Heat Pump Frosting - Defrosting

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LoL... Toggs i had it set on low setting for about twenty min.. Although Adam and I don't really need heat even witht this weather (we just cuddle up under the covers)... Oh well.. He will be staying the remaining 11 days in his friends apartment, and i will be there part of the time.... They too have these Zone Line units there as well, but there of a diffrent design.. More like a window a/c... Pics to come
 
OK so I have a few questions on these things.

When you have a heat pump, do you usually have a furnace too, or does the heat pumptake care of it all? And I also am curious about the amount of heat they put out. I don't think I have seen one of tehse things in person, so I really have no idea.
 
Glenn, thanks for posting the pictures. My favorite part of the de-frost is right at the end when the fan turns back on and you hear the compressor valve reverse, and the large cloud is blown upward for a few moments. Coooool!!!!!

I like your thermostat. It sounds very high tech.

Here’s the one I brought with me from VA, it’s a Honey Well VisionPRO TH8321U1006 (Touch screen)
 
Glenn, also thanks for starting the thread, it’s a very fascinating subject. It makes me wish I had a heat-pump. You’re a very fortunate man. A month after I moved to Texas, my unit went out (21 year old Rheem High Efficiency) and the warranty company paid for my new unit (Payne w/ electric coil heat) and would not pay for a heat-pump, but oh well, it was free so I can’t complain.

Here’s a better pic.
 
Compact, I will try to explain....

Air source heat pumps, the type found in most houses that looks like a conventional air conditioner, are usually set up to run until the outdoor temperature goes down to a certain level and then switch to a backup heat source. In mild climates, the heat source is usually electric heat elements located in the ductwork or in the "air handler" - a cabinet that looks like a small "furnace without the furnace". In colder climates like the Pittsburgh area, heat pumps often replaced air conditioners and are installed with usually gas or sometimes oil furnaces. Alongside, or now inside, the furnace is a "fossil fuel kit" - electronic controls that turn on the furnace or heat pump as needed - but not both at the same time. I say replaced because the electric utility company gave discounts and incentives for homeowners to install heat pumps. The heat pump we had often could not "make up its mind" what heat source it wanted to use so there was a lot of clunking and other sounds that were hard to put up with. Modern heat pumps may have solved that issue.

The "set point" at which the switch over to the furnace takes place is set by the installer - from what I have learned, it is Not supposed to be set by the consumer. The set point is determined by a number called the "Coefficient of Performance" where the heat output equals the heat loss of the building and thus, the heat pump cannot keep up. This is determined by a "manual J" - software that a good contractor will use to determine the size of the unit. Once the Coefficient of Performance equals 1.0, the backup heat comes on. Sorry, I don't mean to sound like a stuck up mathemetician when I use those big words.

The utility company may also dictate what that the setting of the heat pump should be in order to get the discounts and incentives. Duquesne Light sent a representative out to make sure our unit had "their" settings.

A heat pump should be properly sized for summer cooling, which around here is not that extreme, but we do have humidity. A heat pump sized to run at all winter temperatures might be too large during the summer and would run for a short time, cool the house quickly, shut off, not have a chance to remove the humidity and the people inside would feel icky. Ours was properly sized for summer, which may explain the "help me!" sounds when it was below freezing and having a hard time.

Heat pumps that transfer the heat to and from water, as in a ground source heat pump, probably would not need a backup heat source as the temperature in the ground is constantly in the 50s. But such systems require a large amount of property to bury the ground coil and are thus, very expensive. I would think such a system might be a good idea in a rural area, though, where the alternative would be oil heat.
 
Touch-screens are kewl!

On both systems I've had, the indoor thermostat determined when the auxiliary or supplemental electric heat activated. That is not to say that some systems don't have an outdoor temp sensor that makes the switchover. Certainly could be.

Heat pumps always have dual-stage thermostats for heating. First stage is the compressor, second stage is the auxiliary or backup or whatever one wants to call it. The auxiliary typically comes on if the room temp drops approx 2°F below the setpoint, i.e. the heat pump alone can't handle the load. (Or if the setting is manually raised more than 2°F above the current room temp.) Electronic thermostats are more 'intelligent' and can trigger the auxiliary based on time instead of just temperature drop. If the heat pump runs for what the thermostat thinks is too long without reaching the setpoint, even if the room temp isn't actually creeping down, it may trigger the auxiliary.

That's one reason why I added the auxiliary lock-out option. When doing a "smart" setback recovery to 70°F, the room temp may have reached 68°F or 69°F at the target time, so the thermostat would "helpfully" trigger the auxiliary to quickly finish the recovery .... when running without auxiliary for maybe 15 or 20 mins longer would have done the trick. I'd rather have 5,000 watts of compressor running for a little longer time than 15,000 to 25,000 watts of resistance.

My two-speed Lennox had an adjustment on a controller board in the condensor to set an ambient at which high-speed compressor was (supposedly) forced in heating mode. As I recall, it was set at 40°F. I never could hear an audible difference outside between low- and high-speed compressor (the condensor fan ran at only one speed), but I could certainly discern the difference between low and high indoor blower speeds. It did often run at low indoor blower during heating at outdoor temps below 40°F, but that could have been high-speed compressor with low-speed blower.

Dual- or variable-speed indoor blowers coupled with two-speed (or dual-compressor Trane) units may tend to have a warmer output. High-speed (or both) compressors with low blower makes for slower airflow and slightly higher output temp. In any case, output temp is "warm" not HOT as it would be with typical gas or electric heat.

There's also much less incident of static elecricity from dry air with heat pumps. They don't turn the house into a giant clothes or hair dryer the way electric heat does.

Also, as mentioned previously, the "furnace" activates during defrost to counteract the cold air (air conditioning) that would otherwise be blowing in the house -- cooling and heating at the same time. Obviously one doesn't want defrosting to happen any more than necessary.
 
Duuuude! That is so neat how you can lock out the auxiliary heat. It’s defiantly worth letting the compressor work a little longer to get the house up to the set point rather than waist energy and money by using the supplemental electric heat. It sounds like your thermostat has a micro-processor that will allow the thermostat to start earlier each day to warm the house based on the time it took to reach the target set point from the previous day and considering the starting temperature. The lock out feature is definitely a great feature to have.

My thermostat has the available optional outdoor temperature sensor, but I don’t have it since I really don’t have the need w/o a heat-pump. And besides, I have a weather station so I can tell the outdoor temperature and humidity.

Glenn, I know you said your Carrier is a 12 SEER system. Does it have a 2 speed or dual compressor?

A heat-pump makes a house much more comfortable than any other kind of heat, because it blows an almost constant flow of warm air rather than shots of extremely hot dry air. People feel comfortable all the time rather than cold and hot.

I agree that one doesn't want defrosting to happen any more than necessary because of the use of the auxiliary heat, but it sure is fun to watch when it does happen.
 
Question from over the ocean!!!

Hey srry just wondering. The heating pump technologie is just coming up around here in Belgium. We want to install such a heating pump, but they've said us that the only way to get lower heating costs is to have the pump working during night (see lower electricity rates) but then you need an extra reservoir to stock the heated water. When the house needs heating, the water is pumped through the pipes (mostly during day-time). Is this true or are there other way's to heat with a heating pump? Just to say, we don't use air furnaces but only waterheating machines. Excuse-me I was not so good at spelling:$
 
Please excuse the logorrhea. Innuendo count: NONE.

I am not aware of many residential US consumers having time-of-day rates with peak (penalty) and off-peak ("gift") rates. Perhaps someone will tell us. This is a great idea to encourage load-shifting. In NYC larger business/industrial consumers pay HUGE penalties for their demand usage- I believe defined as the gretest constant 15 minute draw.

Heat-pumps tend to use much less energy as compared to straight electric resistance heating. In your market however, straight electric used off-peak with heat stored to use during the day (on-peak) may be less expensive overall.

As you stated, my understanding is that much of Europe uses hyronic (hot-water) heating as opposed to air-heating/cooling furnaces.

[Boilers=> heat water to make hot water or steam.
[Furnaces => produce fan-forced warm-air or ancient ones produce gravity hot-air].

IIRC Greece used to use German units that had electric resistance coils/heaters wrapped around clay/ceramic "heat-sinks" ("storage devices"). A computer would decide how much energy to store during off-peak (night and weekend) lowered electrical rates.The heat was then released during the day by simply having a fan push it out. My understanding is that they looked like hotel-style PTAC units. Anyone has a name for this, a name-brand and a link?

Demand response in New York City (NYC):
[note: steam powered {absorption} A/C to get around demand metering. This utlity provides STEAM service.
Link:

Mitisubishi Mr. Slim split systems.
Comrpessor speed up to 50% greater in cold weather to booster heat ouput.
Link:

PTAC UNITS:
Link:

AIR-TO-WATER heat-pumps:
Link:

Hey Bobbins and other people in metric lands, what is a KW in terms of heating cooling capacity?[Hint: Ff you tell me "1,000 watts for an hour, I will have to BEAT you! *LOL* ]Would you be able to tell me how many equavalent BTUs? TYVM

Water-to water heat-pumps
Check out those extremely high EER's *WOWZA*
Link:

Geothermal, Etc.
Link:

Fedders brand water-source heat-pumps (water to air)
Link:

Hot water heat pumps
Hi Bit boys *WAVES* Use waste heat in a commeicial laundry room, or a commerical kitchen to provide domestic hot water to taps, etc. This is amazing in warmer climates to provde "free" cooling to commercial kitchens that would otherwwise not have any.
Link:

YIASOU
CIAO
See ya later.
 
Ok here's the in the wall unit A/C-Heat gizmo.. This is whats at the apartment we are staying at for a few days (actually adam is)..Not a heat pump
 
BRRRRR....Baby it's cold outside

This morning it was 14 degrees outside. The air from the vents supplied by the heat pump was much cooler than usual. It took about 2 hours to bring the house up from 63 degrees to 68 degrees. About 1/2 hour before the thermostat's target recovery time, the electric resistance heat(auxiliary) came on intermittently. I guess with more observation, I can figure out at what low outdoor temp the heat pump can no longer keep up on it's own.

Exploder: The A/C above looks like a GE standard sleeve back-breather(with no outdoor side vents). IIRC, a GE standard sleeve is just a little bit smaller than everone else's(Fedders, Friedrich, etc.).

P.S. The neighbor's frosty heat pump was not functioning properly and she is having it repaired.
 
GE zone-lines

My grandfather worked as an engineer for Reynolds Metals back in the 50's. When he had an opportunity to design his own home and build it back in 1959, he built one of the most modern homes of the time, and it looked it. I believe I posted a few before & after pictures here a good while back, of how it looked when it was occupied by my grandparents, and how the new owners have "raped" it and destroyed it's beautiful mid-century modern apperance.

Well, anyways, back to the topic, one of the most modern things the home had was it's heating and air conditioning systems. General Electric, who at the time owned Trane, partnered with Reynolds to develop the spine-fin coil that became their pantented design that's still used to this day by Trane. My Grandfather received a great deal on 5 General Electric Zone-line heat pump units to install in his new home. One went into each bedroom, another into the rear "great room" (family room, dining, and kitchen combined) and the last one in the former living room up front. For supplemental heating, the house was equipped with an oil fired boiler that supplied the home with both radiant floor heating, and domestic hot water.

The house was truly unique for it's time, since it was one of the rare residental locations to be fully air conditioned. Part of the deal for getting the zone-line heat pumps (which would normally cost over $1500 each at the time) was that his home was used as a demonstration home for GE/Trane. My mother remembers as a Teenager that my grandfather would bring home executives from both Reynolds, or GE/Trane to show off the system in the summertime, or coldest part of the winter. They were required to keep the home as absloutely as neat and clean as possible to make a good impression.

Make a good impression it did! The house was the talk of the neighborhood, being the fact that it was nice, cool and comfortable all throughout during the summer. Even only the wealthier people had maybe one window unit that would cool a few rooms, but not the whole house....He had 5 wall units cooling AND HEATING the WHOLE house!!! Not to mention the unusual fact that if you walked by the home during cool weather, you could hear the units humming away...very strange to hear indeed at that time.

Occasionally he remembers overhearing people talking about "those strange rich people that keep their air conditioners running even during the winter!" or "Those showoffs, they've got all those air conditioners, and they run them during the winter just to show they could install 5 of them!" The more bolder neighbors came by and were "enlightened" as he was more than happy to demonstrate the magical backwords running air conditioners that heated the home, dispelling the myth that the house was as cold as a refrigerator inside!
 
Speicherheizung

Steve, I think what you are describing is what the Germans call "Speicherheizung". Dimplex is one of the brands that makes them. There are many models, all available in various capacities. I've seen (and used) them in Austria. Personally I found the air in rooms heated with these heaters very dry. Here's a picture of a traditional model.

 
Thanks all and specially foraloysius!! We've decided, our new home will be heated by a pelletstove (stove on kind of woodpowder) and the heatingpump. Our architect was at first not so happy but he really cheered up when he looked our plans and our savings we could do. So next step in building our house; hoping that our plans will be accepted by the local governement.
 

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