Sanyo mini split AC (inverter/variable speed)

[XRinger]

XRinger, sounds like its time for a replacement DHW system, maybe one of those heat-pump units, or maybe some solar preheat on your existing system?

You better believe I've been thinking about getting rid of that big old (1956) oil tank!
I've used preheat solar hotwater before. It's good, but will not cut oil use completely.
The problem with solar hotwater back in the 70s & 80s, was the fact that Woburn water eats copper.. :(

I'm using a little bit of PV solar assist on the oil boiler.. Right now it's getting about 750 watts from my 800w array.
2560 BTUh isn't much, but better than nothing.. :)


A heat pump DHW heater has been considered. But, my smallish basement is 51.6 deg F..
And the unit would pull that temperature down even lower.
When it gets lower, the heater will switch to Grid-Hog mode..

It's 70 down there during the summer, and the dehumidifying would be welcome..
But, I'm not sure I want to spend $1,300 for a heater that might not work during the winter.
By winter, I mean 25 weeks of each year..

I have considered buying a mini-split outdoor unit (that will work down to 5 deg F)
and use a hotwater heat exchanger instead of the indoor air handler..
I could heat my existing boiler, (which can also burn wood, coal & paper junkmail).
http://i46.photobucket.com/albums/f1...HSTARMOT35.jpg
In case it gets so cold that even a good ASHP won't work..

Cheers,
Rich

[SteveK]

Rich, I use the Nyle Geyser HPWH. We too experience ~50F in the basement in the winter where it is installed. It works well down there and we spend ~$16 per month on hot water in the winter. Like you said, the dehumidification is very welcome here too.

The Geyser is a retrofit unit that connects to the existing electric WH tank. It can utilize one element in the water tank if needed however we do not. The outlet air can be ducted which is great for our application. They were at $950 last fall, direct from the factory in ME. Qualified for the tax credit too.

[XRinger]

'The honeymoon is over' is right.. But the weekend is looking pretty nice..

Be careful trusting the forecast. Sometimes they can be off by 8 or 10 degrees (at your house).
At 5F the Sanyos should be okay.. But if it drops much under that..?. Our COP will drop in a rock-like fashion.. :(

We had a good sized group here on Xmas Eve and those Sanyos worked beautifully..
And it was 24.2 °F (average) on the 24th.. http://pauland.net/archive.php

[XRinger]

Rich, I use the Nyle Geyser HPWH. We too experience ~50F in the basement in the winter where it is installed. It works well down there and we spend ~$16 per month on hot water in the winter. Like you said, the dehumidification is very welcome here too.

The Geyser is a retrofit unit that connects to the existing electric WH tank. It can utilize one element in the water tank if needed however we do not. The outlet air can be ducted which is great for our application. They were at $950 last fall, direct from the factory in ME. Qualified for the tax credit too.

And that's in a 760 sq/ft unheated basement? If it is, I'm sold..
Even if used more kWhs heating up my old boiler, it would be worth it, to get rid of that old oil tank!


I assume you are paying about the same per kWh as we are in Woburn.. (16.18 cents per kWh total).

Cheers,
Rich

Edit:
Found this useful post:
http://nepacrossroads.com/about20361-15.html#p241354

[SteveK]

No, we pay $0.117 per kwh. We figure $0.124 with fees.

It is as you describe though three walls are insulated to R-10. Floor concrete, windows single pane DSB glass, uninsulated door. It's a 3/4 buried basement and unfinished/unheated. The coal stoker is there if we need it.

Last year we built a mechanical room to get all the solar, water heater, laundry, chest freezer in that room. We insulated that room. The appliances keeps the room 5 degrees higher than the rest of the basement. The HPWH exhausts from there into the colder part of the basement. 50F in the cold part, 55-56F in the mech room.

[XRinger]

I've seen the Geyser install video before (high mount in a shop) and it sure looks easy to get going..

I wonder if using a bigger unit might be better, since my 76 gallon boiler leaks a bit of heat.?.
I'm thinking maybe a DIY 16,000 BTUh unit might be a better choice, and give us a faster recovery time..
Of course the basement temps would take a terrific dive when it cranked up!
I'm sure it would be great during the summer. When the shower is used a lot more,
and the basement is warm and dank..


It's 19 deg F here right now and the Sanyos are using 1.33 KW..
The average for today has been 1.0 KW, so we are looking at
some serious power use tonight.

[techntrek]

Neat looking boiler, XRinger. Does it have two fireboxes on the right side?

[XRinger]

Neat looking boiler, XRinger. Does it have two fireboxes on the right side?

The clean-out is on the bottom and the top is where you load the solid fuel..
The coal grate is installed, but right now, that whole firebox is filled with FG insulation,
because I have a big resistance heater in the clean-out. (fed by the 800w PV array).
The air intake (for solid fuel only) is a chain going down to the little door on the bottom.
A bi-metal controlled arm lifts it open when the water jacket cools down.

I can convert it back to wood or coal in about 10 minutes.

With free flow turned on, this big steel monster can heat my house
for hours on a few chunks of wood.. Without being on the grid.

[SteveK]

Wish I could put up some nice graphs like you have. I've been testing some temps tonight though. Right now at 13F the 12k split is producing 129F air with an intake temperature of 74F. So we have a ways to go before we fall off the cliff.

Your idea of a DIY HPWH sounds like a hoot. I wonder what could be done to bring the system outside instead of the basement at all? I know we can't duct our HPWH out of doors because the heater would freeze. Your setup sounds better for this.

[XRinger]

It's been going down since lunch (Tue 1/3/2012). Forecast to be at 6.0F at 6AM..

This should be a live look, real time display. From a guy over on the next block. http://pauland.net/daily.php


Sounds like you got it cranked up over there. The Sanyos are down to 19C (66.2F) right now.

The average temperature during the last 22 hours, was 24.3 °F.. (and dropping). We used 23.9 kWh...
Yesterday, the average was 39.5 °F, that's a pretty big difference. I think we used about 14 kWhs..

~~~

I like the idea of locating a DIY HPWH outdoors. It would be very cheap to run during the summer months.
However, if I was using a compressor from an old 18,000 BTU AC (Sears Kenmore), it wouldn't work well in cold weather.
But, it might work pretty well in a cool basement during a cold winter..

IMHO, the best way would be to use a high SEER mini-split outdoor unit with R410A-to-water heat exchanger.
That rig would work super in summer and do pretty well for 90% of the winter..