GB2134645A

GB2134645A - Space cooling system

Info

Publication number: GB2134645A
Application number: GB08332916A
Authority: GB
Inventors: Claudio Rossie
Original assignee: HIROSS INT CO; Hiross International Corp SA
Current assignee: HIROSS INT CO; Hiross International Corp SA
Priority date: 1982-12-10
Filing date: 1983-12-09
Publication date: 1984-08-15
Also published as: CA1234983A; FR2544470A1; DE3341853A1; FR2544470B1; SE8306813D0; GB8332916D0; GB2134645B; DE3341853C2; SE8306813L

Abstract

A cooling system comprises a mechanical refrigerating plant for the treatment of a fluid to be cooled and a radiator (1) connected in series to an evaporator (2) of said mechanical refrigerating plant. The radiator is mounted at the side of the condenser of the refrigerating plant and in contact with the same flow of forced air and is provided with a by-pass and three-way valve (7) enabling the flow of fluid being cooled therein to be reduced and even completely shut off. <IMAGE>

Description

SPECIFICATION A cooling unit for fluids in an air conditioning plant The present invention relates to a cooling unit for fluids in an air conditioning plant or, at all events for working fluids or processing fluids.

A plant for the cooling of fluids comprises a centralized unit which treats the fluid and which is then conveyed through pipes to conditioning units mounted in the rooms requiring air conditioning or to machines or to processes in which cooling is required.

In the customary systems the cooling unit is practically always branched and the fluid treated by the centralized unit in such a way that it is distributed at a predetermined temperature, which is invariably produced by a refrigerating effect.

In certain cases different cooling means from the cooling unit are employed, but there are no known installations of a compact type which function simultaneously with different sources of cooling and which ensure optimum efficiency.

The main purpose of the present invention is to provide an installation which makes the maximum possible use of the air of the external atmosphere as the main source of cold in order to economise in the consumption of energy.

A further object which follows from the first is to provide a unit capable of using different sources of cold either simultaneously or in alternation.

A further object is to provide a unit which utilizes the different sources of cold in an optimum manner, ensuring a high degree of efficiency.

Yet a further aim of the invention, and by no means the least important, is to provide a compact unit which will be simple not only in design but also in operation.

The invention provides a cooling unit for liquids in air conditioning installations or for working fluids comprising a mechanical refrigerating plant for the treatment of the liquid, equipped with at least one aircooled liquid cooler (hereafter calied a radiator) connected in series to at least one evaporator for the unit, the said radiator being mounted at the side of the air-cooled condenser of the refrigerating unit and in contact with a common flow of forced air, the said radiator being preferably "upstream" from the condenser in the direction of flow of the cooling air and provided with a branch with a three-way valve, enabling the reduction and even compiete shut off of the flow of liquid through the radiator.

Note that the term "radiator" refers to a heat exchanger in which a liquid such as water is cooled by an air stream, and may also be considered to be a free-cooling coil. The term "aircooled condenser" refers to a heat exchanger in which the refrigerant of a sealed mechanical refrigerating plant is reduced to a liquid state, transferring its latent heat to the air.

Further characteristics and advantages of the invention will be rendered clearer by the following detailed description of preferred embodiments, discussed purely as an illustrative example without any limitative effect, this description being illustrated on the accompanying sheets of drawings wherein: Figure 1 is a diagram of an hydraulic circuit of the unit.

Figure 2 is a schematic diagram of pairs of heat exchangers, each pair having a radiator and a condenser.

Figure 3 is an alternative version of the system shown in Figure 2.

Figure 4 is a view in perspective of a unit comprising a double radiator-condenser assembly.

Referring to the drawings, it may be seen that where the hydraulic circuit is concerned the unit comprises at least one radiator 1 connected in series to at least one evaporator 2 of a mechanical refrigeration circuit.

The liquid circulation is achieved by a pump unit 3, where necessary, preferably consisting of a pair of pumps 4 and 5 mounted in parallel with each other and capable of functioning in alternation.

The radiator 1 is provided with a branch pipe 6 which leads to a three-way valve 7 situated between the radiator 1 and the evaporator 2.

The circuit may also include an expansion vessel 10. A current of external atmospheric air, indicated by the reference number 11, blown by one or more fans comes into contact with the radiator 1, and immediately thereafter with the air-cooled condenser 9 of the mechanical refrigeration circuit which includes a compressor 17, an expansion valve 1 8 and the evaporator 2 connected with the appropriate piping.

To ensure that the whole installation will be as compact as possible, the radiators 1 and the condensers 9 of the mechanical refrigeration unit are preferably arranged as shown in Figure 2.

In diagrams 1 and 2 it may be seen that the radiators, which in diagram 2 are of the multiple type and which are marked 1, are invariably "upstream" from the condensers 9 in the direction taken by the current of air 11 produced by one or more fans 1 2. The refrigerant of the sealed mechanical refrigerating plant is reduced to a liquid state and its latent heat transferred to air in the condenser.

In this case the atmospheric air comes into contact with the radiator before being heated by any other component of the system: i.e. by the aircooled condenser, and the importance of this will be made clear in the following description.

Furthermore, the said arrangement not only reduces the dimensions of the various parts of the operations but also reduces to the minimum the number of fans 12 required, since the current of air passing through the radiator and the condenser is one single current.

Figure 3 shows an alternative arrangement for the constituent parts of the assembly, with a radiator in this case marked 13, positioned adjacent to a condenser in this case marked 1 4.

The fan 1 5 withdraws the air from the median zone included between the said exchangers 1 3 and 14, so that the current of air 16, here again one single current comes in contact partly with the radiator 13 and partly with the condenser 14.

The unit is required to cool a liquid stream to a temperature dictated by thermostats or other signals.

When the scheme illustrated and also the arrangement and combination of radiator and condenser described above are employed the installation operates by the following alternative methods; Case A: The temperature of the liquid entering the cooling unit is lower than the outside atmospheric temperature; in this case, which may be regarded, so to speak, as "summer conditions", the radiator cannot in any way be cooled by the air of the atmosphere, which is warmer than the liquid; therefore the three-way valve is positioned in order to exclude the radiator and the system functions exclusively with the mechanical refrigeration section.

Case B: The outside astmospheric temperature is lower than the temperature of the liquid entering the cooling unit and therefore the liquid, circuiating through the air-cooled radiator, may transfer some heat to the atmospheric air which produces a cooling effect; the three-way valve is positioned in order to insert the radiator in series with the mechanical refrigeration evaporator; if the radiator is unable to supply to the liquid the whole of the cold required, the fans operate at full speed and the mechanical refrigeration plant acts as a buffer element; when the atmospheric air temperature is low enough to allow the radiator to supply the exact total quantity of cold required by the installation, the fans operate at full speed and the mechanical refrigerating devices are shut off.

Case C: The temperature of the atmospheric air is well below the temperature of the liquid entering the radiator; in this case, event though the mechanical refrigeration devices are shut off, the radiator reaches an excessive capacity, which can then be reduced by: - regulating the speed of the fans.

- reducing the current of air by turning off one or more fans when possible.

- moderating the delivery rate of the liquid by connecting up the branch controlled by the threeway valve.

These systems can obviously be utilized together, in conjunction with one another, individually or as alternatives.

As regards the condenser it should be noted that the current of air passes through it even when not required; in order to eliminate the drawbacks caused by an excessively low condensation temperature, known systems for regulating the capacity of the condenser such as the "flooding" system, are used in the refrigeration circuit.

The foregoing description and illustrations show that the objects in view are atained and in particular that an extremely compact unit has been produced which is simple in its construction, economical in its operation and capable of utilizing, where possible, a source of cooling of low cost and which utilizes the air of the external atmosphere.

The use of one single system of fans obviously reduces the cost of the installation, and the problems which this choice might involve are eliminated thanks to the adoption of an original combination of a radiator with a condenser of a mechanical refrigeration plant.

The possibility of either using or dispensing with this auxiliary radiator renders the instailation particularly flexible in operation and reduces the running costs.

The control and regulating systems are particularly simple and in all respects analogous to the systems already known and used on a wide scale.

Proceeding from the innovative principle adopted in the combination and arrangement of the constituent parts of the assembly the constructional versions can be modified in respect of those shown in the drawings.

The materials and constituent parts used may be any which are most suitable for the needs, dimensions and power of the installation.

Claims

1. A cooling unit for fluids in an air conditioning plant or for working fluids, comprising a mechanical refrigeration plant for the treatment of the fluid, equipped with at least one air-cooled radiator hydraulically connected in series to at least one evaporator for the unit, the radiator being mounted to the side of the condenser of the refrigerating unit and in contact with a common flow of forced air, and with a branch controlled by a three-way valve which is operable to reduce or shut off completely the flow of liquid through the radiator.

2. A cooling unit in accordance with claim 1, wherein the radiator is located upstream from the condenser in the direction of the flow of cooling air.

3. A cooling unit in accordance with claim 1, wherein the radiator is mounted by the side of the condenser of the mechanical refrigeration plant and wherein they are both in contact with the same external current of cooling air.

4. A cooling unit in accordance with any one of the preceding claims, wherein the radiator is provided with a branch pipe and a three-way valve for the connection of the radiator or of the branch.

5. A cooling unit in accordance with any one or more of the preceding claims wherein the three way valve, by means of the branch, enables the circulation of the fluid in the radiator to be reduced to any level down to zero.

6. A cooling unit in accordance with any one of the preceding claims in which there is a battery of fans producing the common current of air and in which the fans operate by suction through the radiator and the condenser.

7. A cooling unit in accordance with claim 6, wherein the fans of the aforementioned battery are of the variable speed type and are capable of being shut off.

8. A cooling unit in accordance with any one of the preceding claims, comprising one or more pairs of heat exchangers each pair including a radiator and a condenser which are arranged to be contacted by a common current of cooling air.

9. A cooling unit for fluids in air conditioning installations or for working fluids, substantially as hereinbefore described with reference to the accompanying drawings.