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David 09-25-14 04:28 AM

Summer Sun and heat and heat and heat ...
 
Hello,

I really enjoyed AC Hackers post on how he hopes to warm his kitchen.
It reminded me of my adventures under my house.

My problem is not heating my house but cooling it this Summer which wiil arrive with a vengence in two months time. If last summers heat is anything to go by we will be surrounded by bushfires and suffer weeks at a time with maximums of 100 degrees Farenheight.

My house was built in three stages first in the 1850s then in the 1880s and finally in 1908.It had an open fireplace most rooms and an oil heater in the kitchen.

The walls are rendered and double brick. I think it is 30+ squares. The ceilings are 11'6".

We moved in, in the summer of 1983. My wife and I were then in our 30s I am now the dreaded 64 .

Our house was very rundown when we bought it, but it was spacious (no furniature) beautifully cool during our summer. Oh bliss we thought. Then winter came and we froze huddled together in 3 sets of clothes and heavy colds.

We determined to put an aircon unit. Problem was there was no way under the house. The whole house, ie. every room sits on massive slabs of Basalt hauled into place by oxen. Nothing for it but to pull up some floor boards 6" wide and 1" thick Baltic Pine.

I had to crawl on my belly from room to room to work out where the ducts had to go. Fortunately each door way was clear below the floor.This was where the ducted heating went. Long sections of the floor sadly had to be sawn to enable the placement of the ducting.

Along the way we too found some old treasures. The best was an old corked bottle of Irish Whisky with about a teaspoon of amber liquid in it.I said to my wife that this was either a sublime drop or a very naughty trap left behind for the future. When I pulled the cork it almost instantly vaporised . What ever it was it smelt divine.

Sorry for the long intro.My problem now is not cold but Heat.The roof is of corregated iron and the ceilings have good 3" fiber-glass batts for insulation. But recent years have shown that whilst we will not suffer the heat for the first 3 to 4 days but thereafter the walls retain absorbed heat and we suffer from unremitting heat during the last couple of months of summer.

Putting aside conventional airconditioners which are undoubtedly part of the problem does any one have a suggestion of what I might do to cool this wonderful old house?

I know that Geo thermal systems work but they are quite pricey and my 1/2 acre block may not be amenable to much change.

I have a Bore/Well (See Earlier Post) that is 25 meters deep .The bore proved to be a failure due to the high salinity etc of the water.I commisioned the bore to save my mighty 60 yr old Golden Elm. But without as I was precluded from using mains water due to water restrictions and massive price increases.

I mention the bore because it delivers a huge amount of very cold water .

I would appreciate any help I can get .

Regards

David

jeff5may 09-26-14 05:58 PM

How humid is it where you are in the summer?

If not too humid, you could run the water through an air handler and have lots of cool air for not much energy. The only downside is the lack of humidity removal. The "cool" well water doesn't force the dewpoint of the air stream low enough to remove much moisture.

Mikesolar 09-27-14 05:35 AM

Insulation is cheap. 3" should be increased to 8-10". Probably unheard of over there but very common here.

Are the outside walls of the house beautiful? Can you add some foam insulation to the outside and reside it. It would make a lot of difference in heat/cool retention of the masonry.

Also, what colour is the roofing. If not a silvered colour consider painting it white.

Other than that, Jeff has the right idea. You can do a "pump and dump" if the humidity is OK.

jeff5may 09-27-14 06:47 AM

What are your heating bills like during the winter? It sounds like you are slowly heating the outdoors through your massive walls and thin roof. Unless really sealed well, the fiberglass roof insulation will not do much of anything when convective currents of air pass right through it. When summer comes, your preheated walls no longer provide the cooling they did before you installed "modern" central heating. They quickly become sun-soaked with heat and pass this heat straight indoors.

In such a dated build, the building science was just not there for the architect(s) to consider. Your main concern, as far as comfort, is figuring out how to regulate indoor temperatures cheaply and easily. IMHO this is going to be a daunting task, since your envelope is only as heat (and cold) resistant as the least insulated part. You will need to play the part of the building scientist to devise a creative way of leveraging your abundance of cool, brackish water to level your indoor temperatures.

jeff5may 09-27-14 07:22 AM

I also remember you were trying to figure out how to purify the well to water your garden. This would be the perfect opportunity to kill lots of birds with one creative stone. The following may sound radical and strange, because it is:

Use the water in the well as insulation.

If run on the outside of the envelope, it will literally shield your massive walls from extreme heat gain or loss.

During the summer months, you should have enough solar exposure to distill a good amount of water.

Now please don't shoot me! This method is and has been used in agriculture for decades. Two paper thin sheets of plastic, pumped up with foamed soapy water between them, will insulate a quonset greenhouse well enough to prevent frost damage to plants inside. The storage tank for the water is buried underground and gains enough heat to prevent freezing. It works well enough to make gas heating economical.

The practice of spraying water directly on a roof in summer to provide cooling has been done to death successfully. In your case, it will also paint your roof for you.

To accomplish your goal, something radical and "weird" will have to happen unless you are filthy rich. If you are merely "wealthy", something strange will come about and you will spend a boatload to keep it from being "abnormal".

David 09-28-14 12:55 AM

Hello Geoff,

Thank you for your thoughts.

Australian summers are typically hot and dry. It is early spring here.

I do not know what you mean when you say:

“The "cool" well water doesn't force the dewpoint of the air stream low enough to remove much moisture.”

Our heating bills are modest, as we seldom need to do much more than have the system on for a few hours in the morning and similarly at night. The ceiling insulation is rated R3.00 we are seldom cold at night. By morning it can be chilly but then the air conditioner kicks in. We tend to keep all doors closed. At other times particularly at night we often side by an open fire. Currently the wood from our now departed elm tree fuels this fire. The interior walls are hard plaster and I have replaced all of the ceilings (once ‘lath and plaster’) with plasterboard.

I am not sure if there is a difference between an ‘air handler’ and an ‘air conditioner’. Up and until you used the term, I had not heard the words “ air handler”. The term we use here is an air conditioner, I suspect they are one and the same.

I was thinking of making a grid of tubular steel or PVC through which I could pump my available cold water. I would think that a simple fan placed behind that would produce a cooling process to occur and an extractor fan in the ceiling could remove the humid air from the room.

I had not thought to introduce this cool air via the heating ducts.
The question is however how do I by-pass the gas fired heating unit.

I guess I will have to devise to accomplish your goal, something radical and "weird".


Hello MIKE SOLAR,

My house is 2/3 cement rendered. The remainder is coarse stucco.

The roofing is green colour bond zinc/alum. The on the inside a layer of sarking has been installed. This is silver on the side that faces the underside of my roof. This prevents condensation that might form on the underside of my roof from dripping down onto my fiberglass insulation.

Could you explain to me what you mean by the term “pump and dump” if the humiditiy is oK.

Thanks to you both,

Regards,

David

Mikesolar 09-28-14 05:55 AM

First, an air handler is just a hydronic coil and ductwork that has the water coming from any source of cold/hot.

As humidity is not a big thing during your summers, taking the cool water from the well, through an "air handler", which may not need any ductwork BTW, and dumping it right back into the well may work for you provided the well can absorb the extra heat. That water can be filtered and used for other things, I suspect, if you wished and not dumped back in.

As nice as the green roof may be, I'll bet a white one will allow less heat gain. I still think doubling or tripling the insulation is a good idea. It is pretty cheap although all it does is slow down the increase in temps in the house, it allows the cooling to keep up with the load better.

I live in a brick house (12" thick) and when I insulated on the outside, the cooling load decreased. In my mind, masonry is superior to wood and insulation which is the predominant construction in N.A. With no other insulation, my house has the same or less heating costs than the wood frame construction. Adobe houses in VERY HOT Arizona can have quite comfortable indoor temps with the wall absorbing the heat in the day and giving it to the cool night at night.

David 09-28-14 08:03 AM

Thanks for the information Mike,.

I am not going to paint the roof white. But I am going to explore Air Handlers.

Using that name I have found a number of very useful sites. They take my unsophisticated thoughts a whole step further.

Trouble is there are so many other things I should be doing.

Kind regards
David

Ps any detailed plans of a cold water based air handler would be mighty useful as I want to start yesterday.

jeff5may 09-28-14 09:05 PM

"Air handler" is a generic term for the unit that contains your indoor blower and has direct contact with your indoor air. With commercial units, the air handler may or may not do anything except direct air between sources and zones calling for heating or cooling. With residential systems, the manufacturers tend to pack whatever they need or want to into the air handler unit.
http://www.perfect-home-hvac-design....es/AHillus.jpg

In a heating-only system, the unit is usually called a "forced air furnace" if it runs off electric resistance elements or a gas burner. If it has a water coil and runs off a separate boiler, they call it the air handler. If it is a heat pump, they call it the air handler.

In home systems that cool, most a.h. units are classified as split or packaged. Packaged systems contain the whole system (except maybe the thermostat), so the only thing that connects indoors is ductwork for supply and return air. Split systems have a separate outdoor unit which contains the refrigerant compressor, outdoor heat exchanger and blower, as well as some control circuitry. With split systems, there are usually no ducts leading to the outdoor unit. The indoor unit may have a stack vent built into it, which indicates it has a gas furnace built into it.

In your situation, a retail product that does what you want to will be called a "chilled water air handler". It will consist of a blower, a radiator of some sort, and a drain pan. They make a jillion bagillion different designs, which may (or may not) contain a pretty cover or box enclosure, ductwork, thermostat controls, pumps or valves, etc.

Basic uncased unit:
http://www.technicold.com/images/ra08b_air_handler.gif

Typical closet unit:
http://www.hvacquick.com/content/ima...gicaire_dv.jpg

Ceiling cassette:
http://www.gohvacrsupply.com/images/...20Cassette.jpg

jeff5may 09-28-14 11:53 PM

Insulating your roof will change the way your house acts. You have a dark, metal roof with a thin layer of "sarking" and r-3 insulation? No wonder it gets hot in summer! You have a big solar thermal collector on top of your home, with not much thermal shielding. The heat just soaks right in.

Here's a typical modern roof design:
http://www.greenspec.co.uk/images/we...75-cutaway.png

The maker pushes wood-fiber insulation. Typical thickness of the shown section is 12 inches. Their low-u designs are even thicker. Passive house designs with pitched ceilings typically have 16-18 inches of insulation between plasterboard and the surface of the roof.

No matter what approach you take with heating and cooling, insulation will reduce your heat load if done. If done correctly and sufficiently, it will dramatically reduce your heat load. Once it's done, it doesn't cost any more and keeps on saving you energy indefinitely. If you can't do it yourself, have a pro do an energy audit for you to see how much of what will save you energy the best. This is an area where a little research up front is money well spent, and can open your eyes to why your home acts the way it does.


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