WO1997015790A1

WO1997015790A1 - Ventilation system

Info

Publication number: WO1997015790A1
Application number: PCT/GB1996/002535
Authority: WO
Inventors: Howard Atkin; Chris Palmer
Original assignee: Advanced Design & Manufacture Ltd.
Priority date: 1995-10-21
Filing date: 1996-10-16
Publication date: 1997-05-01
Also published as: GB9521634D0; AU7311696A

Abstract

A ventilation system (1) comprises a heat exchanger (3) for transferring heat from outgoing air to the fresh air supply suuplied to a room from an outside environment. The ventilator system is free standing and may be mounted on wheels (8). The ventilator system (1) further comprises a conduit (30) extending from the ventilator system (1) and designed to, for example, hang out of an open window (31) in order to allow fresh air to enter the ventilator system and stable air to exit the system.

Description

VENTILATION SYSTEM

This invention relates to a ventilation system and particularly, but not exclusively, to a ventilation system for use in controlling the humidity in a domestic environment, particularly in bedrooms. The invention also relates to a ventilation system combined with a filtration system and/or a de-humidifier, and to each of these systems separately.

Buildings of all types, even when adequately heated, commonly suffer from the effects of condensation and fungal growth, the source of which can be seriously detrimental to the health of the occupants, especially when well sealed and/or inadequately ventilated.

Every day activities such as cooking, washing, drying clothes, bathing and even breathing, significantly increase the levels of humidity within a dwelling. Calculations suggest that in a four person household, up to ten litres of moisture per day may be produced. This amount may easily rise to a daily total of 18 litres.

The moist air becomes trapped within a building through the common use of modern insulation techniques, double glazing and draft stripping. Although this increases the thermal efficiency of the building, it allows little or no natural ventilation.

These conditions lead to the occurrence of condensation on colder surfaces which damages internal decorations, attacks the fabric of the building itself, and produces a generally unhealthy environment.

The occurrence of respiratory problems and asthma appears to be increasing over recent years. Asthma seems to be generated almost exclusively in temperature bands north and south of the equator where humidity levels are at a certain level. In addition, in these areas, buildings lack ventilation as people lmprove the sealing of windows, doors etc to conserve energy.

It is believed that asthma is caused by raised humidity levels and has increased due to reduced natural ventilation in domestic houses as explained hereinabove.

In a typical bedroom, especially with the door and windows closed, the humidity level increases over night. A typical male might sweat about 1 litre of liquid per night, part of which is absorbed into the atmosphere, and part of which is absorbed by the bed sheets.

It is a well known medical phenomenon that house dust mites consume shredded skin flakes. It is however believed that skin flakes are only digestible by the mites when they have on them a fungal growth such as aspergil. The fungus can attach itself to the skin flakes only in appropriate conditions of humidity. Once the mites can digest the skin flakes, they multiply at extraordinary rates and mite faeces are then deposited on bed sheets, pillow cases etc. It is believed that this is the material which enters the lungs and is a direct cause of asthma.

As mentioned hereinabove, it is believed that the humidity levels generally found in temperate zones coupled with the improved sealing of windows etc to conserve energy produces appropriate humidity levels for producing high rates of fungal growth on skin flakes. This theory is reinforced by the fact that the incident of asthma appears to be increasing in the more technically and economically sophisticated tropical and sub-tropical regions of the world where air conditioning units are installed. For example, asthma is now becoming a problem in Israel where it never was previously.

Known air conditioning units and "closed loop" cooling systems do not promote ventilation. In other words such known systems do not allow communication to and from the external atmosphere. This means that an air conditioning unit without ventilation could simulate a typical temperate zone environment thus allowing rapid reproduction of dust mites which in turn increases the incidence of asthma.

There is presently great interest in combatting asthma suffering without having to use drugs. There are known schemes such as a sophisticated vacuum cleaning systems which remove mites, or more particularly mites faeces from bed linen etc. However such systems provide only short term remedies, and are extremely expensive, typical costs being in the region of £2000 for a whole house operation.

Known ventilation systems of the type described hereinabove are generally mounted in an external wall of a room in which the climate is to be controlled.

A disadvantage of installing a ventilation system in an external wall is that a hole must be created in the wall.

It is not always possible for a person to carry out such work to an external wall of a building because, for example, the person rents the property and therefore has no authority to carry out modifications to the fabric of the building.

A ventilation system of the type described hereinabove is described in our co-pending International patent application claiming priority from UK patent application of even date, the contents of which are incorporated herein by reference.

According to the present invention there is provided a ventilator system comprising: a ventilator; and a conduit; the ventilator being positionable within a room in which the climate is to be controlled, and wherein the ventilator is free standing, the conduits extending from the ventilator and adapted to extend externally out of the room.

By means of the present invention, the need to create an aperture in an external wall in which to position a ventilator is obviated. The conduits are adapted to extend out of, for example, a window in the external wall.

Preferably, the conduit is an inlet conduit and an outlet conduit.

The inlet and outlet conduits may be separate to one another, or alternatively a single conduit may serve as both an inlet and outlet.

Advantageously, the ventilator system further comprises cooling means for reducing the humidity of incoming air.

This is particularly advantageous when the ventilation system is to be used in hot tropical countries.

The invention will now be further described by way of example only in which:

Figure 1 is a schematic representation of a ventilator system according to the present invention as viewed from the side;

Figure 2 is a front view of the ventilator system of Figure 1 ;

Figure 2a is a schematic representation of a second embodiment of a ventilator system according to the present invention incorporating a cooling device.

Figures 3 to 10 are schematic representations of the ventilator system of Figure 1 showing arrangements of the inlet and outlet conduits .

Referring to Figure 1 , a ventilator system according to the present invention is designated generally by the reference numeral 1. The ventilator system 1 comprises one or more fans powered by a motor and positioned in the area designated by the reference numeral 2.

The ventilator system further comprises a heat exchanger 3 and a drip tray 4 which collects condensed water. This condensed water is then pumped by a pump 5 and travels up discharge pipe 6 to join outlet conduit 7 and to exit into the external atmosphere. It is also possible to use an electrically heated evaporator which "boils" away condensates. However, this arrangement is likely to use a lot of energy.

Alternatively, it is possible to use a wick which extends from the drip tray to the outlet and which removes liquid water. The wick may be placed within a tube.

The ventilator system 1 serves to provide fresh air from outside the room continually to the interior of the room in which the climate is to be controlled while simultaneously extracting stale moist air from the room. The fresh air may be pre-warmed if necessary. The heat is transferred from the outgoing air via the heat exchanger 3 to the fresh air supply supplied to the room from the outside environment, thus maintaining internal temperatures and providing a fresh environment. Pre-warming of air is particularly important in very cold climates.

The ventilator system unit may conveniently be mounted on wheels 8 in order to allow the unit to be easily moved to an appropriate position in the room. The ventilator system could however be mounted on, for example, coasters, or may be merely positioned directly onto the floor. The ventilator system is surrounded by insulator 9 which reduces heat loss, and noise.

Turning now to Figure 2, further details of the ventilator system 1 are shown. The ventilator system 1 further comprises a room temperature sensor 20 and a room humidity sensor 21. The sensors 20, 21 control the ventilation rate of the ventilator system 1 , as set out in our co-pending application number 9521634.7 of even date the contents of which are incorporated herein by reference.

The ventilator system 1 further comprises a control means 22 in the form of electronic circuits and timers which function in conjunction with the sensors 20, 21 to control the ventilation rate of the ventilator system 1.

A motor 23 may be AC or DC and serves to power fans or impellers 24, 25. The impellers each have a prime number of blades but the number of blades on each impeller 24, 25 is different on each in order to ensure low noise. For example, impeller 24 may have 41 blades and impeller 25 has 43 blades. Prime numbers reduce the number of harmonics produced and are less noisy and less disturbing to the human ear. With two impellers having different numbers of blades, the number of harmonics is further reduced and thus the disturbing nature of the noise is also further reduced. The system 1 further comprises a filter 26 for filtering out pollen and other fungal spores which may be in the air taken from the outside. Directional louvres 27 allow the incoming fresh air to be directed as desired.

Inlet filter 28 prevents lint blocking the system. Lint comes from clothes, bedding, towels etc. It is present whenever items such as these are used, handled or worn and is in the form of fine airborne strands. The filter 28 should remove course dirt but will allow fine mite droppings to pass through the filter.

Detector 29 is a high level cut off detector whilst detector 30 detects the level of liquid in the drip tray 4.

The condensate pump or evaporator are switched on at a predetermmed point by a sensor. If either this sensor fails or the pump or evaporator fails, the water level will continue to rise in the drip tray so a second cut off sensor, the high level cut off detector 29 is used.

Electronic sensors suitable for use in detector water levels in the drip tray could be, for example, thermistor types, thermocouples, electrical contacts etc.

The heat exchanger 3 is in the form of a stretched heat exchanger which results in counter flow of the centre of the heat exchanger which in turn results in maximised heat recovery .

The system 1 is insulated by a thermal acoustic lining 32. An auxiliary heater 33 allows the outside air to be heated up when the outside temperature is low and particularly during the night when the outside temperature can be very low. The heat 33 may also be used to reduce the relative humidity of incoming air.

Temperature sensor 34 senses the temperature of the outside air controlled operation of the heater 33. The humidity sensor 35 senses the relative humidity of the outside air and can also control the operation of the heater 33. Outlet louvres 36 allow the outgoing air to be directed as desired.

Referring to Figure 2a, a second embodiment of the present invention is shown in which equivalent parts to those shown in the embodiment in Figure 2 have been given equivalent reference numerals.

The ventilation system disclosed in Figure 2a is designated generally by the reference numeral 100. The system 100 comprises in addition to those parts already described hereinabove with reference to Figure 2, a cooling device 79. The cooling device serves to reduce the humidity of incoming air. This is especially useful in hot tropical countries.

The cooling device cools the air to below the dew point and allows water to drain off via drain 80. The cooling device has been shown positioned at 79, but could alternatively be positioned at point 78.

The condensate may be removed by means of self regulating heater which causes the condensate to evaporate out through the heat exchanger and so out of the room. The condensate is shown collecting at 81.

Referring to Figure 3, a conduit 30 extending from the ventilator system 1 is shown hanging out of an open window 31 in order to allow fresh air to enter the ventilator system, and stale air to exit from the system. The inlet and outlet conduits are formed separately, as shown in Figure 4 and are shaped in the form of a hook. The outlet conduit 41 allows condensed air to be removed from the room The inlet conduit 42 includes louvres and a vermin mesh to filter incoming air before it enters the room in which the climate is to be controlled.

Referring to Figure 5, the two conduits 41, 42 are shown as extending from the ventilator system 1.

Referring to Figure 6, it can be seen that the separate ducts 41, 42 may be fixed together by means of a suitable clamp 60 for convenience.

Alternatively, as shown in Figure 7, the ducts may be in the form of a single Siamese duct 70 in which a single conduit serves as both the inlet and the outlet ducts. A Siamese duct 70 will have an inlet portion 80 and an outlet portion 81 as shown in Figure 8.

Figure 9 is a schematic representation of a flexible duct extending from the ventilator system 1 and out of a window 31.

Figure 10 is a cross sectional schematic representation of the Siamese ducts 70.

Claims

1. A ventilator system comprising: a ventilator; and a conduit the ventilator being positionable within a room within which the climate is to be controlled, and wherein the ventilator is free standing, the conduit extending from the ventilator and adapted to extend externally out of the room.

2. A ventilator system as claimed in claim 1 where the conduit comprises an inlet conduit and an outlet condui .

3. A ventilator system according to claim 2 wherein the inlet and outlet conduits are separate from one another.

4. A ventilator system according to claim 2 wherein the inlet conduit and the outlet conduit are in the form of a single conduit.