Fixed temperature air

Richard - you should consider fixed temperature air as a tempered air supply to the zones or air flow from another space. The manual advises:

This could be a fixed air flow from another space, or a tempered air supply to rooms. The fixed temperature air flow rate can be specified as an air change rate, an air flow per person or an air flow per square metre. The temperature and % saturation of the fixed air supply must also be specified. Each room included in the calculation will be subject to the specified fixed temperature air supply, which will be assumed to occur throughout the day and night.

Duncan,

Thank you for the prompt response.

For some reason I am having difficulty accessing the manual through the software, I have informed our IT about the issue but have not heard back from them. Its not something which you are able to send me in PDF format is it?

With regards to my original question, I was trying to model a room (both heat gains and heat losses) where fresh air is introduced to the room un-conditioned on a l/s/per basis.

For the heat gains calculation I used the 'fresh air loads' section in the design data tab, and selected 'fresh air introduced locally to the rooms' and input 10l/s/per.

For the heat loss case there isn't a 'fresh air load' section under the design tab, so I used the 'fixed temperate air' and specified 10l/s/per at 31deg and 37% sat (Summer external design conditions of 31deg DB & 20.5 WB).

Is the approach that I have taken correct?

Also under the heat gain calculation, what's the difference between the 'fixed temperature air' and 'fresh air loads', as they appear to do the same thing?

Regards

Richard

Duncan,

 

For the heat loss calculations, the scenario which I have is FCU's within a given room and fresh air is introduced to the room unconditioned. 

The FCU's will need to be sized the account for the heat loss through fabric, infiltration and to accommodate the fresh air load.

If cold air is being pumped into the room at say 0deg then the FCU needs to be able to heat up this volume of air aswell.

That's what I'm trying to simulate.

 

Regards

 

Richard

Richard - That's fine. It just rather unusual to see a requirement for cold air into the space like that. Under these circumstance you would have to use fixed temperature air to emulate that.

Duncan,

Ok great thanks for clarifying.
Thank you for all your help and patients.
Much appreciated.

Regards

Richard

Hi Richard and Duncan,
I think it that what Richard wants, can be simulated via Infiltration: converting the fresh air load into ach. Could you confirm it Duncan?
Regards, Jose

Jose

The requirements were for an a/c per person, rather than on an hourly basis as would be specified in room data. The reply given previously should meet the required criteria.

(edited for clarity)

regards,

Jose

The requirements were for an a/c per person, rather than on an hourly basis as would be specified in room data. The reply given previously should meet the required criteria.

(edited for clarity)

regards,