Indoor and outdoor phase change heating device

Abstract

The invention discloses an indoor and outdoor phase change heating device, and belongs to the technical field of heating equipment. The device aims to solve the problems that existing outdoor combustion heating equipment has carbon monoxide poisoning and fire hazards, and electric heating equipment depends on a continuous power supply. The device comprises a heat preservation box body, a heating system and a phase change heat storage device. The heating system is composed of a plurality of heating films with different power, a PID temperature controller and a plurality of independent mechanical temperature limiting switches, the phase change heat storage device arranged in the box is heated in a wrapping mode, and precise constant-temperature heating is achieved through double-threshold control logic. And a high-enthalpy-value composite phase change material is packaged in the phase change heat storage device. Heat energy is stored in the phase-change material through electric energy, long-time safe, silent and emission-free heating in the outdoor environment without a power source is achieved, and the phase-change heating device is particularly suitable for occasions such as camping in winter and outdoor operation and has the advantages of being safe, portable, environmentally friendly and capable of saving energy.

Description

Technical Field

[0001] This invention relates to the field of heating equipment technology, specifically to a phase change heating device for indoor and outdoor use. Background Technology

[0002] In the field of outdoor heating equipment technology, traditional solutions mainly rely on two major technical approaches. The first type is combustion-based heating equipment, such as wood-burning stoves, gas stoves, and kerosene stoves, which generate heat energy by directly burning fuel. These devices pose significant safety hazards: the combustion process consumes a large amount of oxygen and produces toxic and harmful gases such as carbon monoxide. When used in poorly ventilated enclosed spaces such as tents and RVs, this can easily lead to oxygen deficiency or poisoning for users. Simultaneously, the presence of an open flame also poses a fire risk, which is particularly prominent in complex outdoor environments. The second type is electric heating equipment, which typically uses resistance wires, PTC (Power Transmission Control) devices, and other components to directly convert electrical energy into heat energy. Although it avoids combustion pollution, it heavily relies on a continuous and stable power supply, often requiring connection to a high-power outdoor portable power source or fixed mains power. This not only limits the freedom and mobility of its use but also fails to meet long-term heating needs due to limited battery life.

[0003] In recent years, phase change energy storage materials (PCS) have attracted attention in the field of thermal energy management due to their high energy density and isothermal heat release characteristics. There have been attempts to apply PCS materials to insulation products, such as PCS hand warmers or PCS panels for building temperature regulation. However, simply transplanting these technologies to outdoor mobile heating scenarios faces many challenges: on the one hand, existing PCS products often use simple and crude heating methods, frequently employing single-point or single-sided heating, resulting in uneven heat transfer, low heat storage efficiency, and a tendency to damage the PCS material structure or encapsulation shell due to localized overheating; on the other hand, the lack of a safe, efficient, and intelligent heating and temperature control system deeply integrated with outdoor usage scenarios makes it difficult to achieve rapid and safe energy storage and long-term, stable energy release in environments without power. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a phase change heating device for indoor and outdoor use, which overcomes the deficiencies of existing technologies. It stores thermal energy in the phase change material through electrical energy, achieving long-term safe, silent, and emission-free heating in outdoor environments without power supply. It is particularly suitable for scenarios such as winter camping and outdoor work, and has the advantages of safety, portability, environmental protection, and energy saving.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A phase change heating device for indoor and outdoor use includes an insulated box and a phase change heat storage device. The insulated box is provided with a heating chamber for accommodating at least one of the phase change heat storage devices. The phase change heat storage device is encapsulated with a phase change material for storing and releasing heat energy provided by the heating system.

[0007] A heating system is fixedly installed inside the insulation box. The heating system includes a controller, a temperature detection unit, and multiple heating films. The heating films are arranged in a preset spatial arrangement in the heating chamber, so that when the phase change heat storage device is placed in the heating chamber, it can be surrounded by the multiple heating films from at least two different directions and directly or indirectly contacted for heating.

[0008] The signal output terminal of the temperature detection unit is electrically connected to the signal input terminal of the controller, and the output terminal of the controller is electrically connected to each heating film. The controller is used to receive the temperature signal fed back by the temperature detection unit and coordinately control the start and stop of multiple heating films so that the phase change heat storage device is heated to the target heat storage temperature.

[0009] Preferably, the heating film includes an upper heating film, an intermediate heating film, and a lower heating film, which are arranged vertically at intervals within the heating chamber; the rated heating power of the upper heating film, the intermediate heating film, and the lower heating film are different from each other.

[0010] Preferably, the rated power of the upper heating film is 70W±3%, the rated power of the middle heating film is 185W±3%, and the rated power of the lower heating film is 150W±3%.

[0011] Preferably, the heating system further includes multiple temperature limiting protection units, each of which is connected to a heating film in a one-to-one correspondence. Each temperature limiting protection unit is configured to cut off the power supply circuit of the heating film when the temperature of its corresponding heating film exceeds a first preset safe temperature threshold. The first preset safe temperature threshold is higher than the maximum operating temperature threshold for the controller to perform constant temperature control.

[0012] Preferably, the first preset safety temperature threshold is 130℃±5℃; the maximum operating temperature threshold for the controller to perform constant temperature control is 85℃±2℃; and the target heat storage temperature is 83℃ to 85℃.

[0013] Preferably, the controller is a PID temperature controller, which independently or collaboratively controls the start and stop of the multiple heating films according to a preset temperature control logic; the preset temperature control logic is as follows: when the temperature detected by the temperature detection unit reaches or exceeds a first set temperature, heating is stopped; when the temperature detected by the temperature detection unit drops below a second set temperature, heating is started; the first set temperature is higher than the second set temperature.

[0014] Preferably, the temperature detection unit is a thermistor temperature probe, and the temperature sensing part of the temperature detection unit is fixedly attached to the center area of ​​the heating film with the highest expected temperature among multiple heating films by means of a thermally conductive adhesive material.

[0015] Preferably, the phase change material is a composite phase change material mainly composed of sodium acetate trihydrate, with a phase change point of 59℃±2℃ and a phase change enthalpy of not less than 250kJ / kg.

[0016] Preferably, the phase change heat storage device includes a sealed housing and a handle disposed on the sealed housing. The sealed housing is made of high-temperature resistant polypropylene material, and the phase change material is sealed inside the sealed housing.

[0017] Preferably, the controller further includes a timing unit and a power-off memory unit; the timing unit is used to set the total heating time of the heating system; the power-off memory unit is used to restore the control state before the power-off after the heating system is accidentally powered off and then powered on again.

[0018] The heating system is connected to an external power source via a lead wire hole, which is located on the insulation box.

[0019] This invention provides a phase change heating device for both indoor and outdoor use. It offers the following advantages: By employing a completely non-combustible phase change heat storage and electric heating method, and incorporating a multi-redundant safety system including PID control and an independent mechanical temperature limit switch, it fundamentally solves the inherent safety hazards of traditional outdoor heating equipment, such as carbon monoxide poisoning, oxygen deficiency, and fire, achieving inherent safety even in enclosed spaces like tents and RVs. By using a phase change material encased in a high-temperature resistant shell as the heat storage unit, and in conjunction with a multi-film collaborative intelligent heating system, users only need to pre-store energy in an area with electricity to obtain several hours of continuous heating in completely power-free outdoor environments, completely eliminating dependence on fuel or continuous power and greatly expanding the freedom and scope of outdoor activities. By adopting a natural heat dissipation principle without fans or strong light output, and precise temperature control logic, the heating process is completely silent and free of dry drafts, providing a gentle, comfortable, and sleep-inducing quiet warmth experience, significantly improving user comfort in frigid environments. By utilizing the high energy storage density of phase change materials and the efficient thermal insulation design of the insulated enclosure, combined with a controller with a timer function, users can perform low-cost energy storage during off-peak hours at night, achieving high efficiency, energy saving, and economical operation. At the same time, the entire system can be reused repeatedly without any consumption or emissions, reflecting the concept of environmental protection. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this invention or the prior art, the accompanying drawings used in the description of the prior art will be briefly introduced below.

[0021] Figure 1 A schematic diagram of the structure of this invention;

[0022] Figure 2 A schematic diagram of the internal structure of the insulation box in this invention;

[0023] Figure 3 A schematic diagram of the phase change heat storage device in this invention;

[0024] Explanation of the labels in the diagram:

[0025] 1. Insulated box; 2. Phase change heat storage device; 3. Controller; 4. Temperature detection unit; 5. Heating film; 6. Temperature limit protection unit; 21. Sealed shell; 22. Handle. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0027] Example 1, as Figures 1 to 3As shown, a phase change heating device for indoor and outdoor use includes an insulated box 1 and a phase change heat storage device 2. The insulated box 1 is provided with a heating chamber for accommodating at least one phase change heat storage device 2. The phase change heat storage device 2 is encapsulated with a phase change material for storing and releasing the heat energy provided by the heating system.

[0028] A heating system is fixedly installed inside the heat preservation box 1. The heating system includes a controller 3, a temperature detection unit 4, and multiple heating films 5. The heating films 5 are arranged in a preset spatial arrangement in the heating chamber so that when the phase change heat storage device 2 is placed in the heating chamber, it can be surrounded by multiple heating films 5 from at least two different directions and directly or indirectly contacted for heating.

[0029] The signal output terminal of the temperature detection unit 4 is electrically connected to the signal input terminal of the controller 3, and the output terminal of the controller 3 is electrically connected to each heating film 5 respectively. The controller 3 is used to receive the temperature signal fed back by the temperature detection unit 4 and coordinately control the start and stop of multiple heating films 5 so that the phase change heat storage device 2 is heated to the target heat storage temperature.

[0030] Working principle:

[0031] During the heating and energy storage phase, the user places each solid phase change heat storage device 2 into the heating chamber of the insulated housing 1, and surrounds the phase change heat storage device 2 with multiple pre-set heating films 5 within the heating chamber. After power is connected, the controller 3 controls the heating system to start working. Electrical energy is converted into heat energy through the heating films 5. The heat is rapidly transferred from the surface of the heating films 5 to the shell of the phase change heat storage device 2 via thermal conduction, and then into the internal phase change material. The temperature detection unit 4 monitors the core temperature of the system in real time through a temperature probe tightly attached to the middle heating film 5 (the highest temperature point). The controller 3 sets the target temperature range to 83℃-85℃. When the temperature is below 83℃, the heating films 5 operate at full capacity; when the temperature reaches 85℃, the heating films 5 stop working. Under this cyclical control, heat is continuously and stably input. The phase change material inside the phase change heat storage device 2 absorbs heat, and after the temperature gradually rises to 59℃, a phase change from solid to liquid begins. During this phase change process, the phase change material absorbs a large amount of latent heat (enthalpy ≥ 250 kJ / kg), while the temperature remains basically around 59°C until it melts completely. The controller's set operating temperature of 85°C is much higher than the material's phase change point, ensuring sufficient heat transfer temperature difference to drive the phase change to complete quickly and thoroughly, allowing the material to be completely converted into a liquid state and achieving maximum energy storage.

[0032] In this embodiment, the heating film 5 includes an upper heating film, a middle heating film, and a lower heating film, which are arranged vertically at intervals within the heating chamber. The upper, middle, and lower heating films employ differentiated power designs (e.g., 70W, 185W, 150W). This arrangement simulates optimal heat flow distribution, allowing heat to be injected evenly from different directions, avoiding single-point overheating, improving overall heating efficiency, and optimizing the total heating time to a reasonable range (e.g., approximately 5 hours). Each heating film has an independent 130°C temperature limit switch as redundant protection; even if the temperature controller fails, it can physically cut off the circuit in case of abnormal overheating, preventing fire or equipment damage.

[0033] After heating is complete, the system automatically stops working. At this time, the phase change heat storage device 2 stores a huge amount of latent heat, becoming a high-energy-density "thermal battery".

[0034] During the heat release phase, the user simply removes the pre-charged phase change heat storage device 2 from its insulated enclosure. In low-temperature outdoor environments, the high-temperature phase change heat storage device 2 (with a shell surface temperature of approximately 55°C) dissipates heat to the surrounding environment through natural convection and thermal radiation. As the liquid phase change material inside releases heat, its temperature gradually decreases. When it reaches its phase change point of 59°C, it begins to condense from a liquid to a solid state, releasing its stored latent heat. This phase change heat release process maintains a relatively stable temperature for a considerable period, providing lasting, gentle, and windless warmth, avoiding the rapid cooling characteristic of traditional electric heating devices when power is cut off. Furthermore, the entire heat release process requires no fan or combustion, is completely quiet, light-free, and emission-free, providing users with an immersive, tranquil, and warm experience.

[0035] This invention eliminates the open-flame heating method, fundamentally removing the risks of suffocation and fatal poisoning caused by incomplete combustion of carbon monoxide (CO) from traditional wood-burning and gas-fired stoves, as well as the fire hazards caused by improper use or equipment malfunction. Simultaneously, its operation does not consume oxygen, preventing oxygen deficiency in enclosed spaces. It creatively decouples heating and power supply in time and space. Users only need to spend a few hours "charging" the energy storage device (high-density thermal energy) at a location with a fixed power source (such as at home or a campsite service area) to carry it to a completely power-free outdoor environment for continuous and stable heating for several to over ten hours. This completely eliminates the heavy dependence of traditional electric heating devices on the battery life of portable power banks, generators, or long-distance mains power, giving users unprecedented freedom of movement and adaptability to different scenarios. Whether camping in the mountains, ice fishing, or working outdoors, users can enjoy a long-lasting and reliable heat source.

[0036] Furthermore, the heat dissipation process of this invention utilizes the natural heat dissipation of the phase change material, eliminating the need for forced convection by a fan. Therefore, it operates completely silently, without any machine noise, perfectly suited for nighttime sleep or the need for a quiet environment. The heat dissipation method primarily relies on thermal radiation and natural convection, eliminating the dry, blowing sensation and providing a gentle, comfortable feel, avoiding the dryness and discomfort caused by traditional fan heaters. In addition, the phase change material has extremely high energy storage density, with its latent heat storage efficiency far exceeding that of sensible heat storage, allowing the device to store and release more heat per unit volume and weight. The insulated enclosure significantly reduces heat loss during the heating phase, ensuring efficient conversion and storage of electrical energy. Users can proactively choose to charge at low cost during off-peak hours at night for daytime use, thus significantly reducing heating energy costs. Simultaneously, the device can be reused thousands of times; the phase change material is stable and durable. Compared to disposable chemical hand warmers or continuous fuel consumption, long-term use is more economical and environmentally friendly, with no combustion emissions, making it eco-friendly.

[0037] Furthermore, this invention employs a highly integrated modular design. The heating system is pre-installed within an insulated enclosure, simplifying user operation to a mere three steps: "place in - power on - remove," requiring no complex installation or debugging. The entire system is compact and lightweight, making this invention a safe, flexible, comfortable, economical, and convenient revolutionary outdoor heating solution.

[0038] Example 2, a further preferred embodiment of Example 1, has an upper heating film with a rated power of 70W ± 3%, a middle heating film with a rated power of 185W ± 3%, and a lower heating film with a rated power of 150W ± 3%. The upper, middle, and lower heating films are designed as an asymmetrical but synergistic thermal field. The middle heating film, with the highest power (185W), bears the main heating load and can quickly raise the temperature of the core area of ​​the phase change thermal storage device sandwiched within it. The upper and lower heating films operate with complementary powers (70W and 150W), providing necessary auxiliary heating to shorten the overall time and actively creating a slightly gradient heat flow from bottom to top through the power difference. This aligns with the natural upward convection trend of hot air, reduces ineffective thermal resistance, and allows heat to penetrate the phase change material block more smoothly and evenly. This avoids localized overheating (potentially damaging the material or shell) or incomplete phase change in some areas (reducing energy storage density) caused by uneven heating, thereby achieving higher effective energy storage and a more complete phase change per unit time. Furthermore, the differentiated power allocation is essentially proactive management of the heating system's heat load. It prevents excessive heat concentration in any one area. For example, if the three heating films have the same power, due to differences in structure or heat dissipation conditions, the actual temperature may be uneven, easily leading to one film continuously operating at a higher temperature, accelerating the aging of its silicone substrate or heating element. The power configuration of this solution, combined with the temperature probe positioned in the middle of the heating film, makes the operating temperature field of each heating film more balanced, reducing the risk of single-point thermal fatigue and extending the service life of the entire heating system. Simultaneously, uniform and gentle heating avoids localized thermal shock to the phase change heat storage device's casing, protecting the integrity of the encapsulation and the long-term stability of the internal material properties.

[0039] The aforementioned power scheme is deeply coupled with PID temperature control (83-85℃ range control) and the 59℃ phase change point of the phase change material. The high power of the intermediate membrane ensures that the system can quickly reach and maintain the target high temperature range, forming a sufficient heat transfer temperature difference (approximately 26℃) to drive rapid phase change; the auxiliary power of the upper and lower membranes ensures that heat is continuously and evenly replenished during the maintenance phase. This design makes the control system response more stable, with small overshoot, avoiding drastic temperature fluctuations caused by unreasonable power configuration, thus completing the entire latent heat storage process more accurately and efficiently.

[0040] In Example 3, as a further preferred embodiment of Example 1, the heating system further includes multiple temperature limiting protection units 6, which are connected one-to-one with the heating film 5. Each temperature limiting protection unit 6 is configured to cut off the power supply circuit of the heating film when the temperature of its corresponding heating film 5 exceeds a first preset safe temperature threshold. The first preset safe temperature threshold is higher than the highest operating temperature threshold for the controller 3 to perform constant temperature control.

[0041] By setting up a temperature limiting protection unit as an independent, passively activated physical device, each heating film has its own dedicated "fuse" independent of the controller. When the temperature of a heating film rises abnormally due to local blockage, dry burning, abnormal power, or controller failure, exceeding the first preset safe temperature threshold (e.g., 130℃), only the protection unit of that circuit activates, cutting off the power supply to that heating film without affecting the normal operation of other heating films. This distributed design isolates faults at the smallest unit, preventing a single point of failure from paralyzing the entire heating system or causing overall overheating, achieving localized and refined safety protection. Furthermore, by limiting the first preset safe temperature threshold to be higher than the controller's maximum operating temperature threshold for constant temperature control, the system's "normal operating zone" and "dangerous trigger zone" are clearly separated. The controller's maximum operating temperature threshold (e.g., 85℃) is an optimized target set based on the optimal heat storage efficiency of the phase change material. The safety threshold of the temperature limiting protection unit (e.g., 130℃) is set at a significantly higher level. This ensures that the temperature limiting protection unit will never malfunction during normal and efficient heating, guaranteeing the continuity and stability of the heating process. It will only activate when a genuine system anomaly occurs, with the temperature spiraling out of control and far exceeding the normal operating range. This perfectly resolves the contradiction of safety devices potentially interfering with normal operation, achieving a long-term balance between high-efficiency operation and absolute safety.

[0042] Example 4, as a further preferred embodiment of Example 3, has a first preset safety temperature threshold of 130℃±5℃; the maximum operating temperature threshold for controller 3 to perform constant temperature control is 85℃±2℃, and the target heat storage temperature is 83℃ to 85℃. The temperature of 85℃ ensures a sufficient heat transfer temperature difference (approximately 26℃) relative to the 59℃ phase change point, driving the phase change to proceed quickly and thoroughly, achieving maximum heat storage capacity. Simultaneously, this temperature is beneficial for the long-term stability of the phase change material shell (high-temperature resistant PP) and internal materials. The temperature range of 85℃ to 130℃ serves as a buffer zone for the system to transition from "normal operation" to "abnormal danger." Within this range, the main controller should have stopped heating (stops at 85℃). If the temperature continues to rise, it indicates some kind of anomaly (such as controller malfunction or poor heat dissipation), but has not yet reached the critical point that immediately triggers danger. While critical components such as the silicone heating film and insulation material (rubber and plastic cotton) can withstand 130℃ for a short period, exceeding this temperature long-term will lead to aging, failure, or combustion. Therefore, by setting a first preset safety temperature threshold of 130℃ ± 5℃, it is ensured that when the temperature abnormally rises to a level that truly threatens safety (such as exceeding 100℃ and progressing towards 130℃), the temperature limiting protection unit 6 must decisively cut off the circuit before the situation deteriorates beyond control (reaching 130℃). The tolerance range of ± 5℃ takes into account the consistency of device manufacturing and the stability of long-term use, ensuring that all products can meet this core safety requirement throughout their lifespan.

[0043] In Example 5, as a further preferred embodiment of Example 1, controller 3 is a PID temperature controller. Controller 3 independently or collaboratively controls the start and stop of multiple heating films according to preset temperature control logic. The preset temperature control logic is as follows: when the temperature detected by temperature detection unit 4 reaches or exceeds the first set temperature, heating is stopped; when the temperature detected by temperature detection unit 4 drops below the second set temperature, heating is started; the first set temperature is higher than the second set temperature. By setting controller 3 as a PID temperature controller, the heating process can be improved from a simple "on-off" coarse control to a dynamic and precise adjustment with foresight and disturbance resistance. When the temperature deviates from the set value, the PID controller can adjust the control output smoothly and in real time (e.g., by modulating the heating power through PWM) according to the magnitude, accumulation, and trend of the deviation, greatly reducing temperature overshoot and fluctuations. Combined with the hysteresis logic of "stopping at the first set temperature (e.g., 85℃) and starting at the second set temperature (e.g., 83℃)," the PID controller can stably lock the system average temperature within the narrow, efficient heating range of 83-85℃. This temperature range maintains an ideal heat transfer temperature difference of approximately 25°C relative to the phase transition point (59°C), sufficient to drive a rapid and complete phase transition while avoiding unnecessary energy loss and material burden caused by excessively high temperatures. This achieves a near-optimal latent heat storage rate and total amount per unit time. Furthermore, the PID controller receives temperature feedback from key monitoring points (such as the intermediate heating film) and uses it as a representation of the thermal state of the entire heating chamber, thereby issuing unified control commands to ensure that all heating films operate synchronously under a common objective, achieving overall heat load coordination.

[0044] In Example 6, as a further preferred embodiment of Example 1, the temperature detection unit 4 is a thermistor temperature probe. The sensing part of the temperature detection unit 4 is fixedly attached to the center region of the heating film with the highest expected temperature among the multiple heating films using a thermally conductive adhesive material. The primary advantage of using a thermistor temperature probe as the detection unit is its superior sensitivity to temperature-resistance changes. Compared to other temperature sensors, thermistors have higher resolution and response speed within the target temperature range (e.g., room temperature to 100°C), enabling them to sensitively capture subtle and rapid changes in the heating film temperature. This characteristic provides a high-quality, low-latency input signal for the subsequent PID controller, a prerequisite for achieving precise closed-loop control. Simultaneously, thermistors have a simple structure, stable performance, and controllable cost, making them suitable for long-term reliable operation in the mild-to-high-temperature environment where this device operates. By attaching the sensing part of the temperature detection unit 4 to the center region of the heating film with the highest expected temperature among the multiple heating films, this location most directly reflects the magnitude of the heat flux density transferred to the core of the phase change heat storage device. Controlling the temperature at this point essentially controls the driving force for heating the phase change material. Stabilizing it within the optimal range of 83-85℃ means providing a strong and stable heat source for the entire phase change heat storage process, avoiding problems such as distorted control commands, insufficient heating, or low efficiency caused by improper selection of monitoring points (such as temperature lag areas).

[0045] Example 7, as a further preferred embodiment of Example 1, uses a composite phase change material primarily composed of sodium acetate trihydrate, with a phase change point of 59℃±2℃ and a phase change enthalpy of not less than 250kJ / kg. When the material undergoes a phase change and releases latent heat near this temperature, its shell surface temperature can be stabilized at approximately 55℃. This temperature is significantly higher than the ambient cold temperature, providing a noticeable warmth while remaining significantly lower than the common burn risk threshold (it is generally believed that skin contact with objects exceeding 60℃ may cause burns), achieving a perfect balance between effective heating and safe use. Furthermore, the heat dissipation within this temperature range is primarily through gentle thermal radiation and natural convection, avoiding the burning or dryness caused by high-temperature heat sources. The heat release is gradual and sustained, meeting the human body's physiological need for "warmth" rather than "heat," creating a windless, quiet, and comfortable environment. Moreover, sodium acetate trihydrate itself has a high latent heat value, and through composite modification (possibly including nucleating agents, thickeners, etc.), the problems of supercooling and phase separation are solved while maintaining a high enthalpy. An enthalpy of not less than 250 kJ / kg means that a unit mass of phase change material can store a huge amount of heat. This directly determines that, given the weight and volume of the device, it can provide a longer continuous heating time (for example, compared to sensible heat storage or low enthalpy materials), which is the fundamental guarantee for achieving long-term independent operation outdoors without power.

[0046] Example 8, as a further preferred embodiment of Example 1, the phase change heat storage device 2 includes a sealed housing 21 and a handle 22 disposed on the sealed housing 21. The sealed housing 21 is made of high-temperature resistant polypropylene material, and the phase change material is sealed inside the sealed housing 21. The sealed housing 21 is typically made of high-temperature resistant polypropylene material, which maintains excellent dimensional stability and mechanical strength at the device's long-term operating temperature (approximately 55°C on the housing surface, the internal material undergoing a phase change at 59°C, and the heating environment reaching 85°C), preventing encapsulation failure or structural damage due to thermal deformation. Simultaneously, its upper temperature resistance limit (typically above 100°C) provides sufficient material safety margin for the safety threshold (e.g., 130°C) in the preceding claims, ensuring the housing maintains integrity even under abnormal conditions and preventing the risk of breakage. Furthermore, after the phase change heat storage device has finished heating, its surface temperature can reach approximately 55°C, making it uncomfortable or even risky to directly grasp the housing with bare hands. A handle 22 is provided on the sealed housing 21, and its shape, size, and heat insulation / low thermal conductivity design allow users to safely, securely, and effortlessly grip and carry high-temperature devices. In outdoor scenarios, users may need to frequently move heat sources. An ergonomic handle greatly reduces the difficulty of operation and fatigue, making the product truly easy to use and enhancing its practicality.

[0047] Example 9, as a further preferred embodiment of Example 1, the controller further includes a timing unit and a power failure memory unit; the timing unit is used to set the total heating time of the heating system; the power failure memory unit is used to restore the control state before the power failure after the heating system is accidentally powered off and then powered on again; the entire heating system is connected to an external power source through a lead wire hole, which is located on the insulation box.

[0048] By integrating a timing unit, users can easily set the system to automatically start and complete the heating process during off-peak hours (when electricity prices are low), while using only stored heat energy during peak daytime hours or when away from home. The power outage memory unit is designed to handle unexpected power interruptions that may occur outdoors or in a home environment. The heating process of phase change materials (especially the later stages) requires continuous heat input to complete the phase change. If the system is reset and restarted after an unexpected power outage, not only may the total heating time be extended due to the cold start, but some of the input heat energy may also be wasted due to stagnation and cooling. The power outage memory unit can automatically restore the control state before the power outage (such as target temperature, remaining timer duration, etc.) after power is restored, allowing the heating process to continue almost seamlessly, ensuring the heating task is completed and avoiding both energy and time waste. The entire heating system is connected to an external power source through a lead-in hole located on the insulated enclosure. The dedicated lead-in hole (usually equipped with a rubber sheath or sealing ring) provides a reliable fixing point and stress relief structure for the power cord. This prevents the power cord from being pulled or bent at the connector inside the enclosure during daily movement, carrying, or plugging and unplugging, which could lead to damage to the internal wires, loosening of the connector, or even short circuits.

[0049] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A phase change heating device for indoor and outdoor use, characterized in that: It includes an insulated box (1) and a phase change heat storage device (2). The insulated box (1) is provided with a heating chamber for accommodating at least one of the phase change heat storage devices (2). The phase change heat storage device (2) is encapsulated with a phase change material for storing and releasing the heat energy provided by the heating system. A heating system is fixedly installed inside the heat preservation box (1). The heating system includes a controller (3), a temperature detection unit (4), and multiple heating films (5). The heating films (5) are arranged in a preset spatial arrangement in the heating chamber so that when the phase change heat storage device (2) is placed in the heating chamber, it can be surrounded by the multiple heating films (5) from at least two different directions and directly or indirectly contacted for heating. The signal output terminal of the temperature detection unit (4) is electrically connected to the signal input terminal of the controller (3), and the output terminal of the controller (3) is electrically connected to each heating film (5); the controller (3) is used to receive the temperature signal fed back by the temperature detection unit (4) and coordinately control the start and stop of multiple heating films (5) so that the phase change heat storage device (2) is heated to the target heat storage temperature.

2. A phase change heating device for indoor and outdoor use according to claim 1, characterized in that: The heating film (5) includes an upper heating film, an intermediate heating film and a lower heating film, which are arranged vertically at intervals in the heating chamber; the rated heating power of the upper heating film, the intermediate heating film and the lower heating film are different from each other.

3. A phase change heating device for indoor and outdoor use according to claim 2, characterized in that: The rated power of the upper heating film is 70W±3%, the rated power of the middle heating film is 185W±3%, and the rated power of the lower heating film is 150W±3%.

4. A phase change heating device for indoor and outdoor use according to claim 1, characterized in that: The heating system also includes multiple temperature limiting protection units (6), which are connected one-to-one with the heating film (5). Each temperature limiting protection unit (6) is configured to cut off the power supply circuit of the heating film when the temperature of its corresponding heating film (5) exceeds the first preset safe temperature threshold. The first preset safe temperature threshold is higher than the highest working temperature threshold for the controller (3) to perform constant temperature control.

5. A phase change heating device for indoor and outdoor use according to claim 4, characterized in that: The first preset safety temperature threshold is 130℃±5℃; the highest working temperature threshold for the controller (3) to perform constant temperature control is 85℃±2℃, and the target heat storage temperature is 83℃ to 85℃.

6. A phase change heating device for indoor and outdoor use according to claim 1, characterized in that: The controller (3) is a PID temperature controller. The controller (3) independently or collaboratively controls the start and stop of the multiple heating films according to the preset temperature control logic. The preset temperature control logic is as follows: when the temperature detected by the temperature detection unit (4) reaches or exceeds the first set temperature, heating is stopped; when the temperature detected by the temperature detection unit (4) drops to below the second set temperature, heating is started; the first set temperature is higher than the second set temperature.

7. A phase change heating device for indoor and outdoor use according to claim 1, characterized in that: The temperature detection unit (4) is a thermistor temperature probe. The temperature sensing part of the temperature detection unit (4) is fixedly attached to the center area of ​​the heating film with the highest expected temperature among multiple heating films by thermally conductive adhesive material.

8. A phase change heating device for indoor and outdoor use according to claim 1, characterized in that: The phase change material is a composite phase change material with sodium acetate trihydrate as the main component, and its phase change point is 59℃±2℃, and its phase change enthalpy is not less than 250kJ / kg.

9. A phase change heating device for indoor and outdoor use according to claim 1, characterized in that: The phase change heat storage device (2) includes a sealed housing (21) and a handle (22) disposed on the sealed housing (21). The sealed housing (21) is made of high temperature resistant polypropylene material, and the phase change material is sealed inside the sealed housing (21).

10. A phase change heating device for indoor and outdoor use according to claim 1, characterized in that: The controller also includes a timing unit and a power failure memory unit; the timing unit is used to set the total heating time of the heating system; the power failure memory unit is used to restore the control state before the power failure after the heating system is accidentally powered off and then powered on again. The heating system is connected to an external power source via a lead wire hole, which is located on the insulation box.

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