Heat recovery floor structure and heat recovery floor heating system
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- YAMAURA
- Filing Date
- 2021-12-17
- Publication Date
- 2026-08-03
Smart Images
Figure 0007898683000007 
Figure 0007898683000008 
Figure 0007898683000009
Abstract
Description
Technical Field
[0001] The present invention relates to a heat recovery type floor structure and a floor heating system, and particularly to a floor structure using a heat recovery type insulation technology called Dynamic Insulation (DI), and a floor heating system using such a floor structure.
Background Art
[0002] In the case where fresh air outdoors (specifically outdoors) flows into the room while passing through a window or a wall, the DI technology is a principle of preventing heat transport occurring in the reverse direction of the inflowing air current by advection by passing through a porous material having a breathable function. The heat insulation performance of this technology can be calculated based on the heat equation, suppressing heat loss in winter and heat gain in summer. A ventilation structure using such DI technology includes a window system with double glazing (see Patent Document 1), and this technology has a structure that allows outside air to ventilate through the middle of the double glazing.
[0003] Also, there is an attempt to use the DI technology by passing outside air under the floor (see Patent Document 2). This technology is called a respiratory type, and sucks outside air into the room by a blower provided under the floor and supplies it, or sucks indoor air and discharges it outdoors, and is supposed to recover heat under the floor.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Patent Document 2
Summary of the Invention
Problems to be Solved by the Invention
[0005] The technology disclosed in the aforementioned Patent Document 1 is configured to allow outside air to pass through the middle of a double-glazed window, and heat recovery occurs as the air passes between the double-glazed windows. However, this does not differ significantly from a structure where the air passes through a wall. In other words, the inner wall (inner window) is located on the living room side, and the regulated temperature inside the living room is transferred from the inner wall (inner window) to the inside of the double wall (inside the double-glazed window). Efficient heat recovery cannot be performed unless there is a temperature difference that should be transferred solely by the inner wall (inner window), and as a result, it is assumed that the indoor temperature is sufficiently regulated.
[0006] On the other hand, the technology disclosed in the aforementioned Patent Document 2 is described as performing heat recovery using air passing under the floor. However, the space under the floor functions as a space for supplying outside air when the blower is rotating forward, and as a space for exhausting air when it is rotating in reverse. The supply and exhaust of outside air by the blower is routed through supply and exhaust vents opened in the foundation. Therefore, the other supply and exhaust vent, which should be paired with this one, is constructed with an inorganic foam on the gable wall. When supplying outside air through this inorganic foam, it could not be used as a ventilation system utilizing DI technology. Furthermore, even when supplying air from under the floor, there is no distinction between summer and winter, and even if heat is recovered under the floor, the temperature conditions of the floor surface differ between summer and winter, raising concerns about the efficiency of heat recovery.
[0007] The present invention has been made in view of the above points, and its objective is to provide a highly efficient heat-recovering floor structure and floor heating system, while limiting it to the conditions under which floor heating devices are used during the winter. [Means for solving the problem]
[0008] Therefore, the present invention relating to a heat recovery type floor structure is a floor structure in which a heat source is arranged on the floor surface, wherein a ventilation layer is provided below the floor surface, and the ventilation layer allows outside air supplied from the outside to flow into the living space while transferring heat radiated from the floor surface, and at least an insulating structure is provided between the ventilation layer and the foundation soil.
[0009] According to the floor structure described above, the basic floor structure has a heat source in the floor surface. This heat source contributes to heating the living space as radiant heat transmitted through the floor surface, and the heat loss due to heat radiating from the floor surface to the space below is recovered by DI technology. In other words, since outside air is released into the living space through a ventilation layer provided below the floor surface, the heat radiated from the floor surface is transferred to the outside air passing through the ventilation layer, and as this outside air is released into the living space, a portion of the radiated heat is returned to the living space and recovered.
[0010] In the heat recovery floor structure with the above configuration, indoor air may be exhausted through an exhaust port opened at an appropriate height on the wall surface, or an exhaust layer may be formed between the ventilation layer and the heat insulating structure, and the end of the exhaust layer may be opened to exhaust the air.
[0011] In the above configuration, since the heat source for heating the living space is located at the floor level, the air near the floor is heated, and the temperature decreases in the upper areas. Therefore, if the wall is at an appropriate height, for example, 2 meters or more, exceeding the height of the occupants, the impact of exhaust on the reduction in heating heat felt by the occupants can be kept to a minimum. Furthermore, if an exhaust layer is formed between the ventilation layer and the insulation structure, the heat contained in the exhaust air is transferred to the outside air passing through the ventilation layer, thereby reducing heat loss.
[0012] Furthermore, in a heat recovery floor structure having the above configuration, the floor surface is made of a concrete or mortar floor slab, the heat source is a floor heating device embedded in the concrete or mortar floor slab, and the insulation structure is a double structure comprising a foundation concrete layer and an insulation material layer laminated on top thereof.
[0013] With this configuration, the heat storage properties of concrete, etc., are utilized, and the heat source from the floor heating system is radiated into the living space to provide heating to the living space. At the same time, the heat stored in the concrete, etc., is radiated to the outside air in the ventilation layer and flows into the living space, thus suppressing heat loss. In particular, a large proportion of heat loss under the floor is due to the transfer of heat from the floor surface to the foundation soil (the soil directly beneath the living space). By making the insulation layer a double structure, the efficiency of this transfer is reduced, thereby suppressing heat loss. The floor heating system refers to a heating device used in general floor heating, and includes liquid supply pipes installed as a hot water circulation system and electric heating cables installed as an electric heating system. Insulation materials used in the double-layered insulation structure include inorganic foam or foamed resin.
[0014] Furthermore, in a heat recovery type floor structure configured as described above, where the floor surface is made of concrete or mortar, the floor surface may include a floor plate provided below the concrete or mortar floor slab to support the concrete or mortar floor slab.
[0015] In the above configuration, a concrete or mortar floor slab can be constructed by pouring concrete or the like on the upper surface of the floor slab. Furthermore, even when using precast concrete with a pre-installed floor heating system, it becomes possible to work on the floor slab, thus simplifying the construction of the floor surface.
[0016] On the other hand, the present invention relating to a heat recovery floor heating system is a heat recovery floor structure that uses a floor structure in which the floor surface is made of a concrete or mortar floor slab and a floor heating device as a heat source is embedded in the concrete or mortar floor slab, wherein the floor surface is provided with a communication section for allowing outside air supplied to the ventilation layer to flow into the living room, the ventilation layer is provided with an air intake opening formed by opening the wall surface of the foundation portion at a sufficient distance from the communication section and an air supply device for supplying outside air, and an exhaust passage is provided between the living room and the outside for discharging the air from inside the living room, and ventilation is performed by allowing outside air to flow into the living room after transferring the heat radiated from the floor heating device.
[0017] According to the heat recovery floor heating system with the above configuration, by constructing a heat recovery floor structure with the aforementioned configuration, outside air can be supplied to the ventilation layer of the floor structure, allowing heat recovery while outside air flows into the living space. The air supply device used here can be a sirocco fan or other blowing means, and it is preferable that the airflow can be adjusted. By continuously supplying outside air at the adjusted airflow rate, indoor ventilation can be performed while maintaining the heat recovery effect.
[0018] In the invention with the above configuration, the exhaust passage may be made up of an exhaust port opened at an appropriate height in the wall surface constituting the living room, or it may be made to include an exhaust layer formed between the ventilation layer and the heat insulating structure, a second communication part that allows air from inside the living room to flow into the exhaust layer, and an exhaust port that connects the tip of the second communication part to the outside.
[0019] In the case of a configuration where the exhaust passage has an exhaust port provided on the wall surface of the living room, since the heat source for room heating is provided on the floor surface, for example, if it is provided at a height of 2 m or more exceeding the height of the occupant, the loss of heating heat due to exhaust from the wall surface can be minimized to a level that the occupant does not feel. Further, in the case of a configuration including an exhaust layer formed between the ventilation layer and the heat insulation structure part, the heat contained in the exhausted air is transmitted to the outside air passing through the ventilation layer, and the heat loss can be reduced.
Advantages of the Invention
[0020] According to the present invention related to the heat recovery type floor structure, under the condition of using the floor heating device in winter, the heat source of the floor heating device is released from under the floor, and indoor ventilation can be performed while recovering the waste heat that has been merely a cause of heat loss. It becomes a highly efficient heat recovery type floor structure from the viewpoint of utilizing waste heat.
[0021] Further, according to the present invention related to the heat recovery type floor heating system, since the above-described heat recovery type floor structure is used, it can be a highly efficient heat recovery type floor heating system, and the floor heating device serving as the heat source is embedded in a concrete or mortar floor slab. Therefore, room heating by radiant heat through the concrete or mortar floor slab can be performed, and the occupants in the room can be warmed from their feet and obtain a comfortable living space.
Brief Description of the Drawings
[0022] [Figure 1] (a) is an explanatory view showing an overall outline of an embodiment of a heat recovery type floor heating system, and (b) is a cross-sectional view taken along line IB-IB. [Figure 2] It is a view showing an outline of a preliminary experiment model, (a) assumes an embodiment, and (b) shows a comparison. [Figure 3] It is a cross-sectional view of a preliminary experiment model, (a) assumes an embodiment, and (b) shows a comparison. [Figure 4]This graph shows the results of the preliminary experiment. [Figure 5] These are cross-sectional views of a model used for actual measurement experiments; (a) represents a hypothetical embodiment, and (b) is shown for comparison. [Figure 6] This graph shows the results of the actual measurement experiment. [Figure 7] This is an explanatory diagram showing an overview of the mesh used for CFD analysis. [Figure 8] This is an explanatory diagram showing the structure that will be analyzed using CFD. [Figure 9] This graph shows the results of the CFD analysis. [Figure 10] This is an explanatory diagram showing the state of energy consumption in the structure being analyzed using CFD. [Figure 11] This is an explanatory diagram showing the outline of the mesh in the soil model used for analysis in preliminary experiments. [Figure 12] This graph shows the results of the preliminary experiment. [Figure 13] This is an explanatory diagram showing a modified example of the embodiment. [Modes for carrying out the invention]
[0023] Hereinafter, embodiments of the present invention will be described based on the drawings. <Heat recovery floor structure and floor heating system> Figure 1 shows an overview of an embodiment of a heat recovery type floor heating system. As shown in Figure 1(a), the heat recovery type floor heating system A has a floor heating device 11 embedded in the floor surface 1 of living rooms B and C, and a heat recovery type floor structure 2 is constructed below this floor surface 1. In this embodiment, the floor heating device 11 is an electric floor heating system, and an example is shown in which electric heating cables are embedded at appropriate intervals. Furthermore, the floor surface 1 is exemplified as being made of a concrete or mortar floor slab, and within the living room, a Western-style room or a Japanese-style room can be created by appropriately layering flooring or tatami mats on the surface of the concrete or mortar floor slab.
[0024] The heat recovery floor structure 2 of this embodiment is constructed below the floor surface 1. In general, it consists of a space for forming a ventilation layer 22 above the foundation concrete 21 (between it and the floor surface 1), and an air inlet 23 for supplying outside air to this space (ventilation layer) 22. The air inlet 23 does not open the entire surface of the space (ventilation layer) 22, but rather opens at several points in the space (ventilation layer) 22.
[0025] As shown in Figure 1(b), the heat recovery floor structure 2 has a ventilation layer 22 below the floor surface 1, and this ventilation layer 22 is formed on top of the insulating structure that constitutes the foundation. The insulating structure is formed by constructing foundation concrete 21 on the surface of the foundation soil (the soil portion that constitutes part of the foundation) 20, and then laminating an insulating material layer 24 on top of this foundation concrete 21. In this embodiment, a configuration in which the foundation concrete 21 is provided on the foundation soil 20 with the ground level (GL) as the surface without excavating the ground is illustrated, but the foundation structure is not limited to the illustrated case and may take various forms such as a raft foundation or a strip foundation.
[0026] The ventilation layer 22 is continuous with a connecting section 25 that penetrates the floor surface 1 at a position sufficiently far from the air intake 23. This connecting section 25 is provided at several appropriate locations on the floor surface 1, and outside air that has passed through the ventilation layer 22 flows into the living room through this connecting section 25.
[0027] Therefore, outside air is supplied to the ventilation layer 22 from multiple air inlets 23 that are opened on the side of the foundation concrete 21, and heat radiated from the floor surface 1 (waste heat from the floor heating device 11) is transferred over a wide area of the ventilation layer 22, and the air that has risen to an appropriate temperature while recovering the radiated heat (waste heat) is supplied to the living space. The outside air supplied from the air inlets 23 is supplied by an air supply device.
[0028] In this embodiment, floor supports 26 are erected on the foundation concrete 21, and the floor slab 27 is supported by these floor supports 26. A concrete or mortar floor slab, which will form the floor surface 1, is constructed on the upper surface of the floor slab 27. Since the ventilation layer 22 extends over almost the entire floor surface 1, the floor supports 26 are used to support the floor surface 1 in order to create a wide space below the floor surface 1. Therefore, if the ventilation layer 22 can be constructed over a wide area without providing floor supports 26, then it is not necessary to provide floor supports 26.
[0029] Although the living space is separated from the outside by an exterior wall 3 and therefore omitted in Figure 1, in this embodiment, an exhaust port is provided in the exterior wall 3, and this exhaust port serves as an exhaust passage. By installing a blower such as an exhaust fan in the exhaust port (exhaust passage), the living space can be made negatively pressurized, and outside air can be supplied from the air supply port 23 via the ventilation layer 22. This exhaust fan is used as the air supply device, but outside air may also be supplied by installing a blower or the like in the air supply port 23. In this case, the ventilation layer 22 will be made positively pressurized, and the air that has recovered heat from the ventilation layer 22 can be supplied to the living space via the communication section 25. Furthermore, an air supply fan may be installed in the communication section 25 to supply air from the ventilation layer 22 to the living space, in which case an exhaust port (exhaust passage) for discharging air from the living space will be provided. With this configuration, the ventilation layer 22 is under negative pressure, allowing outside air to be supplied, while the living space is under positive pressure, allowing the air to be discharged through the exhaust port (exhaust passage). Furthermore, the interior is partitioned into individual living spaces by partition walls 4, and a similar heat recovery floor structure 2 may be constructed for each living space. Alternatively, the ventilation layer 22 may be formed as a space common to the floor surface 1 of multiple living spaces, with the connecting section 25 opening to each living space.
[0030] <Example of experiment> (Preliminary experiment) As a preliminary experiment, experimental models as shown in Figures 2 and 3 were constructed, and the power consumption of the floor heating system was measured over an 8-hour period during the night. Figure 2 is an overview of the experimental model, and Figure 3 is a cross-sectional view of the experimental model. In both Figures 2 and 3, (a) represents the heat recovery type floor heating system of the embodiment, and (b) represents a floor heating system for a dirt floor for comparison. The dimensions of each model are as shown, and the entire structure is covered with 8 mm thick aluminum panels 51, with airtightness ensured by sealing the gaps in each joint with silicone resin. In addition, small eaves 50 were provided on all four sides of the roof 5.
[0031] Each model is designed to represent a single living room, with the entire exterior wall 3 made of Styrofoam®. The floor 1 is constructed of mortar, and a floor heating system 11 is assumed, with a heating cable 14 sandwiched between two aluminum panels 12 and 13. A PTC (Positive Temperature Coefficient) heating wire is used for the heating cable 14, and it is heated by applying voltage, with the amount of power consumed being recorded as the power consumption. A PTC heating wire with a maximum output of 20W / m was used, and 30m of this was used (total maximum output of 600W). To maintain a constant temperature in the living room, a thermostat was installed at the exhaust port, and the ON-OFF control of the PTC heating wire was set to a temperature of 20.0℃ (±0.2℃).
[0032] Furthermore, ventilation is provided by installing a sirocco fan 31 in an exhaust vent opened in one of the exterior walls 3, creating negative pressure inside the room. In the model representing the embodiment (Figure 2(a)), outside air is supplied to a ventilation layer 22 formed below the floor surface 1 via an air intake 23, while in the comparative model (Figure 2(b)), outside air is supplied to the living space from an air intake 23 opened in the other exterior wall 3. The sirocco fan is controlled by a voltage controller to provide a ventilation rate of 4.4 m³. 3 I set it to / h.
[0033] Other experimental conditions are as shown in the table below. [Table 1]
[0034] (Preliminary experimental results) The results of the preliminary experiment under the above conditions are shown in Figure 4. As shown in this figure, the preliminary experiment revealed that there was a difference in power consumption over time between the model representing the embodiment and the comparison model. In particular, after 8 hours, the power consumption of the model representing the embodiment was 48.19 kWh, while that of the comparison model was 60.39 kWh, indicating that power consumption could be reduced by approximately 20.2%.
[0035] (Experimental measurement) As a field experiment, the power consumption of the floor heating system was measured over 16 days. The models used in the field experiment (a model representing the assumed embodiment and a comparative model) were basically the same as those used in the preliminary experiment. The comparative model was exactly the same, but the model representing the assumed embodiment was slightly modified. These models are shown in Figure 5. However, Figure 5(a) shows the model representing the assumed embodiment, and Figure 5(b) shows the comparative model. The modification to the model representing the assumed embodiment, as shown in Figure 5(a), was to narrow the gap in the ventilation layer and set the gap in the height direction to 30 mm. Therefore, to raise it by the equivalent of 70 mm compared to the original 100 mm, Styrofoam® was sandwiched between aluminum panels at the bottom. This was because it was determined in the preliminary experiment that a uniform airflow did not occur in the ventilation layer, and along with the above modification to the ventilation layer, the ventilation rate by the sirocco fan was set to 15.7 m³. 3 The setting was adjusted to / h to ensure uniform airflow. Incidentally, 0.33 m³ is required for 0.5 air changes in this model. 3 The value is / h, but this small amount of airflow is smaller than the minimum airflow of the sirocco fan, and is also for the purpose of equalizing the airflow as described above.
[0036] As other conditions, the whole was covered with aluminum panels (8 mm thick), and the joints were made airtight with silicone resin. The outer wall was made of Styrofoam (registered trademark). The floor surface was made of mortar and configured with PTC heating wires assumed for floor heating devices sandwiched between two aluminum panels. Regarding the use of 30 m of PTC heating wires with a power of 20 W / m, the same procedure as the preliminary experiment was followed. As for the temperature setting, the same was done in that a thermostat was installed at the exhaust port, but the set temperature was changed to 20.0 °C (±0.1 °C) for ON-OFF control.
[0037] Other experimental conditions are as shown in the following table.
Table 2
[0038] (Measured experimental results) The results of the measured experiment under the above conditions are shown in Figure 6. As shown in this figure, the cumulative value of power consumption for 16 days was 65 kWh for the model assuming the embodiment, while it was 122 kWh for the comparative model, indicating that about 46% of power consumption can be reduced. In the preliminary experiment, the power reduction rate was about 20%, but the reason for the improvement in the measured experiment is judged to be due to the uniformization of air flow in the ventilation layer. That is, it was found that heat recovery is performed in a wide range of the ventilation layer by the uniform flow of air in the ventilation layer. This means that the heat radiation (exhaust heat) released from the floor surface is sufficiently recovered.
[0039] <CFD analysis> (Analysis conditions) Next, the heat loss and heating load conditions were analyzed using CFD analysis. The analysis used a numerical analysis model consistent with measured values to examine the effects of applying various floor heating systems (embodiments and comparative examples) to a full-scale model. The full-scale model included the installation soil (foundation soil), with an indoor scale of 8m (width) × 8m (length) × 2.5m (height) and a soil scale of 16m (width) × 16m × 1.5m (depth). The outline of the mesh used for these analyses is shown in Figure 7. The finite volume method was used for the CFD analysis.
[0040] Figure 8 shows the structure to be analyzed using the CFD analysis described above. As shown in this figure, four types of structures were chosen for analysis. Figure 8(a) is the structure (embodiment type) that is closest to the embodiment. In this structure, the heat recovery floor structure 2 consists of a foundation concrete 21 provided on the surface of the foundation soil 20, with insulation material 24 provided on top of it, and the layer above this insulation material 24 being a ventilation layer 22. The floor surface 1 is made of mortar, and a floor heating device 11 using electric heating cables is embedded inside. The perimeter of the living space is enclosed by an outer wall 3 made of insulation material. Although floor boards (boards) 27 are provided to support the floor surface 1, floor supports are omitted. Also, the connecting parts for circulating air from the ventilation layer 22 to the living space are omitted. This is because these do not directly involve heat transfer (heat loss, etc.).
[0041] Furthermore, Figure 8(b) shows a simplified structure (simplified type) of the embodiment. Specifically, the simplified structure shown in Figure 8(b) simplifies the heat recovery floor structure 2 and forms a ventilation layer 22 by supporting the floor surface 1 with the outer wall 3. The simplification of the heat recovery floor structure 2 involves omitting the foundation concrete and providing insulation material 24 directly on the surface of the foundation soil 20. However, the floor surface 1 is made of concrete, and the floor heating device (electric heating cable) 11 is embedded inside it.
[0042] On the other hand, Figures 8(c) and (d) are comparative examples. Specifically, comparative example (1) in Figure 8(c) is a floor heating system shown in Figure 8(a) in which the ventilation layer is replaced with an air layer, that is, a state in which air is sealed without ventilation. Comparative example (2) in Figure 8(d) is based on a typical earthen floor heating system and is a structure in which the ventilation layer 22 is removed from the simplified type shown in Figure 8(b). Specifically, an insulating material 24 is provided on the surface of the foundation soil 20, and a concrete floor surface 1 is formed on top of it.
[0043] In the analysis, for configurations having a ventilation layer 22 (embodiment type and simplified type), the surface in contact with the ventilation layer was assumed to be insulated by an insulating material or heat-shielding sheet (not shown), and its emissivity was set to 0.1, while for other configurations (comparative examples (1) and (2)), the emissivity was set to 0.8. To simplify the calculation, the heating method was set to 100 W / m² relative to the volume of mortar or concrete in the floor surface 1. 2 The analysis was conducted assuming floor heating by directly providing the temperature. In the calculations associated with the analysis, except for the calculation of solar radiation in the indoor space, the temperature change of the soil was given as measured values for the ground, and the initial condition temperatures were set to 20°C for the indoor temperature, the floor surface (mortar or concrete) 1 and the floorboards (if installed), and 9°C for the ground surface, foundation concrete 21, ventilation layer 22 and the insulation material 24 in contact with them. Other analysis conditions (however, some are listed twice) are as shown in the table below.
[0044] [Table 3]
[0045] (Analysis results) Figure 9 shows the results of the experimental measurements under the above conditions. Figure 9(a) shows the results for heat loss to the soil, and Figure 9(b) shows the results for heating load. As shown in Figure 9(a), the cumulative heat loss to the soil over 24 hours was -4.7 MJ for the embodiment type and 19.3 MJ for the simplified type, while it was 2.9 J for comparative example (1) and 54.7 MJ for comparative example (2). Furthermore, regarding the cumulative heating load (the energy that should be input to maintain the room temperature at 20°C for 24 hours under the above conditions), it was 151.9 MJ for the embodiment type and 184.2 MJ for the simplified type, while it was 192.1 MJ for comparative example (1) and 242.0 MJ for comparative example (2).
[0046] Here, we will explain the further analysis of heating load (energy to be input) and heat loss. Figure 10 shows the state of energy consumption (heat balance) of input energy (heating load). Figure 10(a) shows the heat balance for the heat recovery type (double floor), Figure 10(b) shows the heat recovery type (earth floor), Figure 10(c) shows the heat balance for the double floor, and Figure 10(d) shows the heat balance for the earth floor.
[0047] As shown in these figures, in the case of a heat recovery type (double floor), of the input energy of 151.9 MJ, 73.6 MJ of energy is directly transferred to the room, and 35.8 MJ of energy is recovered as heat and transferred to the room. In addition, 3.3 MJ of energy is discharged to the outside, and 46.5 MJ of energy is stored as heat from the floor surface to the entire floor structure. Furthermore, in this structure, the amount of heat loss to the soil was -4.7 MJ, resulting in 4.7 MJ of energy being supplied from the soil. This is because, as will be described later, although the outside temperature fluctuates over 24 hours, it is generally low (especially the temperature drops at night). As a result, the outside air passing through the ventilation layer 22 also absorbs the heat stored in the foundation concrete 21, and this is recovered into the room. On the other hand, the temperature of the foundation concrete 21 is lower than the soil temperature, so it is thought that the foundation concrete 21 absorbs energy from the soil.
[0048] From the above results, the heat loss amount is good in both the embodiment type and Comparative Example (1) (both having a double-floor structure). However, for the heating load (energy to be input), it is good in the embodiment type and the simple type. In particular, it was found that the embodiment type is the best in terms of both the heat loss amount and the heating load. Also, since Comparative Example (1) has a configuration in which an air layer that does not allow air to flow is provided under the floor, it had a good heat loss amount. However, for the heating load, the embodiment type can reduce it by about 20.9% compared to Comparative Example (1), and a reduction of 23% can be achieved compared to a dirt floor structure like Comparative Example (2). The reason for the large heating load in Comparative Example (1) is presumably due to the inability to recover heat although the heat loss amount is small. Therefore, it was found that even if an air layer is formed under the floor, it is necessary to provide a ventilation layer 22 that enables heat recovery.
[0049] <Preliminary Experiment of CFD Analysis> Since a preliminary experiment is being conducted to quantify the heat loss to the ground in the above CFD analysis, it is introduced below. As the soil model, it is assumed to be in the state of the subsoil, and the measured values and the analysis values are to be compared. For the measurement, the ground surface was set as 0 (reference point), and the soil temperature every 100 mm up to a depth of 600 mm, the outside air temperature, and the solar radiation amount were measured. For the measurement of the underground temperature, three PVC pipes were inserted into the ground at intervals of 1.5 m, and the temperature on the surface of the PVC pipes was measured for each depth. Thermocouples (Type T) were used for the temperature measurement of the three pipes. The interval for each measurement was 1 minute. The location was within Shinshu University, and the time was 24 hours from 0:00 to 24:00 on March 17, 2021.
[0050] Furthermore, a soil analysis model was created using information obtained from actual measurements during the analysis. The analysis area was 4.0m (width) × 4.0m (length) × 3.0m (height), as shown in Figure 11, with the lower half (1.5m) in the height direction representing the soil portion (underground). For external wind speed, the publicly available wind speed profiles shown in the table below were used, and the change in wind speed with respect to height in the analysis model was considered. Also, since it was a vacant lot, wind direction was not considered, and the wind speed data used was the 10-minute interval data announced by the Nagano Meteorological Observatory (Japan Meteorological Agency) on March 17, 2021, the same day as the actual measurements. For the analysis, the total solar radiation obtained from the actual measurements was separated into direct and scattered solar radiation, and this direct-scatter separation was performed using the publicly available direct-scatter separation method shown in the table below. Note that, since the observation point at the Nagano Meteorological Observatory is at 19.0m above ground level, the wind speed (u) at any height was converted using the following formula, and a wind speed profile was created in advance.
number
[0051] Furthermore, the turbulent energy k(m 2 / s 2 ) and turbulent dissipation rate ε(m 2 / s 3 The formula is as follows:
number
[0052] The details of the analysis conditions are shown in the table below. [Table 4]
[0053] The results of the above measurements and analysis values are shown in Figure 12. Figure 12(a) shows the 24-hour trend of measured values related to ambient temperature, and Figure 12(b) shows the results related to measured and analysis values related to soil temperature. According to the measured values shown in these figures, the temperature at the ground surface (0m) fluctuates with changes in ambient temperature, but the range of fluctuation becomes smaller at 200m underground and is generally uniform at 600m underground. Furthermore, according to the analysis results in Figure 12(b), although there are slight differences at the ground surface (0mm), the measured values and analysis results are almost the same overall, so it was judged that the consistency of the CFD analysis model was ensured. From this, it was judged that the soil model used in the CFD analysis ensures consistency with the measured values and that the analysis of heat loss to the soil is reliable.
[0054] <Summary> The embodiments relating to the heat recovery type floor structure and heat recovery type floor heating system are as described above, and as is clear from the analysis results, it is possible to recover heat radiated from the floor heating device, reduce the amount of heat lost to the soil, and reduce power consumption and heating load. Therefore, according to the heat recovery type configuration of this embodiment (embodiment type and simplified type), it is possible to provide a highly efficient heat recovery type floor structure and floor heating system in winter.
[0055] The embodiments (embodiment type and simplified type) shown above are merely examples of the present invention, and the present invention is not limited to these embodiments. Therefore, the elements of the above embodiments may be modified, and other elements may be added. For example, in the floor heating structure of the embodiment, a floor surface 1 made of mortar is shown as an example, but the invention is not limited to this, and a floor heating structure in which a heating pipe is installed directly beneath the floor surface formed by joists is also possible.
[0056] Furthermore, as shown in Figure 13, a partition plate 6 may be provided directly below the ventilation layer 22, with the area below it forming an exhaust layer 61. In this case, the exhaust of indoor air into the exhaust layer 61 is directed perpendicular to the plane of the paper in the figure, which is different from the direction of outside air flow passing through the ventilation layer 22, thus preventing the exhausted air from re-inflowing. In the aforementioned CFD analysis, the temperatures of the foundation concrete and soil were set to 9°C, but if the soil temperature is even lower, energy supply from the soil may not be expected. Therefore, with this configuration in which the exhaust layer 61 is formed directly below the ventilation layer 22, the purpose may be to recover waste heat from the indoor air instead of receiving energy from the soil. [Explanation of Symbols]
[0057] 1 Floor section 2. Heat recovery floor structure 3. Exterior walls 4 Partition wall 5. Roof 6 partition plates 11. Underfloor heating system 12,13 Aluminum Panels 14. Electric heating cable (PTC heating wire) 20. Basic soil 21 Foundation concrete 22 Ventilation layer 23 Air supply port 24. Insulation layer (insulation material) 25 Communication part 26 bed support 27 Floorboards 31 Sirocco fan 50 Canopy 51 Aluminum Panel
Claims
1. In a floor structure in which a heat source is installed on the floor surface, A ventilation layer is provided below the floor surface, and this ventilation layer allows outside air supplied from the outside to flow into the living space while transferring heat radiated from the floor surface, and at least an insulating structure is provided between the ventilation layer and the foundation soil. The aforementioned heat-insulating structure is configured such that a heat-insulating material or heat-shielding sheet is directly provided on the surface of the foundation soil, or a heat-insulating material or heat-shielding sheet is provided on the upper layer of the foundation concrete provided on the surface of the foundation soil. The ventilation layer is formed between the floor surface and the insulation material or heat-shielding sheet. A heat recovery type floor structure characterized by the following features.
2. The heat recovery type floor structure according to claim 1, wherein an exhaust layer is formed between the ventilation layer and the heat insulating structure.
3. The aforementioned floor surface is made of a concrete or mortar floor slab. The heat recovery type floor structure according to claim 1 or 2, wherein the heat source is a floor heating device embedded in the concrete or mortar floor slab.
4. The heat recovery type floor structure according to claim 3, wherein the floor surface portion comprises a floor plate provided below the concrete or mortar floor slab and supporting the concrete or mortar floor slab.
5. A heat recovery floor heating system using the heat recovery floor structure described in claim 3 or 4, The floor portion is provided with a communication section for allowing outside air supplied to the ventilation layer to flow into the living space. The ventilation layer comprises an air intake opening formed by opening the wall surface of the foundation portion at a sufficient distance from the communication portion, and an air supply device for supplying outside air. Between the living space and the outdoors, there is an exhaust duct for expelling the air from inside the living space. A heat recovery floor heating system characterized by ventilating the living space while allowing outside air to flow in after transferring heat from the floor heating device.
6. The heat recovery floor heating system according to claim 5, wherein the exhaust passage is composed of an exhaust vent opened at an appropriate height in the wall surface constituting the living room.
7. The heat recovery floor heating system according to claim 5, wherein the exhaust passage comprises an exhaust layer formed between the ventilation layer and the heat insulating structure, a second communication section for allowing air from inside the living space to flow into the exhaust layer, and an exhaust port for discharging the air that has flowed into the exhaust layer to the outside.