Sciences (IVA) exchange program, Mälardalen University (MdH), Sweden is acknowledged, and China Scholarship Council (CSC) is also acknowledged to support Weilong and Yukun.

Notations

Acronyms
CHP	combined heat and power
CTES	chemical thermal energy storage
DH	district heating
HPST	high pressure steam turbine
EEM	Eskilstuna Energi and Miljö AB
LPST	low pressure steam turbine
LTES	latent thermal ernegy storage
M-TES	mobilized thermal energy storage
PCM	phase change material
TES	thermal energy storage
Symbols
p	pressure/kPa
T	temperature/°C
F	flow rate/(kg·s-1)

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