Portable Ac with heat single hose for winter heating ?

[ecomodded]

Originally Posted by nokiasixteth

I have some post on here somewhere detailing about a the amount of energy that resistance space heaters used vs my mini split was using . The useage of the mini split turned out was under the power useage that the space heater was using . But produced a lot more heat for me. 1/2 my house vs only 1 room.

Looks like i read in a post that you were using a space heater somewhere. May be cheaper to l let that unit your bought topickup that extra heating for this heating season. Until you can put it on the market. I looked and found my old post when i bought my cheapy mini split . (still chugging along)

http://ecorenovator.org/forum/geothe...ini-split.html

I noticed the heat gain right away its like a furnace !
Told myself to wait until the house repairs are finished before spending money on one of the eBay Senville heat pumps. About $1100 for a 12K plus install fees and assorted material expenses would not be surprised to pay $1700 total

Curious what you payed all in for your Split ? , I will follow the link and see the install etc , thanks !

[ecomodded]

Originally Posted by jeff5may

Ok, so the thing is blowing out Sub-Zero exhaust pipe air at room temperature supply air? Awesome! Good to know the rig puts out nice warm air. More useful heat and less power draw than a hair dryer heater is good news.

What I ended up doing with mine to keep the exhaust pipe air colder than outdoor temperature was to choke the evaporator supply air. I just put a filtrete air filter over the inlet grille. That little bit of restriction gave me about 5 degF outlet air. Like I said before, by the time it got that cold outside, the gas blast furnace was running anyway to keep the house warm.

The above photo with the vent was tested at 0.3c about 3 feet down the pipe from the machine with a 24 to 29c inlet temp. When I tested the machine outside it was making -10c @ 8c outside temp / inlet temp.
So far with the intake hoses out the window its been working well still have not tested the outside vent temp the units in a off moment now or could test it. It should be the same as the readings was getting with the unit running outside. The heat output has been steady at 46c / 115*F front outlet temp with a 7c inlet temp and a 24c room temp that gets blown threw the hot side. The cold side is straight outside air in and out.

Ive noticed it does a auto defrost when needed so far noticed thats in the morning when its still foggy out and in the evening after running for awhile but it drains much more often seems to drain water without loosing heat output most of the time with a few real defrost cycles thrown in here and there where the hot side cools.

[ecomodded]

Might of figured out how to identify the Btu gains

The Btu gain conversion calls for the Fan CFM x 1.1 x difference in inlet vs outlet temperatures.
Using the hot side temps to measure gains seems to work

Room temp of 75f minus by the Hot side of 115f = 40*f gain

Fan 240cfm x 1.1 =264 x gain of 40f =10,560 Btu

The unit is rated to make 11,000 btu

If the hot side in/out numbers are used as the the inlet /outlet temp the math works.

Using the cold intake temp of 44f vs the 115f hot outlet with the above math shows a 19,800 Btu gain. I doubt that right.

The only numbers left are the cold sides in/out of 44*f in / 14 out with a 240CFM fan that math shows a 7920 Btu gain which is closer to the hot sides result

[ecomodded]

The Defrost Cycle


During the defrost cycle both front and rear fans reduce / ramp up / auto shut off as required. The front outlet temperature starts to lower as the defrost cycles kicks in eventually reach 95*f in the end reaching near room temperature at that point the unit starts to drain melted ice in a little stream of water for 3 - 5 minutes during that period the watt draw reduces to a low of 450 watt holds for a few minutes and ramps up to 550 watt the ice is still melting during this period and the front fan is off with a slight breeze leaving the rear vent.

When it enters the later stages of the defrost it flashes the sleep mode indicator
I figured out that anytime the unit is dripping water and blowing hot air is because a defrost cycle has just ended and its beck to making heat.

Tested the defrosts after it finished a defrost cycle by switching the unit into cool mode reversing the valve and it did not melt anymore ice.

Outside temp 3*f Humidity 70 -100% mostly 100%
Be nice when the humidity drops it should improve it cold weather performance

[ecomodded]

First cold weather test


Last night it maintained a house temp of 18.5*c with the outside temp a few degrees above freezing.
Temp was between 34.7 and 35.6*f , 1.5 to 2*c the added workload increased the duty cycle by 10% (from 50 to 55% ) my assumption is the added time was spent defrosting as noticed its been defrosting more often.
It heated with 35*F overnight temps !

[ecomodded]

The ventilation fan arrived and was plumbed up in the spirit of portability despite its large 12 7/8" x 12 3/4" x 10" size and 17 lb weight its easy enough to move.

Model / Air King AK200LS 1.4 sones , 200cfm

Its intake is facing the ceiling to vent the warmest air



Speeds: 1
Design: squirrel cage
Continuous running: yes
Power rating: 60w
Actual draw: 43w

Fan noise s reported to be 1.4 sones that increases proportionately to the pressure or restriction put on it.
I noticed the fans noise increased after being plumbed to 20 feet of flex duct with two 90* bends. Its still much quieter then the AC

The AC was moved from the left side near the vent over to the right side with window access.



Its the first day with the vent so far I can say the upstairs has warmed up 1* and its nearly silent upstairs except for the low whoosh of warm air leaving the flex pipe at the top of the stairs.


The downstairs room is 17x11 x8' = 1400cu.ft the fan will be left running 24-7 to maintain thermal continuity between the upstairs and down.

In closing

The next weeks weather is wet and warmish with 10c average temperatures and 100% humidity along with fog. That weather makes for more defrost cycles but so far unit deals with it without issue.

[ecomodded]

To improve the performance finally added a duct from the ac to the 200cfm fan and straightened out the duct run.





Before the added duct upstairs was 80 degrees after 20 minutes now its reaching over 100 quickly and maintaining it for an hour. Will be readjusting the AC's thermostat to find its new balancing point



This is at the top of the stairs where a splitter was added to reduce the air speed.
100 degree air feels real nice much nicer then 80 degrees which is not bad

Before the downstairs room would reach 24c /75F while the unit was running while the upstairs was 20c /68f , now the downstairs room has been staying at 20*



For winter heating bought a inkbird 308 temp controller it has a switch for heating and cooling. With it can set the exhaust fan to shut off when the vent temp drops / the ac goes off and have it turn on a ceramic heater upstairs at the same time.

This way I will have heat going 24-7 if needed and at no more then 1000w and hour.

Thats the goal , to heat the house on 1000 watts of energy this winter.
So far Im using 500 watts an hour for heat. The kill-a-watt meter makes for easy record keeping the ac has been running on a hour on hour off cycle on auto some days running 4 hrs less some days running 4 hrs more. It always balances out at 50% off 50% on. The other night it ran for 6 straight hours it does what it can with the weather its got. its been wet and warm lately with a 10c average.

For now its clear sailing won't see cold temperatures until the end of December

[DEnd]

Originally Posted by ecomodded

Thats the goal , to heat the house on 1000 watts of energy this winter.
So far Im using 500 watts an hour for heat.
For now its clear sailing won't see cold temperatures until the end of December

You're gonna have to give somewhere to hit that. You've got days coming up where you are going to more than double the temperature difference between indoor and outdoor air temperatures. Or are you just talking about electricity usage?

[ecomodded]

Im using the AC in dual hose mode now and its been running with night temps between 3 and 8c regularly. Its been on the kill watt meter for 505 hours , its working out to run 50% of the time 50% off for a average of 500w an hour.

That costs me $35 a month

I want to use $70 to $75 on heat and $25 to $30 on utilities for $100 total electric costs not $100 on heat as I typed earlier.

So I can double the current heat out put Im using now to heat with a average outside temp of 10c the winter lows are usually 0 to -1 or 2c


Be nice if it squeezes heat out of the air still when its below zero

Im hoping it does as that's the time it can reduce electrical consumption the most

[jeff5may]

If you have the means, please try to log your energy usage over time. There are still people who believe that what you are running doesn't save anything. I know this rig isn't a full size heater compared to a whole home blast furnace, but not everyone has a large home to heat. These units were made for supplemental applications anyway.

Take a look at some of xringer's threads. He does an awesome job at keeping track of the power usage of all kinds of equipment over time. He piggybacks his climate data with weather underground and details the operation of specific rigs to give others more insight into how the things handle bad weather.