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BEr - A3 rating but failing on EPC!

  • 20-06-2013 03:30PM
    #1
    burly
    Registered Users, Registered Users 2 Posts: 314 ✭✭


    Hi all,

    I am advising a Client on a new build in Dublin City Centre. 3 Storey building. Client is rying to achieve an A3 rating.

    I have managed to achieve the A3 rating by following the sample speciifcation contained in Appendix E of the 2011 regs, and the CPC conforms also.
    But the EPC is stuck on 0.47 and I can t seem to get it down below 0.4 no matter what I try.

    Solar water heating is the only renewable at the moment.

    Space heating is the main energy consumer, with a mains gas condensing boiler currently specified, with underfloor heating on the ground floor.

    Any ideas on how I can reduce the EPC?


Comments

  • #2
    No6
    Registered Users, Registered Users 2 Posts: 2,489 ✭✭✭No6


    Try a heat pump instead of the gas, or if have have any fireplaces or stoves, use a timber only stove as the secondary heating. The solar panels alone do not provide enough to achieve compliance.


  • #3
    burly
    Registered Users, Registered Users 2 Posts: 314 ✭✭burly


    Can you tell me please how I enter a heat pump instead of gas into DEAP?

    I have not done this before, and cannot seem to find guidance from the manual.

    Thanks


  • #4
    sydthebeat
    Subscribers Posts: 42,912 ✭✭✭✭sydthebeat


    whats the glazing fraction
    whats the living space percentage
    and whats the solar fraction


  • #5
    sydthebeat
    Subscribers Posts: 42,912 ✭✭✭✭sydthebeat


    burly wrote: »
    Can you tell me please how I enter a heat pump instead of gas into DEAP?

    I have not done this before, and cannot seem to find guidance from the manual.

    Thanks

    the manual does describe how to enter heat pumps... but its very convoluted.


  • #6
    burly
    Registered Users, Registered Users 2 Posts: 314 ✭✭burly


    sydthebeat wrote: »
    whats the glazing fraction
    whats the living space percentage
    and whats the solar fraction

    Glazing fraction is 23%
    Living Space Percentage is 14.52%
    Solar fraction is 52%


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  • #7
    burly
    Registered Users, Registered Users 2 Posts: 314 ✭✭burly


    sydthebeat wrote: »
    the manual does describe how to enter heat pumps... but its very convoluted.

    Can you describe it no me in a non-convoluted way?!!!


  • #8
    sydthebeat
    Subscribers Posts: 42,912 ✭✭✭✭sydthebeat


    not really, you need to follow it step by step and understand exactly what the heat pump is providing.

    are you using any default u values?

    are you using MHRV?

    its incredibly difficult to meet 2011 regs without MHRV


  • #9
    burly
    Registered Users, Registered Users 2 Posts: 314 ✭✭burly


    sydthebeat wrote: »
    not really, you need to follow it step by step and understand exactly what the heat pump is providing.

    are you using any default u values?

    are you using MHRV?

    its incredibly difficult to meet 2011 regs without MHRV

    Problem with MHRV is that it drives up my energy consumption and EPC!

    Is the heat pump entered manually under the space heating tab, using data for heat pumps from the HARP database? The basic advantage of the heat pumps is that they have a coefficient of performance >1.5 which gives you a % efficiency of 150% right, which you then adjust according to DEAP manual, is that right?


  • #10
    sydthebeat
    Subscribers Posts: 42,912 ✭✭✭✭sydthebeat


    burly wrote: »
    Problem with MHRV is that it drives up my energy consumption and EPC!

    Is the heat pump entered manually under the space heating tab, using data for heat pumps from the HARP database? The basic advantage of the heat pumps is that they have a coefficient of performance >1.5 which gives you a % efficiency of 150% right, which you then adjust according to DEAP manual, is that right?

    not if you use a decent HRV system and have a very decent air tightness result !!

    most definitely not actually.....


    most heat pumps, and assuming your talking about air to water will ahve efficiencies in the region of 250-350%... use the highest one you can.

    you will have to use a mathematical formula to calculate the efficiency of the heat pump for water heating.

    im not advocating HPs by the way ;)

    try out the HRV choice first. Aim for at least an air tightness result of 3 (0.15 air changes)


  • #11
    MOTM
    Registered Users, Registered Users 2 Posts: 412 ✭✭MOTM


    burly wrote: »
    Problem with MHRV is that it drives up my energy consumption and EPC!

    Is the heat pump entered manually under the space heating tab, using data for heat pumps from the HARP database? The basic advantage of the heat pumps is that they have a coefficient of performance >1.5 which gives you a % efficiency of 150% right, which you then adjust according to DEAP manual, is that right?

    Read the October 2009 technical bulletin for the heat pump.
    Also, should be more than possible to meet the regs with a condensing boiler, solar thermal, good air tightness and good thermal bridging. Ensure there are no chimneys or open flues. Reduce the pump power according to DEAP table 4f footnotes if the right information is available.

    For several sample dwellings, read teh Regulatory Impact Analysis DECLG did for TGD L development in 2010. (Table 2) http://www.environ.ie/en/Legislation/DevelopmentandHousing/BuildingStandards/FileDownLoad,23658,en.pdf


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