Thermal retention apparatus for heating a liquid on demand

A thermal retention apparatus, comprising:

• (a) an insulated tank enclosing a phase change thermal energy storage unit, the phase change thermal energy storage unit comprising:
• (i) a phase change material, and
• (ii) a heat exchanger assembly immersed in the phase change material, the heat exchanger assembly comprising:
• (A) first fluid pathways connected to and extending through the phase change material between a first pair of an inlet fluid conduit and an outlet fluid conduit for charging the phase change material by a fluid flowing therethrough having a temperature greater than that of the phase change material, the first fluid pathways defining a phase change material (PCM) charging circuit, and
• (B) second fluid pathways connected to and extending through the phase change material between a second pair of an inlet fluid conduit and an outlet fluid conduit for discharging the phase change material by a fluid flowing therethrough having a temperature less than that of the phase change material, the second fluid pathways defining a PCM discharging circuit;
• (b) control components for the phase change thermal energy storage unit;
• and
• (c) an exterior container within which the insulated tank and control components are contained;
• (d) wherein the heat exchanger assembly comprises
• (i) a plurality of heat exchanger modules immersed within the phase change material, each defining fluid paths therethrough forming part of the first fluid pathways of the PCM charging circuit and the second fluid pathways of the PCM discharging circuit,
• (ii) a manifold conduit dividing fluid flow from the inlet conduit of the PCM charging circuit into:
• (A) a first fluid path of a first heat exchanger module to the exclusion of a second of the heat exchanger modules, and
• (B) a second fluid path through the second heat exchanger module to the exclusion of the first heat exchanger module, and
• (iii) a manifold conduit reconsolidating fluid flow from the first and second fluid paths into the outlet conduit of the PCM charging circuit,
• whereby fluid flow through the first and second heat exchanger modules in the PCM charging circuit is in parallel.

A thermal retention apparatus, comprising:

• (a) an insulated tank enclosing a phase change thermal energy storage unit, the phase change thermal energy storage unit comprising:
• (i) a phase change material,
• (ii) a heat exchanger assembly immersed in the phase change material, the heat exchanger assembly comprising:
• (A) first fluid pathways connected to and extending through the phase change material between a first pair of an inlet fluid conduit and an outlet fluid conduit for charging the phase change material by a fluid flowing therethrough having a temperature greater than that of the phase change material, the first fluid pathways defining a phase change material (PCM) charging circuit, and
• (B) second fluid pathways connected to and extending through the phase change material between a second pair of an inlet fluid conduit and an outlet fluid conduit for discharging the phase change material by a fluid flowing therethrough having a temperature less than that of the phase change material, the second fluid pathways defining a PCM discharging circuit;
• (b) control components for the phase change thermal energy storage unit;
• and
• (c) an exterior container within which the insulated tank and control components are contained;
• (d) wherein the heat exchanger assembly comprises:
• (i) five heat exchanger modules immersed within the phase change material, each defining fluid paths therethrough forming part of the first fluid pathways of the PCM charging circuit and the second fluid pathways of the PCM discharging circuit,
• (ii) a manifold conduit dividing fluid flow from the inlet conduit of the PCM charging circuit into each of five fluid paths each fluid path corresponding to a respective one of the five heat exchanger modules to the exclusion of the other heat exchanger modules, and
• (iii) a manifold conduit reconsolidating fluid flow from the five fluid paths into the outlet conduit of the PCM charging circuit, whereby fluid flow through the five heat exchanger modules in the PCM charging circuit is in parallel.

A thermal retention apparatus, comprising:

• (a) an insulated tank enclosing a phase change thermal energy storage unit, the phase change thermal energy storage unit comprising:
• (i) a phase change material,
• (ii) a heat exchanger assembly immersed in the phase change material, the heat exchanger assembly comprising:
• (A) first fluid pathways connected to and extending through the phase change material between a first pair of an inlet fluid conduit and an outlet fluid conduit for charging the phase change material by a fluid flowing therethrough having a temperature greater than that of the phase change material, the first fluid pathways defining a phase change material (PCM) charging circuit, and
• (B) second fluid pathways connected to and extending through the phase change material between a second pair of an inlet fluid conduit and an outlet fluid conduit for discharging the phase change material by a fluid flowing therethrough having a temperature less than that of the phase change material, the second fluid pathways defining a PCM discharging circuit;
• (b) control components for the phase change thermal energy storage unit;
• and
• (c) an exterior container within which the insulated tank and control components are contained;
• (d) wherein the heat exchanger assembly comprises a plurality of heat exchanger modules immersed within the phase change material and arranged such that fluid flow in the PCM charging circuit is arranged in parallel and fluid flow passes only through one of the heat exchanger modules in a lap of the PCM charging circuit.