WO2017134177A1

WO2017134177A1 - Method and apparatus for absorbing, storing and discharging thermal energy from gases

Info

Publication number: WO2017134177A1
Application number: PCT/EP2017/052282
Authority: WO
Inventors: Karl Brotzmann; Dragan Stevanovic
Original assignee: Karl Brotzmann Consulting Gmbh
Priority date: 2016-02-03
Filing date: 2017-02-02
Publication date: 2017-08-10
Also published as: DE102016001163A1

Abstract

The present invention relates to a method for absorbing, storing and discharging thermal energy from gases, in which, in a first step, a gas is made to flow through a bed of a bulk material in a first flow direction for a time period t₁, giving off heat or cold to the bulk material, this being stored by the bulk material, and, in a second step, a gas is made to flow through the bed in a second flow direction for a time period t₂, absorbing heat or cold from the bulk material, wherein the characteristic for the heat transferred per unit volume and per degree Kelvin, defined as t_i m_Gi c_pi / (a V_s Δ), is at least 0.25 kJ/m³K and at most 25 kJ/m³K, wherein i=1,2 refers to the time period t₁ or t₂, m_Gi is the gas throughflow, c_pi is the specific heat capacity of the gas, a is the specific particle surface, V_s is the volume of the bulk material bed and L is the thickness of the bed in the flow direction of the gas; and to a device for carrying out this method.

Description

Method and device for receiving, storing and emitting thermal energy of gases

The present invention relates to a method for receiving, storing and releasing thermal energy of gases, in which a bed of a bulk material is traversed in a first step in a first flow direction for a first time period of a gas, thereby heat or cold to the bulk material which is stored by the bulk material, and in a second step in a second flow direction for a second period of time is traversed by a gas which absorbs heat or cold from the bulk material.

According to the prior art are used as a storage mass for storing thermal energy of gases, especially in the integrated heat recovery z. B. used in ventilation systems, ceramic honeycomb or metal plates. To keep such systems as small as possible, short switching times are chosen between inflowing and outflowing air, z. For example one minute.

For central ventilation systems of larger design, the use of recuperative heat exchangers is known in the art. Disadvantage of these heat exchangers, however, is that the surface for the heat transfer must be large, resulting in large and therefore expensive equipment.

The present invention accordingly has the object to provide a method and apparatus for receiving, storing and emitting thermal energy of gases, especially for integrated heat recovery in ventilation systems that avoids the above-mentioned disadvantages of the prior art and efficient Recovery of thermal energy from gases (i.e., high efficiency recovery) while being more cost effective and compact design of the device necessary for carrying out the method makes it possible.

The present invention is based on the finding that such a method and such a device can be made available if

the coefficient of heat transfer per volume and degree Kelvin, defined as tj m _G ic _pi / (a V _s L), is at least 0.25 kJ / m ³ K, where i = 1, 2 is the time period ti or t ₂ , m _G i denotes the gas flow, c _P j the specific heat capacity of the gas, a (in m ² / m ^{3 of} the bed) the specific particle surface, V _s the

Volume of the bed and L the bed thickness in the flow direction of the gas;

- and if a bulk material of particles is used as the recording, storage and dispensing medium of the thermal energy of the gases, in which the ratio between the bed thickness L in

Direction of flow of the gas and the m mter Parti keldurchmesser dp of the bulk m at least 20 amounts.

The present invention therefore provides a method for the uptake, storage and release of thermal energy of gases, in which a bed of bulk material is traversed by a gas in a first step in a first flow direction for a period of time ti, the heat or gives off cold to the bulk material, which is stored by the bulk material, and in a second step in a second flow direction for a time period t _{2 is} traversed by a gas, the heat or cold of the bulk material aufn immt, characterized in that the behaves is between bed thickness L in the flow direction of the gas and the mean particle diameter d _{P of} the bulk material is at least 20 and the characteristic number for the heat transferred per volume and degree Kelvin, defined as ti m _G ic _P j / (a V _s L) m is at least 0.25 kJ / m ³ K. On the one hand, the method according to the invention offers the advantage that the recovery of thermal energy from gases can be efficiently, ie. H . with high efficiency, can be realized. Furthermore, the device for carrying out the method can be realized in a cost-effective and compact manner if the storage capacity per volume, or per mass of the memory, is significantly higher. A further advantage of the method according to the invention is that the temperature of the gas at the outlet from the bulk material bed remains substantially constant both during the discharge of the thermal energy of a gas and during the absorption of the thermal energy of the gas. With the characteristics defined above, one achieves a significantly lower temperature difference between the gas and the storage material.

In a preferred embodiment, the ratio between bed thickness L in the flow direction of the gas and mean particle diameter dp of the bulk material is at least 30, more preferably at least 40, and particularly preferably at least 50.

Through these preferred embodiments, the heat recovery can be more efficient, d. H. design with even higher efficiency, since the heat recovery rate increases with increasing ratio between bed thickness L in the flow direction of the gas and the mean particle diameter d _{P of} the bulk material and also longer switching times At are possible. For practical reasons, the ratio between bed thickness L in the flow direction of the gas and the mean particle diameter dp of the bulk material is usually at most 2000.

In a preferred embodiment of the invention, the specific particle surface a (m ² / m ^{3 of} the bed) is so large that the ratio between the total surface a V _s (as a product of the specific particle surface and the volume of the bed) and the volume flow of the gas in the normal state v _G i (m ³ _{i N.} / h) multiplies by the time period tj (h) a V _s / (v _Gi ti) is at least 0.05 m ^"1 and a maximum of 1 m 0 ^'1. This allows a very efficient heat transfer resulting from a very low temperature difference between solid and gaseous phases.

Further preferably, the mean particle diameter dp of the bulk material is from 0.5 mm to 50 mm. These particle diameters ensure good flowability of the bulk material bed with at the same time good absorption and storage capacity for the thermal energy of the gases flowing through.

The average particle diameter dp of the bulk material is preferably determined as the Sauter diameter, according to DIN N ISO 9276-2. This is defined as follows: If one were to transform the entire volume of the particles of a bed into spheres of equal size, whose entire surface is equal to the entire surface of the particles, then these spheres would have the Sauter diameter as the diameter. The bulk material is preferably made of ceramic, chamotte, sil icium carbide, zirconium oxide, graph it, Eifel lava, gravel, iron ore, clay, lime, metallic particles or combinations thereof.

The particles of the bulk material may be spherical, gravel-shaped and / or in the form of fracture or gravel. Advantageously, the particles used are approximately uniform.

For example, the bulk material bed can be formed so that it is arranged in a column, ie in turn arranged standing or lying is, or that the bulk material is flowed through radially, as described in the patent DE4238652.

In a preferred embodiment of the method, the first one is different from the second flow direction, i.e. Gas flows through the bed of bulk material during the time period ti in a different direction relative to the bed than the gas during the time period T _2.

More preferably, the first flow direction of the second opposite. In this embodiment, the method according to the invention can be used in a particularly simple manner, for example for room ventilation with integrated heat recovery.

In a particularly preferred embodiment, the bulk material is continuously flowed through by gas and it is changed between the first and the second flow direction after each time period ti or i ₂ . In this embodiment, the bulk material is continuously flowed through by gas in a first or in a second flow direction, ie, once the time period ti or i _{2 has} elapsed, the flow direction is "switched".

This preferred embodiment allows a particularly effective embodiment of the method according to the invention, since the absorption of thermal energy by the gas flowing through the bulk material during a time period t ₂ immediately after the release of thermal energy to the bulk material by the bulk material during a time period ti flowing gas takes place and thus the storage time and thus possibly associated storage losses of thermal energy in the bulk material are minimized. In another embodiment, at least in part, the heat is delivered to the bulk material by an electric heater built into the bed.

The change of the flow direction is preferably carried out by means of at least one blower or a system with a plurality of valves.

Preferably, the following relation is sufficient for the switching time ti or t ₂ :

0.1 - (M _s / m _G i) - (c _s / Cpi) <tj <0.9- (M _s / m _G i) - (c _s / Cpi) where

i = 1, 2 denotes the parameters relative to the time period ti or t ₂ , M _s the mass of the bulk material,

m _G i is the gas flow,

c _s the specific heat capacity of the bulk particles and

c _P i is the specific heat capacity of the gas.

In this preferred embodiment, the thermal energy delivered by the heated gas is between 10% and 90% of the maximum possible stored thermal energy, but the difference remains almost completely in the bulk material.

In a preferred embodiment, ti = t ₂ = At.

In a preferred embodiment, the gas flow rate flowing through the bulk material m _G i (kg / h) per mass of the bulk material M _s (kg) during at least one of, preferably during both time periods ti and t ₂ from 0.05 h ^"1 to 50 h ^"1 .

The inventive method allows the formation of a very advantageous temperature profile within the bulk bed such that in opposite flow direction during the period ti and the period t _2, the temperature at the outlet ends of the bulk bed changes relatively little, while the temperature change in the middle of the bed relatively high is. Therefore, in a preferred embodiment of the method in the bulk material, a temperature distribution is formed such that during each time period ti or t ₂ the temperature change in the middle of the bulk material bed ΔΤ _{Μ is} at least twice compared to the temperature change at one of the outlet ends of the bulk material bed ΔΤ _Ε , d .h. ΔΤΜ> = 2 ΔΤ _Ε , wherein the flow direction during the time period ti is opposite to that during the time period t ₂ . This advantageous temperature profile is formed by a very low temperature difference between the gas phase and solid phase, which in turn is made possible by the fulfillment of the abovementioned conditions.

Preferably, air is used as the gas during the time period ti and / or t ₂ .

In a particularly advantageous embodiment of the present invention, the inventive method for controlled ventilation of a room with integrated heat recovery is used. This means that the bulk material bed is flowed through during the period ti of exhaust air from the room and during the time period t ₂ of fresh air from outside Shen.

The temperature of the room exhaust air when entering the bed of bulk material is normally 1 7 ° C to 35 ° C. The temperature of the fresh air supplied from the outside when entering the bed of bulk material depends on the season and can therefore be from -30 ° C to 50 ° C.

From the relative temperature difference between the exhaust air and fresh air also depends on whether the bulk material bed acts as a heat or cold storage.

In the cold season, when the outside temperature is below the room air temperature, the exhaust air from the room is cooled by the cold air released from the fresh air and stored in the bulk material bed and flows coolly outwards. The outside air, on the other hand, is warmed up so that it enters the room at about room temperature. In this case, heat is thus stored in the bulk material bed. In the warm season, when the outside temperature is above the room air temperature, a reverse process takes place: the exhaust air from the room is warmed up by the heat stored in the storage mass and flows warm to the outside. At the same time, the outside air is cooled down so that it enters the room at room temperature. In this case, so cold, and not heat, stored in the bulk bed.

If the room exhaust air has a high moisture content, a condensate can form in the colder layer of the bulk bed, the z. B. flows to the outside. The energy released by the condensation is stored in the bed and, in the next phase, additionally contributes to the preheating of the outside air.

Warming up the outside air reduces the relative humidity in the air-conditioned room, as the fresh air has a lower moisture content. In winter, especially at temperatures below 0 ° C, the outside air has a very low humidity. Due to intensive ventilation, the humidity in winter can quickly fall below 35%. This in turn can damage the health of people in the room, because the mucous membranes can dry out, the eyes burn, the throat scratch and the risk of infection can increase. Therefore, in addition to heat recovery, moisture recovery in room ventilation systems is very important, but only a few plants have the ability to effectively carry out this moisture recovery.

Therefore, it is advantageous, at least if the outside air has a temperature of below 0 ° C and / or a humidity of less than 35%, to return a certain amount of moisture from the room air. Since the bulk material, on which condensate precipitates from the room air, has a very high specific surface area, the outside air humidifies very quickly to a relative humidity between 35% and 65%. In this way, the inventive method and the device according to the invention comprising a bulk material or its use, at the same time very well suited to remove excess moisture from the room and on the other hand to moisturize dry outdoor air by an inherent recovery of moisture and a room air with a optimum humidity between 35 and 65%.

If an even higher moisture content is desired in the room air, moisture can be added to the air flowing into the room in the ventilation system. If the process according to the invention is operated for a prolonged period in such a way that a condensate forms, it is expedient for the bulk material bed to flow through a heat to the bulk material emitting gas for a time period t3 with the condition t3> ti and t3> t ₂ becomes.

In this case, intermediately means that the drying takes place after a long period in comparison to the time periods ti and t ₂ . For example, at time periods ti and t _2, in the range of 2 minutes to 60 minutes, drying once a day, i. E. once every 24 hours.

In this case, t3 is preferably 3 to 5 times as large as ti or t ₂ . For example, at ti = t ₂ = 5 minutes, the drying can be done so that once a day for 20 minutes, the flow in the direction of the cold side, so that the bulk material is completely dried again and thus avoid possible mold growth. In addition to the controlled ventilation, this also regulates the humidity.

In a preferred embodiment of the method according to the invention, in particular in the embodiment for room ventilation, two bulk beds are used, wherein ti = t ₂ and, while bulk material 1 is traversed by a heat-emitting gas for a period of time ti, simultaneously bulk material 2 of a cold-emitting gas for a Time period t ₂ flows through and vice versa. For example, in the Method for room ventilation bulk material 1 flows through a period of time ti of exhaust air from the room and the bed of material 2 simultaneously during a time period t ₂ = ti of fresh air and switching to each other flow direction also occurs simultaneously. The procedure in each of the two beds of bulk material can be carried out independently of one another in one of the (preferred) embodiments described above.

In the colder season, when the outside air is below the room temperature, the exhaust air releases the heat to the bulk material bed 1 and flows out relatively cold. At the same time, the outside air flows through the bulk material bed 2, wherein the heat stored there previously in the bed heats the outside air, which then enters the room at room temperature.

After, for example, ti = t ₂ of 5 minutes, the direction of flow in both bulk material beds changes, for example due to the reverse direction of rotation of the corresponding blower. Then the outside air is heated with the heat stored in the bulk material bed 1 and bulk material bed 2 stores the heat from the room air, which then flows cold to the outside.

The switching of the flow direction in the two bulk beds can be done in various ways:

- by blowers operated in both directions; - by two fans, which convey the air in different directions. It is then, depending on the operating phase, in each case a fan in operation;

- By a system of several valves as changeover, which is advantageous for larger ventilation devices.

Preferably, the switching between the two beds of bulk material is carried out by a double design of the blower, which promote the air in different directions, with only one fan is operating at each operating phase. In a further advantageous embodiment of the present invention, the store consists of two or more bulk material layers each of uniform particles.

In a preferred embodiment, the bulk material bed has at least two regions with particles of different particle diameter, the region at the end of the bulk material bed, which is first flowed through in the flow direction by the heat-absorbing / cooling gas, having the larger particle diameter.

For example, the bulk material can each consist of half particles with smaller and larger particle diameter. In a particularly advantageous embodiment, the particles in each area consist of different materials.

In embodiments in which the bulk material bed has a plurality of regions i with particles of different particle diameter, the ratio between bed thickness L in the flow direction of the gas and average particle diameter d _{P of} the bulk material is calculated as the sum of the ratios between bed thickness Lj in the flow direction of the gas and the mean particle diameter d _P j of the bulk material of all subareas. For example, the ratio between bed thickness L in the flow direction of the gas and the average particle diameter dp of the bulk material in a bulk material bed having two partial areas is calculated as follows: l ^ / dpi + L ₂ / d _p2 .

This embodiment is particularly advantageous in applications in which a great deal of condensate formation in the bulk material is to be expected. Thus, the capillary effects are less pronounced and the resulting condensate can drain easily without it accumulates in the bulk material. The process according to the invention can also be used advantageously at higher temperatures, exploiting the same excellent properties:

- very effective heat transfer,

- high heat recovery,

- high specific storage capacity,

low temperature difference between gas and storage mass,

- Advantageous temperature distribution and

- small temperature change at the outlet ends.

Furthermore, the present invention provides an apparatus for carrying out the method according to the invention in any of the described embodiments, wherein the apparatus comprises a bed of a bulk material for flowing through gases and_the bulk material absorbs and stores heat or cold emitted by the gases, characterized that the device is set up to achieve the following:

the coefficient of heat transfer per volume and degree Kelvin, defined as tj m _G ic _P j / (a V _s L), is at least 0.25 kJ / m ³ K and a maximum of 25 kJ / m ³ K, where i = 1, 2 denotes the time period ti or t ₂ , m _G i the gas flow, c _pi the specific heat capacity of the gas, a the specific particle surface, V _s the volume of the bed and L the bed thickness in the flow direction of the gas;

the ratio between the bed thickness L in the flow direction of the gas and the mean particle diameter dp of the bulk material is at least 20 and at most 2000;

the specific particle surface a is so large that the ratio between the total surface area a V _s (as product of the specific particle surface and the volume of the bed) and the Volumeflow of the gas in the standard state v _G i (mi _N ³ / h) is at least 0.05 m ^"1 and at most 1 0 m ^{" 1} .

In a preferred embodiment, the bulk material consists of ceramic, chamotte, sil icium carbide, zirconium oxide, graph it, Eifel lava, gravel, iron ore, clay, lime, metallic particles or combinations thereof.

Preferably, the bulk material consists of spheres, gravel-like particles, or particles in the form of fracture or gravel.

In a preferred embodiment, the device comprises a device for changing the flow direction in the bulk material bed, which preferably comprises at least one fan or a system of several valves.

In a preferred embodiment, especially when the device is used for room ventilation, the device comprises two, preferably independently flowed through bulk material beds of the above type.

In this embodiment, the device preferably comprises two fans, each of which conveys air in different directions, with only one fan operating in each operating phase and switching of the flow direction being effected by starting the respective other fan.

Preferably, the fans are housed between two bulk beds.

The bulk material bed or the bulk material beds preferably comprises two or more bulk material regions and each bulk material region has a different average particle diameter and / or another particle material. A further preferred embodiment of the device according to the invention is particularly suitable for retrofitting in existing buildings.

In this embodiment, the bulk material bed (i.e., the heat storage mass) is located in a container outside a building wall, which is preferably vertical to the wall. Preferably, the bulk material bed flows through parallel to the wall.

Furthermore, the bulk material bed is advantageously flowed through in this embodiment so that excess condensate can drain freely from the bulk material bed down. This embodiment of the device according to the invention, which is particularly suitable for retrofitting, has the advantage that the cross section of the wall passage / break required for the passage of air can be kept low. For example, the diameter of a cross-sectionally circular wall passage / fracture can be 60 to 100 mm, whereby an air passage of 20 to 60 m _{i N.} ³ / h is made possible. This is very advantageous for retrofitting.

The advantages of the present invention will be further elucidated on the basis of examples with reference to the following figures, which show: FIG. 1: the temperature profile in a bulk material bed with the ratio bed thickness / particle diameter = 25;

2 shows the temperature profile of the preheated air during an outside air phase, or the cooled exhaust air during an exhaust air phase, in the same bed of bulk material as in FIG. 1; 3 shows the temperature profile in a bed of bulk material with the ratio bed thickness / particle diameter = 83; 4 shows the temperature profile in a bed of bulk material with the ratio bed thickness / particle diameter = 1 000 and at high temperatures;

Fig. 5a and 5b: an advantageous embodiment of the retrofit systems. In FIGS. 1, 3 and 4, the arrow indicates the direction of flow of the air.

Examples

1. In this example, the inventive method using a ventilation system with heat recovery in a flow direction 1 0 cm thick bulk material bed of gravel from about the same size, spherical-like particles with a diameter of 4 mm simulated, in which thus the ratio between the bed thickness in the flow direction and the average particle diameter 25 is (c _{s of} the particles about 1 kJ / kgK, flow rate 20 nrii.N. ³ / h, mass of the bulk material 5 kg). The heat transfer coefficient defined above is 6.0 kJ / m ³ K.

In this case, the same amount of 20 nrii / h of air flows for one period ti = 5 minutes from one inlet side to the other (exhaust air phase) and then t ₂ = 5 minutes in the reverse direction (outside air phase) through the bulk material bed. The temperature of the outside air is 0 ° C when entering the bulk material bed and the temperature of the exhaust air is 20 ° C when entering the bulk material bed.

In Fig. 1, the resulting temperature profile is shown in the bulk material bed.

The system is in a quasi-stationary state, or the temperature profiles are repeated periodically. The abscissa axis shows the position within the bed and the ordinate axis the temperature. The presented temperature profiles are drawn during an outdoor air phase: the first at the beginning (0th minute) and then every one more Minute later, until the profile at the end of an outside air phase (5th minute). At the beginning, the outside air flows through the bed at 0 ° C and heats up to room temperature of 20 ° C. The temperature of the preheated air remains at 20 ° C for up to two minutes. From the second minute on, the temperature of the preheated air drops, initially to a minimum, and at the end of the fifth minute to 14 ° C. The mean temperature of the preheated fresh air is 18 ° C and the heat recovery 90%.

The emitted thermal energy is about 43% of the maximum possible stored thermal energy. Fig. 2 shows the temporal temperature profile of the outlet temperatures of the same arrangement as in Fig. 1, wherein the upper curve shows the course of the temperature of the preheated outside air and the lower curve shows the course of the cooled exhaust air.

The upper curve shows the temperature of the preheated fresh air, as well as its mean value. The lower curve shows the temperature of the cooled exhaust air.

In the entry areas of the bulk bed, the temperature change during each full 5 minute switching period is 5 to 6 ° C, while in the middle of the bed the temperature change is about 14 ° C (ie about 2.5 times as much as in the entry areas) ,

In the embodiment described in Example 1, the switching time is 5 minutes. This short switching time is well suited for small systems, eg for the ventilation of individual rooms. For larger systems with an air flow of more than 1, 000 m ³ / h, however, a longer switching time, ie. of more than 5 minutes, beneficial.

2. In this example, the inventive method is based on a ventilation system with heat recovery in a direction of flow 25 cm thick bulk bed of gravel from about the same simulates large, spherical-like particles with a diameter of 3 mm, in which thus the ratio between the bed thickness in the flow direction and the mean particle diameter 83. The switching time, and thus the time periods ti and t _2, is 20 minutes in this example. Thus, the above-defined heat transfer coefficient value reaches 2.1 3 kJ / m ³ K.

In Fig. 3, the resulting temperature profile is shown in the bulk material bed.

The outside air flows through the bed at 0 ° C and heats up to 20 ° C. For about 10 minutes, the temperature of the preheated air remains constant. From the twelfth minute, it sinks and reaches a temperature of 16 ° C after 20 minutes. The mean temperature of the preheated outside air is then 19 ° C and the heat recovery level about 95%.

In the entry areas of the bulk bed, the temperature change during each full 20 minute switchover period is about 4 ° C, while in the middle of the bed the temperature change is about 14 ° C (ie 3.5 times as much as in the entry areas) , Therefore, over the embodiments of Examples 1 and 2, greater heat storage is possible. 3. In this example, an advantageous embodiment of the device according to the invention for carrying out the method according to the invention will be described, which is particularly suitable for retrofitting in existing houses and apartments. This embodiment is shown in Figs. 5a and 5b. In a vertically arranged container (1) is a bulk material bed (2) as a heat storage mass. The device is attached to a wall (3) having an opening (4) connecting the exterior and interior. The opening (4) can be significantly smaller than the cross section of the Container (1), which is very advantageous for retrofitting.

The vertical arrangement facilitates the unhindered outflow of excess condensate. A fan (5), which transports exhaust air or fresh air, can be mounted directly on the wall (Fig. 5a) or below the bulk material bed (2) (Fig. 5b). The fan position can thus, depending on the installation location (outside or inside), be selected so that the noise emissions are minimized in the interior.

4. In all three previous examples, the ventilation systems are shown, which operate at ambient temperatures. Preferably, this method is also very well suited for significantly higher temperature ranges and significantly longer switching times. In this example, the method according to the invention is simulated on the basis of a high-temperature installation for storing and emitting thermal energy in the temperature range between 550 ° C. and 1100 ° C. The bulk material bed made of 12 mm aluminum ball is 1 2 m high. Thus, the ratio between the bed thickness in the flow direction and the particle diameter is equal to 1 000. The switching time is 10 hours and the air flow 25,000 m _{i N.} ³ / h. The above-described heat transfer coefficient is 0.68 kJ / m ³ K.

In Fig. 4, the resulting temperature profile is shown in the bulk material bed.

Claims

claims

1 . A method for receiving, storing and releasing thermal energy of gases, wherein a bed of a bulk material is traversed in a first step in a first flow direction for a period of time ti by a gas, which emits heat or cold to the bulk material, which from the bulk material is traversed, and in a second step in a second flow direction for a time period t _{2 is} traversed by a gas which absorbs heat or cold from the bulk material, characterized in that a) the heat transfer coefficient per volume and degrees Kelvin, defined as tj m _G ic _pi / (a V _s L), is at least 0.25 kJ / m ³ K and at most 25 kJ / m ³ K, where i = 1, ₂ denotes the time period ti or t ₂ , m _G i the gas flow, c _P j the specific heat capacity of the gas, a the specific particle surface (in m ² / m ^{3 of} the bed), V _s the volume of the bed and L the bed thickness in the flow direction of the gas; b) the ratio between the bed thickness L in the flow direction of the gas and the mean particle diameter dp of the bulk material is at least 20 and at most 2,000, c) the specific particle surface a (m ² / m ^{3 of} the bed) is so large that the ratio between the total surface area a V _s (as a product of the specific particle surface area and the volume of the bed) and the volume flow rate of the gas in the standard state v _G i (mi _N ³ / h) multiplied by the time period tj (h) at least 0,05 m ^"1 and maximum 1 0 m ^"1 , and d) the time period ti or t ₂ satisfies the following relation:

0.1 - (Ms / m _G i) - (Cs / Cpi) <ti <0.9- (Ms / m _Gi ) - (Cs / Cpi), where i = 1, 2 is the time period ti and i _2, respectively M _{s is} the mass of the bulk material, m _{Gi is} the gas flow, c _{s is} the specific heat capacity of the bulk material particles and c _{pi is} the specific heat capacity of the gas.

2. The method according to claim 1, characterized in that the mean particle diameter d _{P of} the bulk material of 0.5 mm to 50 mm.

3. The method according to any one of the preceding claims, characterized in that the gas flow rate m _G i per mass of the bulk material M _s during at least one of the time periods ti and t ₂ of 0.05 h ^"1 to 50 h ^{" 1} .

4. The method according to any one of the preceding claims, characterized in that it is used for the controlled ventilation of a room with integrated heat recovery.

5. The method according to claim 4, characterized in that the

The temperature of the fresh air supplied from the outside when entering the bulk material bed is from -30 ° C to 50 ° C.

6. The method according to claim 4 or 5, characterized in that in the bulk material bed, a moisture recovery takes place and the relative humidity in the room is always in the optimum range of 35 to 65% relative humidity.

7. The method according to any one of the preceding claims, characterized in that the bulk material bed for drying intermediately of a heat to the bulk material emitting gas for a period of time t ₃ with the condition t ₃ > ti and t ₃ > t ₂ flows through.

8. The method according to any one of the preceding claims, characterized in that the bulk material bed has at least two regions with different particle diameter and the region at the end of the bulk material bed, which is first flowed through by the heat absorbing / cooling gas in the flow direction, larger particle diameter.

9. The method according to any one of the preceding claims, characterized in that takes place during one of the time periods ti and t _2, the heat supply by an electric heater.

10. A device for carrying out the method according to one of the preceding claims, wherein the device comprises a bed of a bulk material for flowing through gases and wherein the bulk material receives and stores heat or cold emitted by the gases, characterized in that the device is arranged so that that a) the heat transfer coefficient per volume and degree Kelvin, defined as ti m _G ic _P j / (a V _s L), is at least 0.25 kJ / m ³ K and at most 25 kJ / m ³ K, where i = 1, 2 denotes the time period ti or t ₂ , m _G i the gas flow, c _pi the specific heat capacity of the gas, a the specific particle surface (in m ² / m ^{3 of} the bed), V _s the volume of the bed and L is the bed thickness in the flow direction of the gas; b) the ratio between the bed thickness L in the flow direction of the gas and the mean particle diameter d _{P of} the bulk material is at least 20 and at most 2,000, and c) the specific particle surface a (m ² / m ^{3 of} the bed) is so large that the ratio between the total surface area a V _s (as the product of the specific particle surface area and the volume of the bed) and the volume flow rate of the gas in the normal state v _G i (mi _N / ³ ) multiplied by the time period t, (h) at least 0.05 m ^"1 and maximum 1 0 m ^{" 1} .

1 1. Apparatus according to claim 1 0, characterized in that the

Bulk material consists of ceramic, chamotte, silicon carbide, zirconium oxide, graphite, Eifel lava, gravel, iron ore, clay, lime, metallic particles or combinations thereof.

12. The device according to claim 1 0 or 1 1, characterized in that the bulk material consists of balls, pebble-shaped particles, or particles in the form of fracture or crushed stone.

13. Device according to one of the preceding claims 1 0 to 1 2, characterized in that the blower for the determination of the flow direction between two bulk beds accommodated (attached).

14. Device according to one of claims 1 0 to 13, characterized in that the bulk material bed comprises two or more bulk material regions, and each bulk material region has a different average particle diameter and / or another particulate material.

15. Device according to one of claims 1 0 to 14, characterized in that the bulk material bed is located in a container outside a building wall, which is arranged vertically to the wall.

16. Device according to one of the preceding claims 10 to 1 5, characterized in that during one of the time periods ti and t _2, the heat supply by an electric heater, which is installed in the bed takes place.