ES2318941A1 - Combined refrigeration and air conditioning system - Google Patents

Abstract

The invention relates to a combined refrigeration and air conditioning system, which simultaneously carries out the functions of an industrial cold and air conditioning system of an installation or premises by means of refrigeration cycles by direct expansion of a refrigerant. To that end, it comprises two or more compressors (10, 20) sending the compressed refrigerant to a common point, a series of expansion valves (12, 22) and several heat exchangers (11, 13, 23), two of which carry out the exchange with the medium to be cooled with the industrial cold system and with the premises or installation to be air conditioned. The operation mode of the air conditioning system is easily changed from heating to refrigeration by means of the action of two series of valves (50, 51).

Description

Combined cooling system and air conditioning.

Field of the Invention

The present invention relates to a system combined cooling and air conditioning that allows to improve the efficiency of cold energy conversion in facilities that require, at least temporarily, air conditioning, and whether it is to provide cold or heat, and cooling of chambers, exhibitors, or any other object or medium.

In particular, the system can be used in a refrigerating installation of a room also equipped with a system of comfort air conditioning such as a unit of refrigeration of one or more merchandisers located in a trade with air conditioning system.

State of the art

The technical sector to which the invention is that of refrigeration and air conditioning.

The premises where storage occurs or the sale to the public of perishable products, always have two thermal systems, independent of each other, that work from independent and isolated way. On the one hand the systems are arranged of industrial cold typical of perishable products and on the other the comfort air conditioning systems of the premises.

Most often, the cold installation industrial comprise a conventional refrigeration system of mechanical compression, and the air conditioning systems of the premises are equipped with air-to-air heat pumps.

A basic refrigeration cycle by understanding  Mechanical and direct expansion consists of four elements or stages: compressor, condenser, expansion valve and evaporator.

In the evaporator, the refrigerant evaporates and absorbs heat from the space it is cooling and its contents. TO then the refrigerant vapor passes to a compressor that It increases your pressure, which increases your temperature. This gas superheated at high pressure is subsequently transformed into liquid in a condenser cooled by air or water.

After the condenser, the liquid passes through a  expansion valve, where its pressure and temperature are reduced until the conditions that exist at the entrance of the evaporator, closing the cycle.

Description of the invention

The present invention relates to a system of  Complete and unique refrigeration and air conditioning, comprising two independent subsystems today, which are cold industrial and air conditioning of the premises (the latter being able to heat or cool according to comfort needs).

Taking advantage of these two subsystems, you get energy savings upon reaching heat pump operation of the main system with the basic elements of the industrial refrigeration and air conditioning installations.

This system offers energy savings by optimize the condensation phases of compressors and systems Full compression of cold installations and air conditioning. This saving occurs in heating of the premises in winter, and take advantage of the performance of older equipment capacity in summer.

In addition, the procedure allows to improve the safety and reliability of compressors and main systems of main system power, because by grouping the same, supports are obtained at a time of failure of any of they. Mainly the air conditioning systems will support the industrial cold systems, since its operation is priority not to spoil the refrigerated products or frozen

The present invention therefore relates to the union of industrial refrigeration and conditioning systems of the air in one. The residual energy of one of them, Generally of the industrial cold system, it is used to carry out the air conditioning of the room by means of the heat pump that is formed.

The proposed system consists of a system of  traditional refrigeration, which could be completed for greater energy saving with an additional subsystem as an injection controlled electronics or liquid pump.

In a compression refrigeration cycle Mechanical heat is always absorbed from a cold spot, furniture, Downtown cameras, year-round, and delivered to a spotlight warm during condensation.

According to the invention, this hot spot will correspond to the premises during the time when it should be heated (which we call winter in this specification, regardless of the season of the year in which it occurs and of its duration) through the air conditioning system. With the invention, the heat generated from all or part of the condensers of the industrial cold installation, which used to be degraded, in the air conditioning of the premises. When necessary, it accompany this source of heat by other sources such as electrical resistors, hot water, steam, solar energy or other power source.

When it is required to lower the temperature of the local, time that we will call summer, it will be necessary to maintain the industrial cold system, and in parallel activate the system room air conditioning to cool. At this time, it will work from the main cold power system for both subsystems, as a traditional installation but taking advantage of the union of the two systems to look for the best performance, using A team of greater capacity.

In industrial cold systems, it is common  install two subsystems in parallel, called positive cold and of negative cold, each one of them allowing to cool until a given temperature The negative cold subsystem cools to a lower temperature than positive cold. For example, between -10ºC and -35 ° C.

In this way the negative cold subsystem is you can use to preserve frozen products while the positive cold subsystem can be used for products chilled (butter, fish, meat, etc.)

Both subsystems can share elements, although they are generally independent because of safety against possible leaks.

In the rest of the report there will be no mention of the existence, or not, of a separation into two subsystems, interpreting that, in case of division in the two subsystems of positive cold and negative cold, the combination of air conditioning system and industrial cooling system can be carried out with either of the two subsystems, or even with both (further increasing energy efficiency).

Anyway it is usually more interesting perform the combination with the positive cold subsystem.

For this, the system of the invention comprises two compressors, or two pluralities of compressors in series or parallel, which we will call first and second compressor, whose output Compressed refrigerant is done to a common point. The flow of refrigerant from this common point to the compressor inlet It will vary according to the mode of operation so that:

In summer mode of operation a first  heat exchanger will perform condensate functions of the coolant following the common point, and will pour a condensed refrigerant to two parallel branches, each of they comprising an expansion valve, either of the type electronic, mechanical, constant reheating or any other type, and a heat exchanger in function of evaporator.

In particular, in a first branch the refrigerant will pass through a first expansion valve and a second heat exchanger, which will remove heat from the medium that it is desired to cool by the industrial cold system. In the other one branch will cross a second expansion valve and a third heat exchanger that will exchange heat with the premises or installation to be heated, in this case cooling it.

After the second and third exchanger, returns to the suction inlets of the compressors, which  they can be connected so that one compressor supports the other in failure case.

In winter mode of operation, the refrigerant will follow a first branch from the common point reaching the third heat exchanger, which in this case it will condense the refrigerant and provide the heat extracted to the premises or installation to be heated, at whose exit the first will be arranged expansion valve and the second exchanger, which follows functioning as an evaporator and removing heat from the medium object of the industrial cold.

Optionally, and to achieve greater variability between the heat contributed to the premises and the extracted through the industrial cold system, a second can be created branch that starts at the common point and continues on the first heat exchanger, which will condense the refrigerant. From there, and through a section that can optionally comprise a liquid pump or a reservoir, the refrigerant enters the First expansion valve. This increases the industrial refrigeration system refrigerators without affecting the system air conditioning.

If on the contrary you want to heat more in the air conditioning system, without changing the fridges provided by the industrial cold system, since the third exit exchanger can take the coolant to a third expansion valve followed by a fourth exchanger that evaporates the refrigerant removing heat from an external element both systems of air conditioning and industrial cold. Finally the refrigerant will return to a compressor, for example the second compressor.

To change an operating mode to other, advantageously, two series of valves whose opening or closing defines the mode of operation of the system (summer or winter). These valves can be operated manually, by servomotors controlled by an automaton, or by Any other means.

The most obvious variant that can be applied to This basic installation is the existence of several compressors in series or parallel replacing the first or second compressor. From In the same way, any heat exchanger can be replaced. heat or any expansion valve by several exchangers or several expansion valves, in series or in parallel, respectively.

Another variant is to use the room exchanger, which according to the operation described only acts in winter, as a condenser in summer. To do this, it must be bridged The third expansion valve.

The system regulates itself by the temperatures detected in each of the objects, premises and facilities that it is desired to cool or condition, such as the exhibitors of perishable products, cold rooms and rooms sales

In order to ensure the comfort of the installation, a support system can be provided through electric heaters, hot water batteries, boilers or other means, for the air conditioning system in periods of winter, where, well by extremely hot temperatures low or due to compression system failure, if necessary further heat the building to make sales of the center.

Flow control equipment will be installed coolant to make power changes in one or the other address, be it cooling or air conditioning. These teams will be composed of:

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mechanical control valves

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electronic valves of control

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pressure control automatons and temperature

In addition, all types of equipment will be installed required by a refrigeration installation such as valves overpressure safety, pressure gauges, purge valves, coolant tanks, etc.

Description of the drawings

For a better understanding of the invention, to Then we briefly describe a mode of embodiment of the invention, as an illustrative example and not limiting it. For this reference is made to the drawings attachments, in which:

Figure 1 shows an operating scheme in summer, while Figure 2 presents the operation in winter.

Finally, Figure 3 shows a possible general scheme of connection of the combined system.

Description of an embodiment

The combined cooling system and air conditioning consists of an air conditioning system that can cooling or heating the ambient air of a room, and a system of industrial cold, which in turn can be divided into a subsystem of positive cold and an independent negative cold subsystem or With common elements.

The air conditioning system recovers part of the energy that a priori was going to waste the industrial cold system, operating in two different modes.

To do this, the operation must be separated in two modes, one that we will call summer, in which the air conditioning has to cool the environment, and another that we will call of winter, in which the air conditioning has to heat the local.

The industrial cold system will comprise a first compressor (10), a first heat exchanger (11) in condenser functions, a first expansion valve (12) and a second heat exchanger (13) in evaporator functions. While the air conditioning system will comprise a second compressor (20), a second expansion valve (22) and two heat exchangers, one of them evaporating and the other condensing

Each of the mentioned teams can correspond in reality to a plurality of equipment located in series or parallel. Thus, for example, there may be a plurality of first compressors (10) arranged in parallel or a plurality of first exchangers (11).

As you can see in Figure 1, the mode of Summer operation is the least complex, since which performs a coolant pooling of both systems, (if any between one or both subsystems of positive cold or negative, usually the first and the air conditioning system). In addition, both systems are arranged in parallel, so that the refrigerant passes through the first exchanger (11). Is convenient to place at least two exchangers in parallel to better regulate the power and if necessary, be able to disconnect one of the two exchangers to perform the maintenance, repair of the other, or even when one of the two have enough capacity, to perform the condensate of all refrigerant.

After said first exchanger (11), and after a  reservoir (40) and a liquid pump (41), optional both, are separate the flow lines into two branches, crossing a first flow line the first expansion valve (12) and the second exchanger (13), which acts as an evaporator in the cold system industrial, before returning to the first compressor (10), while that the second flow line crosses the second valve of expansion (22) and a third exchanger (23) (depending on evaporator of the air conditioning system, and cooling the room) and go back to the second compressor (20).

For the change to winter operation, performs the opening and closing of valves so that the arrangement Schematic becomes the one corresponding to Figure 2.

In said Figure 2 both compressors are appreciated (10, 20) arranged similarly to the previous one, but with a significant variation in the arrangement of the exchangers (11, 13, 23).

After the common point, located at the exit of both compressors (10, 20) a first branch (1) carries the compressed refrigerant to the third exchanger (23) or battery of air conditioning, which instead of performing the evaporator function, performs the function of condensation, providing heat to the room instead of cooling it. This heating method can be complemented by other sources of heat such as electrical resistors, water hot, steam, solar or other energy source.

After the third exchanger (23), the fluid crosses the first expansion valve (12) and the second exchanger (13) that continue to perform the same functions as in summer mode, to return to the first compressor (10).

In short, only the third exchanger (23) It changes its operation between condenser and evaporator. For it it must be taken into account that both a capacitor and a evaporators are heat exchangers, and can work in one form or another depending on the temperature of the fluids that are exchange heat, being possible that one of the two fluids condense while the other evaporates.

It is possible to provide a first variation to this scheme to unbalance in a sense the ability to cooling and heating of both systems in winter.

If you want to increase the power of the system industrial cold, from the common point, located at the exit of both compressors (10, 20), a division of the flow is performed, the refrigerant can go through two different branches (1, 2) in Only one time.

The second branch (2) carries part of the refrigerant to the first exchanger, (11) that continues to perform the  condensation. From there the condensed refrigerant reaches the first expansion valve (12), where it meets the rest of the refrigerant. In this way it evaporates in the cold system industrial some refrigerant that has not condensed in the HVAC system, similar to summer mode. For this, in the example represented in the figures, must be crossed the lower section (3).

The refrigerant flow through this second branch (2) can be brought to a point such that it is not performed no condensation in the third exchanger (23), when the local temperature is adequate for sale and does not require air conditioning (halftime mode).

If on the contrary you want to heat more in the air conditioning system, without changing the fridges provided by the industrial cold system, the flow of refrigerant that passes through the third exchanger (23) and performs a division of the refrigerant, arriving part of the refrigerant to the first expansion valve (12) and the second exchanger (13), while the rest of the refrigerant reaches through the lower section (3) to a third expansion valve (32) and a fourth exchanger (33) that evaporates the refrigerant, using the refrigerators in something other than the cold system industrial (or discarding).

It is also possible to provide more heat to the air conditioner by external heat source.

A variant that makes the best use of the room exchanger is as follows: change the operation of the room exchanger (33), making in summer operation condense the refrigerant in parallel with the first exchanger (eleven). For this, a small change will have to be made in the connections of the elements of the invention that are considered evident to an expert in the field (place a bypass of the third expansion valve (32) that can be activated or not and the circuits and valves necessary to reorient the flow).

It can be seen in Figure 2 as the section lower (3) does not present any defined flow direction in the winter operation, but the direction of movement of the refrigerant will vary between two points before the third expansion valve (32) and to the first expansion valve (12) according to the difference in refrigerant pressure at both points.

In that lower section (3) the tank (40) where the refrigerant that passes through the tank is stored combined cooling system and liquid pump (41) mentioned above, optionally.

A schematic of the installation according to the invention, where they are represented, simplified, all the elements of the invention, and two series of valves (50, 51), preferably automatic, which allow Select the operating mode.

When the first series of valves is closed (50) and the second series of valves (51) is opened, the summer run. If the first series of valves is opened (50) and the second series of valves (51) is closed, the winter run

This scheme must be completed with the measures of usual security and maintenance in the systems of refrigeration, such as flow meters, purge valves, safety valves, pressure gauges, etc. You are considered to be measures are known by any expert in the field, in addition to being often required and set by current regulations, and not They need to be described.

For example, a connection can be installed between the suction inlets of the compressors (10, 20) to that one supports the other in case of a hypothetical failure of one of the two systems

The condensation means of the cycle can comprise one or more condensers cooled by air, water, evaporative or otherwise, outside the premises with axial type fan or inside the premises with centrifugal fan, or any equipment compatible with the precise energy source for condensation, designed in good measure for positive cooling and air conditioning systems in one of them and negative cold system for another one of them. This teams they are standard equipment that are normally installed in these installations.

In addition, and reiterating what has been mentioned above,  each of the elements of the system can be replaced by a plurality of elements of the same type placed in series or parallel.

This procedure can be done with any known refrigerant, for example refrigerants R404a, R507 or R134a.

Claims (9)

1. Combined refrigeration and air conditioning system, based on a refrigeration cycle by direct expansion of a refrigerant, characterized in that it performs the functions of industrial cooling and air conditioning system of a facility or premises, and because it comprises:

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a first and second compressor (10, 20), whose refrigerant outlet tablet is made to a common point;

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a first, second, and third heat exchanger (11, 13, 23), the second exchanger (13) being the one that exchanges heat with the medium to be cooled by the industrial cold system, and the third exchanger (23) which exchanges heat with the installation or premises;

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a first and a second expansion valve (12, 22);

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a first and second series of valves (50, 51);

and because in a first mode of operation, called summer:

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after the common point, the first exchanger (11) condenses the refrigerant, and pour the condensed refrigerant to two branches in parallel, each of them comprising an expansion valve (12, 22) and a heat exchanger (13, 23) based on evaporator, before entering the compressors (10, 20); Y

in a second mode of operation, called  winter:

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after the common point the refrigerant takes a first branch (1) and crosses consecutively the third exchanger (23) in functions of condenser, the first expansion valve (12) and the second exchanger (13) before its reintroduction in the first compressor (10);

and because: the two series of valves (50, 51) allow the transition from one mode of operation to the other, so that when close the first series of valves (50) and open the second series of valves (51) summer operation occurs, and when the first series of valves (50) is opened and the second one is closed series of valves (51) the operation of winter. 2. System according to claim 1, characterized in that, in the winter mode, and after the common point, part of the refrigerant takes a second branch (2), in which the refrigerant crosses the first exchanger (11) performing functions of refrigerant condenser, before being introduced into the first expansion valve (12). 3. System according to claim 1, characterized in that, in winter mode, after the third exchanger (23), performing functions of the refrigerant condenser, part of the refrigerant passes through a third expansion valve (32) and a fourth exchanger ( 33) of heat, before the reintroduction of the refrigerant into the second compressor (20). System according to claim 3, characterized in that, in summer mode, the third expansion valve (32) is bridged and the fourth exchanger (33) functions as a condenser in parallel with the first exchanger (11). System according to any one of claims 1 to 4, characterized in that it is completed with a liquid pump (41) between at least one exchanger (11, 23, 33) operating as a condenser and an expansion valve (12, 22, 32). System according to any one of claims 1 to 5, characterized in that at least one of the compressors (10, 20) corresponds to a plurality of compressors located in series or parallel. System according to any one of claims 1 to 6, characterized in that at least one of the heat exchangers (11, 13, 23, 33) corresponds to a series of exchangers arranged in series or parallel. System according to any one of claims 1 to 7, characterized in that it comprises a connection between the suction inlets of the compressors (10, 20). 9. System according to any of claims 1 to 8, characterized in that in the winter mode the air conditioning system comprises other sources of heat.