HP COP vs NG boiler $ Balance point - Page 2

buffalobillpatrick · 10-21-14, 06:27 PM

Balance Point Formula from post #1

Kwh = .16
Mcf = 8.00
constant of 10.25 converts Mcf to Therm
Boiler Eff = .85
Kwh in a Therm = 29.3

BP = ( .16 / (( 8.00 / 10.25) * (1 / .85)) * 29.3);

Gives correct result on Arduino: BP = 5.11

Mikesolar · 10-21-14, 06:48 PM

Quote:

Originally Posted by buffalobillpatrick

Thanks guys,
I can buy a flat plate HX on Ebay 5"x12" 30 plate, 120Kbtu for $150
I already have a 5gal unopened propylene glycol made for heating systems.

I could sleep better doing the 30% propylene glycol in everything outside house.
Not only is it 100' from house to HP in shop, it is also 75' from shop to Solar panels/tank.

Enthalpy of fusion - Wikipedia, the free encyclopedia

Also this opens the door to the possibility of using "Latent Heat of Fusion"
(enthalpy of fusion) by allowing ice to form around the HP source HX tubes in the 1,000g Solar tank.

This would only occur after a long period without Sun, and supports the bottom end of ESWT at 0*C increasing the Solar tanks heat capicity by about 2x

http://punktwissen.at/pdf/punktwisse...System-LEO.pdf

Laramie, Wyoming - Thermal Battery Systems | Thermal Battery Systems

I don't know if system would ever need to use 0*C ESWT as this would require my calculated economic "Balance Point" from post #1 to drop below a COP of about 5.0

BTW, has anyone checked my math?
OR
the thread idea presented?

Not checked your math but most manufacturers of HX rate the heat transfer at 20F dT, Your system may be different.

buffalobillpatrick · 10-21-14, 07:05 PM

So Mike your suggesting that when Ice forms around the HX that the ESWT would go below 0*C?

It would, but I don't know how much, I mostly was restating what I've read in the hyp for Ice storage.

Ice is a better heat conductor than water.

Mikesolar · 10-23-14, 06:04 AM

Quote:

Originally Posted by buffalobillpatrick

So Mike your suggesting that when Ice forms around the HX that the ESWT would go below 0*C?

It would, but I don't know how much, I mostly was restating what I've read in the hyp for Ice storage.

Ice is a better heat conductor than water.

Hmmmm, I'm not exactly sure how you want to pipe this but, I've been replacing a few flat heat exchangers in solar systems where (due to a controller failure) the glycol has continued to flow when it is -20 out and 3AM. There was no flow on the water side and the HX split. Eventually the concentration of glycol diluted enough that the panels and piping split as well. I am, thus, quite wary of creating ice around a HX unless you can ensure proper flow.

That said, I have to look at this ice box thingy a bit more.

buffalobillpatrick · 10-24-14, 02:57 PM

The Shocking Truth About Heat Pumps

http://www.energyvanguard.com/blog-b...formance-Homes

SDMCF · 10-25-14, 03:14 AM

Quote:

Originally Posted by buffalobillpatrick

The Shocking Truth About Heat Pumps

Quote:

The shocking truth about heat pumps is that they might well be a great fit for your home. Or they might not. It depends.

Well who would have thought it?

Does this really come as a shock to anyone?

10-21-14, 06:27 PM	#11
buffalobillpatrick Master EcoRenovator Join Date: Mar 2014 Location: Florissant, Colorado Posts: 599 Thanks: 814 Thanked 59 Times in 55 Posts	Balance Point Formula from post #1 Kwh = .16 Mcf = 8.00 constant of 10.25 converts Mcf to Therm Boiler Eff = .85 Kwh in a Therm = 29.3 BP = ( .16 / (( 8.00 / 10.25) * (1 / .85)) * 29.3); Gives correct result on Arduino: BP = 5.11 Last edited by buffalobillpatrick; 10-21-14 at 06:58 PM..

10-24-14, 02:57 PM	#15
buffalobillpatrick Master EcoRenovator Join Date: Mar 2014 Location: Florissant, Colorado Posts: 599 Thanks: 814 Thanked 59 Times in 55 Posts	The Shocking Truth About Heat Pumps http://www.energyvanguard.com/blog-b...formance-Homes Last edited by buffalobillpatrick; 10-24-14 at 03:04 PM..

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10-21-14, 07:05 PM	#13
buffalobillpatrick Master EcoRenovator Join Date: Mar 2014 Location: Florissant, Colorado Posts: 599 Thanks: 814 Thanked 59 Times in 55 Posts	So Mike your suggesting that when Ice forms around the HX that the ESWT would go below 0*C? It would, but I don't know how much, I mostly was restating what I've read in the hyp for Ice storage. Ice is a better heat conductor than water.