Rianai have 3 major issues when used off grid.
1) The phantom load when I checked was over 30 watts continuous. That's
over 700 w-hr/ day.
2) They need pure sine wave, and even have trouble on Trace SW
inverters. (One system I took over has a separate Exeltech on its own
battery and AC charger to run the Rianai, since they have Trace
inverters. Talk about a waste!)
3) They still have the hard well water scaling issues.
Ray
Remote Solar
On 3/20/18 12:03 PM, Dana wrote:
It used to be that “tankless” water heaters were very sensitive to
stable temperature production as flows from single handle facets shut
down the hot and opened the cold flows.
I can fully recommend the Rianai heaters of today as we have 2 in
offgrid and 0 issues. I have family members that have had them in
residential homes for several years also and 0 issues.
They do require 120 vac & have digital controls. The water temperature
is very stable & consistent. I have not measured the phantom load but
could if someone needs to know.
2 thumbs up for Rianai heaters from MHO.
----------------------------------------------------------------------------
Dana Orzel Great Solar Works, Inc.
*C - 208.721.7003 d...@solarwork.com*
Idaho Contractor - # 028765 Idaho PV # 028374
NABCEP # 051112-136 www.solarwork.biz <http://www.solarwork.biz>
_"Responsible Technologies for Responsible People since 1988" ___
*P*Please consider the environment before printing this email.
*From:*RE-wrenches <re-wrenches-boun...@lists.re-wrenches.org> *On
Behalf Of *cwarfel
*Sent:* Tuesday, March 20, 2018 11:48 AM
*To:* re-wrenches@lists.re-wrenches.org
*Subject:* Re: [RE-wrenches] Electric Water kWh/ person
What are the issues with tankless water heaters? I have heard them
described as having "issues", but I haven't read anything that
describes what they are. They are very popular where I live. Any
info? Thanks, Chris
On 3/20/2018 1:07 PM, Dave Angelini Offgrid Solar wrote:
And a big maybe for Offgrid where we like multiple ways to
charge/heat/cool and make hot water. The default method is almost always
the most reliable. For a typical home a 50 gallon propane tank water
heater with a zinc change every 7 years is the norm.
An air to water heat pump, an open loop solar water panel or closed loop
if conditions warrant it are great secondary methods. To me heating water
with electricity does not work because of winter and is a last thing to
add.A tankless and their issues are near the end of the list. Ground
source heat pumps are even lower to me with very nice prices on extremely
efficient mini split air source pumps.
I always try and minimize generators but if you need them then it allows
one to have more options.
Dave Angelini Offgrid Solar
"we go where powerlines don't"
http://members.sti.net/offgridsolar/
e-mailoffgridso...@sti.net <mailto:offgridso...@sti.net>
text 209 813 0060
Maybe. I designed my own house to incorporate this. The most efficient
are
the vertical type, and at 6' the company advertised 20% recovery for
about
$1,300 if I remember correctly. This I'm sure is for a new copper pipe,
and
anyone who's ever taken apart a sewer pipe after a few years will know
all
pipes get a bacterial mat of a couple mm thick. I suspect this might be
a
pretty good insulator. At any rate there is a whole lot of copper
involved
and associated inherent environmental challenges. I can't help but think
for the house design challenge to accommodate such a long perfectly
vertical pipe and expense another kW or more of solar would offset more
energy.
On Tue, Mar 20, 2018 at 9:50 AM, Drake
<drake.chamber...@redwoodalliance.org
<mailto:drake.chamber...@redwoodalliance.org>
wrote:
Daniel,
That sounds like an intriguing technology, much along the lines of
an
air
to air heat exchanger. Thanks for the recommendation. These systems
could
keep a lot of CO2 out of the atmosphere if widely used.
Drake
At 10:09 AM 3/19/2018, you wrote:
Content-Type: multipart/alternative;
boundary="----=_NextPart_000_0077_01D3BF6A.5EF88420"
Content-Language: en-us
Drake,
Have you or the client looked into the drainwater heat recovery
units?
They make both a vertical and horizontal mounted version. They just
help
recover the waste heat from shower water going down the drain.
My understanding is that economically they are barely past the
breakeven
point when considering offsetting grid power. If using PV costs as
the
benchmark, the economics would be better. If somehow this is off
grid,
then
I’d say it’s a home run. (Hopefully though this is not an
all-electric
off-grid building.)
The main benefit, as far as I understand it, is that you can get by
with
a
smaller unit, with a smaller heating element to perform the same
task,
OR
you can get much longer showers from the same sized unit. Depending
on
the
clients goals, this might be a useful tool to bring into the
situation.
Here are two brand names that I know of.
Vertical mount: renewability
Horizontal mount: ecodrain
I have not used these products, so I cannot endorse any of them,
just
though it may be worth consideration.
With Regards,
Daniel Young,
NABCEP Certified PV Installation ProfessionalTM: Cert #031508-90
*From:* RE-wrenches<re-wrenches-boun...@lists.re-wrenches.org>
<mailto:re-wrenches-boun...@lists.re-wrenches.org> *On
Behalf Of *Drake
*Sent:* Thursday, March 15, 2018 1:00 PM
*To:* RE-wrenches<re-wrenches@lists.re-wrenches.org>
<mailto:re-wrenches@lists.re-wrenches.org>
*Subject:* Re: [RE-wrenches] Electric Water kWh/ person
This discussion has been a great help. The house is built and the
plumbing
is in, but could be modified. Wood stoves are not a likely
solution. I
think we need a different water heating strategy.
Thank you all!
Drake
At 09:21 AM 3/15/2018, you wrote:
Content-Type: multipart/alternative;
boundary="------------EE4E9806B711DEF636076840"
Content-Language: en-US
This is what I came up with:
The calculation is Q = mcp delta T
Water Temp out =Â 120
Water Temp in = ground source Temperature @ 50F?
delta T = 70F
m = mass flow rate. ASHRAE is the source for this. 20gals per
person
per day = 20 gallons x 8.34 lbs/gallon =Â 167lbs/day/person
cp =Â 1 BTU/lb-degree F
Q = 167 x 1 x 70 = 11,676 BTU/day/person
Divide this by the efficiency of the water heating system (I'll
assume =
.86)Â =11,676/.86 = 13, 577 BTU/person/day
convert to kWh if necessarym 13,577/3412 = ~4 kWh/person/day, 120
kWh/month
I checked this against one month and it seems reasonable.
Website assuming ~3.5 family size comes up with @ 400kWh per month.
They
approached it another way with assuming run times.
https://www.google.com/search?safe=active&source=hp&ei=
Z3KqWvXiNsGb5wKJ2Kf4DA&q=electric+water+heater+use+annual+consumption&oq=
electric+water+heater+use+annually&gs_l=psy-ab.1.2.
33i22i29i30k1l3.279.9222.0.12475.35.19.0.7.7.0.451.2360.
0j6j4j0j1.11.0....0...1c.1.64.psy-ab..18.16.1952.0..
0j0i67k1j0i131k1j0i22i30k1.0.CiU8wYZigpI
Chris
On 3/15/2018 8:09 AM, Mike Kocsmiersky wrote:
Barton makes a good point with regards to the incoming ground water
temperature and the amount of heat required to bring it up to shower
temp.
 My recollection is that ASHRAE states 20gal/person/day for the
first
2
people, then 15gpd or 12gpd thereafter. However those rates vary
wildly
with consumers, from those that never bathe to the high schooler
that
needs
3 showers a day. In the northeast water heating can be up to 19%
of
the
total household energy load for the year. Also, I would
recommend the
air
source heat pump water heaters if you have significant humidity or
an on
demand unit. Water tanks are typically under insulated and can
lose
2kWh/day in standby losses.
Â
Mike Kocsmiersky
Principal
Spirit Solar Inc.
(413) 734-1456
Â
Â
Â
From: Barton Churchill [mailto:bar...@solarips.com
<bar...@solarips.com> <mailto:bar...@solarips.com>]
Sent: Wednesday, March 14, 2018 7:31 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Electric Water kWh/ person
Â
You first need to know your ground temperature. Then figure a delta
to
100
or so degrees. Most but not all showerheads flow 2.5gpm and showers
are
typically 10 minutes. You can then find a calculator online to
calculate
how many Btus are required to raise water temp for your delta per
gallon.
Convert to kWh, add some contingency and you should be good.Â
On Wednesday, March 14, 2018, <drake.chamber...@redwoodalliance.org
<mailto:drake.chamber...@redwoodalliance.org>>
wrote:
Hello Wrenches,
Is there a good way to estimate the power that will be consumed for
electric water per person per day? We are estimating the amount of
power
that will be used by an all electric duplex, and the water heater
amount
seems high. The current model we have claims 3493 kWh/ year per 26
gallon
tank will be consumed. With the two units, that would add up to
6986 kWh
/
year for hot water, pushing the system size to humongous for a 1300
ft
sq
building.
Does that seem high? There will be a maximum of 2 people per unit.
The owner is considering going to 115 V units with a 15 gallon
tanks. I
think the smaller tank would help, but it would seem that the
amount of
hot
water consumed would be the main issue.
How can we get a good estimate for a per person energy usage for
electric
hot water? Any other suggestions are welcome.
Thank you,
Drake
--
--Â
Barton Churchill
406.587.5295 <(406)%20587-5295> Â
2430 North 7th Bozeman, MT 59715
www.solarips.com <http://www.solarips.com>
[image: Image removed by sender.]
Â
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www.solarips.com <http://www.solarips.com>
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