EcoRenovator  

Go Back   EcoRenovator > Improvements > Geothermal & Heat Pumps
Advanced Search
 


Blog Register 60+ Home Energy Saving Tips Recent Posts Search Today's Posts Mark Forums Read


Reply
 
Thread Tools Display Modes
Old 11-12-15, 07:48 AM   #11
stevehull
Steve Hull
 
Join Date: Dec 2012
Location: hilly, tree covered Arcadia, OK USA
Posts: 829
Thanks: 241
Thanked 164 Times in 122 Posts
Default

I use a dual tank set-up- and it works great! The first tank is preheated by the superheater in my geothermal heat pump. In the summer, this provides about 80-100% of our hot water needs. I used to have my drain back solar system plumbed into it, but I get a lot more efficiency from the GT heat pump by cooling off the desuperheater.

This tank is just a 50 gallon standard dual element hot water tank. It was a "dent" special from Lowes for $50.

The output of that first preconditioning tank then goes to a tankless water heater for a small boost (if needed).

My ground water temp is about 60F and I need 110F water - delta t of ~ 50 degrees F. In the summer, the temp is often 100-105F (or higher) in this preconditioned tank, so I save some 80-90% on water heating costs.


I do have the electric resistance elements hooked up in the preconditioning tank for back-up, but I have literally never turned them on. This tank is wrapped in fiberglass, then scrap bubble wrap and finally some re purposed laminate fashioned into a cylinder (additional R40) surrounding the extra insulation. Put it on a safety pan with a drain hose and it just sits there and has for years.

At installation, I did put in a bypass (with unions) for the tankless so that if I need to remove the tankless for service/replacement, then I still have hot water.

Very basic, inexpensive and it works well. I can't understand why a air source geothermal hot water tank then feeding into a tankless would not offer similar attributes.

Steve

__________________
consulting on geothermal heating/cooling & rational energy use since 1990
stevehull is offline   Reply With Quote
Old 11-12-15, 08:14 AM   #12
jeff5may
Supreme EcoRenovator
 
Join Date: Jan 2010
Location: elizabethtown, ky, USA
Posts: 2,273
Thanks: 338
Thanked 574 Times in 480 Posts
Send a message via Yahoo to jeff5may
Default

Quote:
Originally Posted by Ice View Post
Hi All,

My first post.

I wonder what UNCSoc is using for a tankless water if his electric element backup is inefficient? If it is gas, the best you could expect is 80% efficient whereas electric element would give 100% efficiency. Now cost may be a different story but efficiency is a different story.

Ice
Here's what we can tell about the site and OP:

Two sources of energy exist, not including solar: electricity, propane. This suggests a location outside a municipality, due to no natural gas availability. Usually, this is a favorable condition for solar, no HOA problems, less stringent building codes, etc.

OP is using all available sources of energy. He is trying to improve the overall efficiency of the system. Serious consideration must be made before chopping up a working rig. Otherwise, the expenses add up in a hurry. Cobbling things together doesn't usually turn out well. Resistive electric tank is burning a hole in the bank account.

Future solar plans: wish-I-coulda-hadda. Not going to happen this cycle.

For today, a possible upgrade could be a new split heat pump (minisplit or whole home) with a desuperheater plumbed into the existing water heater tank. Another could be a retrofit HPWH such as the Airtap unit Xringer has chronicled. In tandem with a gas-powered tankless WH (as steve just mentioned), lots of electricity would be saved over resistive heating normal DHW during modest usage events. When a high-usage event comes along, the tankless unit could serve as a backup source.

A PV module could be added now or later to directly improve energy savings. This would not affect operation of the rest of the system whether the sun was shining or not.


Last edited by jeff5may; 11-12-15 at 08:47 AM..
jeff5may is offline   Reply With Quote
Reply


Tags
heat pump, tankless water heater, water heater

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 09:49 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Ad Management by RedTyger
Inactive Reminders By Icora Web Design