make existing single zone system multi zone
make existing single zone system multi zone
(OP)
Hello All - my first post.
I'm looking at a large single zone mixing/recirc AHU with hot water coil and space for chilled water coil. This supplies a large open factory in Ireland. The factory is being converted into offices, several zones some small, some large.
My first thought is to relegate the AHU to fresh air supply only then use VRV/VRF for individual zone control, but I'm wondering if it can be done with VAV less expensively and install a chilled water coil etc onto the AHU...
Any ideas guys?
I'm looking at a large single zone mixing/recirc AHU with hot water coil and space for chilled water coil. This supplies a large open factory in Ireland. The factory is being converted into offices, several zones some small, some large.
My first thought is to relegate the AHU to fresh air supply only then use VRV/VRF for individual zone control, but I'm wondering if it can be done with VAV less expensively and install a chilled water coil etc onto the AHU...
Any ideas guys?





RE: make existing single zone system multi zone
RE: make existing single zone system multi zone
I like the idea. I haven't seen them used here before. Trying to reuse the existing plant obviously cannot provide simultaneous heating and cooling in adjacent offices without another system...
RE: make existing single zone system multi zone
RE: make existing single zone system multi zone
Also presumably higher ceiling preferable for comfort. Do these work well in heating mode? what range do they have 100% air volume down to 30%
RE: make existing single zone system multi zone
Use the existing AHU to serve either the internal or perimeter zone( depending on design air flow requirements).Provide VAV boxes with terminal reheat coils.
Provide a seperate AHU for the internal zone which will be doing cooling most of the time again with VAV boxes with no reheat.
If it is an air based system for heating,I would suggest ceiling height to be kept around the 2.8m mark.
RE: make existing single zone system multi zone
RE: make existing single zone system multi zone
The building is a big 2 storey open box which will be fitted out for call centre and cellular offices. There is an existing AHU which has space for a chilled water coil to be fitted.
Most of the year will be predominantly a cooling load with small perimeter heating load.
I've reached the conclusion the lowest cost adaptation is to use the AHU for the call centre and position the cellular offices around the perimeter of the building with perimeter radiators and local DX systems (VRF or VRV).
It would be possible to convert the AHU to VAV but the duct is not pressure tested, the fans are comparatively weak, the job is cost driven...
High ceilings (4m) for the large call centre are preferable with low ceilings for small perimeter offices (3m).