OBJECT OF THE INVENTION
[0001] The present invention discloses an instantaneous fluid interaccumulator that allows
instant heating of large amounts of water for human consumption and/or food fluids.
It comprises a set of corrugated steel coils of the same length combined with a distributor
that allows the interaccumulator to have only one water inlet and one water outlet.
BACKGROUND OF THE INVENTION
[0002] Water heaters are widely used in industry and homes, and the storage capacity of
their tanks is related to the intended use of the water. The most commonly used hot
water tanks serve a single residence. The capacity of domestic tanks in America varies
from 75 to 450 liters (20 to 120 gallons), in Israel, their typical capacity is 120
to 200 liters. Smaller electrically heated tanks serve only one area of the residence,
such as the kitchen, and are manufactured in sizes as small as 30 liters.
[0003] All hot water storage tanks are insulated to retain heat from the moment of application
until hot water is required. Current insulation methods are unsatisfactory when heat
preservation is required overnight, for example, when solar-heated water is required
for a morning shower. Hot water tanks that are exposed to the elements during the
winter months tend to lose heat for even shorter periods. This problem can be alleviated
by using thick insulation; however, the use of high-quality thick insulation is expensive
and also increases the cost of the tank's outer cover of steel; it can also cause
difficulties when the tank must be moved or installed in a restricted space.
[0004] There are two common types of electric water heaters for domestic sanitary use: accumulators
and instantaneous water heaters. Both types are used because each has certain advantages
and disadvantages.
[0005] Instantaneous hot water production is done at the same time, i.e., the water is heated
at the same time as it is consumed. In contrast, in storage systems, water is heated
slowly and maintained at a consumption temperature inside a tank.
[0006] The advantage of accumulator water heaters is the fact that they can distribute large
amounts of water at a pre-set temperature, well above what is normally required from
faucets in sinks or showers, and therefore can also meet the needs of multiple users
while using relatively low energy consumption; in Italy, this is generally 1200W for
the most common models. However, the disadvantage is that these models require many
hours to complete the supply of hot water once it has been used, and although the
tanks are insulated, they also suffer from strong heat dispersion. In addition, users
of sanitary hot water systems have almost no way of knowing how much hot water, if
any, is available for their use. The hot water storage tank is usually completely
closed, covered with thermal insulation material, and often installed in a difficult-to-reach
location. The common practice is to open a hot water faucet, drain all the water contained
in the pipe coming out of the tank, and manually test the water temperature.
[0007] The US patent
US3666918 discloses a water heating system that includes a tank for storing heated water for
extraction to a point of use and having a cold water inlet to replenish the extracted
water; a conduit having an immersion heater, the conduit having a water intake manifold
for supplying water from the tank to pass in heat exchange relationship with the immersion
heater and having a heated water outlet disposed in flow communication with the point
of use, the manifold having openings disposed in flow communication with different
levels within the tank at which different water temperatures may exist, whereby the
water temperature passing in heat exchange relationship with the heater is an integral
part of the water temperatures of the different levels; and a temperature sensor for
controlling the rate of heat input to the water passing through the conduit in response
to integral temperature.
[0008] In traditional boilers, the heat output largely depends on the amount of water flowing
through the tube bundle or coil. Therefore, one way to increase this heat output is
by modifying the dimensions of each turn of the tube bundle measured orthogonally
with respect to its longitudinal axis. In other words, in this way, coils with different
external diameters are used while the internal diameter remains the same. This increases
the heat exchange surface area of the coil (through which water flows) and, consequently,
the heat output of the boiler.
[0009] However, with this known operating mode, boilers with coils of different diameters
have different geometric characteristics or different external diameters depending
on the heat output generated by them. For these reasons, boiler manufacturers must
produce end closure bodies and components with different sizes (diameters), which
implies high production costs and significant storage costs.
[0010] International patent application
WO2015/140713 describes a method for manufacturing a set of heat exchange cells with a thermal
power within a predetermined range of maximum and minimum values. Each heat exchange
cell comprises at least one heat exchanger mounted in a containment casing. The method
comprises the steps of: a) providing an individual containment casing for a plurality
of heat exchange cells, the casing has a constant extension while the thermal power
of the cell varies within the range of thermal power values and is equal to the axial
extension of the cell having the minimum thermal power within the range of thermal
power values; b) providing a plurality of helically shaped heat exchangers with an
individual thermal power within said range of maximum and minimum values, each comprising
at least one tubular conduit for the circulation of a first heat transfer fluid wound
around a longitudinal axis of the helix according to a plurality of coils; c) mounting
at least one helix-shaped heat exchanger from the plurality of heat exchangers of
the set within said individual containment casing. The plurality of heat exchangers
in the set has an internal diameter that is substantially constant while the heat
output of the heat exchanger varies within a range of thermal power values; the tubular
conduit of the heat exchanger has a radial extension of the coils proportional to
the thermal power of the heat exchanger and thus maintains the axial extension of
the heat exchanger substantially constant while the thermal power varies and is equal
to the axial extension of the heat exchanger having the minimum thermal power within
the range of thermal power values of the set.
[0011] The patent application
WO2012/156954 relates to a heat exchanger that comprises a heat exchanging unit comprising substantially
one or more coaxial coiled tubes and a casing for containing the heat exchanging unit.
The casing has a first bottom wall, a second bottom wall and a peripheral part between
the two bottom walls. Each tube has a first end and a second end. The heat exchanging
unit is supported by the first bottom wall of the casing, with the first end and the
second end of each tube being substantially located in the first bottom wall of the
casing.
[0012] The great advantage of instantaneous water heaters is that they can supply an unlimited
amount of hot water with virtually no heat dispersion, but they use a very high energy
consumption to meet each individual use every time.
[0013] The only difference between a water inter-accumulator and an accumulator is the coil
located inside the former. Both always need to be connected to an external heat source,
generally a boiler, but also, for example, a solar panel or a wood stove, the primary
hot water, produced by the external heat source, heats the sanitary water that is
inside the same tank. The coil is the exchanger that transfers the heat from the primary
circuit to the secondary circuit (ACS). As mentioned, the present invention discloses
a water inter-accumulator that allows the instant heating of large amounts of water
and/or food fluids in a novel way that turns heating into an instantaneous fact, reduces
installation, operational and maintenance costs, increases system efficiency, and
eliminates problems from Legionella and similar bacteria that exist in traditional
facilities.
DESCRIPTION OF THE DRAWINGS
[0014] In order to complement the description being made and to help better understand the
characteristics of the invention, according to a preferred example of its practical
embodiment, a set of drawings is attached as an integral part of said description,
where the following has been illustrated with an illustrative and non-limiting character:
Figure 1 shows a top view of the water inter-accumulator of the invention, where the
arrangement of the coils (8a) and (8b) and the inlet distributor (1) are shown.
Figure 2 shows a view of the components of the water inter-accumulator of the invention,
showing the internal arrangement of the coils (8a) and (8b) and the rest of the components.
Figure 3 shows a top view of the water inter-accumulator of the invention, where the
arrangement of the coils (8a) and (8b) and the inlet distributor (2) are shown.
DESCRIPTION OF THE INVENTION
[0015] The ACS (Sanitary Hot Water) systems are those that distribute consumption water
subjected to some heating treatment. These installations have a certain energy importance
and are susceptible to contaminations by bacteria that find in their interior a warm
and humid medium that facilitates their proliferation. Therefore, they are installations
obliged to comply with specific regulations dictated by the different countries.
[0016] At present, apart from traditional accumulators, there are inter-accumulators of
different types, in all cases the envelope encloses the water or fluid (ACS). This
is heated by another primary fluid that passes through the coils. In these cases,
the exchange capacity is limited, since these systems try to maximize the amount of
accumulated water (they take a long time to heat the water), and they do not eliminate
the possibility of generating bacterial colonies inside.
[0017] There are also semi-instantaneous production inter-accumulators, where heat passes
from the equipment that produces it to the tank through the lower coil, heating the
water in the tank, which in turn semi-instantaneously heats the ACS water that passes
through the 2nd inner coil. For small consumptions (domestic systems), they work well,
allowing for about 4-5 consecutive showers before losing temperature.
[0018] The present invention reveals a novel instant production inter-accumulator for large
quantities of fluid, composed from the outside to the inside by the following elements:
an outer lining that allows protecting the insulating element and is manufactured
in various materials depending on the final location of the inter-accumulator; a thermal
insulator that can be composed of different materials and thicknesses, depending on
the necessary energy efficiency; an envelope that provides structural resistance to
the whole assembly and is responsible for containing the primary fluid that will heat
the ACS. In this envelope, there are hydraulic connections, holes for external probes,
and a drain outlet. For its manufacture, carbon steel or stainless steel is recommended;
distributors whose function is to prevent consumption water ACS from coming into contact
with any other element or fluid other than the external pipes, provide cold water
to the inter-accumulator, or extract it once heated.
[0019] These distributors are made of stainless steel and all connections with the inner
coils are also made of stainless steel. The coils are made of corrugated stainless
steel, which are responsible for transferring the heat generated by the boiler and
contained within the casing to the food fluid that passes through them.
[0020] The interaccumulator of the invention allows for real instantaneous production capable
of heating enormous amounts of water with a significant thermal jump. Currently, there
are no elements in the state of the art that equal or improve the relationship/size
of liters heated per minute.
[0021] The stainless steel distributors at the inlet and outlet of the DHW of the interaccumulator
ensure that the DHW does not come into contact with any element other than the stainless
steel (AISI316) with which all internal elements are made. The fact that the drinking
water does not touch the steel of the casing means that it is not necessary to install
any type of sacrificial anode or electronic anode to prevent corrosion of the casing.
This is a significant economic saving in external elements that are not necessary
to install or maintain.
[0022] The position and location of the distributor allows for a direct connection from
the external conduits to the Interaccumulator with the interior, a firm connection
where the external conduits can be screwed. The casing can be made of any material
that can withstand the temperatures and qualities of the primary fluid, since its
only functionality is to contain the primary fluid, allow the connections of the pipes
and probes. The DHW is never static inside the coils, which means that with an adequate
temperature, it is impossible for Legionella to be generated inside the tanks.
[0023] The coils are very insensitive to calcification and encrustation due to their corrugated
structure, since the turbulence generated inside the coils due to the water flow makes
it more difficult for lime, biological or any other type of incrustation to form,
since the same turbulence generates an erosive effect that prevents them. In case
the water does not flow fast enough to generate that erosive effect, another effect
is produced due to the temperature changes inside the interaccumulator. These temperature
changes cause the coil to expand and contract (amplified by the corrugated format
of the coil). These repeated expansions and contractions significantly delay the appearance
and development of any type of incrustation, whether it be lime, bacterial or any
other type.
[0024] As the coils are corrugated and flexible, they are able to withstand increases in
pressure in the system without being damaged, making the installation more durable,
even in case of expansion vessel failures, water hammer or similar malfunctions in
the installation.
[0025] The fact that there is only one inlet and one outlet for domestic hot water greatly
facilitates the assembly of the interaccumulator, avoiding errors and mistakes in
its installation.
[0026] The insulation used can be rigid or flexible and of various thicknesses, allowing
the equipment to adapt to different locations (indoors or outdoors, cold or warm environments,
wider or narrower passage widths).
[0027] Having both the heat exchange element (coils) and the thermal inertia element (envelope)
in the same volume eliminates many of the elements of the traditional system, also
eliminating its installation, maintenance and cleaning costs. This means that there
is no need to incorporate external heat exchangers or ACS recirculation elements between
accumulators.
[0028] The pressure drops in the system never exceed those of traditional systems and their
plate exchangers. Only during critical consumption moments do we equal these pressure
drops, with the rest of the time being 99.99% of the time a system with lower pressure
drops than traditional ones, and therefore more energy efficient.
[0029] Regarding the energy efficiency of the envelope and assuming a thermal protection
at least similar to that of any traditional system, lower heat dissipation losses
are achieved compared to any traditional system. The dissipation surface (envelope
surface) is much smaller (800L) than that of traditional ones (2,000L), making thermal
losses much lower than any other traditional accumulation system. The energy efficiency
in the heat exchange phase from the primary fluid to the domestic hot water is higher
than traditional systems with plate exchangers or any other system.
PREFERRED EMBODIMENT OF THE INVENTION
[0030] The present invention discloses a new type of instantaneous water interaccumulator
for sanitary or industrial consumption, which presents a technical novelty with respect
to traditional systems of production and accumulation of ACS, managing to solve all
the problems generated by traditional installations.
[0031] The invention facilitates the use of solar equipment or heat recovery, reducing the
operational cost of the installation. It eliminates the installation of plate heat
exchangers, with the consequent economic savings in their installation cost, maintenance,
and heat losses. The primary fluid is contained in the interaccumulator envelope and
allows heating/cooling of the secondary fluid, usually water for human consumption.
[0032] The interaccumulator of the invention incorporates an inlet (A) of the fluid to be
heated/cooled at the top of the structure and an outlet (B) of the hot/cold fluid
arranged on one side of the bottom of the structure. It also includes an inlet distributor
(1) of the fluid to be heated/cooled and an outlet distributor (2) of the hot/cold
fluid, a purge outlet (3) arranged at the bottom of the structure for multiple uses
that allows the purging and emptying of the fluid, a probe socket (4) arranged at
the top of the structure for multiple uses such as purging and filling the fluid,
a plurality of entries and exits (5) for the primary fluid, arranged on one of the
sides of the structure of said interaccumulator, an interaccumulator envelope (6)
of any material that supports the physicochemical characteristics of the primary fluid
and stylized both for heating and for cooling the secondary fluid and supports the
internal and external components, a thermal protector (7) that allows the thermal
insulation of the whole set to make its operation more efficient, at least one interior
coil (8a), and at least two exterior coils (8b), where said coils (8a) and (8b) are
corrugated and have the same length.
[0033] The need for the coils (8a) and (8b) to be corrugated is due to the fact that, for
the same length of coil, the corrugated design has a much larger contact surface area
between the fluids than if the coil were smooth. Heat exchange occurs through contact,
and the larger the contact surface area, the more heat will pass from one fluid to
the other. Additionally, being corrugated, the coil has the ability to increase its
length through thermal expansion with variations in temperature, making it more difficult
for limescale deposits to form. These deposits typically become partially detached
due to these contractions and expansions, delaying the onset of faults due to this
reason. Furthermore, having corrugated coils (8a) and (8b) reduces the probability
of failure in the event of a fault in the installation tank. This is because the increase
in volume due to a localised increase in water temperature can be absorbed by the
coils, delaying the increase in pressure and hence additional damage to the installation.
[0034] It is important that the length of the coils be equal so that the flow of water,
as well as the flow rates and retention times of the fluid in the tank, are similar.
[0035] Each of the different coils are manufactured in stainless steel corrugated pipe,
which together with the inlet and outlet distributors, make up the internal hydraulic
system.
[0036] The insulation used can be rigid or flexible and of various thicknesses, allowing
the equipment to adapt to different locations (indoor or outdoor, cold or warm environments,
wider or narrower passages).
[0037] The interaccumulator allows for the incorporation of multiple lateral outlets to
be used as probes, viewers, auxiliary outlets, fillings, etc.
[0038] The innovative interaccumulator of the invention has a very low total volume/instantaneous
flow rate ratio, allowing it to replace traditional accumulators of large volume,
that is, greater than 2000 liters, with interaccumulators of 800 liters with a much
higher instantaneous availability of hot water than the traditional accumulator. This
fact makes it very easy to introduce a tank during the construction of a building
and build around it, for existing installations that need to replace deteriorated
traditional tanks, where the main problem is to remove the current accumulators and
replace them with others of the same size, due to the logistical problems that this
entails. This results in significant cost savings by avoiding complicated logistics.
[0039] In the invention's interaccumulator, the domestic water never comes into contact
with the steel casing (6), and since there is no flow or accumulation of hot water
for human consumption, there is no need to install any sacrificial or electronic anodes
to prevent corrosion of the casing. This represents a significant cost saving in external
elements that are not necessary to install or maintain. Additionally, the interaccumulator
is compatible with different energy sources such as heat pumps, boilers, and solar
energy.
[0040] The casing (6) can be made of any material that can withstand the temperatures and
qualities of the primary fluid, as its only functionality is to contain the primary
fluid and allow connections of pipes and probes.
[0041] The connecting elements between the pipes outside the casing (6) and the coils (8a)
and (8b) are made of stainless steel, eliminating the risks of Legionella.
[0042] The innovative interaccumulator simplifies systems for water recirculation between
tanks, avoiding stratification and "dead" zones, resulting in lower installation costs,
simpler maintenance, less likelihood of breakdowns, and lower energy costs.