IES-VE User Forum

Hello everybody,

I'm trying to produce an SBEM calculation on IES. The systems consists of a heat pump and underfloor heating.

Is is it possible to put the SCOP of the heat pump or only the seasonal efficiency? The manufacture shows 157% of seasonal efficiency and I'm a bit concerned because it looks a bit low to me.

Thanks in advance for your help.

Hi there,

The terminology between IES and heat pump literature can be confusing. I usually enter the heat pump's SCoP in the 'seasonal efficiency' field and let the 'delivery efficiency' to default, then IES calculates the 'SCoP' of the whole system, which is lower than the heat pump's SCoP.

The reason for this is that the final 'SCoP' takes into account the SCoP of the generator plus thermal losses from pipework/ductwork and duct leakage. Ducts don't apply to the underfloor heating, so if it's only pipework losses the delivery efficiency should be in the range of 90%.