Running geothermal system killing hot water heater temperature
Last Post 03 Nov 2014 11:08 AM by newbostonconst. 51 Replies.
Printer Friendly
Sort:
PrevPrev NextNext
You are not authorized to post a reply.
Page 2 of 3 << < 123 > >>
Author Messages
docjenserUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:1400

--
18 Jul 2013 12:22 AM
Posted By ascorbate on 09 Jul 2013 10:02 AM
Posted By docjenser on 02 Jul 2013 12:14 AM
The issue is in COOLING mode, not heating mode.


Confused... I'm losing heat from my hot water heater during BOTH the Cooling (summer use) and the Heating (winter use) mode!


It is also possible that you have thermal siphoning going on. A checkvalve on the outgoing piping of your tank might solve the problem.
www.buffalogeothermalheating.com
Deborah MarshallUser is Offline
New Member
New Member
Send Private Message
Posts:1

--
22 Aug 2014 10:20 AM
Having same issue with my system. Did you find a solution to problem?
joe.amiUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:4377
Avatar

--
25 Aug 2014 12:34 PM
How is your system plumbed Deborah?
Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort!
mngeotherm1User is Offline
New Member
New Member
Send Private Message
Posts:6

--
24 Sep 2014 05:00 PM
Having the same problem, whats the solution?

I have a closed loop geocomfort geothermal system with a DSH and a 105 gallon Marathon water heater (no buffer tank).
docjenserUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:1400

--
24 Sep 2014 09:10 PM
Guys (and girls), again, the issue is that you have one tank versus two tanks. The tank where the desuperheater is dumping warm water in must not be powered by another heat source in order to be effective. Secondly, we found that there must be a check valve in the cold water feed to the DSH in order to avoid thermal siphoning. 2 tanks are the solution!!!!
www.buffalogeothermalheating.com
mngeotherm1User is Offline
New Member
New Member
Send Private Message
Posts:6

--
25 Sep 2014 01:51 PM
Hi Doc, thanks for the info. I guess I will go back to my installer with this... I am fairly certain he will say it is set up correctly. I looked in the Geocomfort manual and they show a single tank configuration as well as a dual tank configuration as approved. What is your response to that? Thanks for the help!
Bill NeukranzUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:1103

--
26 Sep 2014 10:04 AM
Posted By mngeotherm1 on 25 Sep 2014 01:51 PM
Hi Doc, thanks for the info. I guess I will go back to my installer with this... I am fairly certain he will say it is set up correctly. I looked in the Geocomfort manual and they show a single tank configuration as well as a dual tank configuration as approved. What is your response to that? Thanks for the help!

My response would be that the DSH will work fine, and so will the geo unit.

But...the geo unit will not operate in an optimum efficient manner.  I.e., you stand no chance of it operating at the efficiency performance that the manufacturer claims.

I too have a direct connected DSH to a gas-fired HWH.  I also have a performance monitoring system that includes recording temp measurements for the various pipe lines, such as refrigerant line temps, E/LWT temps, and DSH E/LWT.

After looking at a lot of the system's data and charts, in cooling mode (dominant for me here in Dallas area) it was obvious that DSH usage was heating up the refrigerant.  I.e. you got benefit to the HWH from the DSH in and out lines, but you lost the benefit in heating up, not cooling further, the refrigerant lines.  It's clearly obvious to see this phenomena during the intense parts of the cooling season.

As the manual shows, a direct connected DSH to a HWH 'works' fine.  And thus it is an alternative connection you'll find in the manual.  This connection allows for those who spent extra money on a DSH option to be able to connect it up.

But, what the manual doesn't point out is that performance is sub-optimal.  You really must have the buffer tank to reach the next levels of efficiency that the DSH's presence offers,

BTW, since I have no buffer tank, my DSH is turned off.

Best regards,

Bill
Energy reduction & monitoring</br>
American Energy Efficiencies, Inc - Dallas, TX <A
href="http://www.americaneei.com">
(www.americaneei.com)</A></br>
Example monitoring system: <A href="http://www.welserver.com/WEL0043"> www.welserver.com/WEL0043</A>
Bill NeukranzUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:1103

--
26 Sep 2014 10:11 AM
Further, the manuals really do DSH usage a disservice.  Since the manual (WF is no different) shows a direct connected DSH to a HWH, an installer can say 'it's hooked up in an acceptable way, per the manufacturer.'

Bill
Energy reduction & monitoring</br>
American Energy Efficiencies, Inc - Dallas, TX <A
href="http://www.americaneei.com">
(www.americaneei.com)</A></br>
Example monitoring system: <A href="http://www.welserver.com/WEL0043"> www.welserver.com/WEL0043</A>
stickmanUser is Offline
New Member
New Member
Send Private Message
Posts:31

--
26 Sep 2014 01:47 PM
Posted By docjenser on 24 Sep 2014 09:10 PM
Guys (and girls), again, the issue is that you have one tank versus two tanks. The tank where the desuperheater is dumping warm water in must not be powered by another heat source in order to be effective. Secondly, we found that there must be a check valve in the cold water feed to the DSH in order to avoid thermal siphoning. 2 tanks are the solution!!!!


I recently added a buffer tank as per Bergy's diagram and with the guidance of the pro's here. I did ask if any check valves were needed, but was told no. Has the recommendation changed?
joe.amiUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:4377
Avatar

--
27 Sep 2014 08:30 AM
Bill I don't believe when your system was installed the manufacturer only allowed for 1 tank set-ups with electric water heaters.
Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort!
joe.amiUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:4377
Avatar

--
27 Sep 2014 08:43 AM
Mngeotherm,
First for the one tank set up to be correct, it must be exactly like the instructions with the coaxial pipe from the bottom and the lower element disabled or set very low.
If your installer did all that then you may get a very little bit of btu's from your system. Just remember if it is a 50 gallon tank and you are not running your geo much, you may only have 25 gallons of hot water.

The one tank design is simply unevolved. I have measured a one tank set up moving heat from the hot water tank to the loops......costing the homeowner money.

j
Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort!
docjenserUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:1400

--
27 Sep 2014 02:25 PM
Manufacturers endorse 1 tank setup, but also state that 2 tank setup is more efficient. In other words, do you want your DSH to contribute 10% or 60%.No one could give me a rationale why they still have 1 tank setup in their installation manuals.


Check valves: I recommend it to stop thermal siphoning.
www.buffalogeothermalheating.com
fun2driveUser is Offline
New Member
New Member
Send Private Message
Posts:68

--
28 Sep 2014 12:03 PM
I have a question about the 2 tank system approach using geothermal. The desuperheater (DSH) getting warmed by the discharge off the compressor makes sense as does using the desuperheater tank as a store for the domestic hot water (DHW) (by the way I am using the full names in the beginning for new readers of the forum trying to figure out that those abbreviations mean). I have a number of friends that have this 2 tank system set up and works fine. The question I have is the output of the DSH to another source to heat water to the temp a suitable for DHW seems to be a tank heated by electric elements. I have access to natural gas and was thinking of a 2nd tank heated by natural gas or a tankless system heated by natural gas. I have homes with both thankless and hot water tank and except for cleaning the scale off the heat exchanger on the tankless system it does an excellent job.

Joe- Doc what do you guys know or think about a tankless heater to boost the DSH temps to acceptable levels for DHW?
Am I wasting money to put a tankless system in when I can use a hot water tank heated by natural gas to boost the DHW temps?
Thanks
arkie6User is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:1453

--
28 Sep 2014 01:20 PM
Have you looked at an electric hybrid heatpump water heater for the finishing tank in a 2 tank setup with the DSH heated tank being a standard unpowered electric hot water heater tank? The advantage of a heat pump water heater in a southern location is high efficiency plus room cooling and dehumidification. Plus, with a heat pump water heater tank that is essentially totally encapsulated with insulation, the standby losses would likely be less than a gas fired water heater tank that has the heat exchanger pipe right up the middle that is vented to atmosphere.
engineerUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:2749

--
28 Sep 2014 07:47 PM
That's the arrangement I have in a deep south house. Availability of NG moves the needle quite a bit in some locales. Be careful specifying tankless heaters downstream of a DSH; some tankless aren't versatile enough to properly cope with elevated incoming water temps
Curt Kinder <br><br>

The truth is incontrovertible. Malice may attack it, ignorance may deride it, but in the end, there it is - Winston Churchill <br><br><a href="http://www.greenersolutionsair.com">www.greenersolutionsair.com</a>
joe.amiUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:4377
Avatar

--
29 Sep 2014 07:56 AM
There's little that's cheaper to make hot water with than Nat Gas.
Heed Curt's warning about EWT's and tankless.
Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort!
docjenserUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:1400

--
29 Sep 2014 10:42 AM
Posted By fun2drive on 28 Sep 2014 12:03 PM
I have a question about the 2 tank system approach using geothermal. The desuperheater (DSH) getting warmed by the discharge off the compressor makes sense as does using the desuperheater tank as a store for the domestic hot water (DHW) (by the way I am using the full names in the beginning for new readers of the forum trying to figure out that those abbreviations mean). I have a number of friends that have this 2 tank system set up and works fine. The question I have is the output of the DSH to another source to heat water to the temp a suitable for DHW seems to be a tank heated by electric elements. I have access to natural gas and was thinking of a 2nd tank heated by natural gas or a tankless system heated by natural gas. I have homes with both thankless and hot water tank and except for cleaning the scale off the heat exchanger on the tankless system it does an excellent job.

Joe- Doc what do you guys know or think about a tankless heater to boost the DSH temps to acceptable levels for DHW?
Am I wasting money to put a tankless system in when I can use a hot water tank heated by natural gas to boost the DHW temps?
Thanks


http://welserver.com/WEL0478/
http://welserver.com/WEL0288/
2 systems with buffer tank and on demand supplement, either gas or electric. Nothing wrong either with gas fired tank backup tank
www.buffalogeothermalheating.com
mngeotherm1User is Offline
New Member
New Member
Send Private Message
Posts:6

--
03 Oct 2014 11:55 PM
So I just switched our system from cool to heat (looks like heating season has begun in Mn) and am already running out of hot water again. I know it is not the most accurate, but when I use an IR temp measuring gun the on the copper pipe out of the DSH it is at around 65 degrees. Does this seem right? I know the copper is not the same temperature as the water, but it can't be 40 degrees cooler... Thoughts?

I'm frustrated.

joe.amiUser is Offline
Veteran Member
Veteran Member
Send Private Message
Posts:4377
Avatar

--
04 Oct 2014 09:22 AM
what's the water temp going into the dsh? Why use a measuring device who's results you don't trust?
Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort!
mngeotherm1User is Offline
New Member
New Member
Send Private Message
Posts:6

--
04 Oct 2014 02:34 PM
Hi Joe, the water in/out varies from 61-74 going in and out. I have measured it where the temp is higher going into the DSH and where the temp is higher going out of the DSH. As for the measuring device, its all I have. I don't have the equipment or knowledge to do an inline measurement...
You are not authorized to post a reply.
Page 2 of 3 << < 123 > >>


Active Forums 4.1
Membership Membership: Latest New User Latest: hudson2000 New Today New Today: 0 New Yesterday New Yesterday: 2 User Count Overall: 34707
People Online People Online: Visitors Visitors: 245 Members Members: 1 Total Total: 246
Copyright 2011 by BuildCentral, Inc.   Terms Of Use  Privacy Statement