I'm not saying it's a rip off or price gouging if an HVAC contractor hires out the loop installation. All I'm saying that if they do, it WILL increase the cost overall which means a higher price for the customer. The HVAC contractor will add a percentage to what he is charged. I do know for a fact in some industries it is double. I have no clue if it's done in this area and said that in the first post. That's why I was asking.
wp.....my original post on here was not a rant. I think you are still thinking of my original thread on 'Why is geo so exp'
Nobody mentioned that if you need a lic to install geo above the HVAC lic?

Posted By tinoue on 30 Jan 2012 07:07 AM

Posted By docjenser on 30 Jan 2012 04:00 AM
So there was a thermostat/zone issue. Loop temps in the upper 20s are not making a geosystem fail. Stay away from the installer who suggested that all the loop heat is gone and you should shut it off for a couple weeks. He must have a complete lack of understanding of geo systems.
Most of our loops run in the low 30s by now, some fresh ones in the upper 20s. Totally OK. Let them run!
Watch your system in the next days and let us know how things are going with the fixed wiring.

I'm surprised by the repeated assertion that the installer who suggested a ground loop recovery period is incompetent. In fact, the advice it totally sound.

The only thing that matters to the performance/output of the GSHP is the temperature of the loop fluid that is delivered to the heat exchanger. These systems have their rated output typically assuming a temperature in the high 40's. If the loop field is delivering temperatures in the mid 20's to the system, the system will be delivering about 25% less heat to the house, shifting the balance point of the house/GSHP system to a higher temperature. But, since it's still cold out, the heating demands remain high and the system will run longer and longer, further depressing the loop field temperature and the system output.

This cycle continues until the balance is struck between the amount of energy the loop is extracting from the ground matches the far-field ground energy transfer rate - that is, the ground can keep up with the heat demands. It's all physics and rates of energy transfer. If the ground loop area is too small, the ground cannot supply energy at the rate of extraction. Same thing if the loop isn't thermally connected to the ground or the thermal conductivity of the surrounding ground isn't sufficient.

Turning the system off for a while is *GOOD ADVICE*, especially if the ground around the loop has frozen, which it has in this case since the incoming water temperatures are below freezing. It might take a week or two for the ground to thaw out and the ice to melt and bring the entering water back into the mid 30's. This will allow the system to deliver about 20% more heat to the house, which is substantial. Telling the OP that it's fine to run a GS heat pump and keep reducing the ground temperature to this extent shows a lack of understanding of the physics. If you're going to let your ground temp drop that low, you may as well just get an air source heat pump. Commercial scale GSHP systems are meticulously simulated/designed to maintain a EWT in a range that keeps them operating at high efficiency and with sufficient capacity for years. This includes minimum(winter) and maximum (summer) allowed ground/EWT temperatures. This often is a fairly narrow range, certainly not allowing EWT's below freezing.

I did run the numbers with Geodesigner, and a loopfield designed for a 4 ton, 58 KBTU/H heatloss in Western NY climate will cost you $1085 at 30F min EWT. If you shorten the loop and change the EWT down to 25 F min, you will spend $1165, that is $80 more a year. However, to run the supplement heat by itself for a week will cost you $210 fro that week alone. Makes no sense to me.

You also seem to think that you get the temp up to 35F within a week or two. That is true we, see that when we get warmer periods at the end of the heating season, but as soon as you turn on the heatpump again, it is within a day or 2 back to 30F, since the surrounding ground is still too cold.

Bill, you are correct that each loopfield finds its balance point, but that is at a certain temperature. We shoot for 30F in our heating dominated climate. Here is an example for a perfectly designed system. The graph on the bottom shows that it reaches its 30F balance point about this time of the year, and then stays at 30F until 3 months from now when you pull less heat out and the loop recovers.

http://welserver.com/WEL0448/


Similar things here:
http://welserver.com/WEL0267/

We need to keep in mind that if the loop temp decreases further (if it is short looped for example), the loop pull more heat out of the ground since it has a larger temp differential to the surrounding ground. It also will find it's balance point, just at a lower temp.

So you tell me that I don't understand the physics since it don't think it makes any sense to use supplement resistant to give the loop a rest? Well, the simulation software, which is based on those physics and which is relatively precise by now, tells me that it does not make any sense. Nor does the actual monitoring of system performances and loop temps tell me that it does not make any sense. While I am a fan to oversize our loopfields slightly for the purpose of quicker, more standardized installations (to cover different ground types and also to adjust for the lack of full loop performance in the first and second year), I don't think it is detrimental for a loop to drop down in the mid 20s. Newer heat pumps are designed for an extended range of operation, and reducing the loop size, especially in vertical loopfields, can significantly reducing upfront costs. There are safety margins there, and you can touch those margins if you know exactly how your loops perform.

OhioBuckye,
The pros here have repeatedly told you loop temp isn't a huge concern yet. I have asked for airside design stuff (balance point etc.). Your smoking gun was the disabled auxiliary. Do not turn off the heat pump. Do little but wait and see. For humidity I prefer steam humidifiers as you will notice even stated capacitys of flow through or power humis may be lower with geo air temps.

Tinoue, name calling if you were referring to me was directed at incompetant service technicians. My frustration is raised occasionally with the chuckleheads who have to visit a system 5 times, blame the well driller before turning the auxiliary on, then suggest we turn off the loops causing even more energy consumption. FWIW it was not directed at you.

Rob,
I am unaware of geo licensing requirements. There is an industry standard (IGSHPA) certification and movement a foot to create a national certification, but the areas I'm familiar with only require a mechanical contractors license.

The problem with licensing or national certs. is they are no guarantee of competence. Many a 16 year old will tell you their driver's license did not assure a positive result -we have a few banged up cars around here to attest to that (ones totalled)!

The way you ask your questions is what gets people excited. You don't say "hey guys if you sub out loop installation doesn't that up the price?" You suggest that it must be a 5 figure price swing. So it does not come off as reporting or fact finding it comes off like a headline in a scandal sheet.

You then often discard or at least fail to recognize suggestions to the contrary, such as when I told you my loop installer buys in more volume than I and spreads equipment cost across more jobs, so my customers pay the going rate for loops even though I sub them out.
To this you reply:
"All I'm saying that if they do, it WILL increase the cost overall which means a higher price for the customer."

I tell you it doesn't raise my customers prices and you insist it "WILL".

So you ask a question propose a theory, ignore evidence to the contrary (might as well say we are lying) and wonder why folks are aggravated?

I'm no stranger to aggravating a few people myself - but if you genuinely want to learn more about this stuff your M.O. could use a little polish.

Thanks joe for the info! I don't mean to come across as ahole but I've seen it over and over in other industries where the sub contractor price was doubled to the customer and I just feel that is flat wrong IMO. Glad to see it isn't done in geo installations.

Everyone should play to their own strengths. It likely makes little sense for an HVAC contractor to also own a half million dollar drill rig to bore verticals on his own projects.

Another example is sprayfoam insulation - I as an HVAC contractor and deep energy conservation retrofitter know that sprayfoam insulation properly applied greatly reduces home heating and cooling energy use, especially in cases where cooling ductwork is in a hot attic.

I have developed methods to confirm the performance of a sprayfoam installation. Verifying envelope perofrmance lets me confidently size the HVAC and ductwork.

All that said, I haven't the slightest interest in acquiring a $100k foam rig and dealing with all the logistic, safety, labor and training issues pertaining thereunto...it would detract from my core value adds... I'm much better off working to identify foam contractors who will work to my expectations at a reasonable profit margin, leaving me to focus on my and my crew's core competencies.

Posted By OhioBuckeye on 30 Jan 2012 09:52 PM
Over the weekend, I did turn the geo off and allowed the emergency heat backup to run. In reading everyone's post I see there is a good discussion if allowing the loop field to recover a few days is a good idea. I definatley find all of this interesting. Luckily, Dayton is coming into a mild spell for the next week so hopefully I will not be putting too much strain on the system. A friend of my contractors who designs owns a geo company called me tonight and spoke to me concerning my 4 ton unit and the loop field. Since I am having issues, he is going to come in and perform another manual j calculation and also then determine how large the loop the field should be. Once this has been calculated we will then have a meeting with the installer of the loop field to determine if the right size was installed. He also wants to meet me here at the house to determine if the furnace was installed incorrectly. Based on the information I gave him he already identified one issue, I have the Aprilaire Model 500 for a home that is finished at 3100 sq feet but including the basement is sitting over 5600. He stated the 500 model is undersized especially if there is a lot of wood in the house. We basically only have hard wood floors throughout the house.

Ohio,
Have you ever thought about just going all out and buying and installing a Welserver package?  I think the <$1,000 investment may give you a lot of good data going forward. My entire Welserver install including Wattnode (power consumption of heat pump package) and full monitoring of EWT, LWT, return and supply air temperature, DSH in and out was all purchased for about $800 and has been fantastic to watch.  It will also be invaluable should anything go wrong with the system as I will VERY quickly be able to locate the issue.

Earlier in the thread someone mentioned something about too large of a loop field--can this really be a problem other than a waste of money? I ask because I drilled six loops for two three ton units, but will only have one installed for a year or two until i install the other heat pump. I figured if anything the single unit would run very efficiently in the meantime.

Posted By vanstelp on 19 Sep 2012 10:00 PM

I figured if anything the single unit would run very efficiently in the meantime.

That is the way I see it.

One issue I know of with larger than necessary loop fields is that the Return on Investment could be very long. That is why most Heat Pump Systems employ a third stage to keep the design parameters vs.cost within a reasonable range and balance that with the Heating/Cooling degree days that keep your system delivering the best overall COP/SEER. In your case where all the energy from your loops will eventually be used, there is no problem. If you are pumping the necessary flow rate to keep the EWT in a reasonable range, then it is all set.

If a customer plans on upgrading to geothermal water heating or adding on to the house we will extend the loop and let it run more efficiently, its certainly less costly to dig up the ground and lay pipe once rather than twice.

Thanks for the input. I'm glad to see that my thought process wasn't too far off.