Fridging good

Hello readers,

Winter has set in well and truly for Motueka, however not quite as bad as what our friends and family have been experiencing in Christchurch of late - what with all that recent snowfall and all. We didn't have any snow here during the recent storms, but we did experience quite heavy rain fall and relatively cool temperatures. The hills beyond us however are snow capped which makes for a beautiful view.

The heatpump has been going flat tack, and so has the oil column heater in the corridor to take the chill away. The electricity bill turned up this month for less than $300 however, which isn't too bad for this house with no underfloor insulation and little ceiling insulation. I expect this will likely increase in the next month however.

House Design


We are pretty busy with reading up on architecture and pattern language and how to design our future home. The aim is to work out how to build a not-so-big-house that will be both a cozy home and affordable. We want to live debt free, principally so that any new improvements can be financed directly from what would have otherwise gone to the bank as interest. We don't know if what we want is possible, but we are at least going to attempt it.

There is certainly much to be said about building a smaller (perhaps scalable) house. One has to consider increasing the utilisation of space with consideration to efficiency of usage. You can start to get an appreciation of this when you look at how motor homes and yachts are designed - there is a lot that can be done in a smaller space if you allow yourself to think a little differently. As the kids get older, we may start scaling the house by putting on more rooms as necessary - but the real crux of the design is to ensure that there is a good vision of how the extensions will be done in the future and where they will go, so that the first stage of the house can be designed with those elements in mind. This has to be done correctly or we risk the house looking like a bunch of ad-hoc buildings.


Fridge/Freezer

Of late our upright fridge-freezer has been giving us issues. The fridge compartment stopped working, so we had to put everything on the back porch. Being winter this wasn't a bad thing as the average temperatures were <10 degC, most of the time <5 degC overnight. However this wasn't always ideal and we did have things go bad on us. The freezer also decided to make a terrible "fan scraping" noise (probably the frost free fan) and was also struggling a bit to keep things frozen. It was a bit of a "old-dunga" of a fridge which we were given by one of the local villagers here to use when we first arrived - however I think it may be time for it to RIP.

However I have for some time been intending to convert a chest freezer into a fridge,  and idea originally inspired by this article:
http://mtbest.net/chest_fridge.html

The chest freezer contains the cold in a cavity (compared to an upright fridge/freezer where the cold escapes whenever you open the door), and is better insulated because the temperatures are typically colder.  I managed to find on TradeMe (local equivalent of eBay) an old Haier chest freezer which came with a bottom drawer which they say was a "soft freezer" ... or "not so cold freezer". Of course I always wanted a drawer fridge so this looked like it would do a good job - for $250 delivered (from Blenheim, 2 hours away), it was a score! It didn't bother me too much that it had a dismal energy rating of 399 kWh/year as I wasn't going to run it as cold.

I purchased a temperature controller and put it into an old metal box I had lying around. I got a short extension lead and cut it in half so I could plug the system into the wall on one end, and the freezer can be plugged into the socket which is controlled by the temperature controller - nice an easy!  no modification required to the freezer. You can see the black wire below which is the temperature probe that is put in the freezer compartment.

The idea here is to reduce the electricity requirements for freezer and fridge as we will be on solar power. This reduces the system design requirements and/or increasing the run time of the batteries.

So what's the verdict?

I'm pretty impressed. We we playing around with the settings for a bit but in general it looks like running this system at -12 to -15 degC seems to create a good enough freezer in the top compartment, and somewhere in the 2-5 degC in the drawer compartment which we are using as a fridge. Brilliant! We have a new chest fridge-freezer, yaye! Note a Fisher and Paykel drawer fridge is about $2800 new, so being able to get similar functionality at a fraction of the cost is pretty good - of course it is bigger and has more bling, but that doesn't matter to us. 

This setup seems to be drawing on average ~300 watt hours per day (equivalent to 109 kwh/year) which is about 2-3x better than most Gram fridges or fridge-freezers (Gram makes super efficient upright fridges and fridge freezer). The picture below shows the reading at about 45 hours of running from the start. I anticipate as things start to settle and come into equilibrium, the system here will likely draw less again.


To give some contrast to this, the previous upright fridge/freezer used to draw 1000-1200 watt hours per day. So we are looking at a 3-4x reduction in power usage, potentially higher. The guy who originally inspired me was getting down to 100 watt hours per day (which is super impressive), however he is only running it as a fridge, not a fridge/freezer as I am doing.

Here is the setup as I have it:

The temperature controller.  You can adjust many parameters in it like temperature setting, hysteresis, cooling or heating, time delay switching and temperature limits.
This is the chest freezer setup with the controller perched on to at the moment. I will be getting some magnets to attach to the bottom of the case so it will stick to the top cover and not slide off.

The contents of our fridge. Although smaller than what we were used to, it is perfectly fine for our requirements.

The freezer compartment (which is actually bigger than the fridge). The extra size might be handy if we have to put some chickens, pig or a goat in there.


The ideal freezer is of course -18 to -20 degC, so more testing will be required to see if we do need those temperatures or not. I was considering getting another smaller chest freezer for that purpose, and using this solely as a fridge with a crisper drawer.

Other news

In other news ... check out this parsnip which was picked from the community gardens this morning, and made into soup for lunch :)

There have also been many many Mandarins and Feijoas to pick from our garden, we have been doing baskets full like these almost weekly. Would seem to be the season for it.



Katie has decided to try her hand at weaving baskets from Willow branches because we have a tree on-site. This is the result of her first project which I thought was pretty amazing from raw materials into useful-ish.



That's all for now folks.

Thanks to those of you who are encouraging me to write, it's nice to know that people are actually reading this stuff.




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