IES-VE User Forum

Hi,

I am trying to determine why the Notional building has 0% under the pump & fan power heat rejection option whereas the actual building defaults to 10%.

Why does having 10% provide you with a higher delivery efficiency than if the setting is 0%?

Is it common practise to leave the 10% in at design stage or copy the notional and use 0%.

The reason I'm asking is because my delivery efficiency is over 1.0 which is unrealistic and this heat rejection makes a massive difference to the value.

Thanks

Luke

Out of interest for any readers of this post.

I have used a value of 0% as manufacturer data does sometimes state that the compressor and fans have been included in the calculation of the EER.

The NCM Modelling Guide 2013 states the following on Page 16 for the SSEER:

"TheSSEER includes, inter alia, chiller efficiency, heat gains to pipework and ductwork, duct leakage, and removal of latent energy (whether intentional or not). It does not include energy used by fans and pumps (but does include the proportion of that energy which reappears as heat within the system). Electricity used by heat rejection equipment associated with chillers is accounted for in the SSEER (not as auxiliary energy). Electricity used within room air conditioners for fan operation is also included in the SSEER value since it is included in the standard measurement procedure for their EER."

The part in bold highlights what this option is for. It is allowing for heat to be recovered from the pumps and fans to be reintroduced into the system where it will have a positive effect on the efficiency. Thats my understanding/interpretation anyway

Luke