Below, we have described a normal conference room that has façade contact and thereby both heating and CO2 sensors. If the conference room is in the core of the building, often neither heating nor CO2 sensors are required.
Offices with control of ventilation, cooling, heating, lighting and standby shutdown of electricity.
Flexibility
With the MTC supply air diffuser with a reactive slot, you obtain the same good air diffusion and energy performance as with the TTC. The major difference is that all sensors are built in to the controlling damper or on the walls. With the MTD diffuser, no electrical installation to the diffuser is required, and the cost per diffuser becomes lower as the MTC diffuser does not contain any sensors or electronics. This means that there are also fewer service points for the future. Because all diffusers that are located after the damper must be in the same zone, flexibility for future refurbishments is inferior.
However, both TTC and MTC can be installed in the same diffuser box; i.e. TTC can be fitted later without the duct system having to be ripped out. All that has to be done is to change the diffuser section, supply power to the TTC diffuser and set the existing damper regulator for supply air to fully open. The diffuser should ideally be placed with a spread that allows division into offices at a later stage.
Ventilation
The MTC supply air diffuser has reactive damper opening that works using counterweights. The smart damper DVC-BL controls the ventilation with the help of sensors for temperature, flow and CO2 where applicable. Occupancy is detected with a wall-mounted occupancy detector. When the room is empty, the system goes into economy mode, returning to comfort mode when the occupancy detector is triggered (after an adjustable time delay). The flow is then raised to an "occupancy flow" (typically defined as 30% of maximum flow); when there is excess heat the air flow increases to achieve the right temperature. For maximum energy saving, strongly under-temperature air is used to reduce the fan electricity consumption as the flow then becomes lower.
Flow balancing
The supply air flow is balanced in our solutions with the help of the smart damper DCV BL.
Silent
The design of the diffuser means that the diffuser can take in large amounts of air at low pressure without noise problems; the damper reduces the pressure and this requires a sound absorber.
Heating
The DVC-RC can control heating in sequence with radiator actuators and also functions with thermostats, but it can then be more difficult to exploit economy mode when the office is not occupied and there can be a risk that heating and cooling will operate simultaneously. However, this scenario can be easily detected with our web server LINDINSPECT.
MTC can also work with over-temperature air with good mixing, but if the supply air temperature cannot be adapted for different parts of the property, this tends to be a rather "insensitive" solution.
Lighting
Lighting control in a larger space can be done in a number of ways. Our solution for off/on is effected either with a local CBR relay box connected to DVC-RC or with a communicating SBR relay box which can be placed anywhere on the bus line and connected to any defined lighting zone.
Conference room with supply air via the MTC reactive supply air diffuser and smart regulating damper. The damper uses built-in regulators and sensors to regulate temperature (and where applicable carbon dioxide) and the quantity of air in the room. The pressure (i.e. the flow) regulates the slot size on the diffuser for draught-free air supply over the whole span with strongly under-temperature air. By measuring the flow and the damper angle, pressure optimization of the aggregate takes place via a CMA or server. The flow is set at three different levels: absence, occupancy and maximum flow. The built-in occupancy detector also controls economy and comfort modes after an adjustable time delay.
Extract air
Extract air with DCV-SL damper control with flow measurement to DCV-RC. Adjustable offset can compensate for fast flow.
Heating
The regulator on DCV-RC can regulate the valve actuator on the radiator. This works via both 0-10V and on/off. Adjustable cold draught protection. The flow temperature and circulation pump on/off for heating can be optimized.
Extra heating/cooling steps
Further heating or cooling steps can be connected to the DCV-RC for extreme operating modes.
Extra sensors
CO2 or air quality sensors can be connected in the DCV-RC. This input can also be used for other sensors if required. The sensor signal is used to regulate an adjustable P band.
Lighting
The CBR lighting control box or SBR is used to connect push buttons and 230 VAC to the lighting. The lighting is turned on and off either via a signal from the occupancy sensor placed in the supply air diffuser or from connected push buttons. The time to automatic switch-on (one operating mode) can be set, as can the time to switch-off after the last recorded movement.
For dimming of the light, a Switchdim switch is connected in series with the relay box.
The number of on and off operations and the number of hours with lighting illuminated are registered for measurement of the number of burning hours for the armature and thereby the optimal time for replacing fluorescent tubes.
The cable used throughout is a PVC-free shielded combined supply and communication cable. It is pre-terminated in the diffuser's diffuser section with ready-made contacts in the other end for rapid installation. For other products, it is connected in the same way throughout.
Cable lengths
The bus cable can be pulled for long distances in respect of communication, but the voltage drop must be taken into account for voltage supply. See electricity design guide.
The limiting factor for cable length is that each CMA ("communication hub") can only have 100 nodes/products installed on it.
Power supply and transformers
In a normal situation, one transformer is installed per 12-15 diffusers/products but this is a rule of thumb that applies with short distances between products. See electricity design guide.
In some cases, you may wish to place a larger transformer in cable recesses instead of many smaller ones deployed throughout the installation. This can be done, but you must take note of the voltage drop in cables, and you will need separate thick 24 VAC cables on cable ladders...
Different installation principles for easiest/cheapest installation
Instead of pulling the cable on a ladder outside the cellular office, you can pull the cable in line into the room to avoid having to go in and out of the room.
If the CBR box is to be installed for lighting control, it is useful to use some kind of FMP bracket assembly product for pre-assembly and shorter installation times. An SBR box can be placed anywhere on the bus line.
As long as you stick to an installed cooling capacity of about 80 W/m2, there is no problem with the draft in the occupied zone. With a recommended distance of about 3000 mm between the centers of two diffusers there won't be draftproblems.
However, quite often there is need for really high cooling loads in a small space in a conference room. Then the diffusers ability to tilt the lamellae is used så that the air is distributed asymmetrically.
Preferably, the air aims to flow to one of the short sides that are often also an outside wall where the occupied zone ends 500 mm from the wall.
This circumvents the problem with draft in a simple way.