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Old 06-04-15, 03:18 PM   #1751
Marc_NL
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I'm not sure that I know what a 'thermal wax valve' is?
They are quite like what you describe except that a heater is used to make the wax expand and actuate the valve. Therefore every open valve draws some 5W (seems the most popular value).

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I don't think that brine is being used much in North America. I'd like to know more about your interest in it, and what its advantages are.
Well, overhere they just use the term brine for the closed loop ground source (either horizontal or vertical) circuit. I think water/glycol and water/ethanol is mostly used as coolant. So it doesn't reference the salty stuff.

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There are many lessons to learn from all of this. Not the least of which are:
  • Pay great attention to the architectural aesthetics, and how they affect the occupants.
  • Design the thermal aspects of the house (especially windows), giving the "mechanicals" a smaller role.
  • Pay greater attention to the foundation and floor insulation.
  • If a controller is required, try to find a commodity controller, should controllers fail, or owners change.
Thanks for the extensive info. I will have a look at the links later on. The story indeed touches a good few of the basics. Our home will have triple glazing. Double glazing just loses too much energy and with low temperature distributed heating there is a big chance of causing a draft. I think the best way to prevent issues is to also draw air out of the house above the large windows. This hopefully cancels any tendency of air to cool and fall along the window.

The plan for the moment is to use the best possible insulation of the foundation; put thick insulation directly onto the ground and pour the concrete foundation (including heating) on top of this. Hopefully this will work in the location we have found, depends on soil conditions.

Some form of control will be needed and used but the story you tell is another reminder to adhere to the KISS principle.

Cheers,

Marc

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Old 06-09-15, 11:23 AM   #1752
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So, the auction ended today and much to my surprise I got away with buying a GSHP for the opening bid which including auction fees and taxes is around USD 2000, new on pallet. I seriously don't understand the way people buy at auctions, because an identical unit went for 50% more.

Anyway, it is a Danfoss DHP-C 6 which is a 6kW heat pump including 180L DHW tank (with electrical back-up heating up to 9kW) and including the heat exchanger for 'natural' cooling (without the heat pump active). It is rated at a COP of slightly above 4 (including pumps) for 0C water in and 35C water out (which is more than enough for the underfloor heating). Surely the COP for DHW will be much lower.

I think this price is just perfect. I might have been able to DIY one for this, but apart from that even the chinese no-brand units would have cost me more.

However, as this is the DIY heat pump manifesto thread, this is no place for me to continue on rambling. Many thanks for all the info here which inspired me to start looking for a donor unit (and ended up with finding a complete unit...) and for the constructive look at our plans. Please don't hesitate to contact me if you have any questions about the unit just bought or any of the house plans. Our plan is to get a sort of blog / website online detailing our plans and progress. Hopefully I may contact you guys for any future general eco-friendly house conversations.

Regards, Marc
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Old 06-09-15, 12:16 PM   #1753
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Marc

Good deal for a 6Kw hp. I think I have almost that much in my DIY 5 Ton shop heat-pump.

Randen
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Old 06-09-15, 09:19 PM   #1754
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Quote:
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... it is a Danfoss DHP-C 6 which is a 6kW heat pump including 180L DHW tank (with electrical back-up heating up to 9kW) and including the heat exchanger for 'natural' cooling (without the heat pump active). It is rated at a COP of slightly above 4 (including pumps) for 0C water in and 35C water out (which is more than enough for the underfloor heating). Surely the COP for DHW will be much lower...
Sounds like quite the find, and at a price that you like!

I understand BTUs better than kW... so, 6kW works out to 20472 BTU, which will certainly be ample, especially if you are going with Passive House standards as your guide.

How many square meters is your home going to be? On one floor or multiple levels?

Best,

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Old 06-17-15, 10:25 AM   #1755
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Thanks guys. A rare find it is, I've never seen heatpumps at such an auction before. It really helped that I'll need the smallest unit, others went for about three times the price.

Dimensions. Outside is going to be 88m2 for the lower floor and 152m2 for the upper flower (upside down living). The garage will be around 40m2.

If all goes well the unit will be picked up tomorrow and I should soon be able to have a look at it. For the moment mostly interested in the pumps used for the ground heat exchanger and the one for the underfloor heating. The characteristics of these pumps are the details I lacked to go and design both these circuits (with all the info in this thread I should be able to do this!) Then I can hopefully score the required parts in some auctions as well.

Marc
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Old 06-17-15, 11:23 AM   #1756
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...A rare find it is, I've never seen heatpumps at such an auction before. It really helped that I'll need the smallest unit, others went for about three times the price...
Congratulations on your heat pump find. I hope that it will work out to your satisfaction.

However, I think that it would be most appropriate for you to start a new thread regarding your project. You can link from this thread to your new project.

This thread, "The Homemade Heat Pump Manifesto", is actually for people who want to build their own heat pumps from scratch, rather than buy packaged units to deploy. To my knowledge, there is no other site on the Internet that caters to this particular interest, so I prefer to reserve this space for those people.

I have a keen interest in you new build and, I will be joining you in your new project thread... as will a very large number of other EcoRenovators.

BTW, I do have a suspicion that if you pursue the Passive House goal, and wish to use a GSHP for supplemental heat, the unit you bought will be over-sized by a large margin. If things turn out that way, come on back to this thread, because that kind of work would be a great fit for the 'Manifesto'.

In fact, not being able to find a heat pump small enough, is exactly why I decided to build my own heat pump and subsequently started this thread.

Best of luck in your project, Marc!

Sincerely,

-AC_Hacker
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Old 09-14-15, 11:47 AM   #1757
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Thanks, AC hacker, for starting this thread! I didn't find it looking for GSHP, but in looking for information on running r290. I have an old r22 unit that I am going to be installing as a fresh install to an old house that never had AC. I've done two installs before (one used and one brand new) but I only knew enough to make them work correctly and I've been happy with the fact they seemed to do what they were supposed to. After reading this thread (it took several weeks), I've decided to replace the evaporator coil and change from cap tube to TXV before I do this next install.

Since you mentioned that people all over the world read this, I thought it might be good to list some of the unique conditions we face in the bottom half of our state... Selling AC to Floridians is like selling heaters to Eskimos. The AC guys love to tell you that your unit is shot and that you need to buy a new one (that they will happily sell you). I've always contended that an AC is just a couple of boxes that hold two radiators, a compressor, a couple of fans and some sort of expansion device. AC companies are very happy to over-charge and people seem all too happy to blindly pay it. Anyway, back to Florida... We have a lot of heat and a LOT of humidity. About the dumbest thing that's been introduced to Florida is the Energy Recovery Ventilator. The AC just simply can't keep up with the introduction of humidity into the conditioned space. We also don't have anything like the winter that the rest of the country has. In fact, most of the country would say that we have two seasons - spring and summer. I can't remember the last time we ran the heat during the day. If it dips below 40 at night, it's a big news story. So, anyway, we are completely AC down here.

That brings me to another thought... One of my projects is a rebuild of a house on a river down here. I've always looked at that river and thought "there's got to be a good way to use all that (relatively cool) water for something good..." Now I know about Pond (or river) Source Geothermal (closed loop). And that made me think of a subject that hasn't really been covered heavily - that is the subject of pumps...

I remember reading about the Taco pump and another brand, but I've dealt with all types of pumps before - diaphragm pumps, centrifugal pumps, impeller pumps, vane pumps, gear pumps to name a few... We use centrifugal pumps in pools down here, but they suck a lot of power. I'm also thinking you need different pumps for the heat exchanger vs the ground loop? You might have 1" - 1 1/2" HDPE for your loop, but 1/2" openings in your heat exchanger? I'm just looking at pictures but, if that's true, the pumping requirements for the two should be very different.

What are the generic details on the different types of pumps and what types seem to work with the least energy consumption?
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Old 09-14-15, 02:45 PM   #1758
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paramax55,

Welcome to the party!

Glad you made it through the 'Manifesto'. There is a lot of info there.

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I'm looking for information on running r290. I have an old r22 unit that I am going to be installing as a fresh install to an old house that never had AC.
I need to start every discussion with the warning that R290 is hazardous, especially in large quantities, like you will be using, and that you need to assume responsibility for the consequences.

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Anyway, back to Florida... We have a lot of heat and a LOT of humidity. About the dumbest thing that's been introduced to Florida is the Energy Recovery Ventilator. The AC just simply can't keep up with the introduction of humidity into the conditioned space.
I'm surprised to hear that. I suppose that if your cooling system includes in its functioning, a way to bring in fresh air from outside your house, then it might not be so advantageous.

But there are HRVs (Heat Recovery Ventilators) and ERVs (Energy Recovery Ventilators). The biggest difference is that the ERVs return the water of condensation back to the building, so yes you are quite right. But HRVs will bring in fresh air and not lose the heat (or in your case 'coolness'), and the water of condensation is directed out of the house. So in Florida, they should rename the HRV to CRV (Coolness Recovery Ventilator).

The idea of a CRV is that it uses fans but no compressor and relies on a heat exchanger (HX) to bring in fresh air, and not lose coolness, and to reduce humidity (less than the AC but still possible).

Somewhere on EcoRenovatio, I did a study of this very issue and determined that if your CRV is a really efficient one, it can bring in fresh air, and help remove some of the dehumidification burden from the central air conditioner. As I recall, the actual efficiency would need to be in the neighborhood of 80%+.

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I remember reading about the Taco pump and another brand, but I've dealt with all types of pumps before - diaphragm pumps, centrifugal pumps, impeller pumps, vane pumps, gear pumps to name a few... We use centrifugal pumps in pools down here, but they suck a lot of power. I'm also thinking you need different pumps for the heat exchanger vs the ground loop? You might have 1" - 1 1/2" HDPE for your loop, but 1/2" openings in your heat exchanger? I'm just looking at pictures but, if that's true, the pumping requirements for the two should be very different.

What are the generic details on the different types of pumps and what types seem to work with the least energy consumption?
I think you really might be on to something here.

If you really start looking into information that is freely available on some of the circulation pump sites, I think you will find what you are looking for.

Essentially, the circulation pump have been in use for such a long time that just about every characteristic that could effect an optimal installation is well understood, and there is reliable design data to be used to choose exactly the right pump.

Some of the circ pumps are designed to maximize volume, and some are designed to maximize the overcoming of fluid resistance, and there are designs that are various shades of compromise.

I'd advise you to raid the manufacturer's technical documents from manufacturers such as Taco, Gundfos, Upinor, Bell and Gossett, etc.

Taco would be the best place to start.


There are many experienced 'regulars' here on EcoRenovator that have had experiences with projects very similar to your own who will be quite happy to help you along the way (that includes myself), so I invite you to start a new project thread, within the "Geothermal and Heat Pumps" area. If you post the URL to your new thread, then readers of this thread will know where to find you.

Best,

-AC
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Old 09-16-15, 12:26 PM   #1759
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As far as the flammability of r290 goes, I'm not that concerned. I'm a firefighter here and I've only been to three fires involving propane. Two were BBQ grills with old rubber hoses. The third was just sheer stupidity. A poor family had hacked a camp stove into the kitchen because they couldn't afford electricity. That part I can understand. Where they messed up is when they used a garden hose to plumb the propane through a window to get it into the kitchen. Even with a situation so horrendously bad, it didn't start a fire until the hose got old enough to be discolored and broken down by the sun.

Many of our fire stations (and many homes down here) use propane for cooking and hot water. There is usually a tank (or two) of the stuff right outside that's a good ten feet long and three feet in diameter. Then it's plumbed through something less robust than an AC lineset (there's usually a corrugated, flexible hose somewhere in the circuit) to a device that's designed to leak propane in a flammable ratio and burn it. I know the key point is that it's DESIGNED to BURN it, but that doesn't always happen. Things fail and gas leaks and USUALLY nothing catches fire. Anyway, an AC should hold no more propane than a camp stove and any leak should be over the course of a year or more. With a little care, it should be much less dangerous than gassing up the family sedan.

An interesting point on humidity... our department is building a bunch of new fire stations and I had the opportunity to speak with one of the contractors today. The newest station is getting a total 9 tons of AC cooling. What's interesting is that it's also getting a 10 ton dehumidifier. Humidity is such an issue that it's getting more de-humidification than it is getting cooling - more than doubling the refrigeration capacity...
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Old 10-16-15, 06:13 AM   #1760
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Default very extensive information

Hi friends,
I found this site doing a google search. It seems very interesting, but it has almost 200 pages!!!
I'm in a hurry to know if what I thought makes any sense and I would love to read a quick answer from you guys.
I have a house with 200 m2 heated by a diesel furnace and hydronic radiators distributed all over the house (high temperature water of about 70 ºC).
This setup consumes a lot of diesel and in the past I thought on replacing the diesel furnace by a wood pellets furnace keeping the radiators.
However, recently I've installed a photovoltaic solar panel array of 8 KW and an electric heat pump started to make sense. However, my electricity provider pays me for the produced PV electricity and so saving in my electricity bill still makes sense.
The GSHP has a better COP but the installation cost is prohibitive. Then I found this site which claims that a DIY GSHP will cost under $2000.
Of course I presume this price does not include any kind of radiators. My main question is: Can I maintain my hydronic radiators with a $2000 DIY GSHP or the required temperature is too much for this system to be efficient?
Best regards. Joao

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