Fan Coil Unit

[pipedesign]

I have a problem that I don't understand !!!

I am useing a FCU (vertical cabinet) to cool the air in the summer and to make it hot in the winter !

The FCU I am useing is in the 2 pipe chage over system, so the coil is used by the cold water (7-12 grdC) and by the hot water (80-70 grdC) !

Here is the problem : my room need the same quantity of heat in the winter as it need in the summer : 1000Watt ; but the FCU provides me in the summer 1000Watt and in the winter 2500 Watt minimum !

How do I solve the problem? I dont need that much heating capacity in the winter !

Can I use this FCU ? Can I make it work in the winter at 1000Watt ? What are the implications ?

I must also say that I cant use the 4 pipe system, with separate coils for winter and summer !

Please help me , cos I'm in a big dilema !
Thank you very much !

 

[ChrisConley]

The one thing that you can easily control is flowrate. Add a control valve to the inlet and reduce the flow through the coil in the winter.

As far as implications I'd speak with the manufacturer of the fan coil unit and see if they have any recommendations.

 

[DLANDISSR]

Pipedesign:

Could use two coils in parallel and shut off the flow to one in the winter?

Could you bypass some the the air around the coil in the winter?

or

Could you, as Chris Conley said, add a control valve two or three way depending on the system.

 

[Cooky]

The problem of a FCU having more heating than cooling is a natural consequence of the greater temperature differential between air and water when in heating mode.

The normal method of controlling the room temperature with a FCU, is to have a 3-port water control valve. This is controlled by a thermostatic fan speed switch (with automatic change-over). Assuming you don't need really tight temperature control, a 3-port water control valve with an on/off rather than a modulating head will do the job just fine.

Hope this helps

Cooky
Carrier Air Conditioning