Glasshouse heating

[Tree]

Hi

Im after ideas for heating a small glasshouse. The ideal temp to be maintained is a min of 20 deg C and currently the glasshouse is going as low as 9 deg C. (with outside temp as low as 5 deg C).

Any comments welcome.

Thanks

[mescalito]

Is the aspect right for the best solar charge?

A few ideas:insulate with pink bats the SE side and roof.

get as many plastic water containers as will fit in the spare section of the greenhouse paint them black and fill'em up with water.They'll act as a sort of 'battery' for heat

[ 19. July 2004, 18:07: Message edited by: mescalito ]

[Tree]

Thanks for your reply mescaleto - some good ideas . I have already put insulation on SE side (Astrofoil) and the base is paved with bricks. Also glasshouse is positioned to get the best winter light.

I think using black water containers is a good one and worth a go.

I guess its all about increasing the thermal mass - have already put as many potted plants in there as I can for this reason.

Thanks again, take care

[Seeker]

Hi Tree

For me both temperature and humidity were a "lack of" problem in a small greenhouse. The fix cost me $65 from my local chemist. Ah, not as stupid as it sounds. The fix? A humidifyer,used for treating persons with breathing problems such as asthma. Trust me it works but beware scolding steam, point the out outlet in a non critical direction. Beware the type of humidifyer which uses carbon electrodes to heat the water, they can give off fumes which will severely effect what ever it is you are growing. The one I use is made an "extralife" "Steam Vapouriser" made by "Felton Grimwade & Bickford Pty Ltd"

Hope this helps. BEWARE THE STEAM OUTPUT it can severely damage your plants

Seeker

[mescalito]

Paint the bricks black too it's all about heat

[Tree]

Thanks for replies

Interesting idea seeker - For now I will try to get away without using electricity but just for interest how much power does the vaporiser use? Also what sort of temperature are you getting from it?

Mescelito - now to find some suitable black paint.

Thanks again.

[waterdragon]

the thermal mass ideas may work in a small glasshouse, i use those methods in my hothouse and they barely work at all.

a small kero heater will do the trick but it also boosts the growth a bit and forgetting to light it on a cold night can be detrimental to your plants. chickens give off a lot of body heat (confined in under-bench cages), also a lot of shit and carbon dioxide, be sure they can escape to an outer pen during the day.

[Tree]

Thanks for reply WD - Interesting methods you are using. Some questions.

What sort of kero heater do you use? How is it setup eg: Does it have a chimney? What sort of temperature do you get from it? How do you control temp?

Good idea using chickens.

Has anyone used a solar water heater for this purpose?

I was thinking (dreaming) of one day getting a new glasshouse only for tropical plants and putting the house hotwater heater in it - one day.

Thanks again

[waterdragon]

kero heaters are to be found at every second tip site these days so you can be fussy and shop around, i got the idea from an engligh book on hothouses but there they're called parrafin heaters i believe. the temps are easily adjusted by dials on the unit, these things were used extensively to heat houses until the price of kero climbed and cleaner methods happened along. they don't have a chimney that i'm aware of just a reflective surface behind the heating mantle to radiate heat.

the chicken idea may have came from the same book but i'd make sure the chooks had a good escape route as the daytime temps could kill just about any animal in most hothouses.

[gerbil]

Not too sure how well this can be applied to backyard glasshouses, but look into heating by laying hot water pipes on the ground.

But the boiler is the problem, have no idea about small scale use of these.

Maybe solar to boil the water or something like that.

Would probably be a little $$ to setup at first though. Something to ponder.

[t st tantra]

i have greatly improved the happiness of my psycotria carthigensis by putting an old esky lid under the pot,it no longer sits on a concrete floor and i'm thinking it no longer has cold feet!

it has gone from hibernating to active growth in mid winter!i put it behind a sheet of glass too but the improvement didn't come until the foam.

the white foam reflects light too,so it should increase light levels a tad in winter.

t s t .

[Tree]

Thanks for replies

WD - The kero heater sounds good - the reason I asked about a chimney was how does the fumes affect the plants??

Gerbil- The idea of using hotwater is something I have vaguely been thinking of. Too expensive for now but definately worth looking into. Using hotwater pipes along the floor sounds good. The ideal setup would be solar although I thought of placing the household heater in the glasshouse.

Tst - Good idea about the foam, something I could try under the worst cold effected plants. My Cacoa and Kava have been hammered by the cold this winter .

Thanks again some good food for thought.

[waterdragon]

venting the fumes would just about have to also vent the heat, have never heard of the fumes causing probs but on edibles with extensive use it could be an issue. the running of a radiator style system could be worth looking at, hot water types or a chimney flue if one is nearby. being a small area even an electric heater fan on a timer with an earth leakage protector for safety could do, although it mightn't take much as your temp only goes down to 9, i'm getting minus five regularly and still got kratom alive.

[Seeker]

Hi Tree

Been away for a few days. Steam heater rated at 240W. Temperature drops to about 17 C overnight (outside temp 2 C). Day temp to 25 C (outside temp 12/15 C). Humidity 75/80 night and day. The volume to be heated could be critical.

Hope this helps

Seeker

[Tree]

Thanks for your replies.

I think I will look for a kero heater for now. Some good ideas to consider for the future.

Thanks again, take care

[mescalito]

Electric fan heaters are OK but be careful of the RH drop across the heater element they do a good job of clearing the fog after a shower if you know what I mean

Another prolly cheaper and more ecological way would be a small LPG camp burner or lamp with a circulating fan somewhere..LPG burns pretty cleanly and would benefit the plants by burning O2 and producing CO2 while providing heat-a nice relationship!

Once again keep an eye on humidity levels when you start heating the growspace that's why it's called 'relative' humidity the water holding characteristics change dependent upon temperature...anyway it won't be long 'till spring

[t st tantra]

i vaugely recall an idea of having a compost heap in a glasshouse to provide heat.

t s t .

[Guest electro]

you can buy solar bar-b-ques ... big mirror dishes that focus the sun into a point to cook on (like a massive backwards magnafying glass) ...

these arent too expensive and could be easily aimed at a metal water containing vestle inside a green house ...

there are a few designs of these, but im sure most could be adapted to this purpose...

solar panels wired to rechargable bateries wired to 12 volt heaters would work well too.. especially if you had the ability to turn it on when the temp dropped to a certain temp (saving battery) ..

[Rev]

If building compost inside be careful of ammonia generation which can be harmful!

[Absinthe]

You can get those emergency safety blankets, they look like foil and feel like plastic, and "reflect 99% of body heat." I bought myself a few of these for $2 each, and stuck them on the walls to increase light and heat in my greenhouse last winter, but burnt some cacti with the increased light. Better planning, and I could've increased the heat if I directed them better. Now I just have open glass in winter, shadecloth in summer. Melbourne temps, and my plants are happy, including some tropicals.

Jon

[waterdragon]

for the depths of winter where propagation is the issue a cloche/coldframe within the hothouse can create a heated zone. use a thermometer iside the cloche which shows your min/max temps to ensure things don't get too hot.

[Ed Dunkel]

Compost was used (in the old days) underneath a small greenhouse to heat the floors. The fumes would be guided away from the greenhouse itself.

Thanks for reminding me about that again.

E D

[Flip]

depending upon your setup

I might suggest also using the heat from a clothes dryer

take the vent and pipe it in.

You may run into a carbon monoxide problem if you let it vent out into the greenhouse. All of that can be corrected by rigging a heat exchange of some sort.

it's not going to be constant heat

only a booster on wash days

better to use it vs letting it go wasted.

[ 04. August 2004, 16:09: Message edited by: Flip ]

[Tree]

Some more good ideas to ponder.

Mesc - Will consider humidity drop with heating - good point. I like idea of using an LPG gas heater - the only concerns would be the risk of an explosion if the flame went out. Also could be a problem if putting cactis in glasshouse with toxic gas effect??

Tst - I like the idea of using compost heat. Dose anyone have any info on what temperature comes out of compost? My concerns with this method would be - the ammonium gas - and the fact that you could not turn it off when the weather warmed up. Also would the compost attract plant pests of disease? Using a heat exchange setup could get around theses problems though.

electro - A couple of good solar solutions. The idea of using solar to heat water storage tank sounds like the go. Would be wary of fire with a solar-barbie but worth considering. Still think using a solar hotwater system may be easier.

CM - The safety blanket material is similar to the 'astro foil' insulation I am currently using. (two foil sheets seperated by a double bubble wrap). It works well but I think most of the heat is being lost through the glass.

WD - The cloche/ cold frame method - is this a closed area inside the glasshouse? ie. the idea of making a frame covered with plastic for the worst cold effected plants?? If so have you or anyone used this method? Sounds good more info please.

Flip - The idea of using the heat from household appliances using a heat exchange device is a good one. I still think the hot water system is the best heat source for this as it is constant - although it would be good to save wasted heat from other appliances ie the dryer and oven. This leads to ideas of making the house more heat/energy efficient and enviro-sound. All good thought.

Thanks again - many more good solutions to consider. Keep em comming

One more....

Stratotherms - blowing heat from the highest point in the glasshouse to the floor. Has anyone used this method?? More info please.

Take care

[mescalito]

Ok we got this far so now...

One of the biggest heat losses in your room is the one that draws heat at a predictable and a constant rate.

ie.the temperature of this medium changes very little but is below your target temperature and therefore taxing heat.

Clue:I bet it's not insulated and I bet if you look down you'll see it