Air-control-

[Blueboy]

I have an application that uses a heat pump and an air handling unit to heat/cool several different areas. The problem I have is that with only one air temerature available all except the largest area are too hot or to cold. My solution is to put actuator controlled dampers on all of the outlets except in the main area enabling them to shut off the air to any area should it be come too hot or too cold. I have to say I have fresh air to all areas via another source.

What I need is a controller that will sense the duct temperature behind the damper compare it to the room termerature that is being requested and decide to open the damper if the air in the room is hotter or colder depending on the room requirement. Please see the example below

duct temp 26 room temp 20 stat set 22 = open damper
duct temp 26 room temp 23 sat set 22 = close damper

Duct temp 17 room temp 26 sat set 21 = open damper
Duct temp 17 room temp 21 stat set 21= close damper

Can any one help, I know carrier do something withh VVT that is similar to this are there any other manufactures who can offer this sort of control.

[frank]

Hi Blueboy

I use quite a few of the products made by these people http://www.electrocontrols.co.uk/

Have a look at the temperature controllers (room stats 0-10v output) and the damper motors.

Sounds like all you need is a 24v power supply then a 0-10v room stat controlling a damper on each outlet.

[TSK]

Hi Blueboy
Try Thermofuser Grilles, these use a wax motor (expansion piston) that senses the temp in the room and closes off the outlet to suit, these are not cheap as grilles go but the up-side is theres no controls needed over and above the grilles, they can cope with warm or cold air supplies and adjust the air flow dependant upon room condition / settings. Have had 12 sat on shelf for years waiting for an application that could use them, scrapped the lot just before Christmas (sorry)needed the space, last got an up to date price on these from Axair Climate (used to work for Climate that's how I came across the Thermofuser) they used them with the Hitachi Econofresh units.

You will need to allow air to return to the AHU in your chosen scheme or the heat -pump with trip on HP if the air is restricted too much, or freeze up in cooling mode, there is a device in the neck of the thermofuser to allow the air flow to by-pass into the void for return.

And no I don't sell them, if I sound too enthusiastic!