Zero-energy-consumption building envelope design based on multi-natural-cold-source refrigerating system

Abstract

The invention discloses a zero-energy-consumption building envelope design based on a multi-natural-cold-source refrigerating system, and belongs to the field of zero-energy-consumption building technologies, renewable energy utilization and building envelope energy-saving design. The system comprises a sky radiant panel, a heat pipe, a fluid pipeline and an evaporative cooling refrigeration device. The sky radiant panel is installed above the roof, a heat pipe condensation section is embedded in the sky radiant panel, and a heat pipe evaporation section is located on the outer layer of the wall body. The wall body is divided into three layers, a heat pipe evaporation section is embedded in the outer layer of the wall body, the middle layer of the wall body is of a concrete structure, and a fluid pipeline is embedded in the inner layer of the wall body. The wall body outer layer can store cooling capacity of sky radiation and night ventilation at night, and fluid of the wall body inner layer refrigerates the internal space of the building through the evaporative cooling refrigeration device. According to the system, the thermal inertia of a building envelope can be remarkably improved, the stability of the indoor environment temperature is improved, and the building cooling load requirement is lowered.

Description

Technical Field

[0001] This invention relates to the fields of zero-energy building technology, renewable energy utilization, and energy-saving design of building envelopes. Specifically, it relates to an innovative building envelope system that integrates sky radiation cooling, heat pipe heat transfer, wall cold storage, and evaporative cooling technologies, aiming to achieve zero-energy building cooling. Background Technology

[0002] With the urgent global demand for energy conservation, emission reduction, and sustainable development, the development of zero-energy or near-zero-energy buildings has become an important direction in the construction industry. As the heat exchange interface between the indoor and outdoor environments, the building envelope's thermal performance directly affects the building's air conditioning energy consumption. Traditional building envelopes typically rely on insulation materials to reduce heat loss, but lack the ability to actively regulate the indoor thermal environment. In hot summer regions, a large amount of heat still accumulates indoors, leading to dependence on active cooling systems.

[0003] Passive cooling technologies, such as nighttime ventilation, evaporative cooling, and sky radiation cooling, offer possibilities for reducing building cooling energy consumption. Sky radiation cooling utilizes atmospheric windows to radiate heat into outer space, keeping the temperature of objects below ambient levels, making it particularly suitable for nighttime cooling. Evaporative cooling utilizes water evaporation to absorb heat, resulting in high energy efficiency. However, single passive cooling technologies have limitations: the peak cooling capacity of sky radiation cooling occurs at night, which is out of sync with the daytime cooling load peak; evaporative cooling efficiency decreases in high-temperature and high-humidity environments; and nighttime ventilation is constrained by outdoor weather conditions and cannot be precisely controlled.

[0004] Existing research attempts to couple various passive technologies, such as combining phase change materials with skylight radiant panels for wall cooling. However, these systems often suffer from low heat transfer efficiency, mismatch between cold storage and release in time and space, system complexity, or high initial investment. A key challenge in achieving zero-energy cooling for buildings is how to efficiently, compactly, and cost-effectively integrate multiple natural cold sources into the building envelope itself, transforming it not only as a protective barrier but also as an active cold source supply with "temperature regulation" capabilities.

[0005] Therefore, there is an urgent need for an innovative building envelope design that can efficiently integrate the spatiotemporal characteristics of multiple natural cold sources, achieve efficient collection and storage of nighttime cooling energy, and release it on demand during the day. At the same time, it can be combined with efficient daytime passive cooling methods to construct a building cooling system that does not rely on traditional compressor refrigeration and has near-zero energy consumption. Summary of the Invention

[0006] This invention aims to overcome the shortcomings of existing technologies, such as the limited effectiveness of single passive cooling technologies, the complexity of multiple cold source coupling systems with low integration with the building envelope, and the reliance on high-energy-consuming active systems for daytime building cooling. The purpose of this invention is to provide a zero-energy building envelope design based on a multi-natural cold source cooling system. This design deeply integrates skylight radiant panels, heat pipes, layered thermal storage walls, and external evaporative cooling devices, creatively transforming the building envelope itself into an intelligent thermal regulator capable of autonomously completing a "cold energy collection-storage-release" cycle, thereby achieving the goal of zero or near-zero energy consumption for building cooling in summer.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] A zero-energy building envelope design based on a multi-natural cold source refrigeration system is characterized in that the system is a composite thermal regulation system deeply integrated with the building body, mainly including a sky radiation cooling and heat pipe transmission module, a layered heat storage / release wall module, and an external evaporative cooling supply module.

[0009] The sky radiation cooling and heat pipe transfer module includes a sky radiation panel installed above the building roof and several heat pipes. The surface of the sky radiation panel is preferably covered with a high infrared emissivity coating, and the condensation section of the heat pipes is tightly embedded within it. The evaporation section of the heat pipes extends vertically or obliquely downwards and is uniformly embedded in the outer layer material of the building's exterior wall. As a highly efficient, non-powered heat transfer element, the heat pipes can rapidly transfer heat from the outer layer of the wall to the sky radiation panel and dissipate it through radiation into space.

[0010] The layered heat storage / release wall module is the core cold storage and radiant cooling unit of the system. The building's exterior wall is designed as a three-layer composite structure from the outside to the inside: the outer layer is made of a material with high thermal conductivity and high heat capacity, with heat pipe evaporation sections densely packed inside, serving as the main storage body for nighttime cold energy; the middle layer is a load-bearing or filling structure with good thermal insulation performance, used to block outdoor daytime heat flow and reduce heat exchange between the inside and outside of the wall; the inner layer is the interior decorative surface layer, with coil-shaped fluid pipes embedded inside, serving as radiant panels or convective heat exchangers that release cold energy into the room during the day.

[0011] The external evaporative cooling module is an independent device installed outside the building, including a water tank, a spray system, a fan, and an air-fluid heat exchanger. This module is connected to a fluid pipeline embedded in the inner layer of the wall to form a closed loop. Its working principle is to use the low-temperature air generated by evaporative cooling to cool the circulating fluid through the air-fluid heat exchanger, and then the circulating fluid transports the cooling energy to the pipelines in the inner layer of the wall, thereby cooling the interior.

[0012] The core workflow of this system is mainly divided into two collaborative modes:

[0013] On clear nights, the temperature of the sky radiant panel drops to its lowest point due to radiant heat dissipation, activating the heat pipe's operating cycle. The heat pipe continuously "pumps" the daytime heat accumulated on the outer layer of the wall to the sky radiant panel and dissipates it into outer space, gradually cooling the outer layer of the wall and storing a large amount of cold energy. At the same time, the cool outdoor air at night can be used to enhance the pre-cooling of the water storage tank and system circulating fluids through ventilation, accumulating even more cold energy for daytime operation.

[0014] During hot days, the fully cooled outer layer of the wall acts as a large cold source, slowly and steadily transferring heat to the interior through the middle layer of the wall, offsetting some of the indoor heat gain. Simultaneously, the external evaporative cooling module is activated. This module uses outdoor air to reduce the temperature of the circulating fluid through evaporative cooling. The cooled fluid flows through coils in the inner layer of the wall, efficiently and actively cooling the interior through wall radiation and convection, maintaining a comfortable indoor temperature. The middle layer of the wall effectively isolates the high outdoor temperature from interfering with the cooling capacity of the outer layer of the wall and prevents the humid air from evaporative cooling from penetrating into the room.

[0015] Preferably, the heat pipe is a gravity heat pipe, which operates by relying on the phase change of the working fluid and gravity reflux, and consumes no energy at all.

[0016] Preferably, the fluid pipes in the inner layer of the wall can be combined with a floor or ceiling radiant system to create more uniform indoor cooling.

[0017] Preferably, the system is equipped with an intelligent control system that automatically makes decisions and switches working modes based on meteorological conditions, wall temperature and indoor temperature to optimize system operation.

[0018] Compared with existing technologies, the building envelope design provided by this invention has the following significant advantages:

[0019] The system operates entirely through natural processes such as sky radiation, nighttime ventilation, and evaporative heat absorption, eliminating the need for compressor refrigeration and achieving zero energy consumption on the building's cooling side.

[0020] The innovative use of heat pipes solves the problem of efficient long-distance transmission of radiant cooling from the sky to vertical walls, enabling precise cold storage of the wall-mounted cold storage from the rooftop cold source; evaporative cooling is used for active daytime cooling, perfectly compensating for the insufficient daytime cooling capacity of radiant cooling.

[0021] Transforming the building's exterior walls from a static "heat insulation barrier" into a dynamic "cold storage and release intelligent body" greatly enhances the building's thermal inertia and thermal regulation autonomy, significantly improving indoor thermal stability.

[0022] Each module can be seamlessly integrated with the building structure, ensuring a harmonious appearance, making it particularly suitable for applications with stringent requirements for building facades. The external evaporative cooling unit does not occupy indoor space. While reducing or even eliminating cooling energy consumption, it provides cooling through a combination of radiation and convection, resulting in uniform indoor temperature, no drafts, and high comfort. Attached Figure Description

[0023] Figure 1 This is a schematic diagram illustrating the overall structure and principle of a zero-energy building envelope provided in an embodiment of the present invention.

[0024] The components represented by the labels in the diagram are:

[0025] 1. Sky radiation panel;

[0026] 2. Heat pipe;

[0027] 3. Building exterior wall; 31. Outer layer of wall; 32. Middle layer of wall; 33. Inner layer of wall;

[0028] 4. Fluid pipelines; 41. Circulating pumps;

[0029] 5. Evaporative cooling refrigeration unit; 51. Water storage tank; 52. Water supply solenoid valve; 53. Spray water supply pump; 54. Spray water pipe; 55. Spray head; 56. Water baffle; 57. Outdoor air inlet; 58. Outdoor air outlet. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0031] It should be noted that in this embodiment, the orientation or positional relationship indicated by "upper", "lower", "inner", "outer" etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing this application and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on this application.

[0032] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Please see Figure 1 It demonstrates the overall architecture and core component connection relationship of the zero-energy building envelope design based on a multi-natural cold source refrigeration system of the present invention.

[0034] The sky radiant panel 1 is fixed at a certain angle above the building's roof structure, and its surface is coated with a selective radiation coating. Inside the sky radiant panel 1, along its length, several heat pipes 2 with condensation sections are embedded at equal intervals. These heat pipes 2 are preferably gravity heat pipes, with their evaporation sections penetrating the roof insulation layer and structural layer, extending downwards and embedding inside the outer layer 31 of the building's exterior wall. The number of heat pipes 2 is determined based on the building's bay width and the designed cooling load to ensure uniform cooling distribution.

[0035] The building's exterior wall 3 exhibits a clear three-layer functional structure. The outermost layer, 31, is constructed of concrete incorporating high thermal conductivity materials such as graphene and carbon fiber, resulting in high thermal conductivity and volumetric heat capacity. The evaporator sections of all heat pipes 2 are pre-embedded within this layer, ensuring a tight connection. The middle layer, 32, is the primary load-bearing and insulation layer, typically composed of aerated concrete blocks or concrete walls with embedded high-efficiency insulation materials such as rock wool or polyurethane boards. Its thermal resistance is significantly greater than that of the inner and outer layers, making it a crucial thermal insulation layer. The innermost layer, 33, serves as the interior decorative surface, and contains fluid pipes 4. These fluid pipes 4 utilize plastic or metal coils to maximize heat exchange area. The two ends of the coils converge and pass through the wall to connect to the outdoor evaporative cooling system 5. A circulation pump 41 is installed on the fluid pipes 4.

[0036] The evaporative cooling device 5 is installed on the exterior of the building. Its casing has an outdoor air inlet 57 and an outdoor air outlet 58. Internally, it includes a spray zone, a baffle plate 56, and an air-fluid heat exchanger, illustrated in the diagram by a fluid pipe 4 passing through this area. A water storage tank 51 is located at the bottom of the device, from which a spray water supply pump 53 draws water and delivers it to the spray nozzles 55 via a spray water pipe 54. A water replenishment solenoid valve 52 connects to an external water source to replenish the water consumed by evaporation. The inlet and outlet pipes of the fluid pipe 4 in the inner layer 33 of the wall are connected to the air-fluid heat exchanger inside the evaporative cooling device 5, forming a closed-loop circulation circuit. A circulating water pump is installed on this circuit.

[0037] The specific working process and the collaborative mechanism of the core mode of this invention are as follows:

[0038] When night falls and the sky clears, the system enters the cooling storage phase. The sky radiant panel 1 efficiently radiates heat into the cold night sky through its coating, causing its temperature to drop rapidly and significantly below the ambient air temperature. This reduces the temperature of the condenser section of the heat pipe 2 embedded within it.

[0039] The evaporation section of the heat pipe 2, embedded in the outer layer 31 of the wall, absorbs heat from daytime solar radiation and outdoor high temperatures, resulting in a relatively high internal working fluid temperature. Driven by the temperature difference between the two ends of the heat pipe, the liquid working fluid in the evaporation section evaporates, and the vapor rises to the condensation section, where it condenses into liquid on the cold pipe wall, releasing its latent heat of vaporization and dissipating into space through the sky radiation plate 1. The condensate flows back to the evaporation section along the pipe wall under gravity, and this cycle repeats. This process is like a pump-free "heat transport system," continuously and efficiently extracting the heat accumulated in the solid material of the outer layer 31 of the wall and releasing it into space.

[0040] After running all night, the temperature of the outer layer 31 of the wall can be reduced to near the lowest nighttime air temperature, storing a large amount of sensible heat. Simultaneously, due to the good insulation of the middle layer 32 of the wall, this heat is effectively preserved and will not dissipate rapidly. Furthermore, the intelligent control system can activate the ventilation function or operate at low power of the evaporative cooling device 5, allowing cool, dry nighttime air to flow through the device and directly pre-cool the water in the storage tank 51 and the circulating fluid flowing through the heat exchanger, further enhancing the system's cold storage capacity.

[0041] During the hot daytime, the system switches to cooling mode. At this time, the sky radiant panel 1 may heat up due to solar radiation, the heat pipes stop or reverse heat transfer is weak, and their main function becomes shading. At night, the outer wall layer 31, which has been cooled, begins to function. Because its temperature is much lower than the daytime outdoor temperature, and there is an insulation layer 32 between it and the interior, a temperature gradient is formed from the inside to the outside. The cold energy stored in the wall is slowly released through the middle wall layer 32 to the inner wall layer 33 and the interior space through heat conduction, acting like a huge "cold battery" to smooth out indoor temperature fluctuations and offset some of the load generated by heat sources through windows and inside the building.

[0042] When the indoor temperature needs to be further reduced, the active cooling cycle is activated. The intelligent control system turns on the evaporative cooling unit 5. Outdoor air is drawn in through the outdoor air inlet 57 and flows through the spray area. The spray water supply pump 53 sprays water from the water storage tank 51. The water evaporates in the air, absorbing a large amount of latent heat, which significantly reduces the air temperature. This low-temperature, humid air becomes low-temperature, dry air after most of the water droplets are removed by the baffle plate 56, and then flows through the air-fluid heat exchanger.

[0043] Simultaneously, the circulating water pump starts, driving the fluid to circulate between the coils in the inner layer 33 of the wall and the heat exchanger in the evaporative cooling device 5. As the low-temperature, dry air flows through the heat exchanger, it undergoes efficient heat exchange with the circulating fluid inside the pipes, cooling the fluid. The cooled circulating fluid is then pumped into the coils embedded in the inner layer 33 of the wall. Through heat conduction with the inner surface material of the wall and convection and radiation of the surface to the indoor air, the coils release cooling energy evenly and gently into the indoor space, achieving precise and comfortable cooling. The fluid, after absorbing heat and heating up, returns to the evaporative cooling device to be cooled again, thus completing the cycle.

[0044] During this process, the working air and makeup water of the evaporative cooling device 5 both come from outdoors, without interfering with indoor air quality, achieving completely independent external circulation. The middle layer 32 of the wall effectively prevents the outdoor high temperature from invading the cold energy of the outer layer of the wall, and also isolates the moisture from the evaporative cooling process.

[0045] In summary, this invention achieves free nighttime cooling storage and passive cooling through "sky radiation + heat pipes + wall-mounted cold storage," and efficient active cooling during the day through "external evaporative cooling + wall-mounted pipe circulation." These two subsystems are organically integrated and work collaboratively within the building envelope to construct a powerful, stable, and zero-energy building cooling system. It not only significantly reduces building cooling requirements but also improves indoor environmental quality, providing an innovative technological path to achieving truly sustainable buildings.

[0046] Inspired by the core concept of this invention, those skilled in the art can make adaptive adjustments and optimizations to the area and tilt angle of the sky radiation panel, the type and arrangement density of the heat pipes, the material and thickness of each layer of the wall, the arrangement of the fluid pipes, and the specific form of the evaporative cooling device. All such changes fall within the protection scope of this application.

Claims

1. A zero-energy building envelope design based on a multi-natural cold source refrigeration system, characterized in that, include: Sky radiation panel (1), installed above the building roof; The heat pipe (2) has its condensation section embedded inside the sky radiation plate (1) and its evaporation section embedded in the outer layer (31) of the building's exterior wall. The building exterior wall (3) includes, from the outside to the inside, an outer wall layer (31), a middle wall layer (32), and an inner wall layer (33); the evaporation section of the heat pipe (2) is uniformly embedded in the outer wall layer (31); a fluid pipe (4) is embedded in the inner wall layer (33); and a circulation pump (41) is installed on the fluid pipe (4). An evaporative cooling refrigeration device (5) is installed outside the building and includes a water storage tank (51), a water supply solenoid valve (52), a spray water supply pump (53), a spray water pipe (54), a nozzle (55), a baffle plate (56), an outdoor air inlet (57), and an outdoor air outlet (58). The inlet of the spray water supply pump (53) is connected to the water storage tank (51), and the outlet is connected to the nozzle (55) through the spray water pipe (54). The inlet and outlet of the fluid pipeline (4) form a circulation loop with the evaporative cooling refrigeration device (5) through the pipeline. The system is configured to have at least two operating modes: a nighttime cold storage mode, which uses the sky radiation panel (1) and nighttime ventilation to cool and store cold on the outer layer (31) of the wall; and a daytime cooling mode, which uses an evaporative cooling refrigeration device (5) to cool the fluid flowing through the fluid pipe (4) to cool the interior of the building.

2. The zero-energy building envelope design according to claim 1, characterized in that, The heat pipe (2) is a gravity heat pipe, and several of them are arranged vertically or obliquely between the sky radiation plate (1) and the outer layer (31) of the wall. The number of them is determined according to the width of the building's outer wall and the heat load.

3. The zero-energy building envelope design according to claim 1, characterized in that, The outer layer (31) of the wall is made of a material with high thermal conductivity and volumetric heat capacity, used to store the cold energy transferred by the heat pipe (2); the middle layer (32) of the wall is a concrete or lightweight masonry structure with good thermal insulation performance; the inner layer (33) of the wall is an interior decorative surface layer, and the fluid pipe (4) embedded inside it is in the form of a coil.

4. The zero-energy building envelope design according to claim 1, characterized in that, In the nighttime cold storage mode, the sky radiant panel (1) radiates heat to the night sky, making its temperature lower than that of the ambient air and the outer layer of the wall (31), driving the heat pipe (2) to work, transferring the heat in the outer layer of the wall (31) to the sky radiant panel (1) and dissipating it, thereby transforming the outer layer of the wall (31) into a low-temperature cold storage body.

5. The zero-energy building envelope design according to claim 4, characterized in that, In the nighttime cold storage mode, the outdoor air inlet (57) and outdoor air outlet (58) of the evaporative cooling refrigeration device (5) can also be opened, so that the cold air at night flows through the internal channel of the evaporative cooling refrigeration device (5) to pre-cool the water in the water storage tank (51) and the fluid flowing through the fluid pipe (4) directly or indirectly.

6. The zero-energy building envelope design according to claim 1, characterized in that, In the daytime cooling mode, the spray water supply pump (53) is started, and the water in the storage tank (51) is pumped to the nozzle (55) for spraying. Outdoor air enters from the outdoor air inlet (57), flows through the spray area and is evaporated and cooled. The generated low-temperature air is used to cool the fluid in the fluid pipe (4) flowing through the heat exchange unit inside the evaporative cooling refrigeration device (5). The air that has absorbed heat is discharged from the outdoor exhaust port (58).

7. The zero-energy building envelope design according to claim 6, characterized in that, The evaporative cooling refrigeration device (5) is equipped with an air-fluid heat exchanger, and the circulation loop of the fluid pipe (4) passes through the heat exchanger; the low-temperature air after being evaporated and cooled flows through the heat exchanger and indirectly exchanges heat with the fluid in the fluid pipe (4).

8. The zero-energy building envelope design according to claim 1, characterized in that, The system also includes a circulating water pump, which is installed on the pipeline connecting the fluid pipe (4) and the evaporative cooling device (5) to drive the fluid to circulate between the pipe in the inner layer (33) of the wall and the evaporative cooling device (5).

9. The zero-energy building envelope design according to claim 1, characterized in that, The surface of the sky radiation plate (1) is coated with a selective radiation coating with high infrared emissivity and low solar absorptivity.

10. The zero-energy building envelope design according to claim 1, characterized in that, The system also includes an intelligent control system, which automatically switches between the nighttime cold storage mode and the daytime cooling mode based on the outdoor temperature, sky radiation intensity, indoor temperature and wall temperature, and controls the start-up and shutdown and operating intensity of the spray water supply pump (53), the circulating water pump and the air outlet.

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