HEAT-CARRYING FLUID LOOP FOR REFRIGERATION SYSTEM

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. provisional patent application No. 63/636,194, filed on Apr. 19, 2024.

TECHNICAL FIELD OF THE INVENTION

The present disclosure relates to a refrigeration system including at least one separate heat-carrying fluid loop, preferably with reservoir, other than the main refrigeration loop with the main refrigerant flowing therein. The separate heat-carrying fluid loop with reservoir typically includes at least a cold (to improve condensation of the main refrigerant during pre-determined constraining environmental conditions) or warm (to separate recuperation units from the main loop) fluid reservoir.

BACKGROUND OF THE INVENTION

Traditionally, in typical refrigeration systems, it is well known to desuperheat the refrigerant coming out of the compressor units to lower the refrigerant temperature down to condensation temperature. Once at the condensation temperature, it is needed to further cool down the refrigerant temperature to essentially liquefy all the refrigerant before it reaches the evaporator units downstream of an expansion unit to make the low temperature refrigerant gaseous again. This is typically done using a heat exchanger, such as a condenser or a heat reclaim unit to warm up the air inside a building, especially during chilled or cooled evenings and nights, or during winters.

To improve the efficiency of the evaporator units, it could be advisable to even further cool down, or subcool the refrigerant temperature, and use that latest energy extracted from the refrigerant to heat up another fluid that needs that energy. As the subcooling process is not always possible, since it depends on many parameters such as external conditions, required capacity of the refrigeration system, etc., it is usually rather expensive to build-in the equipment required for such process, especially when using the same main refrigerant.

However, in specific pre-determined combination of operating and environmental conditions, there is a need for more heat to be removed from the main refrigerant to cool it down and thereby increase the efficiency of the overall system. For example, when the outside temperature is relatively high, such as in summer peak periods, the cooling down of the superheated refrigerant fluid cannot be efficiently done using typical condensers, gas coolers or the like, and although some heat could be reclaimed to dehumidify inside ambient air via an air conditioning system or the like, there is still a need to remove further heat from the refrigerant.

Also, typical installed refrigeration systems use a refrigeration unit with an outside air condenser. This type of system requires a large amount of refrigerant due mainly to the use of an air-cooled condenser which, in order to control the condensation pressure to a minimum of operation, must be drowned (entirely filled, saturated) with liquid refrigerant during temperate and cold periods.

The use of refrigerant reservoirs is imperative considering the fluctuation of the amount of refrigerant required to flood the condenser during temperate and cold periods outdoors.

In addition, the use of a refrigeration system requires a lot of piping filled with liquid and gaseous refrigerant in order to connect all the evaporators on site that could be at appreciable distances from the refrigeration system (room), thus increasing the amount of refrigerant.

Heat reclaim via the refrigeration system is achieved by adding hot liquid and gaseous refrigerant piping to the various stations requiring heat via heat exchangers to heat up different fluids such as water or air, thus increasing the amount of refrigerant and the risk of leakage by this added piping.

Accordingly, there is a need for a refrigeration system having at least one separate heat-carrying fluid loop, preferably with reservoir.

SUMMARY OF THE INVENTION

It is therefore a general object of the present disclosure to provide a refrigeration system having at least one separate heat-carrying fluid loop, preferably with reservoir, that obviates the above-noted drawbacks and problems

An advantage of the present invention is that the refrigeration system has a separate (independent loop, but could be the same type of fluid/refrigerant) fluid used for the heat recuperation system via a coil located in an air conditioning system when air heating or dehumidification is needed, than the main refrigerant already running through another heat exchanger such as a gas-cooler, condenser or the like. The fluid flowing into each separate heat-carrying fluid loop is typically a water-based fluid (such as glycol or the like) to help reducing the cost of the refrigerant itself, and/or the manufacturing and maintenance costs of the separate heat-carrying fluid loop. Depending on the specific use of the separate heat-carrying fluid loop, it could be either a warm water loop or a cold water loop, although one loop of each could be independently connected to the main loop of the refrigeration system if needed. Each heat-carrying fluid preferably contains a good portion of water (such as glycol water or the like) circulating in a relatively small quantity (because of a small loop, especially when compared to the size of the main loop of the refrigeration system).

Another advantage of the present invention is that the refrigeration system, by having fluid reservoir(s) to receive from and/or transfer heat to other equipment(s), via the respective heat capacitor fluid, is capable of cooling any refrigerant or fluid at any time. These fluid reservoirs can also be cooled down at any time (simultaneously and/or independently, when pre-determined outdoor/indoor conditions occur) after storing heat therein. Typically, the heat capacitor fluids are respective heat-carrying fluid used in the respective loop.

A further advantage of the present invention is that the above fluid reservoir(s) can also be used as real-time heat exchanger(s), depending on the needs, due to the operation and/or environmental conditions.

Another advantage of the present invention is that the refrigeration system, when using a cold reservoir, allows to momentarily operate the compressor unit back at a ‘normal’ temperature range to meet predetermined efficiency ratio with the refrigeration system operating at high capacity. The ‘cold or frigorific production’ of the evaporator units of the main refrigeration loop is increased. And this implies that the work to be performed by the compressor units is reduced (as the pressure levels/ratios are reduced), with a reduced compressing ratio, a more ‘normal’ (not at the extreme) mechanical working effort from the compressor units, and an improved lubrification thereof. This further helps to increase the life cycle of the compressor units while reducing the quantity and complexity of maintenance required. And the overall improvement is the increase of the coefficient of performance (COP) of the refrigeration system, due to the lowering of the condensing temperature of the main refrigerant, via a lower temperature of the separate independent loop (kept cold via the cold reservoir), and the lowering of the refrigerant gaseous pressure at the output of the compressor unit.

Yet another advantage of the present invention is that the independent separate fluid cooling loop could further be used to preheat, in real-time (immediate need), the city water supply, or to warming up an independent reservoir to have lukewarm water ready-to-use or to pre-heat or warm other fluids (gas and/or liquid) or other equipment(s).

Yet further advantages of the present invention are:

• • Significant reduction in the amount of primary refrigerant in the refrigeration system for equivalent and greater refrigeration (cooling);
  • Reduced risk of primary refrigerant leaks since there is much less piping containing liquid or gaseous refrigerant for both heat reclaim and evaporators connections;
  • Reduced risk of leakage at the various heat transfer exchangers by using a warm (or tempered, as opposed to hot) secondary fluid that reduces thermal stress;
  • Allows to accumulate cold (reservoir) during periods when in use and/or external conditions are reduced or less extreme (e.g. end of day, evenings, nights) in order to make use of this ‘bank’ (reservoir) of cold to lower or cool the temperature of the secondary fluid used to extract (or remove) heat from the refrigeration system(s);
  • Refrigeration systems never operate in extreme conditions, regardless of outdoor conditions (e.g., such as heat waves in the summer); and
  • Reclaim cold by heating a fluid such as water or air via the secondary fluid in the cooling loop, such that both cold and heat are recovered (reclaimed) at the same time, for a doubled beneficial effect.

According to an aspect of the present disclosure there is provided a refrigeration system having a main loop operating with a main refrigerant and including a main tubing extending between a compressor unit and an expansion unit upstream of an evaporation unit, the system comprising:

• • a (separate) cooling loop having a first (heat-carrying) fluid circulating therein using a first pump unit and having a first heat exchanger unit being connectable to the main tubing via a heat exchange interface to cool down the main refrigerant, the first fluid running to a cooling heat exchanger unit located downstream the first heat exchanger unit to cool down the first fluid.

In one embodiment, the heat exchange interface includes the first heat exchanger unit and a first portion of the main tubing connecting to the first heat exchanger such that the main loop is directly connected to the first heat exchanger unit to cool down the main refrigerant.

Conveniently, the first heat exchanger unit is a cooling reservoir filled with a first heat capacitor fluid, the cooling reservoir being a heat accumulator selectively storing heat received from the main refrigerant.

In one embodiment, the heat exchange interface further includes an intermediate loop having a second (heat-carrying) fluid circulating therein using a second pump unit, a second heat exchanger unit and a first (cooling) valve arrangement unit, the first valve arrangement unit selectively connecting a second portion of the main tubing to the second heat exchanger unit to transfer heat from the main refrigerant to the second fluid, the intermediate loop connecting to the first heat exchanger unit.

Conveniently, the intermediate loop further includes an intermediate exchanger unit and a second (intermediate) valve arrangement unit, the second valve arrangement unit selectively allowing the second fluid to flow between the second heat exchanger unit and the intermediate exchanger unit, the second valve arrangement unit further selectively allowing the second fluid to bypass the intermediate exchanger unit and flow between the second heat exchanger unit and the cooling reservoir.

In one embodiment, the second valve arrangement unit further selectively allows the second fluid to successively flow from the second heat exchanger unit to the intermediate exchanger unit, and to the cooling reservoir before coming back to the second heat exchanger unit.

Conveniently, the cooling loop includes a third valve arrangement unit connecting downstream of the cooling reservoir and upstream of the cooling heat exchanger unit, the third valve arrangement unit selectively allowing the second fluid to flow between the cooling reservoir and the intermediate exchanger unit.

Alternatively, the second valve arrangement unit further selectively allows the second fluid to flow between the cooling reservoir and the intermediate exchanger unit.

In one embodiment, the intermediate exchanger unit is an intermediate reservoir filled with a second heat capacitor fluid.

Conveniently, the second heat capacitor fluid is the second fluid.

Alternatively, the intermediate loop further includes an intermediate reservoir filled with a second heat capacitor fluid, the intermediate reservoir being a heat accumulator selectively storing heat received from the second fluid.

In One Embodiment, the First Heat Capacitor Fluid Is the First Fluid.

In one embodiment, the cooling loop further includes a cooling reservoir filled with a first heat capacitor fluid, the cooling reservoir being a heat accumulator selectively storing heat received from the first fluid.

Other objects and advantages of the present invention will become apparent from a careful reading of the detailed description provided herein, with appropriate reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the disclosure will be described by way of examples only with reference to the accompanying Figure, in which:

FIG. 1 is a simplified schematic diagram of a refrigeration system in accordance with multiple embodiments of the present invention, showing different independent fluid loop(s) with multiple valve arrangements depending on the operating and/or environmental conditions of the system.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, there is shown multiple embodiments of a refrigeration system 10 in accordance with the present invention, as typically used in a supermarket, grocery store or the like (where such typical refrigeration systems have a relatively large the main refrigerant loop/circuit which is and becomes expensive when maintenances or repairs are needed). The refrigeration system 10 of the present invention has a main (or first) loop 20 operating with a main refrigerant and including a main tubing 22 (and 22″ as described hereinbelow) extending between a compressor unit 24 and an expansion unit 26 upstream of an evaporation unit 28 to cool down a fluid represented by arrow 29. The system 10 typically comprises a second (or cooling) loop 30, separate (independent) from the main loop 20 in such it has a first heat-carrying fluid circulating therein using a first pump unit 32. The cooling loop 30 includes a first heat exchanger unit 34 being connectable to the main tubing 22 via a heat exchange interface 12, represented by long stippled lines 22′ to cool down the first refrigerant. The first fluid also runs or flows to a cooling heat exchanger unit 36 located downstream the first heat exchanger unit 34 to cool down the first fluid by warming up another fluid represented by arrow 38. The cooling heat exchanger 36 could also be any geothermal network or the like that absorbs heat, such as when some air needs dehumidification, etc. The heat-carrying first fluid used in the cooling loop 30 is preferably a water-based fluid/refrigerant, such as glycol water or the like, especially to lower maintenance cost and complexity.

In a first embodiment, wherein the heat exchange interface 12 typically includes the first heat exchanger unit 34 and a first portion 22′ of the main tubing 22 that connects to the first heat exchanger unit 34 such that the main loop 20 is directly connected to the first heat exchanger unit 34 to cool down the main refrigerant.

Typically, the first heat exchanger unit 34 is a cooling reservoir filled with a first heat (sensible heat capacitor when a same fluid state is considered or could also be latent heat capacitor when a phase-changing condition of the fluid is considered) capacitor fluid, preferably the first fluid, and essentially becomes a heat accumulator that selectively stores heat received from the main refrigerant, by warming the first fluid filling the cooling reservoir 34.

In a second embodiment, the heat exchange interface 12 further includes an intermediate (or third) loop 40, separate (independent) from both the main loop 20 and the cooling loop 30 in such it has a second (heat-carrying) fluid circulating therein using a second pump unit 42. The intermediate loop 40 also includes a second heat exchanger unit 44 and a first (cooling) valve arrangement unit 46. The first valve arrangement unit 46 selectively connects a second portion 22″ of the main tubing 22 to the second heat exchanger unit 44 to transfer heat from the main refrigerant to the second fluid, as illustrated with solid line connections 22″ in the valves 46, the intermediate loop 40 connects to the first heat exchanger unit 34 (or preferably cooling reservoir). Alternatively, the first valve arrangement unit 46 selectively connects the main loop 20 directly to the first heat exchanger unit 34 to cool down the main refrigerant, as explained hereinabove in the first embodiment and illustrated with long stippled line connections 22′ in the valves 46.

Typically, the intermediate loop 40 further includes an intermediate heat exchanger 48 (or typically an intermediate reservoir filled with a second heat (sensible heat capacitor when a same fluid state is considered or could also be latent heat capacitor when a phase-changing condition of the fluid is considered) capacitor fluid, preferably the second fluid) and a second (intermediate) valve arrangement unit 50. The second valve arrangement unit 50 selectively allows the second fluid to flow between the second heat exchanger unit 44 and the intermediate reservoir 48, as illustrated with stippled line connections in the valves 50a and 50c. The second valve arrangement unit 50 further selectively allows the second fluid to bypass the intermediate reservoir 48 and flow between the second heat exchanger unit 44 and the cooling reservoir 34, as illustrated with solid line connections in the valves 50a and 50b, and via the second pump unit 42.

Typically, the second valve arrangement unit 50 further selectively allows the second fluid to successively flow from the second heat exchanger unit 44 to the intermediate reservoir 48, and to the cooling reservoir 34 before coming back to the second heat exchanger unit 44, as illustrated with stippled, solid and dotted line connections in the valve 50a, 50b and 50c, respectively, and via the second pump unit 42.

Typically, the second valve arrangement unit 50 further selectively allows the second fluid to flow between the cooling reservoir 34 and the intermediate reservoir 48, as illustrated with stippled line connection in valve 50a and dotted line connections in the valves 50b and 50c, and via second pump unit 42.

Typically, the cooling loop 30 includes a third valve arrangement unit 60 connected downstream of the cooling reservoir 34 and upstream of the cooling heat exchanger unit 36 to selectively allow the first fluid to flow between the cooling reservoir 34 and the intermediate reservoir 48, as illustrated with stippled line connection in the valves 60, and to selectively flow between the cooling reservoir 34 and the cooling heat exchanger unit 36, as explained hereinabove in the first embodiment and illustrated with solid line connection in the valves 60, and via the first pump unit 32.

For the first embodiment used as an example in a typical grocery store, supermarket or the like, the cooling reservoir 34 of the cooling loop 30 would generally be filled with the first fluid at a “cold” temperature typically varying between about 60° F. and 115° F. (about 15° C. and 45° C.), such that the main refrigerant coming out of the compressor unit 24 at a “hot” temperature typically above about 180° F. (about 85° C.) can easily be, at least partially, cooled down when flowing into the first heat exchanger unit 34 when needed (via first portion stippled line 22′). And similarly, when the conditions would be favorable, such overnight (at cooler/colder outdoor temperatures) when an air conditioning facility or the like other heat exchanger can be used, the first fluid coming out of the first heat exchanger unit 34 can easily be, at least partially, cooled down when flowing, via the first pump unit 32, into the cooling heat exchanger unit 36 typically via a relatively colder air flow 38 from an air conditioning unit or the like.

Similarly, for the second embodiment, when the cooling reservoir 34 of the cooling loop 30 would generally be filled with the first fluid at a “cold” temperature typically varying between about 60° F. and 70° F. (about 15° C. and 20° C.), while the intermediate reservoir 48 of the intermediate loop 40 would generally be filled with the second fluid at a “warm” temperature typically varying between about 105° F. and 115° F. (about 30° C. and 45° C.), such that the main refrigerant coming out of the compressor unit 24 at a “hot” temperature typically above about 180° F. (about 85° C.) can easily be, at least partially, cooled down when flowing into the second heat exchanger unit 44 when needed (via second portion solid line 22″). And similarly, when the increasing temperature of the second fluid becomes too warm, the second fluid coming out of the second heat exchanger unit 44 can easily be, at least partially, cooled down when flowing into either the intermediate reservoir 48 or the first heat exchanger 34 (or preferably cooling reservoir 34), or successively one after the other. And, ultimately, the first fluid coming out of the first heat exchanger unit 34 can easily be, at least partially, cooled down when flowing into the cooling heat exchanger unit 36, when applicable as hereinabove described.

Although not illustrated in FIG. 1, it would be obvious to one skilled in the art that other heat exchanger unit(s) of any type(s) well known in the art (such as a desuperheater unit, a condenser unit for partial heat reclaim or the like) could be operatively connected to the main tubing 22 of the main loop 20 to simultaneously and/or alternatively be used to cool down the temperature of the main refrigerant, depending on the specific conditions of operation (percentage of maximum capacity with environmental conditions) of the refrigeration system 10, without departing from the scope of the present invention.

Similarly, although not illustrated in FIG. 1, it would be obvious to one skilled in the art that other arrangement(s) of other fluid loop(s) could be operatively connected to either one, or both of the cooling 30 and intermediate 40 loops, and especially to the respective cooling 34 and intermediate 48 reservoirs, to share the heat capacity of the reservoirs 34, 48 to either warm up or cool down the temperature of their respective fluid when suitable and applicable depending on the specific conditions, without departing from the scope of the present invention. To this end, any additional heat exchanger, such as heat exchanger 70 illustrated in stippled lines, could be integrated within anyone or both the cooling loop 30 or the intermediate loop 40 (although only shown in the intermediate loop 40 for clarity purposes) to dissipate (or provide) heat elsewhere, within or outside of the refrigeration system 10, as a fluid represented by arrow 72.

Although the two first 34 and/or intermediate 48 heat exchangers could be any well-known typical heat exchangers, they can also be heat storage reservoirs filled with a respective heat capacitor fluid. When the first heat exchanger 34 and/or the intermediate heat exchanger 48 are filled with respective water or the like (sensible or latent) heat capacitor fluids, they are used as closed-type reservoirs (identified with stippled line filling in FIG. 1), with no water running into or out from the respective reservoir 34, 48. Alternatively, the reservoirs 34, 48 could be filled with the first or second fluid, respectively, such that the reservoirs 34, 48 would become open-type reservoirs (identified in FIG. 1 with a partial stippled line of the respective loop that runs there through), with the respective first or second fluid (only sensible heat capacitor fluid in this case) running there through and being therefore part of the cooling 30 and intermediate 40 loops, respectively. When the two first 34 and/or intermediate 48 heat exchangers are not reservoirs, such reservoirs could be located anywhere else along the respective cooling 30 (as illustrated for example with reservoir 74 in stippled lines) and/or intermediate 40 loops (only shown in the cooling loop 30 for clarity purposes).

Although the present disclosure has been described with a certain degree of particularity and by way of an illustrative embodiment and examples thereof, it is to be understood that the present disclosure is not limited to the features of the embodiments described and illustrated herein, but includes all variations and modifications within the scope and spirit of the disclosure as hereinafter claimed.