Heat Pump Power Requirements

[soapstar]

Hi Folks,

 

Bit of a concerning questions has arisen relating to our heat pumps energy requirements. In order to be MCS certified we are required to 'prove' that the electricity supplier is aware we are installing a heat pump. Around the time of making our electric connection we did not think we would be using a heat pump at the time so never said anything.

 

Now a few years later we ARE installing a heat pump, a Grant Aerona 17kw pump, details are here (HPID17R32 model)

 

https://www.grantuk.com/media/3225/grant-aerona3-r32-range-data-sheet-july-2019.pdf

 

 

Now from what I can gather we have a 100amp cut out fuse from the transformer - would this be sufficient? Sorry my knowledge of electrics is very limited! I can help with any other information if required!

 

Thanks

 

[ProDave]

Page 2 of the linked document says "Max running current 25.3A" so it will be fine on your 100A supply.

 

But before you commit to that model and place the order, check with the supplier that it is an inverter driven heat pump.  It does not mention an inverter or variable speed operation which might suggest it does not.

 

[soapstar]

26 minutes ago, ProDave said:

Page 2 of the linked document says "Max running current 25.3A so it will be fine on your 100A supply.

 

Thanks @ProDave

 

I assume this figure is in theory added to all the other power consumers in the house, with the total being under 100amps (hopefully)?! There is nothing else I can think of which will have a huge load, we do not plan on a electric car hook up at this time. Everything else is pretty standard, gas/electric cooker, 3x electric towel rails (duel fuel) and all the other standard fitting a typical 4 bed house would have.

 

Yes from what I can gather these pumps are referred to as 'inverter driven'

 

Our connection is supplied by a 50KVA transformer - assume this is a reasonable size? It is currently serving 2 properties, soon to be 3..

Edited November 10, 2020 by soapstar

[arg]

There's two separate issues: whether your house's supply is adequate, and whether the supply to the whole neighbourhood is adequate.

 

You may well have a 100A (23kW) supply to the house, but the distribution network will have been planned on the basis of only about 2.5kW per customer sustained capability - on the assumption that you will only use your full 100A for short periods.  This forecasting makes assumptions about the kind of load - the number will be a bit higher (but not much) for estates originally built with electric storage heating rather than gas, for example.  Your heatpump can be drawing 5kW+ for hours on end, which is much more of concern for the network than your electric shower which might be drawing 10kW but only for minutes at a time - hence the shower is a concern against your 100A fuse but the network operator aren't too bothered, while the heatpump fits easily within your 100A fuse but is a concern for the network operator.

 

So when you install new equipment which changes the nature of the load in your premises, you are required to notify the network operator so that they can plan accordingly; this is almost certainly what you are being asked about.

 

Look here under the heading "connecting electric vehicles and heat pumps":

 

https://www.energynetworks.org/operating-the-networks/connecting-to-the-networks

 

Depending on the circumstances (size of equipment, existing supply), this requires either that you get permission first, or that you go ahead with installation and just have to send in a form to tell them what has happened.  I'm guessing from what you said that you fall into that second category - so you (or the installler) just need to fill in the form, send it to the DNO, and keep a copy for your MCS paperwork.  But obviously you will need to check the numbers first.

Edited November 10, 2020 by arg

[soapstar]

@arg thanks, this makes a lot of sense actually - so perhaps its not a case of worrying if we need to upgrade our supply, its just a case of informing the DNO of our intentions so they can plan accordingly...hopefully

[joe90]

Does that mean a house holder needs to inform the DNO if they instal a 10kW electric shower??.

[arg]

1 minute ago, joe90 said:

Does that mean a house holder needs to inform the DNO if they instal a 10kW electric shower??.

 

No, since that's only a short-duration load (like most other loads), you only need to consider it against the rating of your supply (ie. the main fuse).  Of course, if you install enough of them you may need a supply upgrade and be in contact for that reason.

 

It's only for sustained loads which fit within an existing supply but are likely to break their statistical planning that you need to notify - heatpumps, EV charging, PV generation.

[joe90]

I did not inform our DNO of our intention to build a new house with a heat pump as I had been told they still think they are not inverter driven, we are on a 80amp fuse and the heat pump (4KW runs rarely )it’s a well insulated house.

[arg]

5 minutes ago, joe90 said:

I did not inform our DNO of our intention to build a new house with a heat pump as I had been told they still think they are not inverter driven, we are on a 80amp fuse and the heat pump (4KW runs rarely )it’s a well insulated house.

 

Well, strictly speaking you should have informed them after the install, but since it's such a small demand in practice it's not going to cause any trouble.

[soapstar]

just to confirm the outcome...I was worrying for nothing (again), I informed the DNO and there is absolutely no issue with having the heat pump, our connection was allocated more than the average house at 13kVA..