GB2349687A

GB2349687A - Air conditioning apparatus

Info

Publication number: GB2349687A
Application number: GB9906333A
Authority: GB
Inventors: Glenn Ferguson
Original assignee: GLACIATION AIR CONDITIONING SY
Current assignee: GLACIATION AIR CONDITIONING SY
Priority date: 1999-03-19
Filing date: 1999-03-19
Publication date: 2000-11-08
Also published as: GB9906333D0

Abstract

An air-conditioning apparatus containing a refrigeration unit comprises a condenser (26) and an evaporator (36) the evaporator being positioned such that water from moist air condensing on the evaporator (36) is channelled onto the surface of the condenser (26) to cool the condenser before draining through an outlet (10). The refrigeration unit may be located in a housing with a fan means (6) for drawing air into the housing past the evaporator (36) and condenser (26).

Description

AIR CONDITIONING APPARATUS This invention relates to air-conditioning apparatus, and more particularly air-conditioning apparatus for use in situations where space is at a premium, for example the interiors of boats and caravans.

Air-conditioning systems operate by passing air from a room over a refrigeration unit and then passing the cooled air back out into the room.

Typically, the refrigeration unit is one which operates on a gas-liquid compression-evaporation cycle in which a refrigerant fluid (usually a chlorofluorocarbon or fluorohydrocarbon) in the vapour phase is compressed to a form a hot, high-pressure liquid which is then cooled and subsequently evaporated to form a cold gas, and then compressed again. Thus, a typical refrigeration unit will comprise a condenser unit, an evaporator unit and a compressor. Warm air is drawn into the air-conditioning unit from the room where air-conditioning is required and is passed over the evaporator. Heat, corresponding to the latent heat of evaporation of the refrigerant fluid, is extracted from the room air and the refrigerant liquid is evaporated to form a cold gas. The cooled air is then channelled back to the room in which the air-conditioning is required. The cold gas from the evaporator is recycled through to the compressor where it is compressed to form a liquid. The act of compressing the gas creates heat and the heated condensed liquid is then channelled to the condenser. The condenser is cooled, either by means of air or water, and the cooled liquid then passes onto the evaporator where the cycle is repeated.

In large scale air-conditioning apparatus, the condenser is typically located externally to the building and air from outside is used to cool the condenser coil. However, in mobile or free standing interior air-conditioning units, air from the room is typically used to cool the condenser coil and the resulting warmed air is then exhausted to the exterior of the building. In such arrangements, it is possible to use several separate air intakes from the room, one connected to ducting passing the air-stream past the evaporator, for cooling, and another connected to ducting for passing the air-stream over the condenser. Alternatively, the air intake can be a single air intake and the air split by means of a valve or deflector arrangement such that a proportion of the air passes over the evaporator and a proportion of the air passes over the condenser.

Most mobile air-conditioning units generate water through condensation of moisture in the air on the evaporator. The moisture must be collected and disposed of, and typically a water collection vessel may require emptying several times a day.

The presence of the water collector and the need to empty it on a regular basis gives rise to several problems. Firstly, the need to gain access to the water collector means that the air-conditioning unit must be placed in a relatively accessible position within a room and this in turn can create a space problem within rooms such as caravans and boat cabins where space is at a premium. A further problem is that the water collection vessel adds significantly to the overall size of the apparatus, again with attendant disadvantages in situations where space is limited.

It is an object of the present invention to overcome the aforementioned problems and to provide an air-conditioning unit which is more compact than known air-conditioning units, and can be located in a relatively inaccessible position in, for example, a caravan or a boat, or the attic of a house or other building.

It is a still further object of the invention to provide an air-conditioning unit which, despite its relatively small size, has a more efficient cooling ability than known air-conditioning units.

In a first aspect, therefore, the invention provides an air-conditioning apparatus containing a refrigeration unit comprising a condenser and an evaporator, the evaporator being positioned such that water from moist air condensing on the evaporator is channelled onto the surface of the condenser to cool the condenser before draining through an outlet.

The evaporator is preferably disposed above the condenser such that water condensing on the surface of the evaporator drains onto the surface of the condenser by means of gravity. In particular, the evaporator may have an angled upper surface to assist drainage by gravity.

The air-conditioning unit of the invention can be mounted such that the condensed water and warmed air passing over the condenser are exhausted through an outlet in the underside of the air-conditioning unit.

In one embodiment, the air-conditioning unit is arranged to be installed in a caravan such that the condensed water and warmed air vent through an opening in the floor of the caravan.

The invention will now be illustrated, but not limited, by reference to the accompanying diagrammatic drawings, of which: Figure 1 is a schematic side view of an air-conditioning apparatus according to one embodiment of the invention; Figure 2 is a schematic view corresponding to Figure 1 but illustrating the air flow through the apparatus; Figure 3 is a schematic view corresponding to Figures 1 and 2 but including some linking pipework; Figure 4 is a view from the opposite side of a mirror image of the arrangement shown in Figure 3; Figure 5 is a schematic view of the refrigeration circuit; and Figure 6 is a plan of the control circuitry of the apparatus of Figures 1 to 5.

Referring now to the drawings, the air-conditioning unit comprises a generally rectangular housing 2 which in this embodiment comprises a one piece moulding 3 and a lid formed from high impact polystyrene, the housing being inverted such that the lid 4 functions as a tray for collecting condensed moisture, as will be explained in more detail below. Purely by way of example, the housing can be approximately 650mm long by 360mm wide by 285mm deep.

The housing 2 is provided with an air inlet covered by an air filter (not shown), and leading to a centrifugal fan 6. At one end of the casing are a plurality of air outlets 8 which in this embodiment are in the form of spigots which can be, for example, approximately 60mm in diameter, and which can be connected to flexible ducting to channel cooled air throughout a room such as the interior of a caravan. On the underside of the housing 2 is an exhaust outlet 10 which in use is mounted in-register with an opening cut into the floor of, for example, a caravan. The opening 10, which can be for example of 150mm outside diameter, has an angled vent 12, the vent 12 having a wire mesh or grille (not shown) mounted therein to prevent small creatures from entering the system. The angled front surface 14 is oriented so as to face towards the front of a caravan or other vehicle to which the air conditioning apparatus is fitted and serves to deflect mud and other debris from entering the opening when the caravan is in transit.

Mounted within the housing, in addition to the centrifugal fan, are a refrigeration system and associated control circuitry. The refrigeration system comprises a rotary compressor 20 and an associated accumulator 22. The upper end of the compressor 20 is linked via tubing 24 to one end of a condenser 26. Condenser 26 in turn is linked via tubing 28 to a dryer unit 30 and capillary expansion device 32 and thence via tubing 34 to an evaporator 36. The evaporator 36 is linked to accumulator 22 by tubing 38.

As can be seen from the drawings, the evaporator 36 is mounted above the condenser 26, both the evaporator 36 and condenser 26 being mounted at an inclined angle relative to the base of the housing. The reason for the inclined mounting angles will become apparent below.

At the end of the housing remote from the condenser and evaporator and located adjacent the compressor and accumulator are a control panel in the form of a printed circuit board, and a capacitor 42 for assisting in the start up of the compressor. The configuration of the control panel and associated circuitry are shown in Figure 6.

Thus, as shown in Figure 6, the control circuitry comprises a transformer 50 which is capable of transforming a 230V AC supply 52 down to 1 2V or 24V DC, and relays 44,46 and 48. The main control relay 46 is linked to the capacitor 42 and thence to the compressor 20, and also to the fan motor 54 and a safety device 56 for the compressor 20. Also linked to the control panel 40 are a return air probe 58 which is located in front of the impeller of the fan 6 and which monitors the air temperature, and an antifrosting probe which measures the evaporator gas temperature and which, as the name suggests, is intended to prevent frosting. The fan speed is arranged to vary with the air temperature detected by the probe. Thus, the controller is programmed to increase the fan speed as the temperature increases and reduce the fan speed as the air temperature falls. A safety cut-out switch 62 is provided which switches off the apparatus in the event that an attempt is made to open the housing whilst the apparatus is on.

The control circuitry is linked to a remote controller 64 via ten-core cable 66, the remote controller being mounted on a suitable surface at a convenient location within the room.

In use, a refrigerant such as"Freon" (RTM) is pumped around the fluid circuit linking the condenser, evaporator, accumulator and compressor.

Thus, liquified refrigerant passes from the compressor 20 along tubing 24 to the condenser 26 where heat is removed by a stream of air 50 from the interior of the caravan drawn into the air-conditioning apparatus through the air inlet by centrifugal fan 6 and then expelled through the vent opening 10 to the caravan exterior.

The partially cooled refrigerant passes along tubing 28 through the drier 30 and capillary expansion device 32 and into the evaporator 36 where it evaporates to form a gas. The latent heat of evaporation of the refrigerant is supplied by the airstream 52 passing over the surface of the evaporator.

Thus the air is cooled, and the cooled air 52 is channelled via the air outlet ducts 8 to appropriate locations within the caravan.

The cooled gaseous refrigerant passes from the evaporator 36 along tubing 38 to the upper end of the accumulator 22 and thence into the compressor 20 where it is compressed to form a liquid. The compression of the liquid results in heating and the heated liquid refrigerant then passes back to the condenser to repeat the cycle.

In most geographical locations, air contains moisture, and such moisture will tend to condense on the surface of the evaporator. In known air-conditioning systems, the condensed moisture is collected in a water collection vessel which must be emptied at regular intervals. However, in the present case, the water condensing on the evaporator 36 is used to cool the condenser and the hot gas therein. Thus, condensed water 60 runs down the inclined surface of the evaporator and drips onto the surface of the condenser 26, before running down the inclined surface of the condenser and then draining into the tray formed by the base 4 of the housing 2.

Thereafter, the water passes out through the outlet 10 to exhaust, assisted by the airstream 50. The effect of the water passing over the surface of the condenser is to cool the condenser and the hot gases therein more efficiently than would be the case if only air cooling were employed. This improves the efficiency of the apparatus and results in a greater cooling effect than would be achieved if air-cooling were used and the condensed water were merely collected and discarded as is the case with conventional compact airconditioning systems. Purely by way of example, in an apparatus of the type shown in the Figures, for air having a relative humidity of 57%, a volume of one litre of condensed water is produced each hour and this gives rise to a significant cooling effect on the condenser.

The air-conditioning unit of the invention is particularly suited for use in circumstances where space is at a premium, for example in caravans and boats. Thus, for example in a caravan, the air-conditioning unit can conveniently be stored in the blanket chests or bed boxes usually found beneath the seats in a caravan. The vent opening 10 communicates with the exterior of the caravan through the floor in the caravan.

Although the invention has been illustrated by reference to an installation in a confined space such as a caravan, the air-conditioning systems of the invention can also be used in buildings, for example in a domestic context. Thus, for example, an air-conditioning unit of the invention could be installed within the attic of a house, the vent opening being connected via suitable ducting to the building exterior, and the cooled air being directed through suitable ducting to required parts of the house, for example the bedrooms. Thus, by means of the invention, an entirely unobtrusive and compact air-conditioning system for domestic use is provided.

It will readily be appreciated that numerous modifications and alterations could be made to the air-conditioning apparatus shown in the accompanying drawings and described above without departing from the principles underlying the invention, and all such modifications and alterations are intended to be embraced by this Application.

Claims

CLAIMS 1. An air-conditioning apparatus containing a refrigeration unit comprising a condenser and an evaporator, the evaporator being positioned such that water from moist air condensing on the evaporator is channelled onto the surface of the condenser to cool the condenser before draining through an outlet.
2. An air-conditioning apparatus according to claim 1 wherein the evaporator is disposed above the condenser such that water condensing on the surface of the evaporator drains onto the surface of the condenser by means of gravity.
3. An air-conditioning apparatus according to claim 2 wherein the evaporator has an angled upper surface to assist drainage by gravity.
4. An air-conditioning apparatus according to any one of the preceding claims configured such that condensed water and warmed air passing over the condenser are exhausted through an outlet in the underside of the air-conditioning unit.
5. An air-conditioning apparatus according to any one of the preceding claims comprising a housing containing the refrigeration unit, fan means for drawing air into the housing past the evaporator and condenser, air inlet means leading to the fan means, and air outlet means for directing air cooled by passing over the evaporator to a desired location.
6. An air-conditioning apparatus according to claim 5 wherein the housing contains control circuitry for controlling the operation thereof, the control circuitry being linked to a remote controller externally of the housing.
7. An air-conditioning apparatus according to claim 5 or claim 6 wherein the base of the housing is configured so as to collect water draining from the condenser and channel the water to an exhaust outlet.
8. An air-conditioning apparatus substantially as described herein with reference to the accompanying drawings.
9. A caravan fitted with an air-conditioning apparatus according to any one of the preceding claims.