IES-VE User Forum

Hi,

We are looking at Monodraft Coolphase Units on a project.

These units use phase change material to create a thermal store. There are more details here:

http://www.jrfchimneys.com/media/coolphase.pdf

On page 15 of the document the EERs mentioned are very high - up to 17! (The SFPs aren't bad either).

Is it acceptable to compare this system to conventional mechanical cooling in the notional building?

I'm not really sure how else you would model it.

Ross

The problem with coolphase from a compliance point of view is that it does not strictly cool to a setpoint and so cannot officially be called air conditioning.

I think the fairest method would be to model it as air conditioning but set it as a mixed mode control which should increase the cooling setpoints in the notional and actual building to 27C which would account for the drop in the cooling load when compared to a true air con system.

Of course this leaves the question of what NCM system type to apply to which I would probably say an FCU system since you can apply the fan power for the coolphase unit as the terminal unit SFP. If there is no fresh air AHU you can either set the central SFP as 0 or match the notional 1.8 depending on your conscience.

As an aside, I was at the IES event last year held at the Inisitute of Physics in London where Monodraught were demonstrating their coolphase technology and I asked if there was any official guidance on how it should be modelled via the NCM. The guy was a bit stumped but he alluded to their being some discussions ongoing with the BRE which may have been done now. If you contact Monodraught and ask the same question you may get a solid response. If you find out, please let us know