Method and system for controlling a state-of-charge of phase change material storage systems

A method of controlling a functioning of a phase change material thermal energy storage system having a variable heat output, comprising:

• a) performing the steps of measuring a state of charge of a phase change material thermal energy storage system comprising;
• propagating a wave through at least a majority of a phase change material along a thermal gradient of the phase change material thermal energy storage system, wherein a property of said wave is dependent on the medium through which it propagates;
• detecting the emerging wave after it has propagated through at least the majority of the phase change material along the thermal gradient;
• determining a wave parameter of the emerging wave, said wave parameter associated with a liquid fraction of the phase change material;
• calculating a ratio between a liquid and solid state of the phase change material using the wave parameter associated with the liquid fraction;
• using the calculated ratio to estimate a state of charge of the phase change material thermal energy storage system at a time of propagation of the emergent wave;
• and
• b) retrieving a range of heat output rates for the measured state of charge at the corresponding time interval from a database;
• c) comparing a heat output of the thermal energy storage system with the retrieved range of heat output rates for the measured state of charge at the corresponding time interval;
• and
• d) when it is determined that the heat output is outside the retrieved range, adjusting the heat output to lie within the retrieved range at the corresponding time interval;
• and
• repeatedly performing steps a to d at predetermined time intervals to continuously control a heat output of the phase change material thermal energy storage system.

A system for measuring a state of charge of a phase change material thermal energy storage system and optimising thereto, comprising:

• at least one wave transmitter of a first type;
• at least one wave receiver of a first type;
• wherein each of the at least one transmitter and each of the at least one receiver are configured to lie along a thermal gradient;
• a signal processing module comprising instructions that, when executed on a processor, perform the steps of:
• converting a wave signal into a state of charge;
• and
• a control module for controlling a functioning of the phase change material thermal energy storage system.

A system for controlling a functioning of a phase change material thermal energy storage system having a variable heat output, comprising:

• at least one wave transmitter of a first type;
• at least one wave receiver of a first type;
• wherein each of the at least one transmitter and each of the at least one receiver are configured to lie along a thermal gradient;
• a signal processing module comprising instructions that, when executed on a processor, perform the steps of:
• converting a wave signal into a state of charge;
• and
• a control module for controlling a functioning of the phase change material thermal energy storage system;
• a database comprising a plurality of predefined heat output rates ranges for a plurality of corresponding state of charge values;
• and
• wherein the control module further comprises:
• a comparison module comprising computer readable media with instruction that, when executed on a processor, perform the task of comparing a heat output of the thermal energy storage system with the retrieved range of heat output rates for the measured state of charge at the corresponding time interval;
• and
• wherein, when it is determined that the heat output is outside the retrieved range, the control module is further configured to adjusting the heat output to lie within the retrieved range at a corresponding time interval.

A self-monitoring phase change material thermal energy storage system comprising:

• a container;
• a phase change material contained within said container;
• at least one heat sink or heat source in a first location in the container;
• at least another heat sink or heat source at a second location in the container at a distance from the at least one heat sink or heat source;
• and
• a system for measuring a state of charge of a phase change material thermal energy storage system and optimising thereto, comprising:
• at least one wave transmitter of a first type;
• at least one wave receiver of a first type;
• wherein each of the at least one transmitter and each of the at least one receiver are configured to lie along a thermal gradient;
• a signal processing module comprising instructions that, when executed on a processor, perform the steps of:
• converting a wave signal into a state of charge;
• and
• a control module for controlling a functioning of the phase change material thermal energy storage system
• wherein each of the at least one transmitter is located proximate to the at least one heat source or heat sink and each of the receiver is located proximate to the at least another heat sink or heat source and laterally aligned such that each of the at least one transmitter and each of the at least one receiver are configured to lie along a thermal gradient.

A pillow plate type self-monitoring phase change material thermal energy storage system comprising:

• a plurality of parallel plates each plate comprised of two sheets welded together with a pattern of embossed impressions;
• a system for measuring a state of charge of a phase change material thermal energy storage system and optimising thereto, comprising:
• at least one wave transmitter of a first type;
• at least one wave receiver of a first type;
• wherein each of the at least one transmitter and each of the at least one receiver are configured to lie along a thermal gradient;
• a signal processing module comprising instructions that, when executed on a processor, perform the steps of:
• converting a wave signal into a state of charge;
• and
• a control module for controlling a functioning of the phase change material thermal energy storage system;
• wherein the at least one wave transmitter of a first type comprises a plurality of wave transmitters of the first type, positioned in at least two of embossed impressions of at least a first plate of the plurality of parallel plates;
• and
• wherein the at least one wave receiver of a first type comprises a plurality of corresponding wave receivers of the first type, positioned in at least two of the embossed impressions of a neighbouring plate of the first plate.

An extruded tube-in-tube type self-monitoring phase change material thermal energy storage system comprising:

• an inner tube, an outer tube and a plurality of internal fins which extend radially from the inner tube to the outer tube;
• a system for measuring a state of charge of a phase change material thermal energy storage system and optimising thereto, comprising:
• at least one wave transmitter of a first type;
• at least one wave receiver of a first type:
• wherein each of the at least one transmitter and each of the at least one receiver are configured to lie along a thermal gradient;
• a signal processing module comprising instructions that, when executed on a processor, perform the steps of:
• converting a wave signal into a state of charge;
• and
• a control module for controlling a functioning of the phase change material thermal energy storage system;
• wherein at least one wave transmitter is affixed to an outer surface of the inner tube and is axially and radially aligned with at least one wave receiver affixed to an inner surface of the outer tube, creating at least one transmitter-receiver pair.