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-   -   Whole house heat pump (https://ecorenovator.org/forum/showthread.php?t=4707)

bdgWesternMass 02-16-16 03:04 PM

Whole house heat pump
 
Hey All,

My name is Ben and I'm pretty excited to find this message board.

I have been trying to figure out how to build/buy a whole house heat-pump.

I could get a Daikin Altherma and that would cover hot water/heating/cooling but it sill misses refrigeration.

I would like to have a split system that also runs my refrigerator.

Anyone have any suggestions or ideas?

Thanks,

Ben

Xringer 02-16-16 03:19 PM

I have not heard about a system that could run a refrigerator too..

Seems like it might be wasteful to crank up a large heat pump (20 to 36k BTUh),
on a nice mild spring day, just to run a refrigerator..?.

If you wanted run your refrigerator for a low cost, there are hacks that will work..
Plus, there's always Solar PV.. A small off-grid system maybe?

During the summer, there are many days when were are not cooling or heating. So, our systems stay off..
But, we always need hot water. So, our hot water system is a stand-alone system..

We use a small heat pump as the main hot water maker, and also use some
solar PV panels to provide much of the hot water on sunny days.
You can buy a hotwater tank with a build-in heat pump..

bdgWesternMass 02-16-16 03:38 PM

Quote:

Originally Posted by Xringer (Post 49155)
I have not heard about a system that could run a refrigerator too..

Seems like it might be wasteful to crank up a large heat pump (20 to 36k BTUh),
on a nice mild spring day, just to run a refrigerator..?.


Yes, I may be out of mind. What I liked about this board is that it seemed like there was an acceptance of foolish pursuits.

My thinking is that when considering the whole house I will find efficiencies. I mostly want to constantly be routing the need for heat and the need for cool around the house constantly all day.

It could be I should just try to marry a hot water heater to a refrigerator and then look for ways to tie that into a larger heat-pump.

Xringer 02-16-16 05:04 PM

Nope, a lot of these guys are resistant to "foolish pursuits"..:rolleyes:
Like when I connected the heating elements of my hot water tank directly to solar PV panels. :p
Most people think it's a waste to use PV to heat up water.. Not efficient. At all.
But, it does work. Pretty well in fact.

Temperature control, turned into a problem, since the tank tends to over heat when solar is too good..
The other day, it was super cold here, and the sun came out.. My hot water
tank zoomed up over 170F.. I had to cool it down..
Normally there's no problem, but PV works much better in extreme cold..
In the summer, I just disconnect one of the arrays for a few months.

The whole house efficiency idea is what I was looking at when I ordered
a 24k BTUh mini-split ASHP. It worked!
But the den (addition) on the back of the house has so much glass, we installed a second mini-split for the den..

After seeing how both of Sanyos work together, I'm starting to think a house
with a 3 or 4 heating zones, could be handled by 3 or 4 mini-split units..
Because, the smaller BTUh units use less power/per BUTh and can work at lower temperatures..
Right now, one of my Sanyos is down. Needs repair.
But, the other Sanyo is doing a pretty good job doing the whole house..
(The den is still a little cool).

So, what happens when it's 97F or 9.7F and your Whole house system goes down?
If you had bunch of small 9k to 12k BTUh 20-30 SEER units, one of them going off-line won't be a big deal..

GREE Terra 9,000 BTU Ductless Mini Split AC FREE 15' Line Set

27 SEER / 14.5 EER / 9.0 HSPF Thems some good specs! :D

AC_Hacker 02-16-16 05:10 PM

Quote:

Originally Posted by bdgWesternMass (Post 49156)
Yes, I may be out of mind. What I liked about this board is that it seemed like there was an acceptance of foolish pursuits.

I think you have guessed right.

These combined forums are infested with dreamers and fools, and with a few practical folks to keep things occasionally reasonable.

You will need to start thinking in energy units, like kilowatts for starters.

Do some poking around about water heaters, and your water heater in particular. You need to know its power consumption over time, like a month perhaps.

You'd also need to know about your typical heating and cooling requirements over time, in the same units (kilowatts) so you can compare.

If your house is monumentally low-performance (leaks lots of heat & cool), compared to your water heater, then the marginal gains that could be made by combining your water heater, would not be worth the trouble. In this case, you should direct your project energies to improving your house thermal efficiency, starting with infiltration...

But if your house is very tight and very well insulated, and the difference in scale between house energy and DWH energy is comparatively small, then it would be prudent to continue your quest.

Best,

-AC_Hacker

bdgWesternMass 02-16-16 05:13 PM

We have a existing mini-split a single compressor and 3 different zones/indoor units.

We actually have spread them across 2 buildings with underground connections.
It is a pretty good system but this weekend I bet it wouldn't have heated the house. We installed them for air conditioning and use it for heating during the shoulder months.

The Daikin Altherma has an electric element for when it is too cold for the heat pump. Which wouldn't help with refrigeration.

bdgWesternMass 02-16-16 05:28 PM

Quote:

Originally Posted by AC_Hacker (Post 49160)
I think you have guessed right.

These combined forums are infested with dreamers and fools, and with a few practical folks to keep things occasionally reasonable.

You will need to start thinking in energy units, like kilowatts for starters.

Do some poking around about water heaters, and your water heater in particular. You need to know its power consumption over time, like a month perhaps.

You'd also need to know about your typical heating and cooling requirements over time, in the same units (kilowatts) so you can compare.

If your house is monumentally low-performance (leaks lots of heat & cool), compared to your water heater, then the marginal gains that could be made by combining your water heater, would not be worth the trouble. In this case, you should direct your project energies to improving your house thermal efficiency, starting with infiltration...

But if your house is very tight and very well insulated, and the difference in scale between house energy and DWH energy is comparatively small, then it would be prudent to continue your quest.

Best,

-AC_Hacker

The good news is that I have been spinning my wheel on this thinking for a while and actually have a lot of the figures you say I will need.

We actually have 2 other buildings that are well insulated on the property. I currently have a centralized utility room in the house of the basement which has 2 natural gas boilers. One is steam for the radiators of the house and the other is hot water for radiant heat in of the out buildings and low temperature baseboard for the other building.

When I was planning the heating for the 2 other buildings I did all sort of heat-loss calculations. We also recently installed a PV solar array that I did all sorts of calculations.

I guess I should comb the site more and come up with a small project to get my feet wet.

I got hooked on the site seeing all the dehumiders being turned into water heaters.

Thank you for the the thoughts.

Ben

jeff5may 02-16-16 10:14 PM

Welcome to the forums, Ben! You will find there are plenty of open-minded, creative thinkers here that can help guide you in your endeavors. I encourage you to start pouring through the forums and reading past threads relevant to your situation. There are literally mountains of information at your disposal.

The dehumidifier-turned-water-heater would be a good engine to retrofit an existing refrigerator into your boiler loop. The external heat exchanger could be rerouted to a refrigerant-to-water condenser hx, which could dump the waste heat into your boiler loop. It would only add a thousand or two BTU per day, but it could work. Whether or not it is worth the effort is all up to you, but it would give you some experience and confidence to move into the full-sized realm.

Tell us more about the multi-zone, multi-temperature boiler loop setup you have running. Natural gas use is incredibly easy to track and log, so if you have been operating this rig for a few years or longer, you should have some good historical data. Even if you have only one gas meter, and haven't been logging each zone's usage. Your gas bills will tell you volumes with respect to system retrofit or supplement options. Due to the fracking craze, natural gas is incredibly inexpensive as an energy source today. Like all good things, they will end eventually, so it is a great idea to have another energy source to fall back on when this eventually happens.

SDMCF 02-17-16 12:45 AM

1 Attachment(s)
Are you considering an air source or ground source heat pump?

I have a NIBE GSHP. The pipe coming into the house from the underground loop passes along the outside of a basement cool room / cold store. Had I thought about it at the time of installation I would have had it run through the cool room. Currently the incoming fluid is around freezing so it would have been a good & cheap way to cool that room and any heat extracted from the room would have offset the heating costs for the rest of the house. I may still try to somehow use that pipe to cool the cool room.

The manual for my heat pump has a section on "free cooling" which I assume could be also used for something similar. It doesn't give details though. All it says is:
http://ecorenovator.org/forum/attach...1&d=1455691255

bdgWesternMass 04-02-16 09:47 AM

Hey All,

Sorry I dropped out for a bit. After my last post I resolved to buy a Daikin Altherma system.
Only to find they are no longer available in North America. After more searching and pleading with various sources the mostly likely story is that they have a 3rd generation model that they are trying to get through UL certification. They stopped bringing in the first generation won't bring in the second so we must wait for the third generation. I don't know if it is true but I will choose to have faith.

To answer some questions.

My set-up is unusual. I live in old plank new england farm house 25'x25'. That happens to have a 7 car garage 60'x24', carpentry shop 25'x30', 13'x30' "school bus garage". All from around the 1920's.

All of the boilers, solar inverters, power, network are in the basement which is a maintain room. We have a Daikin outdoor unit in the far back corner of our lot that has underground tubing and branch points in various buildings so that all the split tubing is concealed and I have a single hidden location for the outdoor units. I also have an additional line set for a Daikin Altherma system that doesn't exist going from this location to the basement 120' away. Currently a gas fired boiler heats up water and pumps it through insulated pex tubing that is buried underground connecting the 7 car garage and the house.

The 7 car garage has more or less 22' x 10" x 59' thermal mass made of masonry sand. This has the appropriate insulation and pex-al-pex tubing. There are times during the heating season when my return water is hotter then my input water.

The carpentry shop has a perimeter with 98' of rental UF-2 low temperature baseboard. The more baseboard surface area the lower the water temperature that can be used. This office also has a Daikin for AC/heating.
I tried to post link for runtal radiators but I need one more post.

Both the buildings are connected together in the garage using a single main loop that is fed by the builder in the house. The main loop also has 1" pex-al-pex connection to the "school bus garage" where I may put solar thermal collectors.

I have done various logging and at this point I can comfortably say that the carpentry shop has negligible impact on my heating. bill.

I believe that my set-up will greatly benefit from a very steady 95-110 degree hot water source.

@Jeff5May you could see how with my thermal mass generate a couple of BTUs a day might add up if I start in aug.

I'm considering an air source heat-pump the COP on hot water to meet my needs when it 13 below F is still over 1 and it will be around 3 most of the heating season.

So what am I going to do. I found that Daikin Altherma line now contains a chiller that looks like it runs off hot water.

We have a PV array and I'm considering expanding to meet the projected load of the Altherma system. I think I'm going to try for net-zero by large solar array and high-surface area of low water temperature. The real trick will be replacing the steam boiler that heats the plank farm house.


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