HVAC APPLICATIONS
HVAC APPLICATIONS
More and more often in systems designed for room heating, cooling and ventilation
there are simultaneously heat exchange, air handling or air renewal terminals with
different operating principles (such as radiators, radiant floor or ceiling panels, fan-coils,
dehumidifiers, mechanical ventilation units with integration of the sensible contribution
for cooling, etc.) that make it necessary to produce heat transfer fluid at different
temperatures. This can be done directly in the boiler room or locally, by controlling a
mixing group.
Control with Ekinex
The unmixed zone directly serves the heat exchange terminals with heat transfer fluid
at the temperature produced in the boiler room. The EK-HH1-TP unit (A) controls
the mixing group (1) by adjusting the flow temperature of the heat transfer fluid for
the mixed zone. For this purpose, the mixing valve (2) equipped with a servomotor
and the circulating pump (3) of the mixed zone are controlled, measuring the flow
temperature by means of an immersion sensor (C). Optionally, it is also possible to
measure the return temperature by means of a second immersion sensor (D). The
outdoor temperature sensor (B) measures the outdoor air temperature for climate
compensation control.
In the case of radiant panel systems also used for summer cooling, the ideal use of
the controller (A) is in combination with a maximum of 16 room thermostats EK-
EQ2-TP equipped with temperature and relative humidity sensors to have an effective
integration between the boiler room regulation (primary) and the room or zone control
(secondary).
In this way, the system on and off as well as the optimal flow temperature of the heat
transfer fluid are automatically selected according to the actual internal conditions of
the building; in cooling mode it is also possible to select the optimal flow temperature
with active protection from condensation.
Control of a mixing group
Control options
Heating
Cooling
Fixed point
√
√
Climatic compensation
√
√
Adjusting to internal conditions
√
-
Adjusting to return temperature
√
-
Climatic compensation and adjusting to internal conditions
√
-
Adjusting to internal thermo-hygrometric conditions
-
√
Climatic compensation and adjusting to internal thermo-hygrometric conditions
-
√
6
7
8
A
2
4
3
1
T
Unmixed
15
16
POWER AUX
3
4
IN1
5
6
IN2
7
8
IN3
20
21
DO1
22
23
DO2
24
25
DO3
9
10
IN4
11
12
IN5
13
14
AO1
17
18
19
OPEN
CLOSE
COM
1
2
L
N
bus KNX
EK-HH1-TP
Mixing group controller
OK
ESC
+
-
Dev.
Line
Area
T
5
B
C
D
zone
Mixed
zone
Mixing substation
Boiler room
Example
Ekinex devices
A) Mixing group controller EK-HH1-TP
B) NTC temperature sensor (external) EK-STE-10K-3435
C) NTC temperature sensor (immersion) EK-STI-10K-3435
D) NTC temperature sensor (immersion) EK-STI-10K-3435
Other system components
1) Mixing group
2) Mixing valve with servomotor
3) Circulating pump (mixed zone)
4) Circulating pump (unmixed zone)
5) Boiler room manifold (flow)
6) Boiler room manifold (return)
7) Thermal generator (warm fluid)
8) Thermal generator (cold fluid)
Focus on the EK-HH1-TP mixing group controller
The EK-HH1-TP controller (A) is a KNX device, fully programmable via ETS, which
allows the flow temperature of the heat transfer fluid to be regulated in heating and
cooling hydronic systems.
The device can be used as a stand-alone unit or in combination with one or more
Ekinex® room thermostats to create single-zone or multi-zone systems (up to a
maximum of 16 zones), controlling the servomotor of a 3-point floating mixing valve,
powered at 230 Vac or 24 Vac, or with 0-10V signal and controlling the circulating
pump of the mixed circuit in run / stop mode. The device manages over-temperature
(in heating) and under-temperature (in cooling) alarms.
The controller has a backlit LCD text display, four membrane buttons for navigating
through the display menu and two LEDs for alarms and switching to manual mode.
The display allows the operating parameters to be monitored; some control parameters
can also be modified with respect to the initial configuration carried out with ETS.
The switchover of the system conduction mode (heating / cooling) can be done from
the bus, from a digital input (configured for this purpose) or manually from the front
keyboard. Alarms from anti-condensation probes can be managed.
The digital outputs, not used to activate a circulating pump, can be configured to
control a zone valve servomotor located on a circuit dedicated to fan-coil units or
dehumidifiers.
To create automation logic, the device is also equipped with 2-channel logic functions
(16 inputs per channel) with exclusive AND, OR, NOT and OR blocks and delayed
activation of the corresponding output.
Terminal no.
Label
Connection
3-4
IN1
Input 1 (fl ow temperature sensor)
5-6
IN2
Input 2 (return temperature sensor)
7-8
IN3
Input 3 (outdoor temperature sensor)
9-10
IN4
Input 4 (confi gurable as AI or DI)
11-12
IN5
Input 5 (confi gurable as AI or DI)
13-14
AO1
0-10 V control output for servomotor
15-16
POWER AUX
TRIAC power supply (230 Vac o 24 Vac)
17
CLOSE
Control output for servomotor (closing)
18
COM
Control output for servomotor (common)
19
OPEN
Control output for servomotor (opening)
20-21
DO1
Uscita a relè comando circolatore
22-23
DO2
Relais output (additional functions)
24-25
DO3
Relais output (additional functions)
Inputs and outputs
Switching the seasonal conduction mode
The seasonal (heating / cooling) mode can be switched in three ways:
- from the KNX bus;
- via the front keypad of the controller;
- by means of a switch connected to an input of the controller.
If switching from the KNX bus is selected, the controller receives the conduction mode
from another bus device (via a communication object), such as an Ekinex® room
thermostat, which has been assigned the master function for seasonal switching.
Switching can be carried out manually using the keypad and the display on the front of
the device: in this case, it is the EK-HH1-TP controller that performs the master function
of seasonal switching for all Ekinex® devices (sensors, actuators) that are on the same
system or part of a system served by the controller.
Switching via a switch connected to input IN5 (configured as DI) is suitable for stand-
alone applications in which there is no need for integration between the boiler room
(primary adjustment) and the rooms or zones (secondary adjustment). The switch can
be the same as the external selector used in the boiler room for switching the operation
of heat generators or shut-off valves of fluids.
The current operating mode is stored in the non-volatile memory of the controller.
Activating the mixing group
The mixing group can be activated in three ways:
- from the KNX bus;
- from a controller input;
- from a controller input and the KNX bus.
By selecting the activation from the KNX bus, the controller connects in logical OR the
flow requests coming from a maximum of 16 Ekinex® room thermostats. To activate the
mixing group it is sufficient that a single room thermostat requires flow.
The activation from an input is suitable for stand-alone applications in which there is
no need for integration between the boiler room (primary adjustment) and the rooms
or zones (secondary adjustment). A time programmer can be connected to input IN4
to activate the group according to scheduled time slots or the request of a stand-
alone room thermostat. In systems with distribution manifolds, the limit switches of the
electrothermal drives mounted on the individual valves can be connected in parallel.
An intermediate solution, on the other hand, involves activation both from the binary
input and from the KNX bus. The input can have priority over the flow requests coming
from the zones via bus (for example an external time zone programming device) or it
behaves as an additional zone (without priority).
In all cases it is possible to set an activation delay (from 1 to 255 seconds) for the
start of mixing; in fact, it is advisable to wait for the electrothermal drives to bring the
valves into the open position to prevent the circulating pump from exerting pressure on
hydraulically closed circuits.
20
21
