Source for EPC 100 = Zero Energy

[Ferdinand]

I have seen comment on BH that an EPC of 100 is nominally a Zero Energy house.

Can anyone give me a source I can reference for this? (Needed for blog post).

 

Cheers

 

Ferdinand

 

[A_L]

@Ferdinand ,

 

Quote

The SAP rating scale has been set so that SAP 100 is achieved at zero-ECF. It can rise above 100 if the dwelling is a net exporter of energy.

 

section 13, page 35 here -

 

https://www.bre.co.uk/filelibrary/SAP/2012/SAP-2012_9-92.pdf

[redtop]

well i looked for ages when getting my SAP done and couldnt find that document, very detailed!

[Ferdinand]

thanks.

 

That is a classic BRE document ?.

 

230 pages including 21 Appendices.

 

Including  ‘Appendix O (not used)’ on a whole page. An army artillery man, there.

 

Should have had a picture of a hat and “This is not an Appendix”.

Edited May 22, 2019 by Ferdinand

[ToughButterCup]

Oh dear oh dear, oh dear.

Direct quote from SAP 2012 version 9.92 (October 2013) Page 7 

 

Quote

Thermal mass

The Thermal Mass Parameter (TMP) is required for heating and cooling calculations. It is defined as the sum of (area times heat capacity) over all construction elements divided by total floor area. It can be obtained from the actual construction elements of walls, floors and roofs (including party and internal walls, floors and ceilings).

 

Tin hats folks, tin hats.

[Ferdinand]

1 hour ago, AnonymousBosch said:

area times heat capacity

 

Shouldn't that be "volume", even down the TM rabbit hole?

[SteamyTea]

Volume is 3 dimentional, area is 2.

So we can discount thermal area as it has no volume, so no way to calculate mass.

Though radiation is related to area, but that is even harder to truly calculate, though others disagree with me here.

[Ferdinand]

On 22/05/2019 at 12:23, SteamyTea said:

Volume is 3 dimentional, area is 2.

So we can discount thermal area as it has no volume, so no way to calculate mass.

Though radiation is related to area, but that is even harder to truly calculate, though others disagree with me here.

 

Flat earthers ?

[Ferdinand]

On 21/05/2019 at 21:53, A_L said:

@Ferdinand ,

 

 

section 13, page 35 here -

 

https://www.bre.co.uk/filelibrary/SAP/2012/SAP-2012_9-92.pdf

 

A final query, @A_L .

 

This is SAP 2012 - are we not on SAP 2018 now? (Admit that I am not familiar with the detail here. But I thought it changed.).

 

Cheers

Ferdinand

Edited May 25, 2019 by Ferdinand

[A_L]

4 hours ago, Ferdinand said:

This is SAP 2012 - are we not on SAP 2018 now? (Admit that I am not familiar with the detail here. But I thought it changed.).

 

Currently on BRE website

 

https://www.bregroup.com/sap/sap10

[Ferdinand]

3 hours ago, A_L said:

 

Currently on BRE website

 

https://www.bregroup.com/sap/sap10

 

Thanks for that. Currently out to consultation.

 

For the record, the list of changes is:

 

2. LIST OF CHANGES
1. CO2 emission factors, primary energy factors and fuel prices, have been updated using the latest data available. The method to derive them is unchanged from SAP 2012 except for the fuel price attributed to electricity exported to the grid, which has been reduced to the electricity wholesale price.
2. The assumed heating pattern has been changed to a consistent daily pattern for all days of the week – previously a different pattern was used at the weekend.
3. Additional design flow (heat emitter) temperature options have been provided for heat pumps and condensing boilers, which affect their efficiencies.
4. Default heat pump efficiencies have been updated.
5. Default distribution loss factors associated with heat networks have been increased.

6. The calculation of lighting energy has been updated to allow recognition of new lighting types with higher efficacy.
7. The options for entering heat losses from thermal bridges have been revised.
8. An additional thermal bridge type has been added for junctions in roof-rooms which don’t fit any of the existing categories.
9. The calculation of hot water consumption has been adjusted to account for shower flow rate.
10. The treatment of mechanical ventilation system heat recovery and aerodynamic performance has been revised.
11. The default efficiencies of some solid fuel heating appliances have been updated.
12. The air flow rates associated with chimneys and flues have been revised.
13. SAP 2012 used a fixed assumption for the proportion of electrical energy generated by Photovoltaic (PV) systems which is consumed within the dwelling. This has been replaced by a formula which also includes recognition of the presence of battery storage.
14. The impact of PV diverters2 is now taken into account.
15. An option to allow the overshading factor used for the PV calculation to be taken from Microgeneration Certification Scheme data has been added.
16. The assessment of summer internal temperatures has been refined and the blind/curtain use factor has been revised.
17. The air-conditioning efficiency (‘SEER’) table has been updated.
18. The treatment of heat losses from heat interface units (used with heat networks) has been adjusted.