[0001] The present invention relates to a condenser/evaporator for production plants of
hot sanitary water/heat pump conditioning comprising a tank provided with a heat exchanging
wall; and at least one pipe wound about the tank and arranged in contact with the
heat exchanging wall.
[0002] As known, a type of condenser/evaporator used in such production plants of sanitary
and/or cold water comprises the tank, adapted to contain a certain quantity of water,
which must be heated or cooled by the pipe wound about the tank and through which
a gas passes, e.g. R134A type gas.
[0003] To allow an efficient heat exchange between the water contained in the tank and the
gas which flows through the pipe, the pipe is preferably made of aluminium or copper,
i.e. materials which have a good heat transmission coefficient and which are easily
cold-deformable. Secondly, the pipe must be shaped so as to maximize the contact surface
with the tank so as to favour the heat exchange.
[0004] Documents
FR 2,549,214,
EP 336,751, and
W02004/085927 show condensers/evaporators or heat exchangers having the features described in the
preamble of claim 1. Each of the pipes shown in these documents has a flat face arranged
directly in contact with the heat exchanging wall of the tank or through the interposition
of conductive adhesive paste.
[0005] Pipes with flat faces have allowed the increase of heat exchange with respect to
circular cross-section pipes but nevertheless require relatively thick walls and/or
accurate fixing of the entire flat face to avoid that the flat face deforms when a
fluid at operating pressure runs through the pipe and markedly reduces the contact
surface between the pipe and the heat exchanging wall.
[0006] The main object of the present invention is to provide a condenser/evaporator for
production plants of hot sanitary water and heat pump conditioning which allows the
production of high heat exchange in a simple and cost-effective manner.
[0007] According to the present invention, a condenser/evaporator is provided for production
plants of hot sanitary water and conditioning; the condenser/evaporator comprising
a tank provided with a heat exchanging wall; and at least one pipe wound about the
tank and arranged in contact with the heat exchanging wall; the condenser/evaporator
being characterized in that the pipe presents a cross-section having a concave area
of predetermined radius and with the concavity facing the heat exchanging wall; the
pipe being dimensioned to deform at the concave area, when a fluid at operating pressure
runs through the pipe, so that the concave area assumes a complementary shape to the
heat exchanging wall and the pipe adheres to the heat exchanging wall along the deformed
concave area.
[0008] By virtue of the present invention, it is possible to use pipes with relatively thin
walls and it is not necessary to perform an accurate fixing of the portion of the
pipe used for heat exchange. Consequently, the present invention determines a substantial
saving of material and assembly time, and guarantees a high heat exchange.
[0009] For a better understanding of the present invention, a preferred embodiment thereof
will now be described, by way of non-limiting example and with reference to the accompanying
drawings, in which:
- figure 1 is a perspective view, with parts removed for clarity, of a condenser for
plants for the production of hot sanitary water by heat pump in accordance with the
present invention;
- figure 2 is a cross-section view, on an enlarged scale and with parts removed for
clarity, of a detail of figure 1; and
- figure 3 is a cross-section view, on a further enlarged scale and with parts removed
for clarity, of a detail of figure 2.
[0010] In figure 1, numeral 10 indicates, as a whole, a condenser for a plant for the production
of hot sanitary water by heat pump (not illustrated in its entirety). Condenser 10
comprises a tank 11 containing a liquid, in particular water, to be heated. For example,
the water at room temperature enters the tank 11 in a direction indicated by the arrow
(F1) and exits cold in a direction indicated by the arrow (F2). Tank 11 has a substantially
cylindrical heat exchanging wall 11A. Condenser 10 comprises a pipe 100 wound about
the tank 11 and arranged in contact with the heat exchanging wall 11A. Pipe 100 is
wound in turns in order to create a coil 20 comprising a plurality of spirals. Coil
20 has a gas inlet 21 and an outlet 22 for the same gas. In use, a gas flows through
coil 20, for example R134A.
[0011] As shown in greater detail in figure 3, pipe 100 has a cross-section 150, which presents
a substantially semicircular-shaped first portion 150A, and a squashed-shaped second
portion 150B substantially defined by a concave area 150C with external concavity
of predetermined radius (R1). The concavity of concave area 150C is not to be confused
with the concavity determined by the helical winding of pipe 100 about tank 11 (figure
2) as the concavity determined by the helical winding of pipe 100 does not affect
the shape of the cross-section of pipe 100.
[0012] According to what is better illustrated in figure 2, concave area 150C (figure 3)
of pipe 100 faces heat exchanging wall 11A of tank 11. In rest conditions, a substantially
closed space is formed between pipe 100 and heat exchanging wall 11A. In other words,
in rest conditions concave area 150C (figure 2) is arranged in contact with heat exchanging
wall 11A solely at opposite ends of concave area 150C. When a fluid at operating pressure
passes through pipe 100, concave area 150C deforms so as to assume a complementary
shape and to allow pipe 100 to adhere to the heat exchanging wall 11A. Pipe 100 is
not shown in the operating configuration in the accompanying figures.
[0013] Pipe 100 is made of metal material and preferably of copper or aluminium or an alloy
containing at least one of copper or aluminium.
[0014] With reference to figure 3, pipe 100 has a first overall dimension (D1) parallel
to heat exchanging wall 11A (Figure 2) and a second overall dimension perpendicular
to heat exchanging wall 11A. Preferably, between the second overall dimension (D2)
and the first overall dimension (D1) of cross-section 150 there is the following relation:
(D2)/(D1) = 0.5 - 0.8.
[0015] Preferably, between the radius (R1) of the concavity and the first overall dimension
(D1) there is the following relation: (R1) ≤ 1.5 - 2.5 (D1),
[0016] In fact, the radius (R1) of the concavity must not be too small or otherwise the
concavity would be too pronounced and section 150 would not deform in the appropriate
manner, but nor should it be too large, as otherwise there would be the same problems
which present themselves with the use of flat faces. In other words, in the latter
case, section 150 would deform in such a way that the contact between the two heat
exchanging surfaces would substantially act as a generator.
[0017] Pipe 100 is made from a circular cross-section cylindrical pipe of diameter (Φ).
The shape of section 150 is obtained, for example, from an aluminium circular section
pipe of initial diameter (Φ)
= 10 mm which is deformed by means of a cold roll-forming operation.
[0018] With this initial diameter value (Φ the preferred values of the first and second
overall dimensions are respectively (D1) = 12 mm and (D2) = 8 mm.
[0019] Pipe 100 presents a thickness (Sp) which is correlated to the diameter (Φ). Preferably,
between the thickness (Sp) and the diameter there is the following relation: (Sp)
= 0.05 - 0.15 (Φ).
[0020] Coil 20 presents a uniform pitch (Ps) of the turn distribution. Preferably, between
the pitch (Ps) of the turn distribution and the first overall dimension (D1) there
is the following relation: (Ps)/(D1) = 1 - 1.5.
[0021] The advantages of the present invention consist in providing a high heat exchange
together with the simplicity of construction and assembly of the condenser.
[0022] Finally, it becomes apparent that modifications, variations, improvements may be
made to the described condenser without departing from the scope of the appended claims.
In particular, in the present description, specific reference has been made to a condenser,
even if the present invention relates to an evaporator, the structure of which is
substantially similar and differs solely due to the operating conditions.
1. A condenser/evaporator for production plants of hot sanitary water and heat pump conditioning;
the condenser/evaporator comprising a tank (11) provided with a heat exchanging wall
(11A); and at least one pipe (100) wound about the tank (11) and arranged in contact
with the heat exchanging wall (11A); the condenser/evaporator (10) being characterized in that the pipe (100) presents a cross-section (15) having a concave area (150C) of predetermined
radius (R1) and with the concavity facing the heat exchanging wall (11A); the pipe
(100) being dimensioned to deform at concave area (150C), when a fluid at operating
pressure runs through pipe (100), so that the concave area (150C) assumes a complementary
shape to the heat exchanging wall (11A) and the pipe (100) adheres to the heat exchanging
wall (11A) along the deformed concave area (150C).
2. A condenser/evaporator as claimed in claim 1, wherein the cross-section (150) of the
pipe (100) has a first overall dimension (D1) parallel to the heat exchanging wall
(11A); and a second overall dimension (D2) perpendicular to the heat exchanging wall
(11A); the ratio between the second (D2) and the first (D1) overall dimension being
in a range 0.5 - 0.8.
3. A condenser/evaporator as claimed in claim 2, wherein the ratio between the predetermined
radius (R1) and the first overall dimension (D1) is in a range 1.5 - 2.5.
4. A condenser/evaporator as claimed in any one of the preceding claims, wherein the
pipe (100) is obtained from a circular-section pipe having a diameter (Φ) and a thickness
(Sp); the ratio between the thickness (Sp) and the diameter (Φ) being in a range 0.05
- 0.15.
5. A condenser/evaporator as claimed in any one of the preceding claims, wherein the
pipe (100) is wound in a helix about the tank (11) in order to create a coil (20)
having a plurality of adjacent spirals.
6. A condenser/evaporator as claimed in claim 5 wherein the coil (20) presents a turn
distribution pitch (Ps); the ratio between the turn distribution pitch (Ps) and a
first overall dimension (D1) of the section of the pipe (100) in a direction parallel
to the heat exchanging wall (11A) is in a range 1 - 1.5.
7. A condenser/evaporator as claimed in any one of the preceding claims, wherein the
pipe (100) is made of metal material, preferably copper or aluminium and alloys containing
at least one of copper and aluminium.