AQUA
4
–AGU-1405-E
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4.2 Innovations Product: solving the defrosting problems
Thanks to two independent thermodynamic circuits, the AQUA
4
unit is essential on the market as an exclusive solution that can
continue to produce hot water for heating or sanitary uses while simultaneously performing a defrosting cycle.
During winter, especially in the -3°C - +3°C range, the high relative air humidity condenses water around the coil fins. Since the coil is at
a lower temperature than the air, any water that touches it solidifies and blocks the exchange of heat necessary for the system to
correctly operate. The defrost cycle is a temporary reversal of the thermodynamic cycle operating the appliance in cooling mode and is
used to melt ice present between the fins. This phase is of course problematic but AQUA
4
system can mitigate this problem through the
following innovations:
Hydrophilic coils are installed. These reduce the size of the water drops along with ice blockage between fins. Due to the
lower surface tension, water tends to slide away due to gravity, thus preventing the formation of frost at low temperatures.
Software management minimises defrosting cycle time, allowing cycle operation only when necessary. Fans operate at
maximum power only when the ice is no longer attached to the fins. It can then be pushed out from the coil.
The two thermal circuits in AQUA
4
M and AQUA
4
P are completely independent. While one defrosts, the other keeps the
machine operating, with basically no thermal discomfort for the user.
4.3 Structure
All AQUA
4
series units have a load bearing base and paneling in galvanized sheet metal painted with polyester powders and
polymerized in the oven at 180°C. The unit is attractively designed and when all doors are closed all the components are inaccessible.
This, along with the extensive use of soundproofing material inside the compartment and around the compressors (available for the
low-noise version), reduces sound to exceptionally low levels. The water/cooler connections are on the back (when looking at the
electric panel) reducing the space required for installation. The unit is fully accessible as all the panels can be removed (except the one
with the water connections). Routine maintenance however only requires access from the front.
4.4 Refrigerant circuit.
The cooling circuit is manufactured in our factory, with top brand components by operatives trained, according to Directive 97/23, on all
the brazing operations.
4.5 Compressors
Only top-quality Scroll compressors are used on AQUA
4
units. Scroll compressors are the best solution in terms of reliability and
efficiency. They also provide the lowest amount of sound emissions. Process optimisation, along with a carefully selected intrinsic
volumetric compression ratio (RVI), clearly improves the isentropic compression performance and reduces energy losses. The use of a
scroll compressor allows low viscosity oils to be used. This, in comparison to higher viscosity oils, reduces thermal resistance at the
evaporator. It also increases the evaporation temperature by over 1.5°C (EER increases by more than 5.5%) compared to other
solutions.
Compressor motors are protected against overheating, overloads and high delivery gas temperatures. They are mounted on anti-
vibration rubber, complete with oil charge and inserted in a soundproof compartment with sound-absorbing material. They are also
equipped with an automatic crankcase heater that, when the compressor stops, prevents the oil from being diluted by the refrigerant.
4.6 Brazed plate heat exchangers
Only brazed plate heat exchangers are used, made of austenitic stainless steel AISI 316, with AISI 316L connections. These feature a
reduced carbon content that favours brazing operations. The brazed plate heat exchanger represents state-of-the-art technology in
terms of thermal exchange efficiency and allows a strong reduction of the refrigerant load compared to standard solutions. The high
degree of turbulence generated by internal plate corrugation, along with plate smoothness, makes it difficult for dirt to accumulate or for
limescale to build up on the condenser circuit. These heat exchangers also make it possible to use R410A fluid which, thanks to the
high-level of its thermal conductivity in its liquid phase and to its azeotropic behaviour, enhances thermal exchange during evaporation.
The performances are improved over other methane-derivative fluids of the HFC group.
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NOTE: due to thermal insulation the data plate (in compliance with PED CE 97/23) is not legible. However, the serial number of the
heat exchanger and the declaration of conformity are both recorded during production and are an integral part of the company
archive.
4.7 Control box
The electric panel is built and wired in accordance with standard EN 60204-1. The electric panel is accessed from the front of the
machine. Before it can be accessed, the unit must be disconnected from the power supply using the mains disconnect switch, which
also functions as a door-lock. All the remote controls are implemented with low voltage 24 V signals, powered by an isolation
transformer inside the electric panel. All the control boards have an air circulation system with auxiliary fans. The position of the main
switch makes wiring operations in the work site easier. This avoids several difficult operations as well as having to twist the power
cords. All the utilities are protected against surges and short circuits. The circuit breaker set-up can be configured for any load
