• Ceiling radiant system in functional building
  • Ceiling radiant system in functional building

Ceiling radiant system in functional building

HVAC applications and controls

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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.

Ekinex devices Other system components
A) Time / astronomical digital switch EK-TM1-TP 1) Distribution manifold for low temperature circuits (flow)
B) GPS module EK-GPS-1 2) Distribution manifold for low temperature circuits (return)
C) Actuator-controller for electrothermal drives EK-HE1-TP 3) Valve with ON / OFF servomotor (warm fluid)
D) Touch&See display EK-EC2-TP 4) Valve with ON / OFF servomotor (cold fluid)
E) 4-fold pushbutton (8 functions) EK-E12-TP 5) Condensation sensor
F) Multisensor EK-ET2-TP 6) Window contact
G) Presence sensor EK-Dx2-TP 7) Ceiling radiant panels (series)
H) Universal interface EK-CD2-TP 8) Thermal generator (warm fluid)
  9) Thermal generator (cold fluid)
Control with Ekinex

The room air temperature is controlled in each zone or room by means of a (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.

Focus on the multisensor

The Ekinex multisensor (F) is a complete device for controlling room air conditioning that combines many functions usually distributed among several sensors and different controllers. The device measures temperature, relative humidity and air quality (parameter: 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 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 relative temperature, relative humidity and CO2

EK-ES2-TP with relative temperature, relative humidity and CO2 and TVOC

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 the activation of the dehumidification or humidification function.

LED Color and information (EK-ES2-TP version)
1 white (heating mode active) and red (heating ON)
2 white (cooling mode active) and blue (cooling ON)
3 blue (dehumidification function active)
4 green (humidification function active)
5
red flashing  (CO2 concentration > threshold 3)
orange (CO2 concentration between thresholds 2 and 3)
6
yellow (CO2 concentration between thresholds 2 and 3)
green (CO2 concentration < threshold 1)
7
red flashing (concentrazione TVOC > soglia 3)
orange (TVOC concentration between thresholds 2 and 3)
8
yellow (TVOC concentration between thresholds 1 and 2)
green (TVOC concentration < threshold 1)