NO20121200A1 - System and method for ventilation of a defined area - Google Patents

Abstract

The present invention describes the system (100) for ventilating a defined area (102), e.g. a closed or at least partially closed basement, crawl space or attic. The system (100) consists of a control unit (110) connected to at least one indoor sensor (104), at least one outdoor sensor (106) and a controllable fan (108), wherein the controller (110) is configured to operate the controllable fan ( 108) if the absolute humidity (AHute) outside the bounded area (102) is lower or equal to the absolute humidity (AHinne) within the bounded area (102) and the temperature (Tinned) within the bounded area (102) is above a predetermined temperature limit when the temperature (Tute) outside the defined range (102) is lower than the temperature (Tinne) within the defined range (102).

Description

SYSTEM AND METHOD FOR VENTILATION OF A LIMITED AREA

TECHNICAL AREA

The present invention relates to a system and a method for ventilating a limited area, such as a closed or at least partially closed basement, crawl space, attic or caravan.

BACKGROUND OF THE INVENTION

There are a number of different types of foundations that are used in the construction of a building, such as e.g. a residential building. The most common types are crawlspaces and concrete mats, where crawlspaces are generally considered to have certain advantages compared to concrete mats. E.g. crawlspaces that form a confined area offer convenient access to pipes, substructures and a variety of other areas that may be difficult or expensive to access otherwise.

Crawlspaces, on the other hand, must be ventilated with outside air, because water from moist soil, moisture that enters from the crawlspace's ventilation holes and moisture that is capillary sucked through the porous concrete will create a perfect environment for the formation of mold on all surfaces in the crawlspace, especially wooden floors and wooden surfaces. plasterboard and certain types of insulation. If one is not aware of this, spores, bacteria, higher levels of chemical vapors and/or radon can migrate into the house.

There is therefore a general desire to regulate the humidity in the crawlspace's interior in order to maintain reduced moisture levels and preserve the structural integrity of the house. For example, WO08039149 tries to solve this by controlling the access to heat in the crawl space, based on known information about prerequisites such as growing time and growing conditions that occurring mold and rot fungi require, and absorption of moisture in occurring materials, which possibly ensures a climate where moisture-related damage cannot arise.

Although WO08039149 provides some protection against the inherent problems with crawlspaces, the homeowner may find it energy efficient to add heat to the ground. There is therefore a need for an efficient and flexible system to monitor and protect limited areas that are sensitive to moisture damage.

SUMMARY OF THE INVENTION

According to one aspect of the invention, the above is at least partially covered by a system for ventilation of a confined area, with at least one indoor sensor configured to measure the temperature and relative humidity of the confined area, at least one outdoor sensor that is configured to measure temperature and relative humidity outside the defined area, a controllable fan adapted to ventilate the defined area, and a control unit connected to at least one indoor sensor, at least one outdoor sensor and the controllable fan where the control unit is configured to determining the absolute humidity within the defined area and the absolute humidity outside the defined area, wherein the controller is further configured to operate the controllable fan if the absolute humidity outside the defined area is lower than or equal to the absolute humidity within the defined area and the temperature within the demarcated area it is above a predetermined temperature limit when the temperature outside the defined area is below the temperature inside the defined area.

The present invention is based on the understanding that there may be an advantage with controlled forced ventilation which is based on a comparison of the absolute humidity "indoors" and the absolute humidity "outdoors" instead of being controlled on the corresponding relative humidity inside/outside the defined area , as is the case with any previous system. Using the absolute humidity inside/outside the restricted area increases the reliability of the system and thus the ability to protect the restricted area from e.g. moisture-related problems and/or damage.

In cases where the ground in the enclosed area is moist, the system can be supplemented with a moisture barrier on the ground to prevent moisture from evaporating into the air due to the increased air flow through the enclosed area. Also, and as noted above, the confined area is not ventilated if the indoor temperature is lower than a predetermined temperature limit and if the outdoor temperature is lower than the indoor temperature. This temperature limit is between 3-10°C, preferably between 4-8°C and most preferably between 5-6°C. This increases the energy efficiency of the system even further as it has become constant! that it is not necessary to ventilate the delimited area when these temperature limits are exceeded, i.e. when the indoor temperature is, for example, below 3-10°C, there are no moisture problems and/or damage. As there is no need to ventilate the demarcated area below the predetermined temperature limit exemplified above, hot air inside the crawl space will not be vented away, which would otherwise affect other areas, for example living spaces bordering the demarcated area. Also, by not ventilating below the specific temperature, warm and possibly humid air from adjacent areas will not be drawn into the mortuary in the event of a failure, possibly affecting the humidity level within the enclosed area. In some cases, however, it may be necessary/appropriate to also ventilate the restricted area even if the indoor temperature is lower than the predetermined temperature limit. In such cases, however, it is desirable to ventilate in a restrictive manner, possibly for shorter periods of time.

Advantageously, the control unit is further arranged, in combination with the above two conditions, to only operate the controllable fan if also the temperature outside the delimited area is above a predetermined temperature limit when the temperature outside the delimited area is below the temperature within the delimited area. This further increases the reliability of the system.

The closed, or at least partially closed, bounded area is preferably a basement, crawl space, loft, shed, caravan, trailer or a cabin. Another confined space that is sensitive to moisture damage is the rooms inside boats. In particular, engine rooms and interior spaces in boats stored in marinas can easily get mould, which gives the boats a rotten smell and which damages the interior of the boats.

In a preferred design, the system consists of at least two outdoor sensors placed on opposite sides of the demarcated area, for example an outdoor sensor is mounted on the northern side of the demarcated area and a sensor on the southern side of the demarcated area. Additional sensors, inside and/or outside the delimited area may of course be possible and within the scope of the invention. Also, by providing the system with at least one adjustable valve connected to the control unit, for example two adjustable valves mounted on the north and on the south side of the confined area, the system is configured to be able to control the ventilation of the confined area , and thus it may be possible to ventilate the restricted area with air from the side of the restricted area where the conditions for the case are most favorable.

In some cases, it is also possible to close at least one adjustable valve if the absolute humidity outside the delimited area is higher than the absolute humidity within the delimited area.

In some cases, it is also possible to equip the system with a dehumidifier connected to and controlled by the control unit, where the control unit can be configured to close at least one adjustable valve and operate the dehumidifier if the relative humidity within the defined area exceeds a predetermined limit, where the relative humidity limit is preferably between 50-90%, preferably between 60-80% and most preferably between 65-75%. Operating the dehumidifier may become necessary if conditions are very unfavorable and obvious moisture-related problems may occur. Such conditions can, for example, be related to specific weather conditions and/or structural engineering problems.

Preferably, the system comprises a storage unit which is connected to the control unit and configured to store data from the indoor and/or outdoor sensor(s). The storage can e.g. be digital storage such as e.g. a USB or flash memory card, e.g. CompactFlash, Memory Stick, Secure Digital etc. and the home owner or possibly another valid user can use the information to review the conditions in the restricted area over a longer period of time, e.g. over a month, a quarter, year and so on to judge the structural integrity of the house.

Alternatively or additionally, the storage can be connected to an external server where the information from the sensor(s) is stored. Thus, other users, such as potential house buyers, brokers, etc., can access the information and thus draw conclusions about the health of the house. The transmission can be through a wired or wireless network, e.g. wired connection such as USB, FireWire, VGA or similar, and wireless connection such as WLAN, CDMA, GSM, GPRS, 3G mobile communication, 4G mobile communication, Bluetooth, IR or similar.

According to another aspect of the present invention, there is a method for ventilating a limited area. The method includes measures to measure temperature and relative humidity within the demarcated area with the help of at least one indoor sensor, measure temperature and relative humidity outside the demarcated area with the help of at least one outdoor sensor, determine the absolute humidity within the demarcated area, determine the absolute humidity outside the defined area, and operate a fan if the absolute humidity outside the defined area is lower than or equal to the absolute humidity inside the defined area, and the temperature in the defined area is above a predetermined temperature limit when the temperature outside the defined area is below the temperature in the delimited area. This aspect of the invention provides similar advantages as discussed above over the previous aspect of the invention.

Further functions and advantages of the present invention will become apparent when one studies the attached patent claim and the following description. A person skilled in the art realizes that the various functions of the present invention can be combined to create further constructions than those described below, without deviating from the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The various aspects of the invention, including its special features and advantages, will be readily understood from the following detailed description and accompanying drawings, in which: Fig. 1 conceptually illustrates a previously preferred embodiment of the system for ventilating a confined area, and Fig. 2 shows a schematic flow chart of a currently preferred method of ventilating a confined area.

DETAILED DESCRIPTION

The present invention is described in more detail below with references to the attached drawings, where a currently preferred embodiment of the invention is shown. However, the invention may be embodied in many different forms and should not be regarded as limited by the embodiment described herein; instead, these embodiments are attached for thoroughness and completeness, thereby conveying the full scope of the invention to one skilled in the art.

Referring now to the drawings and to Fig. 1 in particular where a system 100 for ventilating a confined area is depicted, as e.g. a crawl space 102. The system 100 comprises an indoor sensor 104, e.g. centrally mounted inside the crawl space 102 and a first and second outside sensor 106, 106' which are mounted on opposite sides 102a, 102b outside the crawl space 102. The inside 104 and the outside sensors 106, 106' can be of the same type or be specially adapted depending on their location, e.g. with different waterproof protections. Each of the sensors 104, 106, 106' are configured to measure the temperature (Indoor/outdoor) and the relative humidity (RHindoor/outdoor) at their respective location. The sensors 104, 106, 106' can contain a combination of sensors for sensing temperature and humidity, or can be combined into a single element.

System 100 also includes a controllable fan 108 adapted to ventilate the confined area. The fan 108 is advantageously mounted near a ventilation hole Vi in the crawl space 102 and is configured to provide a ventilation quantity such as depends on the volume/area of the crawl space 102, e.g. with the help of speed control on the fan 108. The fan 108 can work in two directions, for example to draw air from the outside of the delimited area 102 into the delimited area 102, or to draw air from the inside of the delimited area 102 out to the outside of the delimited area 102. The chosen direction depends e.g. on the type of the delimited area 102, where e.g. is an advantage to draw air out of a crawl space, but at the same time to draw air into an attic.

The system further comprises a control unit 110 which is connected to the indoor and outdoor sensors 104, 106, 106' and the fan 108. The connection between the sensors 104, 106 and 106', the fan 108 and the control unit 110 can be wired or wireless (e.g. Bluetooth , IR, ZigBee or similar). The controller 110 may include a microprocessor, microcontroller, programmable digital signal processor, or other programmable device. The control unit 110 may also, or instead, include a special integrated circuit (ASIC), a programmable gate array with programmable matrix logic, a programmable logic unit or a digital signal processor. When the control unit 110 contains a programmable unit such as a microprocessor or microcontroller mentioned above, the processor may include additional code that controls the operation of the programmable device.

The control unit 110 is further connected to a storage unit, such as a memory 116 which is configured to store information from sensors and/or operating periods and speed of the fan 108. Optionally or alternatively, the control unit 110 can be equipped with a communication module 118 to send the stored information, e.g. to a server (not shown).

Fig 1 also shows a number of additional ventilation holes V2, V3, V4 and V5, where two ventilation holes sit on opposite sides 102a, 102b of the crawl space 102 and are connected to the first and second outdoor sensors 106, 106'. The opposite sides 102a, 102b of the crawl space 102 can e.g. represent the north and south sides of a building where the crawl space 102 forms a ground. Each individual, or at least some of the ventilation holes V2, V3, V4 and V5 can be equipped with valves 112 which are connected and controlled by the control unit 110. The valves 112 can be configured to be controlled individually and to be able to be opened to different levels. More (or fewer) ventilation holes, valves and outdoor sensors can of course be used, e.g. one outdoor sensor per ventilation hole/valve.

Certain embodiments of the system 100 can also consist of a dehumidifier 114 which is installed inside the crawl space 102 and controlled by the control unit 110, which e.g. a mechanical/condensation dehumidifier or a sorption dehumidifier. What type of dehumidifier 112 can e.g. depend on the expected temperature within the defined area, where mechanical/condensing dehumidifiers generally only work at temperatures above 12°C. When a dehumidifier 114 is used, water generated by the dehumidifier 114 can be led out of the crawl space 102 by e.g. use a tube or hose (not shown). Traditional disadvantages of using a dehumidifier 114 include a high energy cost. By using the system 100 to complement the dehumidifier, e.g. that the dehumidifier is only operated above a predetermined humidity limit, the humidity limit can possibly be within the range of 50-90%, preferably 60-80% and most preferably 65-75%, it is possible to reduce the use of the dehumidifier and thus reduce the necessary energy use to keep the relative humidity at a low level.

In Fig. 2, a schematic flow chart is shown of a currently preferred method of driving the system 100 to ventilate the crawl space 102. The process starts in steps S1 and S2, where the control unit 110 collects the values of the temperature Indoor/outdoor, and the relative humidity, RInside/outside inside and outside the crawl space 102 with the help of the inside sensor 104 and the outside sensors 106, 106'. Following the collection of the temperature Inside/outside, and the relative humidity, RInside/outside, the control unit determines in steps S3 and S4 the value of the absolute humidity AInside/outside for each of the sensors 104, 106, 106'. That is, in the embodiment shown in Fig. 1, inside the crawl space 102, on the north side 102a outside the crawl space 102 and on the south side 102b outside the crawl space 102. The control unit 110 can determine the absolute humidity, AInside/outside each of the sensors 104, 106, 106 ' by an approximate calculation or by using e.g. a Mollier diagram adapted to the control unit 110.

Depending on the result of the calculation of the absolute humidity AInside/outside each of the sensors 104, 106, 106\ the controllable fan, S5, can be operated to ventilate the crawl space 102. The general condition for ventilating the crawl space 102 depends on whether the absolute humidity AOutside the crawl space 102 is lower than or equal to the absolute humidity AInside the crawl space 102, and furthermore that the temperature Inside the crawl space 102 is above a predetermined temperature limit when the temperature Outside the crawl space 102 is lower than the temperature Inside the crawl space 102.

In the preferred embodiment of the system 100 shown in Fig. 1 and provided with a crawl space 102, the temperature limit is around 5-6 °C and the conditions on each of the sides 102a, 102b outside the crawl space are taken into account in the calculation. This means that during a cold but sunny day when the sun only shines on the south side 102b, the conditions on the north side 102a may be such that the general conditions above are not met, e.g. if one takes the average conditions on the north and south sides, 102a, 102b. If, on the other hand, one only compares the conditions on the south side 102b, the conditions for driving the fan 108 and ventilating the crawl space can possibly be met. If there are valves 112 mounted in the ventilation holes V2, V3 on the north side 102a, these can be closed. When you run the fan 108, only air will be drawn into the crawl space 102 through the ventilation openings V4, V5 on the south side 102b where the valves 112 are open. Other ways of controlling the valves 112 and the fan 108 can of course be used, e.g. where the valves 112 are operated individually so that the crawl space 102 is ventilated in the most favorable way in accordance with the general terms of the invention.

The collection, S1/S2, and the determination S3/S4 is advantageously done periodically, e.g. every minute or every hour. In accordance with this, the best possible ventilation can be created for the crawl space 102. Moreover, essentially parallel to steps S1-S5, the control unit 110 can additionally be configured to operate a further step S6 where the values provided by the sensors 104,106, 106' together with the speed/running time of the fan 108 is stored.

Although the invention has been described with reference to specific exemplified embodiments, many different variations, modifications, and the like will become apparent to one skilled in the art. Variations to the attached embodiments can be understood and carried out by a person skilled in the art when implementing the invention by studying the drawings, descriptions and attached claims. For example, in the above description of the ventilation system has a number of parts, e.g. valves, dehumidifiers, etc. have been included with a system, but the system need not always contain all of the parts shown above, but instead only some of these parts are necessary to demonstrate at least the basic functions of the invention as defined by the claims below.

In some cases, the conditions in a crawl space are also so unfavorable that it is necessary to operate the dehumidifier, e.g. if the relative humidity, R Hinne reaches 70-75%. When that happens, it may be beneficial to close all valves. Furthermore, in those cases where the fan has a valve (not shown) it is also beneficial to close this valve.

Moreover, in the claims the word "comprise" does not imply that other parts or steps are excluded, and the definite form "one" or "an" does not exclude that there may be several of the same kind.

Claims (12)

1. A system (100) for ventilating a limited area (102), consists of: - at least one indoor sensor (104) configured to measure temperature (Tinne) and relative humidity (RHinne) within the limited area (102) ; - at least one outdoor sensor (106) configured to measure temperature (Tute) and relative humidity (RHute) outside the delimited area (102); - a controllable fan (108) adapted to ventilate the confined area (102); and -a control unit (110) which is connected to the at least one indoor sensor (104), the at least one outdoor sensor (106) and the controlled fan (108), where the control unit (110) is configured to determine the absolute humidity (AHinne) within the bounded area (102) and absolute humidity (AHute) outside the bounded area (102), where the control unit (110) is further configured to drive the controllable fan (108) if: - the absolute humidity (AHute) outside the delimited area (102) is lower than or equal to the absolute humidity (AHinne) within the delimited area, and - the temperature (T^ne) within the delimited area (102) is above a predetermined temperature limit when the temperature (Tute) outside the delimited area (102) is lower than the temperature (Tinne) within the delimited area (102). 2. System (100) according to claim 1, where the control unit (110) is further configured to only drive the controllable fan (108) if also the temperature (Tute) outside the delimited area (102) is above a predetermined temperature limit when the temperature (Tute ) outside the delimited area (102) is lower than the temperature (Tinne) inside the delimited area (102). 3. System (100) according to claims 1 and 2, where the predetermined temperature limit lies within the range 3-10°C, preferably within 4-8°C and most preferably within 5-6°C. 4. System (100) according to any one of the above claims, wherein the bounded area (102) is selected from a group consisting of basement, boat, crawl space, loft, shed, caravan, trailer, container or cabin. 5. System (100) according to any one of the above claims, wherein the system (100) comprises at least two outdoor sensors (106, 106') which are placed on opposite sides (102a, 102b) of the delimited area (102). 6. System (100) according to any one of the above claims, wherein the system (100) further comprises at least one controllable valve (112) which is connected to the control unit (110), and the control unit (110) is further configured to close it at least one valve (112) if the absolute humidity (AHute) outside the delimited area (102) is higher than the absolute humidity (AHinne) within the delimited area (102). 7. System (100) according to claim 6, wherein the system (100) comprises a dehumidifier (114) which is connected to and controlled by the control unit (110), where the control unit (110) is configured to close the at least one valve (112) and operate the dehumidifier (114) if the relative humidity (RHinne) within the bounded area (102) is above a predetermined moisture limit. 8. System (100) according to claim 7, where the predetermined humidity limit lies within the range 50-90%, preferably within 60-80% and most preferably within 65-75%. 9. System (100) according to any of the above claims, wherein the system (100) further comprises an operator accessible storage unit (116) which is connected to the control unit (110) and configured to store the information from the indoor and/or outdoor sensor (one) (104, 106, 106'). 10. Method for ventilating a limited area (102), the method comprises the steps: - collect information in the form of (S1) temperature (Tinne) and relative humidity (RHinne) within the limited area (102) by using at least one indoor sensor (104); - collect data in the form of (S2) temperature (Tute) and relative humidity (RHute) outside the delimited area (102) using at least one outdoor sensor (106); - determining (S3) the absolute humidity (AHinne) within the delimited area (102); - determining (S4) the absolute humidity (AHute) outside the delimited area (102); and - drive (S5) a controllable fan (108) if: - the absolute humidity (AHute) outside the delimited area (102) is lower than or equal to the absolute humidity (AHinne) inside the delimited area, and - the temperature (Tinne) within the delimited area (102) is above a predetermined temperature limit when the temperature (Tute) outside the delimited area (102) is lower than the temperature (Tinne) inside the delimited area (102). 11. The method according to claim 10, where the controlled fan (108) is controllable only if also the temperature (Tute) outside the delimited area (102) is above a predetermined temperature limit when the temperature (Tute) outside the delimited area (102) is lower than the temperature (Tinne) within the bounded area (102). 12. Method according to claim 9, further comprising the step of storing (S6) information from the indoor and/or outdoor sensor(s) (104, 106, 106').