Zero Energy House (ZEH) coordinator [Archive]

Rob Beckers

30th January 2007, 15:06

Hi John,

Great idea! A zero energy house is something I've always wanted to build. There was a time that my wife and I seriously discussed this, then came the move to Canada, and now we're in a house that is pretty well impossible to make zero energy. With the heating requirements here, and the impossible orientation of this heap-o-bricks, it would mean razing it to the ground and starting over. That is not going to happen, neither am I planning to move (again), so my goals now are somewhat more modest. I'm hoping to generate a substantial amount of my energy needs, improve the efficiency of the existing infrastructure, in general make the best of this place.

I was a member of the advisory/review board for Duke's Smart House (http://www.smarthome.duke.edu/). I'm no longer there now, and they finally started building it just after I left. So the topic is near and dear to my heart.

Anyway, I digress. Discussing a zero energy house would be great. Especially if you are actually planning to make yours zero energy, so it's not just a theoretical exercise. Hopefully we can discuss it here, instead of taking it elsewhere.

If I were to build one, my starting point would be a good passive solar design. So the heating/cooling needs would be modest to begin with. There's a very informative book on passive solar, named "The Solar House" by Daniel Chiras. Of course, how much you need this would depend on the climate you live in.

-Rob-

John Allen

30th January 2007, 16:43

Hi Rob,

Thanks for your input. I just ordered "The Solar House" as you recommended. I only have 100k for this project so it is going to have to be done smart, and with a lot of sweat equity.

My house is oriented at a 45 degree offset to the usual grid so for direct solar gain, I have a wall facing southeast and one facing southwest. Does anyone know the impact of using those two directions instead of due south?

My current plan is to have 1000 sq feet of roughly flat roof that I can use for solar collectors, mostly thermal. My family's electrical needs are only about 200 KWH @ month so most of my energy needs are thermal - DHW and space heating.

ja

Rob Beckers

30th January 2007, 19:59

Hi John,

According to Chiras, being off by 45% incurs a penalty of 30% of potential solar gain. I wouldn't worry too much about it though, there's a lot more to passive solar and proper house design/construction than just orientation.

That's within reason, my own house faces north-east. :eek: I'm afraid there's nothing to be done there with passive solar, no matter what...

By the way, 200 kWh/month is very, very good! I don't know what your lifestyle is like, but compare that with the average American or Canadian household that comes in at just about 1000 kWh/month.

Anyway, tell use a bit more of what you have to work with, and what you're planning to do and I'll try to be helpful (hopefully others will too, I'm really not trying to monopolize this forum).

-Rob-

Mark Parsons

31st January 2007, 18:43

John and Rob,

For my benefit please define - 'Zero Energy House'
Every house draws energy to sustain the occupants in a modicum of comfort. Does ZEH mean all energy used is derived sustainably? Such as must be solar, wind, microhydro, biomass?

Thanks.
Mark

John Allen

1st February 2007, 20:09

Hi Mark,

You guessed correctly that the needed energy is generated from renewables, on site. Sometimes the reference is to net ZEH to allow for using the grid as a storage facility.

There are also many flavors of near ZEH, and even some folks who go for beyond ZEH. Personally I'm not attached to getting 100%, it is just a convenient goal.

And you?

John Allen in San Jose, CA

Mark Parsons

1st February 2007, 22:28

Hi John,

Thanks for the ZEH definitiion. Yes, I am working on a ZEH. My wife and I built a 1250 sq. ft. log home cottage beside a beautiful creek, on a 100 acre bush parcel in Eastern Ontario. We had the shell built by contractors in 2005 and we are finishing everything from insulation in ourselves. A time consuming affair that will likely take the better part of 10 years at our current pace since it is a 6 hour drive from our home. However, it is getting more comfortable each visit. At this point the phase 1 electrical energy system is in place - 12V 800A-H battery system capacity with plans and cables in place to get to 24V 1000A-H with 3000W inverter. All lighting is 12V CF. Smart house controls via a PLC (industrial computer)
Energy Sources and harvesting devices:
1. Microhydro - custom built banki turbine provides about 500 watt-hours per day plus a custom built sling pump paddlewheel supplying the cottage water system with 2.5 gpm at 45 PSI.
2. 1 - 85W solar panel with plans to add a second matching unit on the pole this year and plans to eventually add about 1kW solar.
3. 1 - 300W @ 11 m/s custom made HAWT and currently building a 3' wide by 8' tall Savonius VAWT unit expecting about 500W @ 11 m/s
4. 1 - 3' x 8' Flat Plate Solar drainback DHW panel refurbished and ready to roof mount and plumb in the spring.
5. Wood heat for main heating source and plan on water coil loop on the stove for additional DHW. The only fossil fuel use will be propane for cook stove and clothes dryer.

This has been a real challenge for my engineering mind and talents. Going ZEH takes a plan from the beginning and without a large budget requires considerable DIY skills. I'm enjoying every minute.:)

I take it you are planning a similar adventure?

I would love to hear your thoughts and plans since I have been thinking about RE retrofits for my home and am daunted by some of the system modifications required. My wife wouldn't appreciate the extensive tear out and mess for things like solar hot water collectors on the roof with all associated plumbing.

Regards,
Mark

John Allen

1st February 2007, 23:42

Hi Mark,

You must be enjoying yourself or you would not be able to do so much! 10 years, 20 years, who is counting.

I admire your pluck to do the out in the bush trip and I hope to look more closely at your hydo posts later. I did something a little more modest in 1973 and what I remember is that burning wood works well in the country. One time i was out cutting firewood with a friend a couple decades my senior and i was telling him about my solar and hydro plans. He said to me - "So John, how long do you figure it takes you each year to cut all the firewood it takes provide the energy your fancy expensive plans will supply?" I though for a minute and replied "About two days." He smiled and we went back to working on the firewood, which we both enjoyed.

As much as I love a nice fire, I have slowed down on burning wood here in San Jose because I'm just too close to my neighbors. One of my neighbors burns smelly stuff ( I think coal!) and it reminds me that perhaps some of my neighbors do not appreciate the fumes from my fires either.

Enough on that. I'm very keen to learn more about your PLC usage.
My son and I built something similar the Web Energy Logger (WEL) from OurCoolHouse.com (http://www.ourcoolhouse.com/WEL/) but we are bumping up against some reliability problems and he is losing interest in fixing it. The data logging part of our system is accessible here ==> http://svallens.com/templogger/index.php?days=1

We activated the part that controls the closed glycol loop circulating pump on my 4x10 DHW collector a couple days ago and since then we have had more holes in our data, Esp yesterday. Perhaps we are just at the hairy edge on the analog limits of the wiring specification since we have about 100 meters of flat cable by now. I have no idea why it got better at 5:27 this morning, after missing most of a row of data once an hour for a day.

More on my grand ZEH plans another time. They mostly center around solar heating, with a fantasy of converting excess heat to electricity in the summer time. Perhaps a scaled down version of this:
http://www.renewableenergyaccess.com/rea/news/ate/story?id=47266

ja

Mark Parsons

2nd February 2007, 08:19

Hi John,

Thanks for the links to your Data logger model and yesterday's posted log graph. I always enjoy analyzing data graphs. It was interesting to spot the natural logarithmic decay curve of your Attic temperature.

No neighbor concerns at my cottage about wood burning fumes. Nearest neighbor is about 1 mile away.

You are lucky to have a good solar resource in California. I have immediate family down in the LA area. My solar resource up here is better at my cottage than my home due to more marine influence of the Great Lakes at my home. Conversely, my home has a better wind resource than my cottage.

My background is industrial electronics. I plan to integrate an Allen Bradley Micrologix 1100 PLC for monitoring and control of cottage systems.
Details at http://www.ab.com/programmablecontrol/plc/micrologix1100/
The plan is to have it monitor: analogs - battery voltage and current and calculate amp-hours, solar flat plate temp, hot water tank temp, stove loop temp, outdoor air temp, indoor air temp; digital - motion sensors, light sensor, lighting switches.
Control: lights, drainback DHW pump, low voltage disconnect.
PLC's have MTBF numbers up into the millions of operating hours. Reliability has never been an issue in the 25 years I have been using them. Sensors and wiring connections can often be a source of reliability issues.

Attaching a graphic of my water system plan if I can get the attachment function to work.

Living in San Jose you are in the heart of Silicon Valley. Nanosolar has now announced aquiring manufacturing facilities near you and the stated goal of production of their thin film PV this year. Upon successful production we should see the prices dropping significantly allowing you to consider direct solar to electric more economically in the near future. Maybe you could offer to be a beta test site.:D

Take care,
Mark

John Allen

2nd February 2007, 11:26

The PLC approach sounds very solid. Do you suggest I buy directly from the Rockwell Automation Webstore (http://shop.rockwellautomation.com/RA/index.jsp?scrnCurrentStore=RA)or is there another online vendor you would recommend for the parts?

My background is as an applications programmer but I've been away from even that part the field for many years, so the PLC will be a bit of a learning curve for me. With your expertise it seems like, if you are willing, you should lead a thread here at Green Power Talk on monitoring and control systems. As a minimum, many of us could sort of copy what you do for your cottage. What tool did you use to make the schematic you posted?

>Sensors and wiring connections can often be a source of reliability issues.
I believe this is exactly my current problem. My system is running perfectly since I unplugged 3 new sensors, even after I reattached one old one.

I have asked many people if Nanosolar's cost is low enough for them to offer a significantly lower price. As you can imagine, I'm not getting any answers about this most crucial and secret issue. Many folks who currently peddle the existing PV products say that Nanosolar will have little motivation to make the price much lower than the market because there is already a short supply so why should they? I think the truth will be somewhere in the middle for the near term, but I am very hopeful that Nanosolar has a breakthrough technology and they will ramp up to fill the need - at an ever lower price.

Because of my hope for Nanosolar and other PV outfits, I'm not betting the farm on thermal to electric conversion. 75% of my energy needs however are for more heat, so I'm still focused on that. You have the opportunity to use stored chemical energy in the form or renewable wood and I have lots of sun.

BTW, I'm intrigued by your spiral pump and your cottage looks beautiful.

ja

Mark Parsons

2nd February 2007, 15:09

Hi John,

Glad you liked the info and I appreciate the cottage compliment. The photo used in the schematic was from a year ago so things have changed on the exterior. The schematic was done with Microsoft Visio. An easy program to master.

I buy AB (Rockwell Automation) from a local distributor. You would be better to find the local distributor. Should be able to find them from the RA website. There are signficant discounts from list on these items. I buy the Micrologix 1100 base unit for under C$600. You will also need development software worth about the same or a little more. If there is interest in a thread for this type of home systems control automation we can start one.

Luckily (for us consumers) Nanosolar have a number of competitive start-ups on their heels with the thin film technology. Google 'Thin Film Solar'. Each has a slightly different method of printing the film on the substrate. A combined group making production will definitely drive prices down. Costs are much lower for thin film using the printing techniques. No major silicon costs. I am delaying purchase as long as I can to take advantage of expected lower $ / Watt.

For more info on the Paddlewheel Pump, I started a thread under the MicroHydro section. I have lots of details of the physics and performance and math model for a sizing aid. It is an amazingly simple and robust device. Impresses all visitors when I demonstrate the unit by washing the peak of my roof while standing on the ground and directing a garden hose nozzle located at end of 200 feet of garden hose from the unit floating in the creek. The major downside for me is winter. I have to pull it in late fall and float it again in the spring. Hence the reason I am washing in a well this year to provide winter time water. The electric pump will also require more winter electricity.:(

Mark

John Allen

3rd February 2007, 22:33

>If there is interest in a thread for this type of home systems control automation we can start one.

Let's ask Rob Beckers how to best pose that question to the whole green power talk community. Are you there Rob??

I am also waiting for lower prices on thin film PV.

Your hydro thread looks fascinating. I have no stream access here in the city but I'll subscribe just for interest.

ja

Rob Beckers

4th February 2007, 08:04

>
Let's ask Rob Beckers how to best pose that question to the whole green power talk community. Are you there Rob??

No need to ask really, you can start threads as you see fit.
PLC use for monitoring (and possibly even automating a bit) would be a great topic! I'd say either the Balance-of-Systems section or possibly the Building Materials section. Up to you really, any place will do if you feel it belongs there.

As I mentioned, I too have plans to slowly make this house of mine a bit more renewable and efficient. So, I too have an interest in learning more on using a PLC to monitor systems. I've programmed almost everything under the sun, starting with PDP-11's, but never worked with PLCs. It'll be something new. That really illustrates the whole purpose of this forum: To get exposed to new ideas and learn to use new materials, preferably by looking at someone who's already done it.

-Rob-

Mel Tyree

1st April 2008, 10:45

See my new post 'Net-Zero Energy House', but we need lots of different solutions; what works in one place will not be optimal at another place. For example, I can give you a link to 4 Net-Zero energy houses in cities/urban areas of Alberta. All these houses are nearing completion. They all take different solutions. They all are experimental. Once we have seen them operate for a year or so, we can learn how to do it better the next time. My house has been running since Jan 9, 2008, and I am measuring its performance.

Michael Stasse

15th April 2008, 22:21

I've built one in Australia.

We're not off grid though, we're grid tied with 1.28kW of UniSolar US64 PVs on the roof. We also have 800Ahrs of back up batteries for blackouts which switch over seamlessly whenever that occurs.

Over the last three years we have used 4128 kWhrs (including all the power to build the house!), and we've generated 4182 kWhrs. So we pretty well break even or slightly better.

I designed the house myself (that's what I do http://www.greenhousedesign.green.net.au) and it has needed no heating or cooling, even though temperatures dropped to -6C last winter, and we had a couple of 40+C this summer.

We run a fridge/freezer, a TV, a computer (obviously!), lights in every room, and lots of kitchen gadgets (incl a bread maker) but no dishwasher.

All our water is 100% heated by the sun, never boosted. We do use gas to cook, which we buy (about $75/yr) but it's my intention to build a digester and produce all our own gas soon.

I'm new to this forum, and haven't investigated posting pics yet, maybe someone else can help me out here...

Mike.

Mel Tyree

16th April 2008, 10:18

Great job!
I will look into your house desing with great interest. Sounds like you are very nearly zero-emission too. You burn gas for cooking but nothing for heating, is that right?
My next goal is to build a zero-emission off grid house in the cold north. When you do the calculations the main issue is not heating but cooking. With a combination of very good insulation and passive and active solar you can heat a house with very little electricity. The main problem is the electric stove!
I am still trying to figure out how to desnign a house that is reliable off-grid during periods of cloud and no wind. The issue is how much the risk is on any given day of not having enough sun and wind energy. So I need to consider the trade-offs, i.e., the cost of energy storage in batteries vs the risk of not having energy for cooking when needed.

Mel Tyree

16th April 2008, 10:23

Most of you have probably figured this out already, but I have a posting about a net-zero energy house and zero-emission house under the wind energy discussion group. I did not want to post multiple messages. But should have posted under green shelter too!

Joe Blake

16th April 2008, 20:30

I'm new to this forum, and haven't investigated posting pics yet, maybe someone else can help me out here...

Mike.

Hi Mike,

Welcome to the forum.

Re posting piccies, probably the best thing is to open an account with an on-line archive like Photobucket or similar. They have all the appropriate buttons you can push to insert a picture directly into a post or to make a link to a pic. Some of the archives will even re-size the pics automatically to suit where you're posting.

The house sounds good. I'm an ex-pat 'nana bender, but studying to be a Sandgroper. (Only been here 32 years - sitting for my preliminary exams soon - hopefully before I die of old age :D)

Will look forward to some photos. Make sure you open your own thread on them, so there can be plenty of comment and/or discussion.

Joe

Rob Beckers

17th April 2008, 07:12

I've written a little tutorial on how to post pictures to the forum (http://www.greenpowertalk.org/showthread.php?t=5028). It's really, really easy, and the forum will automagically resize just about anything you throw at it.

Since it seems to get overlooked: The form main page will show all the threads that are new or have recent activity on the right side. In addition, clicking the "New Posts" menu option at the top of each page will get you the same.

-RoB-

Mel Tyree

16th May 2008, 10:15

Hi folks,
I have fulfilled a promise to myself to do a ‘scientific’ study of the performance of my Geothermal Heat Pump (GHP) which provides heat, A/C, and some hot water in my Net Zero Energy House. WHY? Because I could not find a heating installer in Clinton County, NY, where my home is located, who would advise me to use one or believed one would actually work at all … or cost-effectively if it did work.
So I have done measurements and written a report close to ‘peer reviewed’ scientific standards, but am not sure anyone will read it! I am a scientist with a very high citation index (upper 0.5% highly-cited in my very narrow field), so I am used to being read but have my doubts about this one. So if at least two people read it I will be happy! Let me know if you do crack a page. It is ‘published’ on the Home page of my SWIEP site;
www.ualberta.ca/~mtyree/SWIEP
Happy reading,
Mel Tyree, Moderator of SWIEP, Dept Renewable Resources, University of Alberta, Edmonton, Canada.
PS- I will double post this on small-wind-turbine sites, the reason being that my turbine provides all the power need for the GHP… maybe that will get me my two readers. It also provides an example of the level of technology I am using to study my turbine.

Stewart Corman

16th May 2008, 12:05

Mel,
Count me as having read your report and a few comments:

just as a suggestion from now on : why not post the direct link, since it took me a while to find it:

http://www.ualberta.ca/~mtyree/SWIEP/Docs/Logging%20of%20Performance%20of%20my%20Geothermal% 20Heat%20Pump16May08.pdf (http://www.ualberta.ca/%7Emtyree/SWIEP/Docs/Logging%20of%20Performance%20of%20my%20Geothermal% 20Heat%20Pump16May08.pdf)

Overall, I think you have proven the nay sayers wrong!

In my 2000 sq ft home with standard insulation the HP will use 7,450 kWh of electricity in an 8010 HDD heating year at a cost of $1,275, which is competitive with fuel oil costs at current market prices.Competitive?? unless I read you wrongly, this is phenomenal.
My climate downstate is more mild than yours.
For a 2750sq ft ranch, I use 850kWh/mo at an avg cost of $100/mo = $1200/yr at a rate of $0.14/kWh ( you pay higher rate)
this includes NO heating other than domestic hot water, NO air conditioning
IF I used oil heat of 700 gal @ 3.50/gal = $2500/yr PLUS extra $30/mo electric costs
I currently used 6 cords of firewood at $140/cd = $850
firewood heating uses electric for blowers and water circ pump

In Fig 1, I note your air temp at 100F and room temp is 70F ...I have a hard time getting much over 65F!

The ‘pumping’ part of the GHP is provided by a refrigeration compressor that pumps freon gas/liquid (or its modern equivalent) through a refrigeration cycle.Why freon compressor cycle? I would think a non-compressor unit (using ammonia ?, or Sterling cycle device) would be more economical from an electrical consumption perspective?
I realize that in winter the juice used by the compressor simply adds to the electrical "heating" of the house anyway and is not lost, but in summer that extra heat is a loss when airconditioning. Is there a means to use the circulating ground water simply as a "chiller" with the compressor turned off?

You mention "well", but didn't you show a photo of "closed loop" coils of 100's of feet of metal tubing buried five feet under soil as the heat sink??

My $0.02:
The circulation pump juice requirement of a closed loop system is a fraction of a (3/4 hp?) well pump ...could also use different fluid with better heat capacity characteristics

The heat transfer coefficient of water-water compared to water-air is about 12:1, so a hot water baseboard heating system is far more efficient than a forced hot air system. For the same reason, these ground water systems are more efficient than the commonplace air "heat pumps". Also, the means to deliver the heat where you want it is far more economical in a water based system....my baseboard runs at 120F from the woodburner and the Taco circ pump runs at 50 watts, this compared to the 500watts 1/3HP air circ squirrel fan to blow 100F air around.

As far as the windpower, if/when the battery bank is fully charged, there is a benefit of using a resistance dump load for 100% efficiency and bypass all the electronics that are inefficient.

Overall, I am still very impressed with your whole setup, and as I had mentioned in our phone call, I had never realized that geothermal was relevant to residential installation unless you lived over a hot spring.;)

found these links:
http://www.geothermie.de/gte/gte32-33/ground_as_a_possible_heat_pump_s.htm
http://www.groundloop.com/geothermal.htm
Stew Corman from sunny Endicott

Paul Bailey

16th May 2008, 14:37

Hello Mel ,Stew ,Rob ...I'm just printing the report,and can't wait to read it since I Love Heating Stuff. I'll try to remain objective since there Is alot of debate out there on GSH Pumps. This may take awhile for me to digest the info and reply but thanks for kick starting my interest in this great subject again Paul:)

Mel Tyree

16th May 2008, 14:50

Wow, that makes 3 readers. I struck the jackpot!:)

Paul Bailey

16th May 2008, 22:10

Mel: I'm still Digesting and reveiwing the numbers and it's impressive.( you were right..you are good at math) and the depth of data collecting with Real world numbers is LONG overdue . This is Jackpot material as you now have no more fuel delivery once the Hardware is installed and commissioned.. I'll save some more objective comments later on this in another post to follow., As not all installs work as well as yours due to a variety of factors such as the usual: Poor design,siteing,install issues, improper heatloss and sizing, bed saturation, soil titration rates and the list can go on and on.. I'm sure youv'e looked into this and your installer was willing to get it right.( you also had a very good well ) I'm truly amazed at the result. Is your heatloss in the 35K btu range.??? and what is the Btu range stated on the heat pump? More to follow. thanks Paul:)

Rob Beckers

17th May 2008, 07:31

Hi Mel,

It is good to see that heat pump manufacturers are not full of it after all. Those are pretty good numbers! One comment: Wouldn't you add the energy needed to run the compressor to the output of the heat pump?

COP = (HS + EA)/EA

Since the compressor heat is produced within the thermal envelope of the building it goes towards heating the structure as well.

I'm surprised how much energy it takes to run the water pump, 3kWh/day (and 1/3 of the heat pump's use) is quite significant. Any ideas on improving that? A variable speed well pump such as the Grundfos SQE series pumps maybe?

-RoB-

P.S. Please don't double-post what is essentially the same. It leads to fractured threads with people replying in both. If you want, refer to the same in multiple threads just put a link to the 'main' post in the other threads.

Mel Tyree

17th May 2008, 09:58

I think the COP is correct because HS = 1.06 CFM dT already includes any heat energy in EA because it heats the air. HS is defined in a document I have on the Water Furnace brand of HP; I will check and if I am wrong I will get back to you.

PUMP the pump in question is a Grundfos SEQ; Actually I am not too happy about the power hungry controller board on my Grudfos. During my test the pump was off 21.5 h per day and drew 3.11 kWh/day (phantom load if you like to call it that)!!! There is no excuse for a controller board to draw that much. I bet you have installed Grudfos's before because they are soft-start. Have you ever checked the off-power usage state? I would like to know if there is something wrong with mine! The HP controller board draws a lot too!

WEAKNESS OF MY STUDY: I did not measure CFM. There is a blinking LED that counts CFM on the GeoMax2 and I assumed that was right. I do have a hot wire annemometer designed to measure ft/min in duct work but do not know the correct way to convert velocity to CFM. If we can assume turbulent flow and UNIFORM velocity in the cross section then it is easy. Do you know how to do this? In my Water Furnace manual (a HP similar to the GeoMax2) it said the ECM motor speed was adjused dynamically to maintain the selected CFM +/- 5 % so I just assumed the +/- 5% applied to the GeoMax2...hence my paper would never make it past peer review!

The COP I report is higher than Heat Controller Inc specifies (4.4 for the model HTV60 = mine).

I attach my Excel sheet for hourly kWh usage in my house including my GridTek10. I am not convinced, yet, the the turbine input values are correct so no guarantees...

--Mel
PS- thanks for pointing out the problem with double posts...I won't do it again. Can I assume any post in any thread is sent to anyone?

Mel Tyree

17th May 2008, 11:30

My heat load calculations at design temperature was closer to 49,000 BTU/h assuming 16 air exchanges per day. About half of that load is due to heating cold fresh air. I have a fresh air heat recovery system that lowers that figure but by how much I can't prove or measure (yet).

My 2 wells came in at 60 GPM during pump tests. My open loop system is more energy efficient than the conventional closed loop system. But to have open loop you have to have a well with a good pumping capacity and good water chemistry... not too hard, not too much iron or sulfur or clay. I had to figure all this out myself. Local installers had ZERO experience. And there is always a financial risk drilling wells...you don't know if it is good until you spend the $$.

Rob Beckers

18th May 2008, 08:12

I think the COP is correct because HS = 1.06 CFM dT already includes any heat energy in EA because it heats the air. HS is defined in a document I have on the Water Furnace brand of HP; I will check and if I am wrong I will get back to you.

That assumes all of the electrical losses end up transferring to the heat exchanger. A percentage will simply heat the surroundings, still useful if it's within the building envelope. Do they build heat pump compressors to be 'cooled' by the freon (or current equivalent)? I.e. is there an attempt to get as much of the electrical losses as possible into the heated air?

PUMP the pump in question is a Grundfos SEQ; Actually I am not too happy about the power hungry controller board on my Grudfos. During my test the pump was off 21.5 h per day and drew 3.11 kWh/day (phantom load if you like to call it that)!!! There is no excuse for a controller board to draw that much. I bet you have installed Grudfos's before because they are soft-start. Have you ever checked the off-power usage state? I would like to know if there is something wrong with mine! The HP controller board draws a lot too!

How much is the current draw (and at what voltage) when the pump is not running? 3kWh/day in stand-by losses seems very excessive! Looking at the specs, the Grundfos CU301 controller is listed to use 5W, so that should make 0.12 kWh/day.

-RoB-

Mel Tyree

18th May 2008, 10:01

That assumes all of the electrical losses end up transferring to the heat exchanger. A percentage will simply heat the surroundings, still useful if it's within the building envelope. Do they build heat pump compressors to be 'cooled' by the freon (or current equivalent)? I.e. is there an attempt to get as much of the electrical losses as possible into the heated air?
-

Yup, good question. My HP is in an unheated basement so I guess the excess energy keeps my basement a fraction of a deg F warmer. My HP uses R-410A refrigerant. I have no idea of the advantages/disadvantages of this over freon other than it is environmentally friendly. The Century line of HPs from Heat Controllers still uses freon

How much is the current draw (and at what voltage) when the pump is not running? 3kWh/day in stand-by losses seems very excessive! Looking at the specs, the Grundfos CU301 controller is listed to use 5W, so that should make 0.12 kWh/day.
-RoB-

It draws about 0.4 amps while off. Attached is a typical raw data sheet. Here is how I check that the value is correct. (1) A similar CT coil is on the hot water tank & it reads <0.001 A when off, (2) I used a hand-held CT coil/meter to check. It agreed with the CT coil attached to the controller. (3) While logging I disconnected the power supply wire to the controller and the CT coil reported nearly zero amps. So where is the power going? I don't know. Perhaps it does not completely shut off power to the pump???

There has been so much interest in my little report that I have felt compelled to improve it. It now has more in methods, data analysis, and a conclusion. So check it out again.

Mel Tyree

18th May 2008, 10:17

Looks like my attachment did not go thru. It was a txt file over the size limit. So I cut out 90% of it so you can see some raw data.

Rob Beckers

20th May 2008, 13:29

Mel, thinking through the water pump energy use a bit more I wonder why it's eating up so much energy while in use (apart from the the stand-by losses). From an energy perspective all that pump needs to do is overcome friction losses in the water lines and heat exchanger. Since the water is dumped back at the same elevation as it was taken from, the pump is not doing any lifting work, regardless of how deep you are pumping from. In your study you're showing the pump lowers overall efficiency from 480% for the heat-pump only to 350% when the water pump is included. That's quite an impact...

-RoB-

Mel Tyree

20th May 2008, 14:38

Rob,
I agree the pump has a large impact but it is about what I expected. In my opinion (might be wrong) I have more than frictional loss because I am pumping to domestic supply pressure (50 psi) and I don't get that back on the down-hill run into the receiver well. The 50 psi on the dischange side is lost as kinetic energy in the water velocity injected into the well. So I think if I lowered the pressure to 20 psi the pump might use less energy. But the controller setting allows a minimum of 40 psi. So that is a moot point. If I lowered the pressure I would have to install another pump (booster pump) for domestic water.
DO YOU HAVE ACCESS TO ANOTHER GRUNDFOS PUMP? It would be great to know if others draw 0.4 A when off. If not then I have an excuse for warranty repair/replacement.
I've thought a little more about how much extra energy might be leaking into the basement from the compressor. I think very little; here is why:
HE = 34,575 +/- 1350 and if you add to that AE = 9378 (= energy to run the compressor) we get 43,953 +/- 1350 (given that the 9378 is quite accurate).
This is not significantly different from HS = heat going to the house = 45,160 +/- 2258. A little extra heat from the pump might make it into the house, but I doubt it is much. HS, HE and AE are all independent measurements, but conservation of energy says that HS can't be more than HE+AE.

--Mel

Rob Beckers

21st May 2008, 08:04

Mel, no I don't have access to another Grundfos pump. I'd just give them a call and ask what the stand-by losses are supposed to be. As mentioned, their specs list 5W. If it's more that should be something Grundfos needs to investigate (broken controller?).

-RoB-

Brian Tellinghuisen

7th August 2008, 14:31

Check out my Green Brick and see if that would help you build a ZEH? Info in my profile.

Rob Beckers

25th October 2008, 16:05

Mel, did you ever figure out why your pump was drawing so much stand-by power?
I'm looking into replacing my 20-year old water pump. It's been quite noisy lately, and while it still works it's just a matter of time. I'd rather replace it while I can put some effort into research of what is most efficient and suitable for the purpose, than having to rush it when the water stops flowing. In addition, I'm also taking another serious look at putting a water-source heat-pump in while I can get the $7,000 eco-energy rebate for that.

We also mused a bit about the large reduction of overall efficiency due to pump losses. As you noted, one reason could be the unneeded pressurization to 50 psi of all the water going through the heat-pump (where something around 5 psi would probably have been enough to overcome friction losses and get sufficient flow). I have been attempting to put a number on pressurization losses, based on your scenario. Here goes:

50 psi equals: 50 * 2.31 = 115.5 feet of head that the pump needs to overcome.
Your heat-pump uses 9.5 gal/min = 36 l/min = 36 kg/min = 0.6 kg/sec of water

Lifting that water up 115.5 feet = 35.2 m takes the following power (energy per second):
Power = 0.6 * 9.8 * 35.2 = 207 Nm/sec = 207 Watt

This is only 7.5% of energy you're running into the heat-pump itself (at a rate of 2.75 kW), so it seems there's not much to be gained by lowering the water pressure to 5 - 10 psi instead of 50 psi.

Please verify that I did those calculations correctly. If correct, that still begs the question why the pump eats up so much energy. :confused1: As mentioned before, the return line for the water should go down all the way to the water line, so you get back the energy spent lifting the water out of the well. Of course there are water friction losses, but for a properly sized water line those aren't more than the equivalent of around 20 feet of head. Pump efficiency can't be that bad. Any new ideas?

-RoB-

Mel Tyree

26th October 2008, 09:45

Mel, did you ever figure out why your pump was drawing so much stand-by power?

Reply: No, the Grudfos rep in NY has been singularly unresponsive. When I point out the pump normally draws 80 to 110 W when off, he says that is normal. When I point out the manual says it should draw 5 W he is unresponsive. When I point out I think the power consumption when off exceeds the power consumtion when on summed over the whole year (I pump 1.3 million gallons a year for my heat pump), he doesn't seem to care. This problem can be fixed by replacing the controller with a simple pressure-sensitive on-off switch.

I'm looking into replacing my 20-year old water pump. It's been quite noisy lately, and while it still works it's just a matter of time. I'd rather replace it while I can put some effort into research of what is most efficient and suitable for the purpose, than having to rush it when the water stops flowing. In addition, I'm also taking another serious look at putting a water-source heat-pump in while I can get the $7,000 eco-energy rebate for that.

REPLY: Good idea.

We also mused a bit about the large reduction of overall efficiency due to pump losses. As you noted, one reason could be the unneeded pressurization to 50 psi of all the water going through the heat-pump (where something around 5 psi would probably have been enough to overcome friction losses and get sufficient flow). I have been attempting to put a number on pressurization losses, based on your scenario. Here goes:
REPLY: I think you can save some energy by setting the pressure to 20 psi. You need 5 psi for the pressure drop in the GHP heat exchanger + 5 psi for an in-line water filter + 5 to 10 for pressure drop in the supply and discharge tubing.

50 psi equals: 50 * 2.31 = 115.5 feet of head that the pump needs to overcome.
Your heat-pump uses 9.5 gal/min = 36 l/min = 36 kg/min = 0.6 kg/sec of water

Lifting that water up 115.5 feet = 35.2 m takes the following power (energy per second):
Power = 0.6 * 9.8 * 35.2 = 207 Nm/sec = 207 Watt

This is only 7.5% of energy you're running into the heat-pump itself (at a rate of 2.75 kW), so it seems there's not much to be gained by lowering the water pressure to 5 - 10 psi instead of 50 psi.

REPLY: Another point is the economics. If you run the GHP at say 20 psi you still need to buy another booster pump to run your domestic water at 50 to 70 psi. So I agree it doesn't seem worth it.

Please verify that I did those calculations correctly. If correct, that still begs the question why the pump eats up so much energy. :confused1: As mentioned before, the return line for the water should go down all the way to the water line, so you get back the energy spent lifting the water out of the well. Of course there are water friction losses, but for a properly sized water line those aren't more than the equivalent of around 20 feet of head. Pump efficiency can't be that bad. Any new ideas?

REPLY: Your calculations assume 100% efficiency of the pump. The only way to know for sure is to measure the current drawn by the pump when it is on. Mine draws 7 to 8 A @ 230 V so we are talking about 1.7 kW when on. If you run at 20 psi you could probably use a smaller pump (maybe 1.2 kW??). But if you are being cost effective, you would have to pump a lot of water to save enough in electrical costs to pay for the booster pump you would need for domestic water.

-RoB-

Do you have a voltmeter with a current transducer coil? If not I can bring one by when I visit you on Nov 15th and we can measure the power consumptionn of your present pump.

Rob Beckers

26th October 2008, 19:17

My current pump is a 20-year old all-or-nothing setup. So there's not much to measure. It uses an old fashioned pressure switch for on-off, no standby losses that way.

If the 80 - 110 Watt standby power for the Grundfos control unit is typical, then that does not bode well. I have been trying to get more information from the Internet regarding their SQE line of pumps, there's very little available, and the reviews are mixed. The most vocal are a few installers that are almost pathologically against any variable-speed-pump such as the SQE. Here is one thread regarding that (http://www.terrylove.com/forums/showthread.php?p=142307), there are more. The comments seem to be that while Grundfos is the best of the bunch, even those will not last more than 5 - 8 years since that is their design life, and having to come on for every drop of water that's tapped means many more cycles than a regular pressure tank setup (then there are comments on how a 10,000 rpm motor/pump has more wear than a traditional 3,000 rpm pump, but I don't really buy those).

Those delivering the criticism are not impartial; as far as I can tell they are in cahoots with the makers of constant pressure valves. One brand in particular that goes under the name 'cycle stop valve'. The problem is that I cannot determine how much of the criticism is valid, and how much is bogus.

The alternative they present is to install a constant pressure valve ahead of pressure switch. The theory is (and as far as I understand it, that part seems correct) that putting back-pressure on the pump will decrease the flow and for the typical centrifugal pumps used in wells that means the pump will see less loading, and draw less power as a consequence. So, apart from the initial drop to make the pressure switch go on, you get constant water pressure and variable flow, while saving power because the pump's power use is proportional to flow.

I have to admit I see a certain elegance in this scheme. The problem is that I can't find any comments on the Internet other than manufacturer's voices that say if it works or not (or how reliable it is). For some information on constant pressure valves please take a look at this link (http://www.cyclestopvalves.com/index2.html).

If this works, it would give virtually constant pressure, while saving energy, for half the price of a Grundfos SQE (and with zero stand-by losses). It also means a regular well pump can be used, with known reliability.

I really miss enough information (and don't have the background) to say if constant pressure valves and the proposed setup will work or not. If anyone has any insights to offer I would be most interested and grateful!:help:

-RoB-

Mel Tyree

27th October 2008, 08:54

Rob,
This is a new technology to me too. I looked at the web site a bit to see how it works. But so far I can't figure out how a constant pressure valve can work with a pressue sensitive switch to turn off the pump when water demand ends. Maybe it is still too early in the AM for me!
But the claim about energy saving is easy to check once you install one. Maybe it could be checked without installing one. The claim seems to be that if you produce a back-pressure on a pump it consumes less energy as puming rate decreases.
So why not put your pump on a manual switch and discharge thru a valve to control flow rate? As you lower the flow (close the valve) the power consumption of the pump should decline. Does it delcine enough to be worth the cost? Seems to me all you need to measure is flow rate (GPM) versus power to get that answer. Measure flow rate with a 5 gallon bucket and watch and power with a multi-meter and CT coil.
With regard to a GHP (10 GPM) versus domestic use (1-5 GPM typical) you would need a test pipe about 1" diameter and a valve capable of 1 to 15 GPM for this test because you need to size a pump capable of running a GHP while domestic demand is high too.
--Mel

Rob Beckers

28th October 2008, 08:41

It seems that my options for using a constant pressure valve or similar device have ground to a sudden halt: Those cheap b$%t@rds that installed the well used 75 psi plastic tubing underground. :mad: With a constant pressure valve the pump will run up all the way to close-off pressure, or 100+ psi for the pump size I would need. Short of replacing the underground tubing (which is now unreachable unless I dig up a nice stone patio and a mature tree) there is no way to do this. Even 20 years ago when the well was made, better tubing was readily available and almost as cheap.

My gas-fitter-slash-plumber-slash-well-pump-guy came by yesterday to hook up a new water heater (http://www.greenpowertalk.org/showthread.php?t=5912) and we talked a bit about constant pressure systems. He has not installed any Grundfos SQE pumps/systems, so no comments on that, but he has installed quite a few constant pressure systems using a device from Italy that goes under the name Mascontrol (http://web.watertech.it/main.php?lang=usa&pag=02_Products&spag=01_Mascontrol). According to Mike they work like a charm. Here is a link to a brochure (http://www.lancasterpump.com/documents/LancPump_Mascontrol.pdf). In any event, his comments on constant pressure valves and similar devices is that they do work, but are hard on the pump because it will run the pump up to close-off pressure. For a good pump that has no impact on life time (avoiding short-cycling will actually extend the life time), but it will cause premature failure in a cheap pump that has lots of plastic parts.

So, it seems my options at this point are to either install a Grundfos SQE and hope it lives longer than the 5 - 8 years reported elsewhere, and that it doesn't draw 100 Watt in standby power, or, stick with the current setup and just replace the pump.

-RoB-

Mel Tyree

6th June 2011, 12:32

I have posted in the past about my Net Zero Enerrgy Home 80 km south of Montreal in NY State (Ellenburg Depot). I recently gave a talk about it at City Hall, London, Ontario. I usually give lectures about 5 times per year. Now that I am living there full time, I have more precise data about total house performance. It turns out I make enough renewable energy from the sun and wind for heating, AC, hot water, all electical applicances AND for driving my plug-in electric car about 16,000 miles (26,000 km) per year. I bought a used Tesla Roadster 1.5 in Feb 2011 (on Ebay) and have added 6,000 miles to the odometer in 4 months.
My talk is too large to post in pdf format (4 MB) so please Email me if you want a copy. The house cost $65,000 extra to build (for the RE systems & geothermal heat pump), but will save $165,000 in energy costs for the home (from 2008 to 2028) + now saved gasoline costs at $63,000 assuming 7%/yr inflation for gasoline (from 2011 to 2031).
--Mel:bigsmile:

Rob Beckers

7th June 2011, 07:19

Tesla Roadster?!
Now I'm really jealous! :hail:

-RoB-

Mel Tyree

7th June 2011, 13:54

Yes Rob,
If you can provide me a plug in point NEMA 14-50, 6-50 or 14-30 I will drive the Tesla up to your place to visit. I want to discuss with you the Ontario PV FIT and if small residential systems still get into the program...but we can also just do this by phone sometime soon. I may be involved in a NZEH project in Ontario so need some info.
Thanks,
Mel

Rob Beckers

8th June 2011, 07:46

Have to take a look at the amperage of my dryer outlet. That should be at least 30A, possibly 50A, so conversion to a socket of your choice can be arranged. I'll make a little extension cord...

-Rob-

Joe Blake

10th June 2011, 08:35