As installers we are asked about just having a grille for air conditioning, instead of an internal unit mounted on a wall. We refer to this as a concealed air conditioning system, as ducting isn’t always required, but the internal unit is always out of sight. This poses a unique set of design and implementation requirements which we will look at in this post.
We will delve into the following areas:
· Grilles and Diffusers
· Chassis Unit
· Sweating
· Supply and return air
· Access for maintenance
· Ducted Systems
Grilles and Diffusers
When concealing an Air Conditioning system, the air will be delivered via either a grille or a diffuser. As the air being delivered is cold the implementation is very important to avoid uncomfortable cold draughts.
A grille will usually be installed high up in a wall and the air passes directly through it mixing with warm air as it crosses the room, and a diffuser will be installed in a ceiling with the airflow being manipulated so that it rolls across the ceiling surface pulling warm air from below to mix with it. In both cases the cold air that comes out is mixed outside of the occupation zone of the room to provide a comfortable room temperature.
If a grille is installed in a ceiling, there will just be a blast of cold air going directly from the ceiling to the floor which will cause a very cold draught in the room.
When using diffusers in a ceiling the air will always need to be ducted from the air conditioning unit to the diffuser.
With a grille the air conditioning unit can sit directly behind the grille or the air can be ducted to it.
The air outlets come in various styles and are custom made to provide the perfect fit for an installation. They can be painted to a specified RAL colour and come in frameless varieties to provide the most seamless appearance.
Chassis Unit
With a concealed system the internal air conditioning units are about twice the size of a wall mounted unit and are known as chassis units. Typical dimensions are about 25cm high, 75cm to 115cm wide and 62cm deep. Additional space is required for the connection of refrigerant pipework and condensate, so a relatively sizeable space is required.
Access needs to be designed so the filters can be cleaned and there is good access to the electrical box and pipework connections.
The units can be in installed in loft voids or built into carpentry within the desired room. The typical units we install come with a wired controller and can be fitted with an infrared remote control and mobile app controller.
Finding a suitable configuration and location for the chassis units can be challenging and if you are planning building works it is advisable to consider the integration of a concealed system early in the design process.
We can work with architects and their CAD drawings to provide markup and service runs for an installation.
Sweating
Sweating is the undesirable effect of water droplets forming on a grille or diffuser and then running down the wall or dripping from the ceiling. This occurs when the surface temperature of the grille or diffuser drops below the dew point temperature of the air in the room. This can happen for several reasons but with careful design and implementation of the system this can be entirely avoided.
If the chassis unit is installed a in remote location such as a loft these can also be liable to condense with water forming on the outer surface and running off. In this scenario full insulation of the unit itself is required.
At Cool Electrics we have the experience, and implementation knowledge to ensure you only find cold air flowing into your room and not droplets of water from a sweating grille or diffuser.
Supply and return air
When the air conditioning is running it will be producing cold air, which we call ‘supply air’, and this comes from cooling the current air in the room which we describe as ‘return air’ as it is flowing back to the air conditioning unit to be cooled.
This is a basic but important design criteria as we need to design and implement a path for ambient room air to return to the chassis unit as well as a path for the cooler supply air.
When the unit it located within carpentry within a room whether it be at the top of the cupboard or built vertically into a TV surround the return air can move freely back to the unit without worrying about insulation or ducting.
However, if the unit is installed a remote location, it’s important that it is the air coming from the area that is being cooled that is returned to the unit. In this scenario both the supply and return air need to be ducted to the chassis unit so that an accurate temperature is measured by the system.
Access for maintenance
Filters will need to be cleaned on a regular basis, so it is important that these are accessible. Pipework connections need to be check on a regular basis for any signs of refrigerant leaks, and it is highly recommended to have access to the electrics and circuit board within the unit should it need to be changed.
If a unit is in a ceiling void its likely to need an access hatch in the ceiling and if the unit has been built into carpentry this needs to be designed to allow ongoing access.
As Cool Electrics offer ongoing service plans for all our installations, we work to make sure these requirements are met so that should anything need remedying in future it doesn’t become a major headache due to inaccessible components.
Ducted Systems
Most concealed air conditioning systems are like wall mounted installations in that every area will have its own dedicated internal chassis unit to provide cooling for that space. The units can be located directly behind grilles or remotely place with the air being ducted to and from the room. However there is no central air conditioning unit that services all rooms.
This practice is contrary to countries such as the USA and Canada where houses tend to be heated and cooled by a centrally ducted air conditioning installation that moves either warm or cool air to the whole house.
Summary
This article discusses the installation and maintenance requirements for concealed air conditioning units. When located within carpentry in a room, return air can move freely without additional insulation or ducting. If installed remotely, both supply and return air must be ducted to ensure accurate temperature measurement. Regular maintenance access for cleaning filters and checking for refrigerant leaks is crucial, and proper access should be designed when units are placed in ceilings or built into carpentry. Most concealed systems have dedicated units for each area, contrasting with centralised systems common in the USA and Canada.