[Greenbuilding] The role of PV in achieving NZE
John Daglish
johndaglish at online.fr
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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