RU2849918C2 - Ventilation and air conditioning system - Google Patents

Abstract

FIELD: ventilation system.

SUBSTANCE: air conditioning and ventilation system (6) for a room, comprising a cooling air supply system, an air duct system (14) and at least one chamber (16) containing an inlet (18), an outlet (20) and heat storage elements (30). The ventilation and air conditioning system (6) is designed so that when the operation of the cooling air supply system is interrupted in an emergency, natural convection air flow passes through the chamber (16) from the inlet (18) to the outlet (20), wherein the natural convective air flow is cooled by transferring heat to the heat storage elements (30). The air duct system (14) is located above the inlet (18) at a distance (A) from the latter, with a gap (38) being established between the air duct system (14) and the inlet (18).

EFFECT: inlet (18) of the chamber (16) is designed to allow constant communication with the room (2) via air flowing from the room (2) through the gap (38) into the inlet (18) of the chamber.

14 cl, 4 dwg

Description

The present invention relates to a system for ventilation and air conditioning in a room.

Modern components and control systems, especially in nuclear power plants, generate enormous amounts of heat through convection and radiation into the plant rooms where they are installed. Therefore, cooling such rooms is becoming increasingly important.

Typically, this cooling is achieved through an active ventilation and air conditioning system that blows cooled air into the production space. However, if the active cooling function fails, the systems in the room typically take approximately two hours to reach their maximum allowable temperature.

It is known, in particular, from document WO 2019/105559 that in order to increase the time (hereinafter referred to as the "cooling period") during which equipment present in the room reaches the maximum permissible temperature, for example, to 24 hours, it is necessary to provide a passive emergency cooling mode. This is achieved, for example, by providing a passive system with phase-change materials.

However, such systems are not entirely satisfactory, particularly in terms of their stability and reliability. In fact, such systems rely on intermediate components, particularly for switching from active to passive cooling mode. These intermediate components can become damaged or lose their functionality when left in standby mode for extended periods, reducing the reliability of such systems.

The present invention aims to provide an emergency cooling mode for an active ventilation and air conditioning system in the event of a failure of the active cooling function, particularly due to a power failure. Specifically, the current cooling period should be extended. The system should operate reliably and be easy to install and maintain.

For this purpose, the invention proposes a ventilation and air conditioning system characterized by the features of paragraph 1 of the invention formula.

The basic idea is to passively switch from active room cooling to passive room cooling using heat storage elements. This passive switchover occurs from forced cooling mode, in which the heat storage elements located inside the chamber are cooled, to natural convection cooling mode, in which the previously cooled heat storage elements transfer their cooling power to the natural convection airflow. Furthermore, this switchover occurs without the need for additional measures or components, increasing the system's stability and thus reliability.

Preferred embodiments are disclosed in the dependent claims and in the description.

The present invention also relates to a structure comprising a room that has a heat source and a ventilation and air conditioning system as described above.

The invention is explained by means of the following description of the configuration, which refers to the attached drawings.

The individual features of the claims and description shall be considered as disclosed in any combination or subcombination provided that they are not technically incompatible.

Preferred configurations of the invention will now be described in detail with reference to the drawings, in which:

Fig. 1 is a top view of a room containing a plurality of electrical or electronic control and regulation components that generate heat during operation;

Fig. 2 is a side view in section along line II-II of the section of the room shown in Fig. 1, in which the ventilation and air conditioning system according to the invention is installed, and in which the active normal cooling mode is shown by arrows indicating the air flow;

Fig. 3 is a side sectional view of the room shown in Fig. 2, showing the operation of the passive emergency cooling;

Fig. 4 is a more detailed sectional view of the ventilation and air conditioning system shown in Figs. 2 and 3.

Fig. 1 shows a top view of a room 2 containing a heat source 4 and a ventilation and air conditioning system 6.

Room 2 is, in particular, a technical room at a nuclear power plant.

The heat source 4 comprises several electrical and electronic components 8, in particular, regulation and control components that generate heat during operation. The regulation and control components 8 are located in cabinets 10, for example, in the central region of room 2.

Alternatively, heat source 4 is a heat source of a different type than the electrical/electronic units described above.

The ventilation and air conditioning system 6 blows cooled air into the room 2 during operation to maintain the room temperature below the permissible maximum value.

The room temperature should be maintained, for example, below 25°C during continuous operation.

Some configurations also use heating, resulting in an integrated heating, ventilation, and air conditioning system.

The ventilation and air conditioning system 6 comprises a cooling air supply system 12, an air duct system 14 connected to the cooling air supply system 12, and at least one chamber 16 comprising an inlet 18 and an outlet 20.

The cooling air supply system 12 comprises, for example, an air cooler equipped with, for example, a refrigeration machine with a vapor compression cycle or with thermoelectric cooling, and a fan or air blower for creating a forced flow of cooled air through the air duct system 14.

For example, the cooling air supply system 12 supplies cooled air at a temperature between 15 and 20°C.

The cooling air supply system 12, which is shown only schematically in Fig. 1, may be located, for example, outside the room 2.

During operation of the cooling air supply system 12, there is a forced flow of cooled air from the cooling air supply system 12 through the air duct system 14.

The air duct system 14 is configured to direct a forced flow of cooled air from the cooling air supply system 12 to the inlet 18 of the chamber 16 during operation of the cooling air supply system 12.

In the example configuration shown in Fig. 1, the ventilation and air conditioning system 6 comprises several chambers 16, which are preferably arranged in parallel.

As shown in Fig. 1, the chambers 16 are preferably arranged in a row and preferably on the wall 34 of the room 2.

As an example, chambers 16 are placed in two parallel rows on two opposite walls 34 of room 2.

Alternatively, the chambers 16 are located in the center of the room 2 and, in particular, between the various components 8.

The air duct system 14 contains corresponding branches to each of these chambers 16.

The air duct system 14 comprises at least one air duct 22.

Preferably, air duct 22 is a pneumatic hose made of a textile material. Textile material includes, for example, a textile fabric, particularly a polyester fabric. Polyester fabrics offer good environmental and chemical resistance and are easy to clean.

Alternatively, a metal air duct 22 can be used.

The air duct 22 directs a forced flow of cooled air from the cooling air supply system 12 to each of the chambers 16.

For this purpose, the air duct 22 comprises, for example, a connection to each row of chambers 16.

Alternatively, the duct system 14 comprises multiple ducts 22, such as one duct 22 for each row of chambers 16.

If air duct 22 is an air hose made of textile material, the air hose preferably has a circular cross-section, as shown in the drawings. This cross-section ensures uniform air distribution. Alternatively, the air hose may have a semicircular cross-section.

The pneumatic hose has a diameter of, for example, between 300 mm and 800 mm.

The air hose is preferably leak-tight across its entire surface. This means that a portion of the forced cooled air flow can escape at any point along the air hose. The air duct system 14 preferably includes base openings 24 that direct the forced cooled air flow from the cooling air supply system 12 to the inlet 18 of the corresponding chamber 16 during operation of the cooling air supply system 12.

Preferably, at least one opening 24 is located opposite the inlet 18 of each chamber 16.

If the air duct 22 is a pneumatic hose made of a textile material, the openings 24 are preferably formed by nozzles. These nozzles 24 are preferably located on the underside of the pneumatic hose. Each nozzle 24 directs a flow of cooled air to an inlet 18 of one of the chambers 16. These nozzles may be, for example, fully conical nozzles that direct a cone of cooled air into the corresponding inlet 18, or non-conical nozzles or nozzles in the form of holes stamped into the pneumatic hose.

Nozzles 24 help to direct the forced flow of cooled air to the inlet 18 of the corresponding chamber 16.

If the air duct 22 is a metal duct, the openings 24 may be formed by nozzles or forced-air grilles. In this case, the openings 24 preferably serve only as air outlets from the air duct 22 for the forced flow of cooled air.

As shown in Fig. 2 and 3, the air duct system 14 is preferably located near the ceiling 26 of the room 2, for example at a distance of at most 20 cm from the ceiling 26.

For this purpose, the ventilation and air conditioning system 6 comprises a holder 28 for suspending the air duct system 14 at a distance from the ceiling 26 of the room 2.

The holder 28 comprises, for example, a rope suspension, preferably a double-sided rope suspension, as shown in Fig. 4. Alternatively, the bracket-shaped holder 28 comprises a suspension rail.

Alternatively, each chamber 16 contains a bracket for attaching the air duct system 14. In this case, the air duct system 14 does not require separate suspension from the ceiling 26.

Each chamber 16 contains heat storage elements 30, which are located inside the chamber 16 between the inlet 18 and the outlet 20. Since all chambers 16 are essentially the same, only one chamber 16 is described below with reference to Fig. 4.

Chamber 16 preferably comprises a rectilinear, vertically arranged section that directs the outgoing air flow during the cooling operation.

Chamber 16 contains side walls 32 (facing the room and the side wall) extending vertically between inlet 18 and outlet 20.

In the example shown in the drawings, one of the side walls 32 is located opposite the wall 34 of room 2.

Chamber 16 contains perforated metal panels 36 forming at least one side wall 32 of chamber 16, and, in particular, forming a side wall 32 of chamber 16 located at a distance from wall 34 of room 2.

These perforated panels 36 define the location of access hatches to the chamber 16, for example for maintenance and repair.

The perforated sheet metal panels 36 are dimensioned by their hole pattern such that the heat storage elements 30 in the chamber 16 can also absorb a portion of the direct thermal radiation in the event of a failure of the active cooling air flow.

The inlet 18 is located at the upper end of the chamber 16, in particular below the air duct system 14.

The air duct system 14 is located above the inlet 18 at a distance A from the latter, wherein the gap 38 is defined between the air duct system 14 and the inlet 18. The distance A is measured along the vertical direction.

As a result of the presence of this gap A, the inlet 18 of chamber 16 is constantly connected by flow with room 2, that is, air can exit room 2 through the gap 38 into the inlet 18 of chamber 16.

The gap A must be large enough to allow sufficient airflow to exit room 2 between inlet 18 and duct 22, and at the same time small enough to ensure that a small flow of cooled air is lost through openings 24. The distance A has a size of, for example, between 50 mm and 250 mm.

Preferably, as shown in Fig. 4, the chamber 16 comprises a partition 40 located at the upper end of the chamber 16 to direct air from the chamber 2 to the inlet 18 of the chamber 16. The partition 40 is configured to direct air from the upper region of the room 2, such as heated air, to the gap 38, while preventing cooled air from escaping from the openings 24 through the gap 38 into the room 2. This means that the forced flow of cooled air from the openings 24 can flow almost entirely through the inlet 18 into the chamber 16.

Air from room 2, in particular heated air in emergency cooling mode, is directed through partition 40 to inlet 18 and then passes through chamber 16. This creates reliable emergency cooling of room 2 in a simple way in the event of failure of cooling air supply system 12.

Outlet 20 leads into room 2 and forms the air outlet point for chamber 16. Outlet 20 is located near floor 41 of chamber 2, as shown in the drawings. Outlet 20 contains, for example, grate 42.

The chamber 16 comprises a support structure 44 located inside the chamber 16. The heat storage elements 30 are located inside the chamber 16 by means of the support structure 44 so that during normal operation the forced flow of cooled air provided by the cooling air supply system 12 passes through them.

Although there is some pressure drop due to the heat storage elements 30, the remaining free space between the heat storage elements 30 and/or between the heat storage elements 30 and the side walls 32 of the chamber 16 ensures that the air flow between the inlet 18 and the outlet 20 is not blocked.

The heat storage elements 30 are preferably in the form of a plate, in particular with flat sides oriented parallel to the main direction of flow.

According to one configuration, several heat storage elements 30 are arranged in parallel and/or one after the other relative to the direction of flow within the chamber 16.

The heat storage elements 30 are preferably made of a phase change material PCM 46 (a phase change material, PCM).

The PCM 46 of the heat storage elements 30 is preferably selected so that it freezes upon contact with the forced flow of cooled air from the cooling air supply system 12, which typically has a temperature in the range of 16°C to 30°C.

PCM 46 is also selected so that the phase transition from solid to liquid occurs in the temperature range from 16°C to 30°C.

In other words, PCM 46 preferentially melts by natural convection with a melting point in the range of 16°C to 30°C.

In such freezing/melting, hysteresis must be taken into account.

PCM 46 is preferably based on salt hydrates, as salt hydrates are non-flammable or at least have a low flammability hazard. Furthermore, salt hydrates do not exhibit a memory effect, which negatively impacts their ability to accumulate heat during multiple freeze-melt cycles. Salt hydrates also have a high volumetric capacity for storing latent heat.

Alternatively, PCM 46 is based on paraffins.

Next, with reference to Fig. 2, a description is given of the normal cooling mode of the ventilation and air conditioning system 6, that is, during the operation of the cooling air supply system 12.

In Fig. 2, the air flow through chambers 16 and through room 2 is shown schematically by corresponding arrows.

The cooling air supply system 12 generates a forced flow of cooled air. This forced flow of cooled air is then distributed through the air duct system 14. The air duct system 14 and, in particular, the base openings 24 in the air duct 22, direct the forced flow of cooled air from the cooling air supply system to the inlet 18 of the chamber(s) 16. The forced flow of cooled air then passes through the chamber(s) 16, thus cooling and freezing the heat storage elements 30 during normal cooling operation and preparing them for any subsequent emergency cooling operation.

In the normal cooling mode, the heat storage elements 30 are continuously cooled and can thus retain cold.

Preferably, for safety reasons, the temperature before and after the heat storage elements 30 is measured to determine their heat storage capacity.

After passing through the heat storage elements 30, the cooled air exits each chamber 16 through the corresponding outlet 20 and is then distributed throughout the cabinets 10 by natural airflow across the floor. Due to the higher density of the cooled air, the airflow within the room is maintained at a low level, especially near the floor.

The air in the room is heated by the heat generated by components 8 and rises toward the room's ceiling. The heated air is then removed from room 2 through exhaust system 48 under ceiling 26.

In the normal cooling mode, therefore, the heated air is almost completely drawn through the exhaust system 48 of the room 2 and only a small portion of the heated air enters each corresponding chamber 16 through the corresponding inlet 18.

As described above, the ventilation and air conditioning system 6 is designed such that during operation of the cooling air supply system 12, there is a forced flow of cooled air from the cooling air supply system 12 through the duct system 14 and then through the chamber(s) 16 from the corresponding inlet 18 to the corresponding outlet 20, thereby cooling and, preferably, freezing the heat storage elements 30.

Now further, with reference to Fig. 3 and 4, there follows a description of the emergency cooling mode of the ventilation and air conditioning system 6, that is, when the operation of the cooling air supply system 12 fails.

If the cooling air supply system 12 fails, for example due to a power failure, then the cooling air supply system 12 and the exhaust system 48 will not create a forced flow of cooled air and therefore no cooled air will exit the duct system 14 into the inlet 18 from the chamber(s) 16. In this case, the temperatures in the room 2 and between the components 8 can exceed a critical value relatively quickly.

The passive emergency cooling mode is shown schematically in Fig. 3 with arrows indicating the direction of flow.

Heated air, having a temperature in the range of, for example, from 24°C to 52°C, rises to the ceiling of the room and through the corresponding inlet 18 enters each of the chambers 16 in the form of a natural convection air flow due to the temperature difference in the cooled interior of the chamber(s) 16. The heated air then passes through the chamber(s) 16, and in particular, through the heat accumulation elements 30, and cools.

Switching from forced air flow to natural air flow is thus accomplished without any additional active or passive function.

During the passive cooling process, the PCM 46 of the heat storage elements 30 is heated by the warm air flow passing through it, and its state changes from solid to liquid (melting). Due to the phase transition of the PCM 46 and the accompanying latent heat, a relatively high heat storage capacity can be achieved. The heat storage elements 30 thus act as a latent heat reservoir and provide cooling power for the natural convection air flow. Thus, the temperature of the PCM 46 is maintained approximately constant until complete melting.

As in the normal cooling mode, cooled air exits from each of the chambers 16 through a corresponding outlet 20 in the bottom area and is distributed by natural air flow to the heat-generating components 8 for cooling them.

In this way, a natural convection air flow is established and maintained through the room 2 and through the chamber(s) 16 until the cooling capacity of the heat storage elements 30 is exceeded.

As described above, the ventilation and air conditioning system 6 is designed in such a way that when the operation of the cooling air supply system 12 fails, a natural convection air flow occurs through the chamber(s) 16 from the corresponding inlet 18 to the corresponding outlet 20, and the natural convection air flow is cooled by transferring heat to the heat storage elements 30.

If the cooling air supply system 12 returns to normal operation, for example when the power supply is restored, the forced flow of cooled air through the chamber(s) 16 is established again and the heat storage elements 30 are therefore frozen again. Switching from natural convection airflow mode to forced airflow mode also occurs without any additional active or passive function.

This ventilation and air conditioning system 6 ensures that the room is essentially cooled safely for a certain period of time even in the event of a power failure.

Overall, the system according to the invention enables a relatively long cooling period, for example up to 24 hours of passive (emergency) cooling, to be achieved after a failure of the cooling air supply system 12. The exact cooling period depends, in particular, on the number of heat storage elements 30 used by the PCM 46 and the geometry of the chamber 16.

The inventors conducted experiments and numerical calculations for a system according to the invention, where the system comprises a total of twelve chambers 16, each chamber containing a stack of 180 heat storage elements 30 with PCM 30 based on salt hydrates. Each heat storage element 30 had dimensions of approximately 450 x 300 x 15 mm, a weight of approximately 630 kg (including the chamber and the base frame), and a heat capacity of approximately 83,000 kilojoules. These tests and calculations confirmed that such an exemplary system can provide a total cooling capacity of approximately 1,000 MJ for a room with an area of approximately 72 ^m2 and a height of 3.4 m with a heat load of approximately 11.5 kW for at least 24 hours.

In addition, the passive switchover from forced air flow mode to natural air flow mode without additional devices or measures ensures stability and thus reliability of the ventilation and air conditioning system 6.

Claims (14)

1. A ventilation and air conditioning system (6) for a room (2), wherein the room (2) comprises a heat source (4) and a ventilation and air conditioning system (6), wherein said ventilation and air conditioning system (6) comprises: a cooling air supply system (12) comprising at least one chamber (16) which comprises: an inlet (18) located at the upper end of the chamber (16), an outlet (20) configured to release air into the room (2), and heat storage elements (30) located inside the chamber (16) between the inlet (18) and the outlet (20), and an air duct system (14) connected to the cooling air supply system (12); wherein the ventilation and air conditioning system (6) is designed so that during operation of the cooling air supply system (12), a forced flow of cooled air is provided from the cooling air supply system (12) through the air duct system (14) and then through the chamber (16) from the inlet (18) to the outlet (20), for cooling and preferably for freezing the heat storage elements (30), when a failure in the operation of the cooling air supply system (12) occurs, a natural convection air flow occurs through the chamber (16) from the inlet (18) to the outlet (20), and the natural convection air flow is cooled due to the transfer of heat to the heat storage elements (30), characterized in that the air duct system (14) is located above the inlet (18) at a distance (A) from the latter, and the gap (38) is determined between the air duct system (4) and the inlet (18), the inlet (18) of the chamber (16) is made with the possibility of constant flow connection with the room (2) due to air passing from the room (2) through the gap (38) to the inlet (18) of the chamber. 2. The system according to claim 1, characterized in that the air duct system (14) contains at least one air duct (22), preferably a pneumatic hose made of textile material. 3. The system according to paragraph 2, characterized in that the air duct (22) is a pneumatic hose made of textile material and having a round or semicircular cross-section. 4. A system according to any one of paragraphs 1-3, characterized in that the air duct system (14) contains base openings (24) which, during operation of the cooling air supply system (12), direct a forced flow of cooled air from the cooling air supply system (12) to the inlet (18) of the corresponding chamber (16). 5. A system according to any one of paragraphs 1-4, characterized in that the ventilation and air conditioning system (6) contains at least one bracket (28) for suspending the system (14) of air ducts at a given distance from the ceiling (26) of the room (2) or each chamber (16) contains a bracket for attaching the system (14) of air ducts to it. 6. A system according to any one of paragraphs 1-5, characterized in that the chamber (16) contains perforated metal panels (36) forming at least one side wall (32) of the chamber (16). 7. A system according to any one of paragraphs 1-6, characterized in that the chamber (16) comprises a partition (40) located at the upper end of the chamber (16) and configured to direct air from the room (2) to the inlet (18) of the chamber (16). 8. A system according to any one of paragraphs 1-7, characterized in that the heat accumulation elements (30) are made of a phase transition material (46). 9. The system according to claim 8, characterized in that the phase transition material (46) performs a phase transition from solid to liquid within a temperature range from 16 to 30°C. 10. The system according to claim 8 or 9, characterized in that the phase transition material (46) is based on salt hydrates. 11. A system according to any one of paragraphs 1-10, characterized in that the heat accumulation elements (30) have the form of a plate. 12. A structure containing a room (2), wherein the room (2) contains a heat source (4) and a ventilation and air conditioning system (6) according to any one of paragraphs 1-11. 13. The structure according to clause 12, in which the outlet (20) is located adjacent to the floor (41) of the room (2). 14. The structure according to claim 12 or 13, wherein the heat source (4) comprises a plurality of electrical and electronic components (8).