Solar Hot water panel questions

[russ]

From firebird - http://www.firebird.ie/Portals/0/doc...at%20pipes.pdf

Angle of inclination permitted 15

[russ]

From the Solar Shop http://www.thesolarshop.eu/acatalog/...tion-Notes.pdf

Collector inclination
The collector should be installed at angles between 15

[jrd1990zr1]

Where in NY are you?
If you are in the Adirondacks check that the heat pipes are rated for -30F. Some of the brands heat pipes were freezing & bursting in extreme cold. I know someone that lives on Lake Winipeg that had his freeze, the company covered the replacements under warranty with the lower temp rated HP. The replacement pipes had a thicker wall and had alcohol added.

I am about 30 minutes southwest of Albany. This year the coldest it got was -20.

You bring up an excellent point, I'll check the minimum allowable temperature for any heat pipes I decide to use.

BTW SunMaxxSolar has a training facility about an hour from me with some systems set up. I am going to plan a road trip.

Thanks for the advice, John

[jrd1990zr1]

[QUOTE=russ;20266]From the Solar Shop http://www.thesolarshop.eu/acatalog/...tion-Notes.pdf

Collector inclination
The collector should be installed at angles between 15

[russ]

No problem John - I learn at the same time as you do.

Many links I maintain in a file for easy access and pick up new ones all the time.

Russ

[Naptown]

Water only in the heat pipe is generally not a problem there are only a couple of drops in there and the pipe is under a vacuum to allow the water to boil at a lower temperature.
freezing water is only damaging if it has no where to expand to as it freezes. There's lot of space in the heat pipe for it to expand to.

[russ]

Except that it does not expand equally in all directions.

I have no idea of the actual volume of liquid in one.

Anyone care to cut one open and see? It would be interesting.

Russ

[russ]

The problem I have with supplying hot water from a thermal system to hydronic in floor heating is one of volume.

If one receives a total of 2000 watts/day/m2 insolation during the heating months of December and January it would be a good day. 4 hours * 500 watts/m2 It would most likely be on the low side of 2000 watts

If a 2 m2 collector is 40% efficient then maybe you collect 1.6 kW/m2/day

It would take a lot of panels to make much difference.

Agreed or am I doing something wrong?

Russ

[Naptown]

The problem I have with supplying hot water from a thermal system to hydronic in floor heating is one of volume.

If one receives a total of 2000 watts/day/m2 insolation during the heating months of December and January it would be a good day. 4 hours * 500 watts/m2 It would most likely be on the low side of 2000 watts

If a 2 m2 collector is 40% efficient then maybe you collect 1.6 kW/m2/day

It would take a lot of panels to make much difference.

Agreed or am I doing something wrong?

Russ

Generally about 10-20% of the floor area in collector area. so yeah a lot of panels. Plus heat dumps for summer. Here we have about a 3-4 month heating season so hardly worth it.
Now if someone would come out with a small absorbsion AC unit that will run off of solar that would be a better solution. I have only seen them 10 ton and up

[Naptown]

Except that it does not expand equally in all directions.

I have no idea of the actual volume of liquid in one.

Anyone care to cut one open and see? It would be interesting.

Russ

It will expand in the direction of least resistance however.

[russ]

LucMan mentioned some units freezing up and bursting as I understood?

[LucMan]

I think that the copper may thin out a slightly after each freezing and thawing cycle and after several years they will just split, tilt angle may also enter into the equation. The guy in Canada that I was talking to got through the first year with the standard heat pipes with no problems with temperatures down to -30F and lower. The second year he lost quite a few heat pipes and the remaining were all bulging. The company replaced them with -50C rated heat pipes (heavier copper tubing with alcohol added)
I don't have enough experience yet with the EV tubes to know for sure how low of a temp they can tolerate, for how long or how many freezing cycles.
It may take a few years to find out as with many new products.
In my area -5F is a cold night and we only get 2-3 of these per year so the standard heat pipes might be OK just have to wait and see.

I could really use a 5 ton Yasaki absorber.

[russ]

The Yazaki unit is interesting! Any idea of cost for the 10 ton unit?

Russ

[Naptown]

No idea on cost.
Someone was making smaller units up till a few years ago. I guess the residential market where these would be useful was not big enough

[LucMan]

Back in the late 70's I installed 4 Arkla Servel 5 ton package gas fired absorbtion units. Haven't seen them since. There was no market for them as they were only 50% efficient and if you were not getting your gas for free they were expensive to run and maintain compared to standard 6 SEER A/C.
Lots of heat is wasted in the aborbtion process, but it sure would beat just dumping excess BTU's in the summer.