I've also imported a quantity of hot water heat pumps from different manufacturers), with mixed results - the addition problem I had (apart from various failures) was a crooked business partner. The failures have cost me personally tens of thousands of dollars, but I have honoured ALL individual warranties - the only ones I have ignored were units fitted for a large housing company.
A working hot water heat pump is an extremely useful energy saving device - the only problem to resolve is the reliability.

Error in above statement "Not NZ" should read "Not just NZ"
TC

I was on of those who imported air source heat pumps, all that could be done to ensure reliability was done. I purchased 6 unit and tested for 6months. Proir to ordering a couple of containers.
Yhe trail units were fully stripped, wall thinkness of pipes were tested, number and size of cores in cable, solder type, system cleanliness, full fault simulation was undertaken and of course subsequent problems caused. A number of recommendations were made, and seem to have been completed. (at the same time a Swedish engineer was undertaking similar procedures) As an enginner, I am fimilar with imported products, so want to ensure a reasonable level of quality.
Un be known to all costumers(importers in to many countries) the manufacture in its wisdom (or foolishness) decided that it would change it is own production specifications and production methods.
generally as a rule, slightly less material in all components. This is what has caused many of the failures. The first problems did not show for approx a year, after 2 years it became more than just a odd unit. At which at this time I and many others companies withdrew the product of the open market. The cost to the importers (not NZ) was considerable.
Even though there was manufactures faults, most were actually caused by incorrect installation and use. Excurating the manufactures short comings
A heat pump is not a boiler, and can not be tret in the same manor.
No support was given from the manufacture.
Some of the larger companies were able to take this loss, whilst the smaller companies folded. (the position I was forced into, it did not help with finance companies and property developers also folding owing many $1000's)
I still firmly believe that hot water heat pumps are the near future of water heating, very much like air heat pumps went through the ups and downs, now they are extremly main stream, reliable, with sufficent backing.
" You can not build a Rolls Royce for the price of Lada" Some were in between is what we all try to achieve.
Those who purchased the units are the true heros, they have moved in the right direction.
TC

....hope your coffee was suitable for your unique NZ tastebuds..... ;- 0

Any systems using heat pipes must have a good water flow through the headers, each heat pipes surface area in contact with the water is quite small and to efficiently get rid of the heat the flow has to be higher than other systems.

The way is to monitor the temperature to and from the panel array with the pump running around midday, the differential should be < 15 degrees, anything less, the pump flow is too low.

If you have a custom solution then you may need a higher flow pump.

Cheers
Mike

Oh Dear, someone didn't get their morning cup of coffee!

Typical pathetic Kiwis! All the time the same rubbish about the "unique NZ conditions"
One way to keep technically advanced know how and products from overseas away :-((

Mavrick, how do you think a product becomes established, some one has to take a punt. (some times they win and sometimes they loose) If we all waited to for every product to be proven in NZ then we would still be living in caves.
I do not understand what are so different about NZ conditions, I keep hearing this.
As far as the Avon Electric (Cleanaire) an excellent company, but their units have been expensive in the past. (this has limited their sales)
Synergy, is based upon a Ventaxia unit out of the UK, so is fairly well established.
As far as HWHP, yes in many cases the importers were the innovators, who used their best efforts to supply cost compative and reliable product. Again at some point someone took the punt.
Why will a plastic heat exchanger rot away, plastic does not seem to rot away in a land fill!!!
By the way I recommend enthalpy heat exchanger, such as lossnay.
Any heat exchange system is better than any PPV system

Why buy a product like the synergy that it so new on the market not even tested for nz conditions.
It has a plastic core and they will rot out,
Its a no brainer people do your reasearch its all there.
Just like hot water heat pumps all these companys selling this stuff and we find out 3 years later the heat exchangers are not up to it.People need to be carefull and go with a product thats been around for a while to know all the problems.

Go for the Cleanaire you wont regreat it.
The synergy unit wont do the job as well and wont last as long.
Trust me you get what you pay for.
Cleanaire have been making HRVs for 30 years they know there stuff.

I rang them: they use heat pipe.

On a sunny day the readings can get pretty high. I like the sound of your diagnosis of pump speed. I'll have a look and see if there is a speed setting on them (there is on the central heating water-pump, but the solar pumps are much smaller)

As for U-Tube vs Heat-pipe, I'd go for heat-pipe but I don't know, I was going to check the manual wasn't I.

Does this tell you anything? http://www.leapltd.co.nz/index.php?page=solar-genius-technical#a (It's a standard version of our system)

Cheers,
Russ

In place of regularly purchasing throw-away plastic water bottles which leach BPA and other chemicals when left in the sun, why not try a re-usable, durable, stainless steel bottle that is BPA-free and will not leach toxins into your drinks?

Over the long-term both ECOtankas and Klean Kanteen are not only practical and beautiful, but safer, healthier, more economical and eco-friendly.

Stainless steel ECOtankas™ come in 6 sizes and have 3 types of interchangeable lids including a sippy spout adapter for toddlers. They also feature kooler covers in a variety of colours.

Klean Kanteens are the original stainless steel drink bottle. They come in a variety of colours, sizes and types including wide mouth, insulated, wine karafes, classic kanteen, and a sippy spout kanteen for toddlers. They also feature a variety of additional accessories including lids, carabineers, totes, slings and bike cages.
http://www.environmentservices.co.nz/

Forgot to add :)
Yes I am looking at using an air to water HP as the heat source for the UFH.
Long and low heat rather than quick and high. The house has R5.5 walls and also two Woodburners so hopefully the idea of the UFH is to keep the background heat from dropping below about 18C.
Pete

Hi Ben,
Thank you for the compliment.

Yes you are correct about slab areas that you should avoid. I sheathed using 25mm conduit that I bought from Mastertrade.

Firstly, I sheathed 200mm either side of a slab cut. If there were to be any differential movement either side of the cut then I'm hoping the conduit will take up the slack rather than the UFH pipe itself. Not sure if this is over the top but the belt and braces approach gives me piece of mind. I also sheathed in an area where the pipes needed to cross a slab thickening (unavoidably), as we were not allowed to insulate in this load bearing area.
Finally, the flow pipes running down the hall were sheathed in an attempt to lessen the heat flow into this part of the building (these pipes go to a granny flat on the western end of the building). The returns from the granny flat are unsheathed as I don't mind any residual heat being given up here.

Hope this helps, best wishes for your own build.

Pete

Compressor air cars are already potentially available (in Portugal Iz Think) Compressor air in less efficient, than your water. If you want mechanical potential energy, wind up a rubbber band.

You are right, halving the height and doubling the mass will not change the energy. However you will therefore need twice the volume of water through a pipe to get the same flow rate.

2000 tons is about 12 boeing 747-400's! Are you sure you want to build something to hold that much weight 4 stories high? I don't think you would get any change from $1M. Also the storage container and tower would come at a higher environmental footprint that a battery pack.

Hi Pete,

I just had a look through your construction photos - nice looking house!

I am about to start building my own home and am putting UFH in the concrete slab like you. I noticed in some of your shots there are portions of the piping that seemed to be sheathed in something.

What is the sheath and what areas are you protecting? I am aware you need to be careful not to run the piping under any walls as nails/bolts used to fix the bottom plates will puncture the pipes. And we also need to try and avoid running pipes under the proposed slab cuts, but is there anything else I should be aware of?

Finally, what are you using to drive your UFH? Air-to-water HP?

Regards,
Ben

So, (please correct me if my logic goes astray) if 1000 tons hanging at 20 meters (about 22 yards) will theoretically posses enough energy to charge an electric car, therefore....... 2000 tons hanging at 10 meters should also theoretically be able to do the same thing. A heavier weight lower to the ground might be easier to handle.

Even though these numbers may seem a little impossible, to be honest this is about what I expected. I figured it would have to basically be as powerful as a small bomb.

In order to power it, I'm kind of green lighting on that, and I'm open to any good ideas. It would probably take a solar dish several days to complete the task. If you found a way to hook up a couple excercise bikes to it, I wouldn't be beyond pedalling a little everday. I wanna work out any way. (I apologize if some of these things sound stupid and juvenile, but green lighting and brainstorming is something else I've learned in my engineering classes). Wind is awesomely unrelieable, but it wouldn't hurt to use one or more vertical axis wind turbines.

I like the idea of the compressed air. I'm freaking kicking myself for thinking of that earlier. It would absolutely save on space. I'll do some research and get back to you.

I am interested in this idea

By the way, 1000 cubic metres would need a container measuring is 10 x 10 x 10 metres and would weight 1000 tons. Elevated to 20 metres this would be a significant engineering project and a ridiculous cost....

Buy 55kwh of batteries. That will only set you back 12K it's by far the most cost effective solution.

Chris

Here,s some calcs to make it clear that this won't work.

energy potential of raising 1 cubic metre of water 1 metre is

1000 x 1 x 10 = 10000 joules

1 kwhour is equivalent to 3.6MJ.

so

10000J is 0.0027kwh (in other words 2.7 watts for 1 hour).

1000 cubic metres of water at 20 metres would give you 55kWh. That would seem to be about what would be required. Mmmmm

Similarly, for compressed air.

Chris

how about storing surplus energy as compressed air?

Its going to take a lot less space and (may) be a lot easier to convert to energy when needed.

Once it is at the bottom, what energy are you going to use to lift it back up?

Energy required to charge an electric car:

From http://en.wikipedia.org/wiki/Mitsubishi_i_MiEV:

The car has a range of 130 kilometres (80 mi) for the 16 kWh lithium-ion pack and 160 kilometres (100 mi) for the 20 kWh pack.

So call it 20kWh a charge. Note that it is unclear whether the battery is one that is designed to fully discharge or designed to be only partially discharged.

Seeker

People make mistakes - perhaps they have learnt from theirs. Either way, why would you take the risk. We looked into airfoam prior to the branz report and the fact they they drill through the building wrap and then fill the vent/drain cavity (in a veneer home) was enough to put me off. Common sense tells you that this cant be a good idea. Remove the wall linings, insulate, and reline. Not as hard or expensive as you might think and you get a new looking room.