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Table 68 : While Figures A are warnings for the construction of cylindrical cavities, Figures C and E show that at the ends of cylindrical heat exchangers, heat exchange elements can be added consisting of circular gaps with surfaces that are not only flat but also curved to better withstand internal and external pressure.  Figures B and C are water- refrigerant heat exchangers with the latter occupying the environment of the impeller, Figures D and E are air- refrigerant heat exchangers with the refrigerant occupying the interior of the cylindrical cavity, but whereas in Figure D the air flow exits from the scroll at the bottom, in Figure E the impeller is made so that the air enters and exits from the upper central part of the heat exchanger. Fig. F refers to the fact that when an impeller also sweeps the outer surface of a cylindrical cavity, a ring of baffles attached to the cavity or outer casing of the heat exchanger can push a rotating air flow in a linear direction. Figure G shows a refrigerant heat exchanger - air, water or smoke, made to work in a horizontal position, whose heat exchange elements are hollow disks with labyrinth-type inserts. This configuration is suitable when it is feared that the flow will bring with it substances that could settle on the heat exchange surfaces.

Table 69 : SHALLOW GEOTHERMAL IN THE FORM OF HEAT EXCHANGE WITH THE GROUND USING AIR AS THE HEAT TRANSFER FLUID. In heating mode, this function allows not only to extract heat from the ground, using an air flow as a heat transfer fluid, but also derives an additional source of heat from the condensation of moisture that the contact with the ground transmits to the air flow. Obviously, the underground air must not be fed into the living space, but must be passed through a heat pump or a very efficient air-to-air or air-to-water heat exchanger. This is a more efficient and environmentally friendly alternative to building plants by depositing and leaving kilometres of plastic pipe in the ground after excavation. The figures A show two modes of condensation, in figure A1 on the left, the usual procedure is shown, improved through a continuous circulation of steam through the heat exchanger performed with a fan. This increases the flow rate of the steam on the surfaces, improving the heat exchange. The second figure A2, on the other hand, shows the application of the new physical condensation process for which a patent has been applied for. In the mode drawn, there is no need for a liquid-vapour separator. Fig. A3 shows that instead of a rigid pipe passing through the coils of the inner spiral as seen in fig.A1, one or more flexible pipes can be passed between the coils to the bottom of the exchanger. Fig. B, without the need for major excavations, suggests that heat exchange with the ground can be achieved by constructing an air flow duct on the inside or outside of the wall of a building's perimeter cavity. Figure C suggests doing geothermal with groundwater from an aquifer vein, taking it upstream and feeding it back downstream of the vein after heat exchange. I would like to mention that water veins are commonly found at a depth of a few metres and were searched for when wells were dug and constructed by hand. Fig. D, D2 shows possible low solid brick walls to form a cavity in which a flow of air could flow from a release point to a withdrawal point, covering the area of a rectangular plot of land, for example, even several metres below a single-family house or in an adjacent free area even outside the perimeter of the building. Fig. E2 imagines filling an overburden with large stones in such a way that a flow of air can flow through the space between them, and in order to give this structure more stability and to channel the flow of air, one imagines placing layers of concrete between them. In this way, the thermal inertia of the rock mass used can also be exploited. It is advisable to use strong concrete pipes that are difficult to crush, in order to channel the outflow and return of air flows. Fig E A flow of air is pushed downwards and rises between the rocks, up to the crawl space, an empty space under the floor of the house. Fig D2, low walls of bricks and large stones with a concrete cover create a zig-zag path under a dwelling or contiguous ground. Figure F - L an excavation machine makes large holes in the ground. Vertical probes are placed in the holes, which are connected by horizontal ventilation sections or with a slope between one probe and the other in order to keep the ducts clean by allowing impurities and condensation water to fall to the bottom of the probes. Fig. L shows a mesh cylinder placed in the hole to prevent the penetration of soil and mud. After placing some stone at the bottom of the pit, a vertical plastic pipe is inserted and more stone is placed in the space between the netting and the pipe. Subsequently, a concrete box divided into two halves is placed on top to allow for the insertion of ventilation pipes before being covered with soil. The airflow descends through the stone and rises through the central pipe. Then a concrete box divided into two halves is placed on top so that the ventilation pipes can be inserted before being covered by the soil. The air flow descends through the stone and up the central pipe.

Table 70 a : The first images at the top left and the two figures A and B are just disquisitons about cylinrical cavities of dr heat exchanger. It is explained that, for heat exchangers where the external side of its cylindrical cavity is also swept by the impeller, the inlet and outlet of the fluids may only be possible from the same end of the cavity, and in that case, it can be an excellent solution for the internal spiral to be made up of a single tube or multiple concentric tubes. It is also possible to insert two or more identical spirals of tube within the same cavity. For example, in the case of the new condensation process, one coil discharges the refrigerant vapor to be condensed along with the recirculation liquid, while the liquid for recirculation enters through the other. The use of multiple spirals in the same cylindrical cavity, however, generates more than one path for the fluid within the cavity and I don't see an advantage from this. fig. C this time there is a concentric series of cylindrical cavities interspersed with wide spirals for the passage of air flows driven by a centrifugal fan. This scheme can be realised not only in a circular form, but also in a rectangular one. A scheme similar to a cylindrical interspace heat exchanger with a heat exchange element consisting of a cylindrical interspace with a spiral insert. It could be made for an industrial mixer heated or cooled by a heat pump or by a hydronic heat exchanger. Fig C' , Flat panels or rectangular structures, even open on one side, that are cooling or heating, can also be made with labyrinth-shaped inserts. Figs I, J, K, L are heat pump system layouts with cold or hot water storage tanks equipped with internal refrigerant-water heat exchangers consisting of a spiral formed by two concentric tubes squeezed between two cylindrical surfaces, so that water flows both around and inside the spiral. They are used to power hydronic heating or cooling systems with radiant surfaces or fan coils. In figure I, the circulation of the refrigerant liquid through the pump serves to create a current that transports the refrigerant vapor formed towards the separator. In fig. J, there is an optional circuit with a fan that circulates the refrigerant vapor to promote the condensation of the vapor. Figures K and L depict the same installation functioning as a condenser for hot water production and as an evaporator for cold water production. Fig. M shows the circuitry for the application of the new condensation process for hot water production.

Table 70 b : It is possible to connect an additional condenser for the production of domestic hot water to a heat pump system for heating and cooling, which can operate in conjunction with the system's condenser, be excluded from it, or temporarily take its place when the main condenser (e.g. for domestic heating) is not in use at the time. When, on the other hand, in the warm seasons, the water contained in the tank is already hot, the condenser function can return to the main exchanger which, for example, dissipates heat to the outside. The scheme is in essential form for understanding and obviously some valve needs to be added.

Table 70 c : In this example, the tank has two spiral heat exchangers both located between the same two cylindrical surfaces. The first one, which has a large diameter, facilitates heat exchange between the internal water of the tank and an air flow coming from a thermal solar panel installation, while the second one, with a small diameter, enables thermal exchange between the water in the tank and the refrigerant fluids of a heat pump system and as such, it could perhaps even be connected to an air conditioner of sufficient size, as shown in the figure. There is then a third heat exchanger with concentric circular profiles that serves to transfer heat from the tank to the home's air. While the device in the figure is designed to use the ordinary condensation process, the one illustrated in the window to the side is designed to utilize the new condensation method. In this latter case, a third tube is provided for the return of the non-condensed refrigerant vapor. This can happen when the thermal power of the system is increased and, with a larger volume of steam to be condensed, part of it may pass through the condenser without being condensed. To remove this uncondensed vapour, I thought of a float in the liquid-vapor separator with an electric control that opens a valve allowing access to the compressor suction or to the evaporator inlet.

Table 71 : Attention, this dr heat exchanger may still look identical to many others already shown but it is different. The heat exchange element is somewhat related to cylindrical cavities and the surface with concentric circular grooves but it is the insert that makes it radically different. This insert is indeed an impeller made up of one or more rotating concentric cylinders that extend like a barrier within these cylindrical grooves of the heat exchange surface stopping a short distance from the inner end of the cylindrical cavities. It can be designed to operate in a vertical or horizontal position. The inside of this cavity is divided into two environments by this barrier, so that the fluid injected at the end of one of the two environments must cross the edge of the inner cylinder to reach the other side of the same end. Since the outer surface opposite to these heat exchange elements is also exposed to the fluid moved by the other impeller, this heat exchanger should prove to be very effective. It is recommended that, in the function of the condenser, the horizontal working position and the new condensation process be adopted as illustrated in figures B, C, D, E. What produces a pressure differential for the circulation of a fluid through the exchanger can be a pump if it is a liquid fluid, but generally, it is the rotation of the impeller that should produce sufficient pressure differential in moving the fluid from the center to its edge, and to enhance this effect, at the edge, the impeller may have a crown of deflectors.

Table 72 : BACK TO THE SUBJECT OF AIR FLOW GEOTHERMAL ENERGY.
Fig. A shows how to take advantage of a soil configuration, how it can be a hill, to facilitate the construction of a thermal battery based on a large mass of earth and rock by facilitating the necessary excavation and construction of air ducts capable of exchanging heat and collecting moisture to condense for further heat by means of underground air ducts made of porous natural materials. The idea behind Fig. B is that the ventilation air is first heated or cooled by a first heat exchange with a part of underground air flow, and then, to reach the desired temperature by a subsequent second heat Exchange, via a heat pump with the other part of the ground air flow. The heat pump integrated in this heat exchanger in turn exchanges heat with the underground air flow, but possibly not after the first heat exchange has already altered the temperature of the ground air, but if the flow rate allows it, simultaneously so as to act with maximum efficiency. Figures C and D show how spiral air paths can replace an impeller in various stages of implementation of this device. Figure F shows a possible plant layout of this airflow geothermal heat pump system, in which evaporator and condenser are located in two different units.

Table 73 :ALTERNATIVE SCHEMA OF ABSORPTION CONDITIONING WITH WATER AND AMMONIA SOLUTION SUPPORTED BY THERMAL SOLAR AIR FLOW AND INDIFFERENT TO HOT CLIMATIC CONDITIONS.
In this description, there is no compressor in the refrigeration fluid circuit, therefore it represents an absorption system. The special compressor represented acts on the air of the solar thermal circuit, which constitutes the heat source of the generator.

Table 74 : The evaporation of water in dry summer air, absorbs heat, producing coolness but it also makes the air more humid. In this proposal, the air made humid is expelled after cooling the water in the interspace, beyond the cylindrical heat exchange surface. The air flow that is pushed into the spiral inside the cylindrical cavity is cooled without becoming more humid. It should be noted that the water must not evaporate beyond the amount that turns into a saturated solution, otherwise there will be intense limestone deposits on the heat exchange surface. To avoid this, it is necessary to identify a minimum flow rate that depends on the degree of evaporation, which in turn depends on the air temperature and relative humidity. This means that part of the water must reach the bottom of the exchanger and be disposed of by either reusing it for watering or returning it to the well. In the second figure, the former device also incorporates a storage tank, covered with thermal insulation, to acquire greater thermal storage capacity while the spiral is designed to condense or evaporate refrigerant. The condensation mode considered ideal is the new condensation process because the ordinary mode would be too slow. When the outside air temperature is no longer deemed favourable, the impeller is stopped and the heat exchange of the refrigerant fluid continues in the cavity by means of the pump on the recirculation circuit, with the hot or cold water contained in the tank.

Table 75 : Apart from economic considerations, using air instead of water as a heat transfer fluid for solar thermal panels offers a unique possibility. Water is incompressible but air is not, and when air is compressed, its temperature increases. The compression of a mass of air that, due to the season or the late afternoon hour, a solar thermal panel installation fails to provide more than 60°C = 333°K, would raise its temperature to 406°K = 133°C, sufficient to operate an absorption heat pump, continue a heat exchange, or make industrial applications. Compressing air, however, has a high energetic and economic cost mitigated by the fact that we start from air already heated by the solar thermal system, and proceeding as illustrated in fig. A with a normal compressor and a pressure reducing valve would not compensate for the heat gain because the energy spent for the compression of the air is, from a purely kinetic point of view, completely lost after the pressure reducing valve or expansion valve, referred to generically in this work as valve R, with R intended as resistance to flow. The compressed air that passes through a heat exchanger exits cooler, and the decrease in pressure due to its contraction from cooling is not significant. Therefore, when lowering the pressure of the outgoing air, it is advisable to recover its kinetic energy due to the pressure rather than just wasting it. In hydroelectric reservoirs it is sometimes possible to pump the water back into the dam to reuse its potential energy at a later time. In this case, the dam is equipped with turbines to generate energy from falling water and pumps to lift it into the reservoir. The shape of these pump and turbine impellers can be quite similar. If, absurdly, one were to suppose to pump water up with a pump and let it fall into a turbine, then if purely conjecturally, one were to disregard all losses, the effect would be null because the energy needed for one would be supplied by the other. However, in reality, the turbine could only compensate for a part of the energy required by the pump, but what interests us is that the water from the dam, upon exiting the turbine, retains a residue of its potential energy. This means that if we imagine the dam as a heat exchanger and the pump as the centrifugal compressor, the turbine acts like a pressure reducing valve or expansion valve, with the difference that it has recovered some of the energy. In doing this, it is advisable to place the compressor impeller on the same axis of rotation as the impeller that acts as a turbine, so that it can work together with the electric motor to rotate the common axis of rotation by means of the recovered kinetic energy. The residual unrecaptured kinetic energy can be used to circulate the airflow through the circuit of the solar thermal panels. The compressor illustrated in Figures B and C is based on this principle. The two coaxial impellers have different diameters because, as mentioned, the outgoing air must retain a residual energy necessary for its circulation through the assembly of solar panels. Two impellers coupled into one sharing the same scroll, as shown in Figure D 7, is not suitable; each impeller must be in its own scroll, as shown in Figure D 8, otherwise there would be parasitic air flows from the larger to the smaller one. Furthermore, the two coupled scrolls also have different widths, so that the airflow exiting from the exchanger is faster when passing through the turbine and strikes the turbine blades more effectively. Regarding the cylindrical cavities of the heat exchangers, the impeller sweeps over the external side of the cylindrical space, and the fluid pumped at the bottom of the space must be able to return without the need for a duct external to the surface of the space. In the case proposed in figures E and F, the interior space of the cylindrical cavity is divided into two areas by a cylindrical surface that comes close to the bottom of the space. By crossing the edge of this surface, the fluid can return by ascending the other side of this cylinder. The inserts of this cavity are therefore two spirals positioned on each side of this cylindrical surface.

Table 76 : These air-air or air-water heat exchangers differ and are therefore alternative to those explained in the first part of the site and for which a patent was applied, they are not actually made up of a spiral with three or four concentric tubes, but from a spiral made up of a single-tube or two concentric-tube clamped between two cylindrical surfaces. Here, between figures A and G, it is proposed to realise a monobloc heat pump system consisting of two cylindrical exchangers lowered one inside the other but separated by thermal insulation such that one constitutes the condenser and the other, the evaporator of the system. In Figures H and I, however, it is proposed that the internal exchanger of the packaged system for air conditioning be a cylindrical cavity.
 

Table 77 : Figures A to H are hypothesis-based reasoning for understanding the operation of this energy recovery centrifugal compressor. It is worth returning only to figure G to understand that no matter what speed we wanted to give the centrifugal compressor, as designed, it would be irrelevant and that, despite the air being pressurized in the heat exchanger, the circulation in the rest of the circuit occurs only due to the effect of the applied centrifugal fan E. Instead, in the adjacent figure H, there is no need for the fan E because it is due to the difference between the diameters of the scrolls and the impellers that the device can generate head and thus circulation in the rest of the circuit, and since this solution also sends pressurized air through the heat exchanger, this is the correct form of this device but as mentioned in the previous table, it may be necessary to reduce the thickness of the part that recovers energy by lowering the pressure of the outgoing air. Another thing to consider is that it is the peripheral speed of the impeller that determines the pressure generated; therefore, in a compressor with a smaller diameter, at the same peripheral speed at the edge of the impeller, there will also be less friction because there is less internal surface inside a smaller scroll. Figure X5 shows us a theoretical and a practical diagram of an air dryer made with this compressor. The simultaneous compression and cooling of the air causes the condensation of the moisture contained in the air, similar to a heat pump dehumidifier (which, unlike this, does so without compressing the air but condensing it on cooler surfaces), but with a simpler machine. The uses are various, such as dehydrating food to make dried fruit, accelerating the drying of wood, drying waste to facilitate its incineration, in the paper industry and other applications. While the figures N remind us of tanks with exchangers made up of a spiral tightly placed between two cylindrical surfaces, indicating that it can be found both inside and outside the tank, the figures O explain that the spirals tightly placed between the cylindrical surfaces can be two or more, twisted into one another. The U figures instead explain that, for this type of heat exchanger, which is very efficient in heat exchange between water and air, it is not mandatory to be wrapped around or located inside a tank, a tank that, it is worth remembering, is suitable to function as a thermal accumulator. The other figures show examples of air flow solar systems, figure P shows one not equipped with the energy recovery compressor, while figures P, W1, W3 show various system configurations including this compressor.
I do not recommend the solution to fig. Z because a hazardous fluid, such as refrigerant fluid, which is usually under pressure, is safer enclosed in a tube rather than in a gap between two cylindrical surfaces.

I thought I had found a new solution even in the field of elastocaloric heat pumps, but I realized that it still doesn’t work. However, upon request, I could return to work on it.

If you like this work, let's try not to let it sit in a drawer for twenty-thirty years, and if you're thinking about a study on prototypes, I am available to work on it for you. Unfortunately, to be honest, I am not graduated nor do I speak English perfectly.

You will find the tables reproduced in higher resolution at the following address:

https://drive.google.com/drive/folders/1wHPh3QqZ-666fSXH0x8vCSA-L472bYMU?usp=drive_link

WHAT IMPROVEMENTS CAN THE WORK DESCRIBED HERE BRING TO HEAT PUMP SYSTEMS 

 With a more efficient condensation and/or evaporation process, two things can be done. Either the thermal power is increased while maintaining the same efficiency, or the advantage is taken to lower the condensation pressure (raising its temperature) and/or raise the evaporation pressure (lowering its temperature) in order to reduce the pressure difference between the condenser and evaporator, which reduces the strain and consumption of the compressor, thereby increasing the efficiency of the system.

It must be said that the new condensation and evaporation processes described here are not very suitable for occurring in today's finned tube heat exchangers (finned pack heat exhangers), which are today almost the only ones used in thermal exchanges with air, and perhaps that is why other inventors have not perceived them. Moreover, every type of physical process is more suitable for certain environments of heat exchangers than for others, but the many illustrations contained here describe all cases.

The heat exchangers with concentric circular grooves present in tables 17b, 50, 51, 66, 67a, 67b, 71, 72, 73 are suitable for both the new evaporation process and an improved form of the traditional condensation process, but in the case of the cylindrical cavity heat exchangers, the environment of the impeller is suitable for the new evaporation process but not for the new condensation process described in the first part of the site, which can however take place in the cylindrical cavity of another heat exchanger of the same type.

In a detailed technical article published online by an engineer from an Italian air conditioning company, I discover that there are serious technical gaps concerning the current heat pump systems for air conditioning that are not often discussed. It reports that the efficiency of a machine or of an ordinary air conditioning system operating below its maximum thermal power, decreases significantly.

In current technical language, this phenomenon is called 'coefficient of performance at part load, COP (PL)', and it can drop to dramatically ridiculous values compared to the 'coefficient of performance at declared capacity', COP (DC). To the less experienced, I explain that, with the arrival of days with mild temperatures, when it is expected that the heat pump's consumption will decrease, this does not happen, as expected, due to a drop in efficiency levels.

On the contrary, in devices and systems that use different condensation or evaporation processes and the new types of heat exchangers, under the same circumstances, I expect rather an increase and not a decrease in efficiency. In my modest but alternative opinion, the causes of this phenomenon could be three or four.

As the primary cause, regarding the reduction in power of the compressor in a traditional heat pump system, I envisioned cyclical phenomena with pressure fluctuations but especially with oscillations in the level of liquid refrigerant present in the evaporator and condenser. In fact, an undesirable decrease in the level of liquid refrigerant in the evaporator and an increase in the condenser leads to temporary losses of utilization of a part of their internal heat exchange surface, resulting in a loss of efficiency of the system.

The second cause could be related to the priorities set in the current electronic control systems for maintaining the pressure differential between the evaporator and condenser, which cannot prevent the phenomenon from occurring. The third cause may depend on the nature of the heat exchangers used. If the percentage decrease in thermal power exchanged by them, is greater than the decrease in electrical power, supplied to the system for its operation, then the system's efficiency drops accordingly.

A fourth cause has instead been resolved for some time; it concerns the transition from intermittent operation of on-off systems to the modulated operation of inverter systems, but this alone has not provided a solution. However, let us return to a possible solution for the first cause mentioned above, provided that it takes place in the ways I have described. The new condensation process, I outlined in the first part of the site, stipulates that the internal environment of the condenser (or tank) is filled with liquid, just as happens in the classic, modern evaporation process.

Since liquids are nearly incompressible, in a heat pump system using for example the usual evaporation modality ad the new condensation process, working with both, the evaporator and the condenser, full of liquid, part of the liquid would not be able to leave the evaporator to flood the condenser, and the phenomenon of only partial utilization of the heat exchange surfaces of the condenser and evaporator could not occur. It is therefore likely that the development of new heat pump systems according to the methods  here described, could solve the problems associated with traditional systems, gaining and maintaining high levels of efficiency in almost every situation.

However, an unprecedented evaporation process has also been presented here, and among the classic and new modes of evaporation and condensation, the combinations become at least four and will need to be analyzed and experimented on a case-by-case basis. But the loss of efficiency of current heat pump systems when operating at partial load is not their only problem; there is another issue that is even more serious.

In Europe, heat pumps have been called upon to replace boilers in the role of winter heating, and the problem I am mentioning arises when the evaporator, in order to absorb heat from the air, must go below the freezing temperature of water. The condensation of atmospheric moisture into water is unavoidable, but under such conditions, the heat exchanger freezes this water, becoming covered in ice, and if the heat exchanger consists of fins, as is the case with finned pack heat exchangers, the ice gets lodged between them, creating thick layers that insulate the evaporator from the air.

I read that, even at usual humidity values, the defrost cycles become so numerous that a heat pump becomes less efficient compared to a boiler, but above all the device can no longer provide sufficient thermal power. The heat exchangers described on this site have a heat exchange surface that is free of fins and grips; the formation of the same thickness of ice takes longer because the condensation droplets, detach from the surface before freezing.

In this way, the defrost cycles are not only fewer but also shorter because the ice can detach more easily from the surfaces without needing to be completely melted. If heat exchangers are adopted as evaporators, made with heat exchange elements consisting solely of disc-like surfaces coated externally with a non-stick treatment (such as Teflon), the ice, not being able to grip much on the surface, could be detached from the rotating blades of the impeller without the need for any defrost cycle, significantly preserving the best efficiency values.

If all these considerations are not enough, it can also be demonstrated with theory that the abandonment of finned heat exchangers improves the efficiency of the system. However, as an inventor, I am entering a very technical minefield, overseen by engineers, but I will dare to present my reasons in a necessarily general manner. A heat exchanger equipped with fins requires not only the necessary temperature difference to induce a heat flow between the internal fluid and the external surface but also an additional temperature difference for the heat transfer along the fins in order to interact with the airflow passing through them.

By avoiding this additional temperature difference, the evaporation temperature Te can be increased and the condensation temperature Tc can be decreased, and the formula, theoretical max COP = Te / (Tc - Te), where Te and Tc are indicated in degrees Kelvin, will provide higher values of COP efficiency. Therefore, why do engineers persist in choosing to design heat pumps with finned coil exchangers?

conditioning, according to traditional schemes? And why does no large manufacturing company fear that a competitor will start a change before others by launching new products on the market? If, on the other hand, some company wanted to at least conduct studies on prototypes, I do not have the expertise to replace an engineer but as the author, I have it as a technical consultant, to collaborate with them and certify that the prototypes are indeed what I have intuited.

Jean Michel A. J. Deberti
jmdeberti @yahoo.com