[Greenbuilding] The role of PV in achieving NZE

Thu Jan 27 16:23:58 CST 2011

Bonjour Gordon,

see below

Cordialement

-- 
John DAGLISH

www.batirsain.org

Wednesday, January 26, 2011, 10:53:10 PM, you wrote / vous ecrirez:

GHHME> Hello John:

GHHME> a) Thanks for your comments.  I am appreciating the GBL list and the 
GHHME> people expressing their expertise.  I wasn't wanting to be 
GHHME> obstructing... but I felt that Ross used a few hot words that I 
GHHME> suggest needed to be challenged.  That's why I addressed my comments 
GHHME> to him directly, rather than comment on the expertise of people on 
GHHME> the list generally.  I apologise for being derogatory.  I should have 
GHHME> been clearer.

GHHME> b) Re the Riverdale NZE house energy consumption, as viewed on page 7 
GHHME> of its profile 
GHHME> <http://www.riverdalenetzero.ca/Riverdale_NetZero_house_--_project_profile.pdf> 
GHHME> .
GHHME>     ----- May I suggest that it is important to clarify what the term 
GHHME> "energy use" means.  The PassivHaus standard is NOT 15 kWh/year/m2 of 
GHHME> space heating, but rather it is 15 kWh/year/m2 of net energy 
GHHME> consumption for space heating from the grid (if I am understanding 
GHHME> correctly) -- a biiiiig difference.  The PassivHaus net energy 
GHHME> consumption is net of its internal gains and passive solar gains 
GHHME> (please provide any correction on this).

The specific annual heat demand of 15kWh/m2.yr are the annual losses
(fabric, ventilation) less all the gains (solar passive, equipment
heat loss such as lights, refrigerator, etc., occupants).

see the PHPP calc tab Annual Heat Demand
http://www.passive-on.org/CD/4.%20PHPP%202007%20Demo/PHPP2007_English_Demo.xls

Not necessarily from the grid :) it could be an active solar system,
wood fire, etc.

GHHME>     ----- The RNZ house uses 33 kWh/year/m2 of space heating -- this 
GHHME> is how much energy passes out through the house envelope regardless 
GHHME> of where the energy is source.  The RNZ space heating is provided by 
GHHME> a number of factors, as shown on the profile:  this includes internal 
GHHME> electricity gains, internal people gains and passive solar.  So the 
GHHME> net space heating requirements for RNZ are: Space heating incl fans = 
GHHME> 33.65 kWh/m2 plus mechanical ventilation = 2.02 minus usable passive 
GHHME> solar space heating = 6.88 (37% is useable) minus useable internal 
GHHME> gains = 4.13 (25% is useable), minus active solar space heating = 
GHHME> 9.57 giving a net space heating requirement of 15.08 kWh/year/m2.
GHHME>     ----- How would a PH house do this same type of accounting in 
GHHME> order to achieve 15 kWh/year/m2?
GHHME>     ----- So may I suggest that an apples and apples comparison be made.
GHHME>     ----- I can't imagine a NZE house being rationally made without 
GHHME> being at least really close to the PH standard.

The total energy demand "Specific Primary Energy Demand" calculated
in terms of Primary Energy (not secondary energy)
(http://www.eoearth.org/article/Primary_energy) of
120kWh/m2.an maximum is everything ... all energy use space heating/
cooling, domestic hot water for sanitary uses,
all electricity use ... including white goods - washing machine,
refrigerator,  ..radios, telephones, computers, lighting, etc.

GHHME> c) I agree with you re the Kamloops DreamHome COP...  time will tell, 
GHHME> I am sure.

GHHME> I appreciate your viewpoints and challenge.

GHHME> +Gordon

GHHME> Date: Wed, 26 Jan 2011 13:58:23 -0500
>>From: jfstraube <jfstraube at gmail.com>
>>To: Gordon Howell -- Howell Mayhew Engineering <ghowell at hme.ca>
>>Cc: Ross Elliott <relliott at homesol.ca>,
>>         greenbuilding at lists.bioenergylists.org
>>Subject: Re: [Greenbuilding] PassivHaus and NZE comparison
>>
>>Sheesh Gordon, not sure what you meant by the "the company of facts 
>>and knowledge" but I would say there is quite a bit of that on this 
>>list.  Sounds kind of derogatory, and yet Ross is one of the "good 
>>guys" (eg he is willing to have a rational conversation) and I 
>>basically said what you said.
>>Most of the "facts" you provided are available to anyone surfing the 
>>web and/or talking to CMHC folks.  All of them were built into my commentary.
>>
>>However, it is not true that NZE homes meet the PH standard.  That 
>>is my point.
>>I attach a table of 5 of the houses I compared recently at the 
>>bottom of this message.
>>According to CMHC, the Riverdale Duplex (eg one wall less than a 
>>single family house to loose heat) uses 33 kWh/m2/yr.  This is over 
>>twice the PH standard, eg no where near the target.  I think the 
>>Riverdale house is a exemplary cold climate home, a real step 
>>forward.  And that is my point: you met the 0.5, but not the 15 
>>heating target and yet use less energy than a PH by about 120 
>>kWh/m2/yr. The Ottawa ecoHome fails the 0.6 test and the 15 test, 
>>and the GreenDream meets the 7 and fails the 0.6.  (Note the 
>>Kamloops gets this low by using a ground source heat pump and using 
>>a COP = 5.1, which is crazy, and reality will certainly be closer to COP=3.5).
>>The 120 primary target is an arbitrary but sensible target. By beef 
>>is the 15 and 0.6 numbers, and the lack of climate response and 
>>renewable energy sources.
>>
>>
>>                   Avalon    Riverdale ecohome GreenDream Now
>>Location            Red Deer  Edmonton  Ottawa  Kamploops  Toronto
>>HDD (18C)               5500    5600    4600    3650    4000
>>Floor Area (heated m2) 240      234     310     284     139
>>Total Site Energy (ekWh)13094   14391   20646   11031   13475
>>Heat Energy (kWh/m2)    23.9    33.7    40.2    7       23.1
>>Roof (R)                87      100     60      60      36
>>Wall                    70      56      44      44      40
>>Window          5       7.3/10  5.7     4.5     5.7
>>Basement walls  none    54      40      44      25
>>Slab                    60      24      15      20      25
>>ACH at 50          0.5     0.5     0.65    0.68    2.6
>>PV Installed (kWp)      8.6     5.6     6.2     6.8     2.7
>>SHW produced (kWh)      3886    1907    6665    2099    1824
>>PV produced (kWh/yr)    9569    6224    8184    9963    2800

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