questions about a heat pump issue

[jcl333]

You know, I am quite surprised really how comparitively primitive thermostats really are after this discussion. You guys are joking about it, but do I have a point? I am a computer systems engineer not an HVAC guy, fair enough, but small computers that could do VERY advanced things could be made very cheaply.

Especially in this day and age with the focus on conservation, polution, and money... I would think such a thing would already exist.

Imagine, putting basically a watt wizard on the electrical input to your heating system to measure the electricity, a seperate gas meter for it's gas usage. Measure temperatures all over the place and monitor these statistics over time. You could measure the exact efficiency of the furnace, the efficiency of your living space, etc. You would know when things needed service based on when efficiency dropped. You could decide weather to run heat pump or gas by entering in the cost per KWH and cost per Therm, etc. And all this need not be exposed to the end user if they are not geeks, just a big green light for "good", yellow for "needs service", red for "problem", you get the idea.

Is this really so far fetched?

JCL333

[beenthere]

Cost wise, yes.

Lack of customer demand for it. Would make it as expensive as a complete system install including the duct work.

[kajer]

I beleive the balanceing temp for a heat pump 27 F. If it is not keeping up check your insulation in wall and attic. Do you have a crawl space, basement or slab. Check for air leaks around windows and door ect. By fixing any problems will lomer your heat loss. And in turn will help your heat pump keep up alittle better.

[beenthere]

There is no one fixed temp for a heat pumps balance point.

[kajer]

That is true but it is also text book. And a good starting point.

[beenthere]

In this area, HP balance points vary from 40° to 20°. With most of them being closer to 35°. We size mostly to the cooling load.

An area that sizes to the heating load, can be much lower.

[beenthere]

That is true but it is also text book. And a good starting point.

What text book has 27° as a BP standard in it.

[motoguy128]

You know, I am quite surprised really how comparitively primitive thermostats really are after this discussion. You guys are joking about it, but do I have a point? I am a computer systems engineer not an HVAC guy, fair enough, but small computers that could do VERY advanced things could be made very cheaply.

Especially in this day and age with the focus on conservation, polution, and money... I would think such a thing would already exist.

Imagine, putting basically a watt wizard on the electrical input to your heating system to measure the electricity, a seperate gas meter for it's gas usage. Measure temperatures all over the place and monitor these statistics over time. You could measure the exact efficiency of the furnace, the efficiency of your living space, etc. You would know when things needed service based on when efficiency dropped. You could decide weather to run heat pump or gas by entering in the cost per KWH and cost per Therm, etc. And all this need not be exposed to the end user if they are not geeks, just a big green light for "good", yellow for "needs service", red for "problem", you get the idea.

Is this really so far fetched?

JCL333

Like Beenthere said, lack of demand, and lack of desire to pay 2X or 3X the price of a IAQ or Infinity control for even a basic PID loop controller with enough I/O to act like a thermostat.

I must say, there are times that it would be tempting to get an inexpensive PLC like a Micrologix and improve on my thermosts current logic. But then I'd need a 4-20ma or 0-10V temperature and moisture transmitter and analog I/O isn't cheap either. And tuning a PID loop is another story altogther....but the sky's the limit for control. Oh.. and don't forget the touchscreen HMI. For a little more it can be done all with ethernet IP instead of serial. For $$$$ for equipment plus maybe 40 hours of programming and 3-4 hours for checkout, I can hook you up with a heck of a system.

[ebierley]

The White Rogers touchscreen will bring on the gas furnace if the HP cannot keep up. I believe it is alittle cheaper than the 802.

[jerrod6]

In this area, HP balance points vary from 40° to 20°. With most of them being closer to 35°. We size mostly to the cooling load.

An area that sizes to the heating load, can be much lower.

If you were installing an IAQ with a system and could control the humidty, what would be the cons with sizing for the heating load?

[beenthere]

The key word is IF.

Most places, the blower won't slow down enough to control the humidity.

If, it can. Then there is no big problem.
If it can't, then you would also need to add a whole house dehumidifier.
Take a long time to recover that additional money, from the savings of over sizing a heat pump by a ton or more.

[jerrod6]

The key word is IF.

Most places, the blower won't slow down enough to control the humidity.

If, it can. Then there is no big problem.
If it can't, then you would also need to add a whole house dehumidifier.
Take a long time to recover that additional money, from the savings of over sizing a heat pump by a ton or more.

VS blower with IAQ, or Trane Comfort-R would not be enough?

[beenthere]

If your house needs 3 tons for cooling, at design conditions.

And you have a 4 ton installed.

You won't slow the blower down enough on days when the outdoor temp is below 80°.

First stage will still be 80% of second stage, so you would have a 3.2 ton capacity.
You won't be able to slow the blower enough to reduce its capacity to only 2 tons.
So you will stiil have high SHR, and not remove as much moisture as you need to, in a short time.

[beenthere]

This is one area the carrier 2 stage with the Bristol TS compressor has an advantage.

In first stage, the 4 ton is a little above 2 tons capacity, with the blower slowed down.

[jerrod6]

If your house needs 3 tons for cooling, at design conditions.

And you have a 4 ton installed.

You won't slow the blower down enough on days when the outdoor temp is below 80°.

First stage will still be 80% of second stage, so you would have a 3.2 ton capacity.
You won't be able to slow the blower enough to reduce its capacity to only 2 tons.
So you will stiil have high SHR, and not remove as much moisture as you need to, in a short time.

I got it now Thanks

[rcamner]

After the initial installation of an American Standard (Heritage 16) with an 80% 2-stage Comfort-R furnace and an IAQ tstat, I was running into the same problem as the OP.

1. Adjusting the Aux Heat lockout temp to 40 made a big difference. My house, built in 1983 in the Pacific Northwest, isn't very tight. But I know a guy with exactly the same system with a house built in 2005 that keeps his Aux Heat lockout at 25 and manages just fine...lucky stiff!

2. Even after adjusting the Aux Heat lockout temp, I still had (a smaller) problem with inconsistent behavior with respect to getting up to setpoint in the morning (2* night setback). Contractor replaced the IAQ...after trying a bunch of other things, without success, he said "what the hell, let's try the tstat." Bingo!! System works perfectly now. It's always up to temp when it needs to be. Upstages from 1st stage HP to 2nd HP to 1st furnace to 2nd furnace, just the way it should. It's a great system...I love it. I even send some mental love to the contractor now and then, since he persisted until things came out right!

YMMV...

[jramunni]

You know, I am quite surprised really how comparitively primitive thermostats really are after this discussion. All things considered...regarding comfort control, we are still in the stone age.

Especially in this day and age with the focus on conservation, polution, and money... I would think such a thing would already exist. One would think!

Imagine, putting basically a watt wizard on the electrical input to your heating system to measure the electricity, a seperate gas meter for it's gas usage. Measure temperatures all over the place and monitor these statistics over time. You could measure the exact efficiency of the furnace, the efficiency of your living space, etc. You would know when things needed service based on when efficiency dropped. You could decide weather to run heat pump or gas by entering in the cost per KWH and cost per Therm, etc. And all this need not be exposed to the end user if they are not geeks, just a big green light for "good", yellow for "needs service", red for "problem", you get the idea.

Is this really so far fetched? Actually...We should have been here 20 years ago

JCL333

The only piece you are missing in you fantasy comfort control center is the ability to deliver hot and cold air to only the areas of your home that are in demand. So you could also adjust blower capacity based on cfm demand while managing the H/C capacity staging based on actual supply air temp, outside temp, fuel cost, house kw usuage and maybe even throw in utility peak load times to help out on the grid and hopefully catch a few favors from the elect utility's billing dept.
The frustrating part of this discussion is that it was initiated by someone outside the HVAC world...outside the box shall we say. Thanks jcl333 for the insight!

Do check out the functionality of our "Heat PumPro" zone control, it takes equipment control to the next level. (www.arzelzoning.com)

[jerrod6]

The only piece you are missing in you fantasy comfort control center is the ability to deliver hot and cold air to only the areas of your home that are in demand. So you could also adjust blower capacity based on cfm demand while managing the H/C capacity staging based on actual supply air temp, outside temp, fuel cost, house kw usuage and maybe even throw in utility peak load times to help out on the grid and hopefully catch a few favors from the elect utility's billing dept.
The frustrating part of this discussion is that it was initiated by someone outside the HVAC world...outside the box shall we say. Thanks jcl333 for the insight!

Do check out the functionality of our "Heat PumPro" zone control, it takes equipment control to the next level. (www.arzelzoning.com)

Does anyone know how a system would perform this? I ask because 2 years ago I watched the construction of a high rise condo two blocks from my home. When it was finished I looked at the units during the month of April. One of the selling features was the fact that you were able to control the heating or cooling in each room. The sales rep was using a name for this system but I don't remember what it was, and I think there was some central thing up on the roof that was doing this. They were making a big deal out of the fact that you could have heating and air conditioning going on at the same time. During my visit one side of the unit was receiving direct sun(floor to ceiling windows all over the place - nice view) and cold air was blowing out of the vents in the room I was in. The other side of the unit was in the shade and warm air was being delivered and the air was not blowing at the same cfm.

[jerrod6]

The only piece you are missing in you fantasy comfort control center is the ability to deliver hot and cold air to only the areas of your home that are in demand. So you could also adjust blower capacity based on cfm demand while managing the H/C capacity staging based on actual supply air temp, outside temp, fuel cost, house kw usuage and maybe even throw in utility peak load times to help out on the grid and hopefully catch a few favors from the elect utility's billing dept.
The frustrating part of this discussion is that it was initiated by someone outside the HVAC world...outside the box shall we say. Thanks jcl333 for the insight!

Do check out the functionality of our "Heat PumPro" zone control, it takes equipment control to the next level. (www.arzelzoning.com)

I took a look at the link. This looks very interesting.

Can this system be used with a hot water system or warm air gas furnace or is it restricted to a heat pump.

Where do the dampers get the air needed to open and close?

Can it work with the AC and heat running at the same time, or is it providing cool air by just bypassing the heating source and not delivering any air at all?

[jramunni]

I took a look at the link. This looks very interesting.

Can this system be used with a hot water system or warm air gas furnace or is it restricted to a heat pump.

Where do the dampers get the air needed to open and close?

Can it work with the AC and heat running at the same time, or is it providing cool air by just bypassing the heating source and not delivering any air at all?

Most "forced air" zoning systems can be used on both heat pumps and gas furnaces along with systems that heat and/or cool using water coils.

The air in the Arzel system comes from a medical grade mini pump in the control panel that provides the 2psi of press/vac required to open and close dampers.

Most residential, light commercial zone systems, including Arzel's, can deliver either heating or cooling at any one time but not simultaneously. The Arzel zone controls will allow the system to switch from heat to cool every 20 minutes when it gets a call for both.

These systems are different than some of the very complex and costly commercial/industrial systems that can heat one area while cooling another.