how do I convert Wh/M3 to W/L/S for DEAP and PHPP

fclauson

I am struggelling :mad:

Most german MHRV are quoted in Wh/M3
DEAP requires w/(l/s)

so given 0.45 Wh/M3 - how do I convert it

I thought it would be simple but the answers I get are wrong

sydthebeat

fclauson wrote: »

I am struggelling :mad:

Most german MHRV are quoted in Wh/M3
DEAP requires w/(l/s)

so given 0.45 Wh/M3 - how do I convert it

I thought it would be simple but the answers I get are wrong

is it not w/m3/h ??

fclauson

Syd

thanks

different documents seem to write it differently - may be you are right

So if its w/m3/h to convert that to w/l/s then should be

0.45 /1000 (turn it into W/l/h)
answer * 60 *60 to get w/l/s
but that gives 1.62 which seems high

BryanF

fclauson wrote: »

I am struggelling :mad:.........I thought it would be simple but the answers I get are wrong

that why you employ someone who's done the courses and is qualified to do this for you..:D

sinnerboy

fclauson wrote: »

Syd

thanks

different documents seem to write it differently - may be you are right

So if its w/m3/h to convert that to w/l/s then should be

0.45 /1000 (turn it into W/l/h)
answer * 60 *60 to get w/l/s
but that gives 1.62 which seems high

Your calculations are correct but SAP Q and PHI assessment methods vary. You can't directly compare them.

Same machine - different assessments -

phi and SAP Q

sinnerboy

PS - I can't expand on the nitty-gritty of the 2 assessment methods - I just know they are not exactly the same

BryanF

ok fclauson, I received your 2 disgruntled PM's, yes I was bit harsh there, but it was meant in jest.

There are many differences between the PHpp and DEAP, which include the air-tightness, thermal bridging, heating, heat gains etc.. here's some of the differences:
http://www.aecb.net/PDFs/Combined_PHPP_SAP_FINAL.pdf
here's something on the air-tightness:
http://www.constructireland.ie/index.php?option=com_myblog&Itemid=107⟨=en&show=Dwelling-airtightness-in-Ireland-where-we-are-and-where-were-going.html

http://www.scotland.gov.uk/Resource/Doc/217736/0091333.pdf

with regards to your MVHR is your unit certified for passivhaus?

as M3 air space/volume calc's for the two methods differ then the MVHR output info must differ also. and I beleive there is the more stringent COP assessment on PH units..

BTW are you going to go for passive house accreditation? I can recommend a couple of good consultants in Wexford.. and some that can explain the technical differences outlined above.. maybe not for free though:)

fclauson

BryanF wrote: »

ok fclauson, I received your 2 disgruntled PM's, yes I was bit harsh there, but it was meant in jest.

Thats ok

BryanF wrote: »

.....with regards to your MVHR is your unit certified for passivhaus?

Yes

from the PAUL website - Electric efficiency: 0.23 Wh/m³
from SAP-Q Specific fan powers: down to 0.70 W/l/s

if you take the top one and do the following maths you would have thought it would work out
x 1000 to make it Wh/litres
/60/60 to make it per second

but the maths just does not work out - so I am stumped - I have a machine from Paul - not appendix Q listed (yet) and trying get the DEAP numbers

BryanF wrote: »

....
BTW are you going to go for passive house accreditation? I can recommend a couple of good consultants in Wexford.. and some that can explain the technical differences outlined above.. maybe not for free though:)

Hoping to do my own

BryanF

fclauson wrote: »

but the maths just does not work out - so I am stumped - I have a machine from Paul - not appendix Q listed (yet) and trying get the DEAP numbers

why aren't you ringing Paul?? their selling you the kit!!

sinnerboy

fclauson wrote: »

Thats ok


Yes

from the PAUL website - Electric efficiency: 0.23 Wh/m³
from SAP-Q Specific fan powers: down to 0.70 W/l/s

if you take the top one and do the following maths you would have thought it would work out
x 1000 to make it Wh/litres
/60/60 to make it per second

but the maths just does not work out - so I am stumped - I have a machine from Paul - not appendix Q listed (yet) and trying get the DEAP numbers


Hoping to do my own

Well 0.23 * 3.6 = 0.83 so not a million miles apart. With sincere respect and admiring your tenacity - you will find the dustsheet process more exacting than the spreadsheet.

Or in other words take a pragmantic approach and simply enter the 0.23 - 0.7 figures and move on. ( Again - this is well intentioned advice )

GreenTech

Hi fclauson,

I had the same problem recently. The Paul unit we used was new on the market and was not listed on sap-appendix Q. The SEAI were unwilling to accept any data that was not listed on appendix -Q. I argued the point that it is tested to European Norms but they basically could do nothing to help us out. We were forced to issue the BER with default data as the unit had already been installed. This is the only way that SEAI would accept this. I totally disagree with their take on it as the product is clearly superior to the older Paul units... in fact we upgraded to this unit due to the superior efficiencies.

I contacted Paul and they came back to me with a conversion of 0.29wh/m3 = 1.044w/l/s. This does not stack up against all of the other Paul units on sap-appendix Q when you compare the data on the PHI certs to the data on sap-appendix Q. (as you have rightly pointed out) It doesn't appear to be a simple conversion, and maybe this is SEAI's reason for not accepting this data.

To conclude.... If you want a good BER rating you may need to look at an alternative unit which is listed on sap-appendix Q. If this is not an option and your PHI cert is more important (ie. keeping the unit you had initially specified) you will have to bite the bullet and accept default SFP of 2.0w/l/s and 66% efficiency until SEAI change there guidance to better accommodate Passive Houses!
The unit we used was rated at 0.29wh/m3. PM if you want any further info.

sydthebeat

GreenTech wrote: »

If this is not an option and your PHI cert is more important (ie. keeping the unit you had initially specified) you will have to bite the bullet and accept default SFP of 2.0w/l/s and 66% efficiency until SEAI change there guidance to better accommodate Passive Houses!
.

i think the pragmatic view would be to view the passive certification as much more valuable than the BER cert. When the Paul unit is eventually included in SAP, it will only cost you approx €32 if you want to get an updated BER certificate.

caesarthechimp

fclauson wrote: »

So if its w/m3/h to convert that to w/l/s then should be

0.45 /1000 (turn it into W/l/h)
answer * 60 *60 to get w/l/s
but that gives 1.62 which seems high

Your maths was correct this time; this is the same as multiplying by 3.6 as sinnerboy points out in the next example;

sinnerboy wrote: »

Well 0.23 * 3.6 = 0.83 so not a million miles apart.

Now here's your mistake;

fclauson wrote: »

from the PAUL website - Electric efficiency: 0.23 Wh/m³
from SAP-Q Specific fan powers: down to 0.70 W/l/s

if you take the top one and do the following maths you would have thought it would work out
x 1000 to make it Wh/litres
/60/60 to make it per second

but the maths just does not work out

But now you are reversing the calcs; multiplying by 1000 instead of / 1000 etc.
Hence you probably got the answer 0.064 instead of 0.83

And the guys at Paul also multiplied by 3.6;

they came back to me with a conversion of 0.29wh/m3 = 1.044w/l/s.

But the conversion is never exact because a watt hour is an amount of input electricity. The number of these needed to push 1m3 air is the PHI version.

Litres/second is a rating for fan output. They are probably taking average figures at either the output or the input stages, depending on whose method is used.

fclauson

Thanks for the correction of my maths

The reason the numbers do not match prehaps is that PHI will always downgrade performance by 12% - so may be they up the power consumption by 12% as well

This sort of makes sense of the numbers now - just multiply by 3.6 and add 12% to the SAP Q numbers

sas

fclauson wrote: »

The reason the numbers do not match prehaps is that PHI will always downgrade performance by 12% - so may be they up the power consumption by 12% as well

To th best of my knowledge...

The PHI downgrade the performance of non certified units by 12% as a "finger in the air" penalty for the unknown.

When a unit goes through the certification, the performance\efficiency is actually determined and the 12% never comes into it.

beyondpassive

The testing methodology for both (SAP and PHAI) is based on EN308 however SAP tests works out the efficiency percentage using the temperature decrease % from supply air to intake air where as phi uses the temperature decrease from return air to exhaust air %. The difference between both interpretations of the Euro Norm is that PHI includes the heat loss through ducts and both tests allow the heat output of the fans to influence the air temperature. The exhaust side test is usually about 6% or worse and thats where the 12% penalty comes from. Going for passivhaus on a commercial build and finding that when you really get down into the minutiae of passivhaus verification, you need to disect the test reports.

fclauson

any one found some good web links to ref en308 ?

BryanF

fclauson wrote: »

any one found some good web links to ref en308 ?

http://shop.bsigroup.com/en/ProductDetail/?pid=000000000001094956

beyondpassive

passivhaus critique here, see ventilation section.

http://www.enerbuild.eu/publications/2011-03_ENERBUILD-result_5-3.pdf

see page 13 for comparison of testing methodology betwen DIN EN 308 and PHI Passivhaus Institute.

Heat recovery calulations.jpg

MVHR Andrew

Hi, I've just found this discussion and would like to add this comment:

The Passivhaus certification of fan power is done against a defined pressure loss, that is 100Pa on either side of the heat exchanger. Where as BRE who do the Sap Q listing test against their in house ducting system for which they do not disclose the pressure loss and it is not a constant. This means that converting Passivhaus fan power to Sap Q fan power is not a simple question of maths!
<snip>
All the best folks. Andrew