HVAC APPLICATIONS
HVAC APPLICATIONS
The ceiling radiant panel system is widely used in offices and, more generally, in large
functional buildings such as hospitals, shopping malls, schools, universities, airports or
stations.
In these cases, the suspended ceiling is made up of metal panels (7) that can be
inspected completely similar to those usually used in these buildings, but with hydronic
circuits applied to the upper part and possibly an insulating layer towards the plenum.
The hydronic circuits consist of metal or plastic pipes and metal thermal diffusers that
exchange heat between the pipes and the metal surface of the false ceiling.
The series of radiant panels are powered by distribution manifolds installed above the
circuits served. The system is invisible and uses the entire surface of the ceiling as a
large terminal for the heat exchange (prevailing as radiation). As in the case of the floor
system, the ceiling radiant panels only handle the sensible heat loads; in general, the
ceiling solution offers a higher yield in cooling.
The ceiling radiant system shown in the example is used for heating and cooling the
rooms of a functional building. The distribution is made with a 4-pipe system that make
available both fluids at the same time to heat or cool the room. This type of distribution
can be advantageous when it is expected that the thermal loads can vary greatly during
the same day or depending on the different exposures of the building.
In this application, the air renewal and dehumidification functions are performed by a
system with air centrally treated by an air handling unit and distributed in the rooms by
means of ducted systems and diffusers. As an alternative to the diffusers, and in the
absence of insulation towards the plenum, the microperforation present on the metal
panels can be used for the diffusion of renewal and dehumidified air in the rooms.
Control with Ekinex
The room air temperature is controlled in each zone or room by means of an EK-ET2-TP
(F) multisensor in combination with the EK-HE1-TP actuator-controller (C) that controls
the servomotors of the zone valves that regulate the flow of hot or cold heat transfer
fluid to the series of radiant panels. Thanks to the relative humidity measurement, the
multisensor (F) is also able to calculate the dew temperature and send it via bus to
higher level systems (BMS) through appropriate gateways.
Where necessary, the multisensor (F) can receive a measured temperature value
from an Ekinex® pushbutton (E), normally used to control other bus functions such as
lighting or shading, to control with a weighted temperature value. This can typically be
done in large or high rooms, where the temperature value measured by the multisensor
is not fully significant of the general temperature conditions in the room.
The input interface EK-CD2-TP (H) provides for the acquisition of signals from
condensation sensors (5) and window contacts (6). The condensation sensor (5) is
installed in contact with the first heat exchange element served by the hydronic circuits
in order to timely detect the possible formation of condensation when the cooling
mode is active and let the actuator-controller (C) close the zone valve (4), bringing
the system to safety.
To reduce energy consumption, the operating mode can be automatically switched
when detecting the absence of people within the zone using the EK-DF2-TP presence
sensor (G), recalling temperature attenuations of an opposite sign in the heating and
cooling conduction modes.
Ceiling radiant system in functional buildings
Low-temperature
distribution
7
Boiler room
6
8
3
1
C
9
4
3
1
4
3
2
4
3
2
4
6
D
H
zone 1
A
B
7
5
zone 2
7
5
F
zone 2
E
G
F
zone 1
E
G
Example
Ekinex devices
A) Time / astronomical digital switch EK-TM1-TP
B) GPS module EK-GPS-1
C) Actuator-controller for electrothermal drives EK-HE1-TP
D) Touch&See display EK-EC2-TP
E) 4-fold pushbutton (8 functions) EK-E12-TP
F) Multisensor EK-ET2-TP
G) Presence sensor EK-DF2-TP
H) Universal interface EK-CD2-TP
Other system components
1) Distribution manifold for low temperature circuits (flow)
2) Distribution manifold for low temperature circuits (return)
3) Valve with ON / OFF servomotor (warm fluid)
4) Valve with ON / OFF servomotor (cold fluid)
5) Condensation sensor
6) Window contact
7) Ceiling radiant panels (series)
8) Thermal generator (warm fluid)
9) Thermal generator (cold fluid)
LEDs
The eight integrated LEDs (with light
guide), positioned on the sides of
the front cover, can be configured to
indicate the active operating mode of the
heating system (heating or cooling), the
concentration of CO2 (equivalent) and
TVOC (only for EK-ES2-TP version) and
the activation of the dehumidification or
humidification function.
Focus on the multisensor
The Ekinex® multisensor (F) is a complete device for controlling indoor room comfort
that combines many functions usually distributed among several sensors and different
controllers. The device measures temperature, relative humidity and air quality
(parameters: TVOC concentration in ppb and/or equivalent CO2 concentration in ppm)
using the integrated sensors, with the possibility of sending values to the KNX bus, and
can also act as a controller for each of the measured parameters. With a single compact
device it is therefore possible to control both the thermohygrometric conditions and the
quality of the room air mass.
In special cases (large or high rooms, in the presence of strong asymmetry in the
temperature distribution or when the device is installed in an unsuitable position),
the room air temperature can be controlled by using a weighted average between
two temperature values: the first measured by the integrated sensor and the second
received by the KNX bus. Two independent thresholds for relative humidity and
three thresholds for CO2 and TVOC concentration can be configured. To implement
automation logic, combinatorial functions such as AND, OR, NOT and exclusive OR are
available; thanks to these functions, it is possible to use the information available on the
home automation system to control air renewal according to the actual need (DCV or
Demand Controlled Ventilation).
Versions
EK-ET2-TP with temperature, relative humidity and CO2 eq. measurement
EK-ES2-TP with temperature, relative humidity, TVOC and CO2 eq. measurement
LED
Colour and meaning (EK-ES2-TP version)
1
white (heating mode) or red (heating ON)
2
white (cooling mode) or blue (cooling ON)
3
blue (dehumidification ON)
4
green (humidification ON)
5
red blinking (CO2 eq. concentration > threshold 3)
orange (CO2 eq. concentration between thresholds 2 and 3)
6
yellow (CO2 eq. concentration between thresholds 1 and 2)
green (CO2 eq. concentration < threshold 1)
7
red blinking lampeggiante (TVOC concentration > threshold 3)
orange (TVOC concentration between thresholds 2 and 3)
8
yellow (TVOC concentration between thresholds 1 and 2)
green (TVOC concentration < threshold 1)
1
2
3
4
1
2
3
4
5
6
7
8
26
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