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Redmohawk · 07-13-15, 01:05 AM

Ok I've moved this post here to avoid a Thread hijack, and will continue my build thread from here.

Quote: I've spent approx 12 hours over the last two days skimming info from this forum. I'm very DIY orientated, with a strong fabrication background , I'm familiar with a rudimentary understanding of Gas dynamics in this sort of environment.

Have a electronics background , I'll muse over the info for a day or two before deciding on the eventual initial design. I was initially thinking something very similar to your own design but I see the long term heat transference of a single bore to be an issue for large water heating use.

So I'm leaning more to a water loop purely on a cost to benefit ratio, The entire unit will be 100% solar powered. And need to supply enough water for a 5 person household and medium water consumption levels for around here. Being on rain water alone limits our consumption a little but not that I can convince the females of the house so far.

I would factor around 50 to 60L per person per day, Here in Aust a hot water storage unit MUST heat stored water to 60 deg c every heating cycle , unless the water is NOT in circulation (IE sealed heat bank).

Obviously without going to a CO2 based system this is not feasible , and Though I believe I could source the correct components to achieve this it would be at close to commercial off the shelf units anyway . Negation the whole point of DIY for me (Lower COST).

Desired consumed water temp would not exceed 45 deg c as all clothes washing is done in cold water and dishes will be washed in a dishwasher that heats the water to correct operating temp with electricity. So I'm thinking a extremely well insulated 600L heat bank with a copper coil inside as a heat exchanger for consumed water.

Heated by window mount type unit in a compressor sized to consume around 1.5kw would be about right I hope. Removing the fan completely. Now that I think about it , its probably quicker to fabricate water boxes around the existing air con condenser and evap avoiding opening up the sealed system at all.

Ground is a sand/clay type with a water table around the 5m mark average year round ground temp below 1m is 15.5 deg c . Climate is Mediterranean like , summers are 25 deg nights 36 deg days with peaks of 8 to 10 days over 40 deg c 44 deg 2 to 3 times a year. Winters -8 early mornings frosts day temps around 12 to 13 deg c but ground temp remains 15 deg c below 1m.

I will rummage through my dwindling brain cells for a day or to and nut out a idea. For now I'll get out of your thread and stop this diversion. If all Goes well I'll start a thread and post up some constructions of my own.:

Ac retorted with

Quote:
Originally Posted by Redmohawk View Post
I would factor around 50 to 60L per person per day, Here in Aust a hot water storage unit MUST heat stored water to 60 deg c every heating cycle , unless the water is NOT in circulation (IE sealed heat bank).

Obviously without going to a CO2 based system this is not feasible , and Though I believe I could source the correct components to achieve this it would be at close to commercial off the shelf units anyway . Negation the whole point of DIY for me (Lower COST).
I understand the 60C requirement, but that doesn't totally rule out 'low tech' compressors. If you looked at your heat pump as a pre-heater, you could then do the daily 60C bump-up with your heating source of choice. No need to go CO2 all the way... at least for some years hence, when scrap CO2 compressors come available.

Quote:
Originally Posted by Redmohawk View Post
Heated by window mount type unit in a compressor sized to consume around 1.5kw would be about right I hope. Removing the fan completely. Now that I think about it , its probably quicker to fabricate water boxes around the existing air con condenser and evap avoiding opening up the sealed system at all.
The air-source-HX-in-a-water-box idea is OK for someone who wants to prove that it can be done. But for long time, dependable service, you should go whole hog and get or make a good heat exchanger. (Imagine you family members and member-ettes standing in front of you wanting to know why the thing that you call your exchanger-in-a-box, has become an ugly wad of green-slime, and will not allow them to take a bath!!). Since you are doing this for domestic water consumption, a plate type HX is the wrong choice. Some form of tube-in-tube or tube-in-shell is what you want, to avoid mineral build-up from rapidly killing your system.

Quote:
Originally Posted by Redmohawk View Post
Ground is a sand/clay type with a water table around the 5m mark average year round ground temp below 1m is 15.5 deg c . Climate is Mediterranean like , summers are 25 deg nights 36 deg days with peaks of 8 to 10 days over 40 deg c 44 deg 2 to 3 times a year. Winters -8 early mornings frosts day temps around 12 to 13 deg c but ground temp remains 15 deg c below 1m.
I can not recommend this book more highly: CLGS Installation Guide (#21020). There is information in there to guide you through all the Ground Source considerations.

As far as the actual heat pump hacking... there is no better book than this forum... you are in the right place.

Do not fear breaking into the system... we are here to help.

Sincerely,

AC_Hacker]

07-13-15, 01:05 AM	#1
Redmohawk Lurking Renovator Join Date: Jul 2015 Location: Victoria , Australia Posts: 27 Thanks: 0 Thanked 1 Time in 1 Post	Red's down under heatpump hotwater Ok I've moved this post here to avoid a Thread hijack, and will continue my build thread from here. Quote: I've spent approx 12 hours over the last two days skimming info from this forum. I'm very DIY orientated, with a strong fabrication background , I'm familiar with a rudimentary understanding of Gas dynamics in this sort of environment. Have a electronics background , I'll muse over the info for a day or two before deciding on the eventual initial design. I was initially thinking something very similar to your own design but I see the long term heat transference of a single bore to be an issue for large water heating use. So I'm leaning more to a water loop purely on a cost to benefit ratio, The entire unit will be 100% solar powered. And need to supply enough water for a 5 person household and medium water consumption levels for around here. Being on rain water alone limits our consumption a little but not that I can convince the females of the house so far. I would factor around 50 to 60L per person per day, Here in Aust a hot water storage unit MUST heat stored water to 60 deg c every heating cycle , unless the water is NOT in circulation (IE sealed heat bank). Obviously without going to a CO2 based system this is not feasible , and Though I believe I could source the correct components to achieve this it would be at close to commercial off the shelf units anyway . Negation the whole point of DIY for me (Lower COST). Desired consumed water temp would not exceed 45 deg c as all clothes washing is done in cold water and dishes will be washed in a dishwasher that heats the water to correct operating temp with electricity. So I'm thinking a extremely well insulated 600L heat bank with a copper coil inside as a heat exchanger for consumed water. Heated by window mount type unit in a compressor sized to consume around 1.5kw would be about right I hope. Removing the fan completely. Now that I think about it , its probably quicker to fabricate water boxes around the existing air con condenser and evap avoiding opening up the sealed system at all. Ground is a sand/clay type with a water table around the 5m mark average year round ground temp below 1m is 15.5 deg c . Climate is Mediterranean like , summers are 25 deg nights 36 deg days with peaks of 8 to 10 days over 40 deg c 44 deg 2 to 3 times a year. Winters -8 early mornings frosts day temps around 12 to 13 deg c but ground temp remains 15 deg c below 1m. I will rummage through my dwindling brain cells for a day or to and nut out a idea. For now I'll get out of your thread and stop this diversion. If all Goes well I'll start a thread and post up some constructions of my own.: Ac retorted with Quote: Originally Posted by Redmohawk View Post I would factor around 50 to 60L per person per day, Here in Aust a hot water storage unit MUST heat stored water to 60 deg c every heating cycle , unless the water is NOT in circulation (IE sealed heat bank). Obviously without going to a CO2 based system this is not feasible , and Though I believe I could source the correct components to achieve this it would be at close to commercial off the shelf units anyway . Negation the whole point of DIY for me (Lower COST). I understand the 60C requirement, but that doesn't totally rule out 'low tech' compressors. If you looked at your heat pump as a pre-heater, you could then do the daily 60C bump-up with your heating source of choice. No need to go CO2 all the way... at least for some years hence, when scrap CO2 compressors come available. Quote: Originally Posted by Redmohawk View Post Heated by window mount type unit in a compressor sized to consume around 1.5kw would be about right I hope. Removing the fan completely. Now that I think about it , its probably quicker to fabricate water boxes around the existing air con condenser and evap avoiding opening up the sealed system at all. The air-source-HX-in-a-water-box idea is OK for someone who wants to prove that it can be done. But for long time, dependable service, you should go whole hog and get or make a good heat exchanger. (Imagine you family members and member-ettes standing in front of you wanting to know why the thing that you call your exchanger-in-a-box, has become an ugly wad of green-slime, and will not allow them to take a bath!!). Since you are doing this for domestic water consumption, a plate type HX is the wrong choice. Some form of tube-in-tube or tube-in-shell is what you want, to avoid mineral build-up from rapidly killing your system. Quote: Originally Posted by Redmohawk View Post Ground is a sand/clay type with a water table around the 5m mark average year round ground temp below 1m is 15.5 deg c . Climate is Mediterranean like , summers are 25 deg nights 36 deg days with peaks of 8 to 10 days over 40 deg c 44 deg 2 to 3 times a year. Winters -8 early mornings frosts day temps around 12 to 13 deg c but ground temp remains 15 deg c below 1m. I can not recommend this book more highly: CLGS Installation Guide (#21020). There is information in there to guide you through all the Ground Source considerations. As far as the actual heat pump hacking... there is no better book than this forum... you are in the right place. Do not fear breaking into the system... we are here to help. Sincerely, AC_Hacker]