FROM THE FRANCISCAN TO THE DIALOGIC UTOPIA IN CIELOS DE LA TIERRA
4. Representación metaficcional
The modules are available in two versions. The first is for supplying low temperature circuits, equipped with 3-way mixing valves with motor option. The second version is for supplying high temperature circuits such as radiators and towel drying radiators.
Figure 3.7.2 Mixing module for low temperature circuits. Figure 3.7.3 Distribution module for high temperature circuits.
The modules are composed of:
thermal insulation in expanded polypropylene,
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three-speed pump (not included with DN 40 modules),
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mixing valve with by-pass both on the boiler side and on the system side (mixing module),
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supply valve complete with thermometer and check valve,
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no-return valve complete with thermometer,
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differential pressure control valve (optional).
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The modules are supplied in sizes DN 25, DN 32 and DN 40 and the characteristics are indicated in the following table.
Table 3.7.2 Technical details
Characteristic DN 25 DN 32 DN 40
Maximum operating pressure 8 bar 8 bar 8 bar
Maximum operating temperature 120°C 120°C 120°C
Boiler connections 1”1/2 M 2” M DN 40, 4 holes
Utility connections 1” F 1”1/4 F 1”1/2 F
Valve material OT 58 OT 58 OT 58
Seal material Viton/EPDM Viton/EPDM Centellen
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Figure 3.7.4 Dimensions for mixing and high temperature DN 25 groups.
188 G1”1/2
G1”
394
250 G1”1/2
G1”
394
188 250
© 2008 Valsir S.p.A. © 2008 Valsir S.p.A.
Figure 3.7.5 Dimensions for mixing and high temperature DN 32 groups.
265 120 265
482 483
G2”
120 G2”
G1”1/4 G1”1/4
© 2008 Valsir S.p.A. © 2008 Valsir S.p.A.
Figure 3.7.6 Dimensions for mixing and high temperature DN 40 groups.
320 200 320
615 615
DN40
200 DN40 G1”1/2 G1”1/4
© 2008 Valsir S.p.A. © 2008 Valsir S.p.A.
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TECHNICAL CHARACTERISTICS OF THE COMPONENTS
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Figure 3.7.7 Characteristic diagram for DN 25 variable point mixing module.
0 400 800 1200 1600 2000 2400 2800
Pressure difference ∆P [kPa]
FlowQ [l/h]
∆P P1
P2
Curves created at maximum pump velocity
Grunfos UPS 25/60 e Wilo RS 25/6-3 (low temperature) Residual head of module Pressure loss of module Head of pump
© 2008 Valsir S.p.A.
Figure 3.7.8 Characteristic diagram of fixed point DN 25 mixing module.
0
0 400 800 1200 1600 2000 2400 2800
Flow Q [l/h]
Curves created at maximum pump velocity
Grundfos UPS 25/60 e Wilo RS 25/6-3 Pressure loss of moduleResidual head of module Head of pump
Pressure difference ∆P [kPa]
∆P P2
P1
© 2008 Valsir S.p.A.
Figura 3.7.9 Characteristic diagram of DN 32 mixing module.
50 Curves created at maximum pump velocity
Grundfos UPS 32/60 e Wilo RS 30/6-3 (low temperature)
a]
Residual head of module Pressure loss of module Head of pump
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Figure 3.7.10 Characteristic diagram of DN 40 mixing module.
0 8000 10000 12000 14000 16000 18000 20000
25
Pressure loss of module
Pressure difference ∆P [kPa]
Flow Q [l/h]
© 2008 Valsir S.p.A.
Figure 3.7.11 Characteristic diagram of DN 25 distribution module.
0
0 400 800 1200 1600 2000 2400 2800 3200
∆P P1 P2 Curves created at maximum pump velocity
Grundfos UPS 25/60 e Wilo RS 25/6-3 (high temperature)
Flow Q [l/h]
Pressure difference ∆P [kPa]
Residual head of module Pressure loss of module Head of pump
© 2008 Valsir S.p.A.
Figure 3.7.12 Characteristic diagram of DN 32 distribution module
0
0 1000 2000 3000 4000 5000 6000 7000
Pressure difference ∆P [kPa]
Flow Q [l/h]
Curves created at maximum pump velocity
Grundfos UPS 32/60 e Wilo RS 25 (high temperature) Residual head of module Pressure loss of module Head of pump
© 2008 Valsir S.p.A.
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TECHNICAL CHARACTERISTICS OF THE COMPONENTS
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Figure 3.7.13 Characteristic diagram of DN 40 distribution module.
© 2008 Valsir S.p.A.
0 5 10 15 20
0 8000 10000 12000 14000 16000 18000 20000
45
Pressure difference ∆P [kPa]
Flow Q [l/h]
Pressure loss of module
Figure 3.7.14 Characteristic diagram of pumps for DN 40 modules.
0
0 2000 4000 6000 8000 20000
90
© 2008 Valsir S.p.A.
TECHNICAL CHARACTERISTICS OF THE COMPONENTS
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3.7.1.1 Operating principle of mixing module
The module mixes the return water from the system with the supply water from the generator, by adjusting the valve (3 way mixer) the circuits of the heating system (terminals) are supplied with water at the desired temperature. The mixing modules can be fixed point or variable point. In the fixed point modules (thermostatic) the supply temperature to the system is maintained constant through the action of a thermostatic “head” that is adjusted during the start-up phase of the system.
In variable point modules the supply temperature can be varied through the action of a climatic control unit that increases the supply temperature to the system when the external temperature falls, and vice versa it reduces it when the external climatic conditions are more favourable. In this way it is possible to increase the efficiency of the system while achieving reasonable energy savings.
In this case the mixing valve is activated by a servomotor that is controlled directly by a climatic control unit.
Figure 3.7.15 Variable point mixing module.
Generator Terminals
Mixing module
© 2008 Valsir S.p.A.
The effect of the mixing valve differs according to its position. When the valve is completely open, which is equal to the request for maximum thermal output, within the terminal circuits all of the flow distributed by the generator is present. In this case the pump must overcome the pressure losses of the terminal circuits and those of the generator.
Figure 3.7.16 Mixing module with valve open.
Generator Terminals
Mixing module
© 2008 Valsir S.p.A.
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When the valve is completely closed, that is when the thermal output requirement is null, within the terminal circuits all of the return water from the same circuits circulates. In this case the pump must overcome the pressure losses exclusively in the terminal circuits.
Figure 3.7.17 Mixing module with valve closed.
Generator Terminals
Mixing module
© 2008 Valsir S.p.A.
La regolazione dei moduli di miscelazione può essere realizzata in due modi diversi, agendo con modalità differenti sulla valvola miscelatrice.
Fixed point adjustment: the supply temperature to the system (above the mixing valve) is maintained constant.
The adjustment system opens and closes the valve in such a way as to keep the supply temperature to the system constant. This is completely independent of the external climatic conditions.
Figure 3.7.18 Characteristic diagram of a fixed point system.
10 20 30 40 50 60
Supply temperature [°C]
0 © 2008 Valsir S.p.A.
TECHNICAL CHARACTERISTICS OF THE COMPONENTS
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Variable point adjustment (or sliding temperature): the temperature of the water supplied to the system (above the mixing valve) is adjusted in relation to the external temperature. The relationship between the supply temperature to the system and the external temperature is called “climatic curve”.
Figure 3.7.19 Characteristic diagram of a variable point system.
-40 -30 -20 -10 0 10 20 30 40
External temperature [°C]
10 20 30 40 50 60
0
Supply temperature [°C]
© 2008 Valsir S.p.A.
This type of adjustment is normally carried out with electronic systems (V-CLIMA) that measure both the supply temperature and the external temperature. With the use of a servomotor, these systems open or close the valve itself, thus varying the flow ratio between the heating fluid coming from the boiler, and the return fluid, in such as way as to modify the supply temperature in relation to the external temperature, according to the climatic curve established. Variable point systems require a very precise regulation, setting the climatic curve that allows the system to adapt itself to the external climatic conditions, thus increasing comfort and reducing energy consumption in the management of the system.
3.7.1.2 Calculation of flows
The energy balance carried out on the mixer allows the flow to be determined on the utilities side mu and the boiler side mc once the values are known such as: the output of the system Q, the supply temperature to the heating circuit TMu, the temperature of the water returning from the heating circuit TRu and the temperature of the water leaving the boiler TMc.
Figure 3.7.20 Mixing module, approximate values.
TMu TRu
TMc TRc
mu
mc
© 2008 Valsir S.p.A.
Q = cp · mu · (TMu - TRu) [3.7.1]
Q = cp · mc · (TMc - TRc) [3.7.2]
TRc = TRu [3.7.3]
where cp is the specific heat of the water equal to 4190 J/°C·kg.
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TECHNICAL CHARACTERISTICS OF THE COMPONENTS