The Homemade Heat Pump Manifesto

[Xringer]

Originally Posted by AC_Hacker

I think you posted this entry to the wrong thread...

I think you meant to post this entry to this thread.

-AC_Hacker

I guess that I should have explained the point of my post..
Using the X10 output of the CAI board, already gives me some control of Sanyo#1.
Since I can turn it off and on. (I may set up Sanyo#2 the same way).

I added the part about the current sensors, since that will allow the CAI to watch power use,
and automatically shut down the system, if it malfunctions and draws too much power.
(A big problem with my systems).

Of course, the eight TTL outputs (SSR compatible) would be best way to
control the functions of a system. Much more reliable.

From now on, I'll try to avoid posting anything to this thread..

[randen]

AC Hacker wrote:
Is the unit you have at home a GSHP?

We actually have two GSHPs at home one is a Water to Air unit for airconditioning in the summer and a blast of heat in the winter when the wind is really blowing and cold. The other is water to water that does 90% of the heat load and is a Climatemaster Tranquility 27 3Ton unit. The house has a concrete slab main floor (no basement) with 2 " foam board beneth and 3/4 kitec tube in the concrete. The calculated load for the house is just over 5 Ton but again only when its really cold are both running. The ground loop is 6ton 3600 ft of 3/4 hdpe hoizontal. There are 6 zones. I even heat an attached and three car garage with it.

Randen

[AC_Hacker]

Originally Posted by randen

We actually have two GSHPs at home one is a Water to Air unit for airconditioning in the summer and a blast of heat in the winter when the wind is really blowing and cold. The other is water to water that does 90% of the heat load and is a Climatemaster Tranquility 27 3Ton unit. The house has a concrete slab main floor (no basement) with 2 " foam board beneth and 3/4 kitec tube in the concrete. The calculated load for the house is just over 5 Ton but again only when its really cold are both running. The ground loop is 6ton 3600 ft of 3/4 hdpe hoizontal. There are 6 zones. I even heat an attached and three car garage with it.

Wow randen, you really have GSHP going on!

On the map, your location in Ontario ('A' pointer) is actually further south than mine in Oregon (yellow circle), but because of the warmish Japanese current, it is warmer here. My HDD is about 4500, and if I'm reading it right, yours is about 7000. Big difference.

Your slab floor is the way to go, especially with the Heat Pump. That arrangement brings out the best of both radiant heating and heat pumps.

I'm really curious what tube spacing they used when they put in your slab?

I would guess that the tube spacing in your floor is something like 12" or 9", because that is the standard practice with fossil-fueled boilers.

As you know, I'm on a Jihad regarding radiant floors for low temperature heating, that they ought to be optimized for Low Temperature Heating in general, and heat pumps in particular.

I have looked at several hydronic floor layout computer programs, and they are all set up to expect higher feed temperatures from a fossil fuel boiler system. I really can't fault them for that, because that's what most people use. But when I have worked with these programs, to see what a lower feed temp floor layout might look like, the programs don't provide the range of options, for tube spacing in particular, that I'd like to see.

But it is tantalizing, as far as they do go, because I can see that with closer-than-usual tube spacings, higher efficiencies will result... I just can't find the 'sweet spot' within the limited range that they offer. The computer programs I have worked with have indicated improvements in efficiency down to 4" tube spacing in concrete slabs. With these closer spacing, the friction losses need to be carefully dealt with, but that is part of good design.

I think that the European floor designers, because of higher energy costs (2x greater), are more aware of the advantages of optimizing floor layout for low feed temps. The forum conversations I have had with Piwoslaw have indicated this to be the case.

John Siegenthaler

BTW, I wrote an email about all this stuff to John Siegenthaler, the guy who wrote the book on radiant floor design. He never did me the honor of responding to that email (he responded to other emails), so maybe he thinks I'm nuts, or maybe he's working on a revision of his book to include low feed-temperature floors.

So, this all goes back to your remark about how your homemade heat pump is getting better efficiency than your commercial unit. In your test, you were measuring water temperatures directly, leaving the final HX (the floor) out of the picture. I suspect that your floor HX is where your commercial system is taking the biggest hit.

But still, an overall COP of 3+ is pretty good, especially when the North Winds begin to howl.

Regards,

-AC_Hacker

[randen]

Basically the GSHP is finished. I ran out of fasteners and energy. A hand full of stainless fasteners and a hole for the electrical fittings. Oh yes install a access ring in the top to switch the 4 way valve from heat to cool. This can be done any time later. I like stainless steel. It maybe a little more expensive and a little harder to work with but the final product dosen't need any paint and it will look the same for ever. This was a project in which all the components where re-purposed mostly from the scrap heap. The copper was from a friend cleaning the garage the compressor from an old airconditioner the base and top was from another project that needed to be changed out. and the cover is from a washing machine. Heck, even the propane was destin to be burnt in the BBQ.

The testing turned out surprisingly well (see earlier post) but I'm confident now it will keep me warm this winter.

Tommorrow maybe a full day soldering tubes. I think I will hire a local contractor to purge the system by installing the Propylene Glycol. They have the high pressure pump and the last thing you want is a air trapped in one of the ground loops reducing the efficiency.

The shop has an office area that already has the infloor heat. It was the beta test 25 years ago, before the internet and before, I built my house with in-floor heat. In-floor heat around here was non exsitent and I had asked a lot of contractors who shrugged their shoulders but yes they had heard about it. I guessed at 12" centers 3/4 Kitec pipe in 6" of concrete with an oil fired hot water tank as a boiler. It work amazingly well. Wished then I had that in-floor heat in the shop area.

Today the house had been converted to lower temp.with the same pitch and size tube. The GSHP sends 106 deg F into the floor and it works extremly well. As an added note we also have solar hot water that some days is only pumping 90 deg F thru the floor and thats enough to heat the floor
comfortably.

Included is photos of the complete GSHP its foot print is 23 Dia x 26 high and the location of the GSHP you will notice the Grundfos circ. pumps and the in floor tubes. As well as in the shop area the installed air handler with check and zone valve. This will provide heat as well as the air-conditioning. Included are the early drawings for the 4 way valve and circuit. I will complete and post better drawings after the dust has settled.

Randen

[randen]

The circuit drawing of the refrigerant flow counter current to the water/glycol flow (see previous post). In this the blue is the refrigerant and the magenta is the water/glycol. If you switch the coupled (4 way) valves you see that the flow is always counter current. Any circuits I had seen in comercial GSHP the reversing valve had either the condensor or the evaporator in a parallel flow. Maybe the engineers had a contingency for this I'm not sure. Many years back in biology class we had learned the value of counter flow with blood gases, kidney function or the class demonstrated hot and cold water as seen here.

[Geo NR Gee]

Thanks Raden for all of the pictures and the cool ideas for my own setup. The stainless steel washer tub is a great idea too.

[AC_Hacker]

Originally Posted by randen

Basically the GSHP is finished.

This is more than a heat pump, this is art.

-AC_Hacker

[charlesfl]

Did anyone get their heat recovery ventilator working and what were the results?

Thanks, charlesfl

[AC_Hacker]

Originally Posted by charlesfl

Did anyone get their heat recovery ventilator working and what were the results?l

There has been considerable discussion on the DIY Heat Exchange Ventilator thread.

Your question really is best placed there.

However, there have been a lot of interesting ideas and information, even a set of plans from a 1986 issue of Pop-Sci that you could build yourself.

To answer your question, if anyone has built a DIY HRV, they have not reported back on their results.

Are you handy with tools?

-AC_Hacker

[charlesfl]

Thank you AC_Hacker for a your excellent writings and documentation. I have been following you since I joined in December 2009.