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Old 03-22-10, 04:41 AM   #141
AirSepTech
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Default 15 years of foot dragging

Maybe it is my 'sheltered' region, but I'm hard pressed to find ANYONE that knows much at all on GSHP, minisplits, inverter compressors, etc.

I guess that paper really made me think about how little/slow change comes about.

I would guess with improvments, marketing, and more Eco awareness, the inverter/ductless type of system could destroy the old FAU/duct systems long held ground. With R22 phase out, these new systems have a real chance, not just retrofit, new housing also.

Well, after we sell the ones that are empty.

I liked the fact they were HACKING. Made me think of this site.

The GSHP industry could be a lot farther along than it is.

Cheers

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Old 03-22-10, 11:56 AM   #142
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Default Hacking Potential...

Quote:
Originally Posted by AirSepTech View Post
I would guess with improvments, marketing, and more Eco awareness, the inverter/ductless type of system could destroy the old FAU/duct systems long held ground. With R22 phase out, these new systems have a real chance, not just retrofit, new housing also.

Well, after we sell the ones that are empty.

I liked the fact they were HACKING. Made me think of this site.

The GSHP industry could be a lot farther along than it is.
AirSepTech,

Yeah, all good points...

What with the higher cost of energy in Asia, they have made great strides in efficiency. I sure do agree that we should be seeing more displacement of Forced Air (Scorched Air) units.

In fact, I think we should be seeing more radiant floor installations displacing FA. There are many comfort and efficiency benefits to radiant floors. From what I have read, radiant floors dominate new construction in Europe, by about the same margin as FA dominates new construction in the US.

So, getting back to hacking, before the advent of inverter technology (and other improvements) in air-source heat pumps, there was a goodly advantage in efficiency of GSHP over ASHP, even when both types of units were used to heat air. Some of the numbers I saw were like this:

ASHP = 2.2 COP
GSHP = 2.5 to 3.5 COP

The greater efficiency of GSHP was due to having a higher and more stable source temperature and also, because moving the heat via liquid was more efficient and used less energy than using air.

When comparing the efficiencies of ASHP heating air to GSHP heating radiant floor, the efficiencies looked like this:

ASHP = 2.3 COP
GSHP = 3.7 to 5 COP

This time the greater efficiency of the GSHP was due to higher source temp, the greater efficiency of moving the heat into the house via liquid, and also the very large area of radiant floors means that the temp of the working fluid does not have to be as high to achieve the same heat transfer, thus favoring efficiency.

So, in the meantime, mini-split engineers have improved the efficiency of their units by modulating the power used by the compressors to match the variable heat load requirements. The same idea is used to modulate the fan that drives air though the outdoor unit. and ditto the fan in the indoor unit.

So now, mini-splits ASHPs are exceeding, sometimes by a large margin, the efficiencies formerly found in early GSHPs.

To my knowledge, GSHPs haven't started applying the benefits of power modulation to their compressors and circulation pumps. However, I have seen that variable-rate radiant floor circulation pumps are coming available, not as integral to the GSHP industry, but as improvement to the radiant floor trade.

So, what this suggests for hacking, is that substantial advantages in efficiency might be obtained by successfully converting an inverter technology mini-split to a GSHP, feeding a radiant floor.

So I looked on ebay using this search term: mini-split inverter heat pump ...

I found some new, smaller inverter type units selling for about $500, the shipping would add about $150. Not chump change to be sure, but it does put good hacking material within the reach of many courageous hackers. I even checked out the COP of one of these units and the COP can be calculated by deviding the HSPF by 3.412...

COP = HSPF / 3.412

One cheap unit I looked at had a COP of 4.1

Compare that to early GSHPs and you can see the potential.

Best Regards,

-AC_Hacker

Last edited by AC_Hacker; 03-22-10 at 12:05 PM.. Reason: not finished posting
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Old 03-22-10, 02:44 PM   #143
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"One cheap unit I looked at had a COP of 4.1"..

In the pics on that page, it looks like they unpacked and tested them out on a roof..
I wonder if that's the vendor doing that?
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Old 03-23-10, 10:32 PM   #144
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Default Hacking potential=marketing potential

AC--Thanks for the time/details. I don't get as much time as I would like, and do realize the value. Thanks!!

This thread and yours(diy gshp) got me fired up. The time and detail you guys put forth is second to none. I am scrambling now to move on something, I need it, and I believe the season/availability/old stock is right for good pricing. Summer pricing will be higher.

I would like to innovate or capitalize on something, but really, staying warm efficiantly is good enough. For Now

I'll open it up on another thread, no hijacking.

Thanks Again Xringer/ACHacker
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Old 03-25-10, 06:33 PM   #145
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Default Big truck came today!

The new outdoor unit was delivered today. Just one little dent in the cover.
But besides that, it looks to be in good shape.

It was warm today a little over 65F (now about 60), so it's a good day to pump some vacuum.

Fresh oil in the pump and we are getting down near 200 microns.
The HVAC guy should be here soon and we can crank it up and do some testing.

My wife helped me lift the old unit off the pad (and plastic mounts) and
put the new unit up on it's little pedestals. (After house painting all day)!


~~~

Edit 3/26/10:
The Sanyo seems to be working as good or better than it did before. It's been on for
about 24 hours now (saving some heating oil), putting out good heat.

I'm a little leery about doing the High-Power test, because the amount of power
I see being used, just by calling for a 6 degree increase, makes it climb right up to 3 kW in a few minutes..
(At which time, I discontinued the test). This model is rated for 2.76 kW..


Last edited by Xringer; 03-26-10 at 06:23 PM.. Reason: Add-on
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Old 05-16-10, 01:52 PM   #146
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It's mid-May and we are still using the heat once in a while..
This morning, it was about 68 inside, so we turned on the Sanyo and it was up to 72 in short order.

I've been watching the power meter while the Sanyo is off and I think
that I see a pattern in the parasitic drain..

I think it might be using the temperature sensor on the compressor,
to control power into the Crankcase heater.. Wanting to keep the oil
nice and warm, just in case.



The power usage varies between 30 and 60 watts.
During cooler days, it seems to hang in there at around 60w most of the time.
But, on a nice day like today, it's bouncing around between 20 and 50-60 watts.

Or, I could be way off base and what I'm seeing is just noise inside
the breaker box. I doubt the current probe has any shielding..

I'll have to wait until a really hot day, and leave the Sanyo off,
in parasite mode and watch the power use again..

When the weather gets a tad nicer, I'll likely just open the breakers
and remove the parasitic drain altogether.

I was just checking around, and it seems the DOE is interested in Crankcase heaters in standby mode too.
(But they don't like inductive pickup test equipment)..

DEPARTMENT OF ENERGY

"2.8Electrical power and energy measurements. a. Use an integrating power (watt-hour) measuring system to determine the electrical energy or average electrical power supplied to all components of the air conditioner or heat pump (including auxiliary components such as controls, transformers, crankcase heater, integral condensate pump on non-ducted indoor units, etc.). The watt-hour measuring system must give readings that are accurate to within 0.5 percent. For cyclic tests, this accuracy is required during both the ON and OFF cycles. Use either two different scales on the same watt-hour meter or two separate watt-hour meters. Activate the scale or meter having the lower power rating within 15 seconds after beginning an OFF cycle. Activate the scale or meter having the higher power rating active within 15 seconds prior to beginning an ON cycle. For ducted units tested with a fan installed, the ON cycle lasts from compressor ON to indoor fan OFF. For ducted units tested without an indoor fan installed, the ON cycle lasts from compressor ON to compressor OFF. For non-ducted units, the ON cycle lasts from indoor fan ON to indoor fan OFF. When testing air conditioners and heat pumps having a variable-speed compressor, avoid using an induction watt/watt-hour meter."


Edit May 24:
The parasite mode is only using 30W on the hot days... It's 80F right now..

Last edited by Xringer; 05-24-10 at 02:39 PM.. Reason: more info
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Old 07-06-10, 09:00 AM   #147
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Default It's getting HOT around here!

For those nice summer days when no AC is required, I open the breaker.
No sense heating the compressor oil when it's 70 outside..


These last few days have been HOT! And the Sanyo has been running 24-7.
We are using just under 7 kWh per day. ($1.40 a day).

7kw / 24 hours = 291.66 watts per hour average. Wow!
I've noticed during the day (like right now 8:50AM @ 80F outdoors),
it's using 50 watts. When it comes on a little more, it draws around 400w.
During the night time (no solar gain) it's loafing along at 50 watts a lot..

As an aside, if one had 300 to 500w of PV connected to his grid,
a Sanyo ASHP could cool his home pretty cheaply on these very hot days..



Today, it's going to be really hot again. AccuWeather.com - Woburn Hourly Weather | Hourly Forecast for Woburn, MA

It could be an 8 kWh day!

I was never sure what our old 18,000 BTU Sears AC was drawing, but I'll
bet you a beer it's was at least 16 kWhs on dog days like these..

Cheers,
Rich
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Old 08-01-10, 11:54 AM   #148
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Default Nice Job & Some Added Split System Info

Thanks Xringer for taking all the time to post so much detail about your split system project! Lots of great info! I just put in the smallest Sanyo 9000 BTU split heat pump which is the baby brother to yours.

I'm curious if you had any warranty issues with Sanyo as it was a DIY install? Did you pay an HVAC tech to "sign off" on it to make Sanyo happy? Or the issue never came up? Technically that's the big downside of a DIY install as it voids the warranty.

Also, for those shopping for split systems it's worth mentioning a couple other things:

The "big brand" systems (like Sanyo, Panasonic, etc.) have MUCH better warranties, documentation, support, parts availability than the cheaper models (i.e. Shinco etc.). If a no-name system dies, you might have to junk the whole thing if you can't get a critical component replaced. And most have only a 1 year warranty (vs 5 years for Sanyo) on everything but the compressor.

In my case the Sanyo was efficient enough to qualify for the current federal tax credit and none of the cheaper no-name systems did. With the credit, the Sanyo was actually slightly *cheaper* than the much less efficient no-name inverter systems.

And for those who don't know about inverter vs non-inverter, the inverter systems have variable speed compressors which allow the unit to "throttle" itself down as less cooling (or heating) is needed. This saves a lot of energy (and noise) compared to just slowing down the indoor fan. It allows MUCH lower indoor fan speeds as a standard unit would ice up from too little airflow. It also tends to maintain a more constant indoor temp versus the harsh on/off cycle of standard units. Finally, the lights in the house don't flicker every time the compressor kicks on because the inverter units "soft start" the compressor.

And yes anyone can buy R410A. I would advise caution, however, as the systems run at high pressures and I've read stories of someone doing something as simple as over tightening a flare fitting, causing it to crack the flare with the pipe blowing out, and being hospitalized from having their face instantly frozen by the escaping refrigerant from the failed joint. Frankly I think flare fittings are a poor choice in this application but they're cheap.

And R410A is more eco-friendly but still hard on the environment if it escapes. So you're supposed to use an expensive recovery system if you have to open the system up for any reason and have the used refrigerant properly recycled.

So for anyone considering a system, I'd try to get an estimate to have the refrigeration line set connected, vacuum pumped, and charged by a pro. Then if it leaks, it's their problem, not yours. And Sanyo will also honor the warranty.

Using a pro can save you the (potential) cost of a vacuum pump, manifold gauge set, micron vacuum gauge, tubing cutter, special R410A flare tool, spanner torque wrench, nitrogen tank and regulator, electronic leak detector, and having to buy a $200+ tank of R410A if any refrigerant leaks. True you can probably get by without some of those things, but you may also well end up needing them. So the price of a DIY install can snowball. If you buy all of the above, you can spend $1000+ which is well in excess of the $200 - $300 a pro might charge.

On the other hand, if someone lives in a very remote area where a service call would be really expensive, or you want to roll the dice and try to get by on the cheap, or you have several systems to put in, then doing the refrigeration work yourself might make sense. Just know what you're getting into first and be safe.

Back to your system...

As for using too much power at times, I wouldn't worry too much about it as it's supposed to protect itself from that. The ratings are somewhat arbitrary because the actual power fluctuates with a variety of conditions (as you've discovered).

If you look at the power consumption charts, you'll see the indoor air temp is a big factor. So the warmer you have your set point, the more power it will use in full power mode while in heating. So a lower set point will also lower the peak power needed. Forcing a lower speed will also reduce peak power.

I'm not sure about your model, but the 9000 and 12000 BTU models use the exact same compressor. The 12000 BTU unit simply has a bigger outdoor coil and they run the compressor and fans slightly faster on high to get more BTUs. So it might be similar with your unit having a compressor from an even larger model? If so, I'd worry even less about it using more than the rated current.

The only risk of the system drawing more than rated power is either it going overpressure or exceeding the capacity of the inverter and/or compressor. It supposedly monitors all of the above and will reduce the compressor speed, or shut down completely, if needed.

Another thought is if your lineset is less than 25 feet, your system is slightly overcharged which will also increase the power consumption somewhat.

I agree about the parasitic losses of the crankcase heater. It's only a 20 watt heater in my unit but I think that's an area they need to improve on. Supposedly if the unit runs regularly the normal operation will keep the compressor warm enough. But if you were say away on vacation or it's mild weather when little heating or cooling is needed, it's wasted energy. At least the Sanyo actually monitors the temp of the compressor itself not just the air temp like some systems. So, in theory, the heater only comes on when it's really needed. Some older systems just left the heater on ALL the time.

I have a TED 5000 system with 3 sensors and intend to move one of them to my Sanyo to monitor it. So far I've only used a current probe which isn't very accurate as it doesn't take into account the power factor (A/C units, especially inverter models, are a very "non linear" load so volts times amps does NOT equal watts). But the TED corrects for power factor.

If your energy monitor is not connected to the 240 supply (as well as the inductive pick up) it can't measure the true power. For true KWh it needs to know the phase angle of the voltage with respect to the phase angle of the current. If you look at Sanyo's service data, you'll see the volts time the amps does not equal the watts they list. This is because of the power factor not being 1.0.

I agree with you in Quiet mode the unit is almost certainly less efficient overall. It is probably difficult to measure by how much outside of an A/C lab, but the low airflow, and parasistic losses, are certain to have a negative impact. But at least inverter units can slow the compressor down as well so its drawing much less power (as you've discovered). Non-inverter units suffer horrible efficiency losses at lower fan speeds (which don't go all that low as they'd ice up otherwise).

It's a bit scary that you had an internal failure on your unit but I've been impressed with Sanyo's quality so far. And like you, I'm blown away at how quiet it is. In terms of the noise specs, the 9000 BTU unit is their quietest model. When I first powered it up I thought it was defective it was so quiet.

And your icing problem on the first outdoor unit might have been related to a leak and it being low on charge. Especially when the icing is uneven on the coil (as it was in your picture) that's often a sign there's not enough charge in a heat pump.

So, again, nice job! I'm glad you're saving lots of money over oil heat and doing something good for the environment.
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Old 08-01-10, 01:19 PM   #149
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A HVAC tech didn't "sign off" on it, but did check it over and watched the micron gauge
for a while, before releasing the R410a into the line set.
I think he was happy to be learning how to start up a mini-split. I got his card and used
his company name (one-man company?) when I sent in my warranty info.

When I had the leak, they just wanted to know how long it had been installed.
I was past the free labor point. Or that's what they told me.
They didn't try to wiggle out of helping me out. It just took a long time
to get a new unit from China..

Ductless HVAC Supply sells these units with a 20 foot line-set and they say not to
cut it shorter, or you will have to call a tech to remove some R410a.
I double checked with their support guy and he's 'sure' that 20 feet is perfect.

The new outdoor unit is still working very well. Just like the first one.
I'm not worried about PF, since my power monitor is a bit basic.
I calibrated it using the power company meter. So, it's pretty close.

I have the over-wattage alarm on the power monitor set for 2kW.
And, I make 2 degree changes only (+ or - room temp) to avoid any high wattage use.

The reason I'm being extra careful of any surges, is I think maybe the old unit
got up to high power and the R410a pressure went up, sending the unit
into over-pressure shut-down.
I'm not 100% sure, but maybe that very high pressure blew out a weak spot in the copper.

This new unit was build at the same time, so it might also have a weakness.?.
I'm not taking any chances, so I'm trying to stay away from the 3kW mark..

You are dead-on with the 'inverter vs non-inverter' info. It's the low speeds
of the compressor and large fan unit that really save the watts.

That tax break was a nice 'extra' for us. It more than paid for all the tools
and fees.

The last few days of July turned out nice and the 1st of August is really nice.
So, to avoid crankcase heating, the breaker has been off a few days..

I'm pretty sure this has been the hottest July ever. It has been generally VERY warm!
I checked it out the other day and the mean average temperature last year, was 8 degrees cooler!

During these last 31 days, we used about 116 kW hours. About $24.36 or 78.5 cents a day.
I rounded up the cost to 21 cents per kWh..

Later,
Rich
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Old 08-01-10, 03:44 PM   #150
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It seems unlikely 2 units would suffer the same problem, but I suppose you never know. I can certainly understand not wanting to be without it again as well as swapping out a 200+ pound piece of hardware. At least yours is at ground level, my outdoor unit is on the roof!

You did a great job with the install--you certainly paid more attention to detail than a pro would have done with respect to mounting the units, etc. I like the "awning" as well.

And yeah, 20' is about perfect so it's unlikely it's overcharged by any meaningful amount.

As a side note, on the HVAC forums the "pros" frequent, if they even get a hint you're not a licensed HVAC contractor they basically tell you to "hire someone" rather than answering your question. Some of the forums even prohibit non-licensed users from asking questions related to DIY installs.

Obviously I can understand their desire to protect their job, but it's nice to find forums like this one where this stuff can be discussed openly with minimal bias. This stuff isn't rocket science (although superheat and subcooling do require some math and tricky measurements) or some magic art.

And, as another side note, there are a few split systems out there that come with precharged linesets and rather nice special connectors that are designed to connect under pressure with minimal loss of refrigerant. These connectors use machined fittings and O rings to seal and are likely far less likely to leak than the ancient flare fittings used on most systems. These systems are very DIY friendly, but they're limited to no-name and very expensive high-end systems that are difficult to get in the USA.

I honestly don't know why ductless split systems are not more common for residential use here? They can be very efficient, are far easier to install than ducted systems (with far less to go wrong), and are free of all the noise/security/mounting problems that window units have. Their only real downside is cost. They're the most expensive per ton of any option (excluding the cost of ductwork for ducted systems). But, as you've demonstrated, they can sometimes pay for themselves.

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