Pedal power

Food&Fish

hygicell wrote:

Food&Fish wrote:

Goona have to dissagre with you frank i have a proper glass house with 1000 litre fish tank grow beds that hold 200 litres water [ 600 litre capacity] and a 200 litre sump buried with 4 temp censers on a hot day water starts at 17 deg glass house gets to 45 [beds all black] end of day water 20 deg , overnight ambient drops to10 deg and inside temp12 next morning water around 17 deg [thats with every thing closed] so in my book unless a glass house is double insulated heated and or cooled heat sinks do very little i recon for economy go for fish and plants that suit your area for me this is an enjoyable hobby i do not want to eat $30 fish and $20 lettuce

you know better than that, F@F: double sided or not , if you take all mass (water, tanks, growbeds) out of your greenhouse and leave it empty, the temperature fluctuations will be much bigger.
which proves my point: if you want stabler temperatures, put more mass in the greenhouse
it will work both ways: lower temperatures by day and keep temperatures up at night

double sided will enhance that, there you are right

frank

Yea should have known better

Sleepe

F&F
There was a very nifty mass heat/cool recovery/evaporative system developed quite a while ago over here (was for houses but I can't find the link).
Basically you push the air through external mass (say bricks with all the holes lined up), if you want cooling you use an intermittent spray of water until evap was complete, then reverse the airflow. Big enough mass (external) you could probably passively return the air at night by not using the sprayers.
BTW I have had a few beers so if this makes no sense, sorry :drunken:

Food&Fish

I understand a bit like the old heat bank heaters all i am aiming for is to just keep the heat off the trout over summer the rest can look after its self [ oh yea and as cheap as possable ]

hygicell

spraying needs energy and entrails the risk of legionella
you can obtain efficient evaporation cooling by dipping cloth in water and hanging it on clotheslines
or better have the right type of cloth with it's lower rim dipped in water: capillary action will suck up the water,and keep the cloth moist
choose the cloth color according to purpose: black to absorb heat, white to reflect light on plants

frank

Cyara

hygicell wrote:

spraying needs energy and entrails the risk of legionella

From.... http://en.wikipedia.org/wiki/Legionella

Quote:

Controlling potential sources of Legionella

Common sources of Legionella include cooling towers used in industrial cooling water systems as well as in large central air conditioning systems, domestic hot water systems, fountains, and similar disseminators that draw upon a public water supply. Natural sources include freshwater ponds and creeks........

Temperature affects the survival of Legionellae as follows:

* 70 to 80 °C (158 to 176 °F) - Disinfection range
* At 66 °C (151 °F) - Legionellae die within 2 minutes
* At 60 °C (140 °F) - Legionellae die within 32 minutes
* At 55 °C (131 °F) - Legionellae die within 5 to 6 hours
* 50 to 55 °C (122 to 131 °F) - They can survive but do not multiply
* 20 to 50 °C (68 to 122 °F)- Legionellae growth range
* 35 to 46 °C (95 to 115 °F) - Ideal growth range
* Below 20 °C (68 °F) - Legionellae can survive but are dormant
The above data can be confirmed in an online article by Reliance World Wide.[11]

Control of Legionella growth can be through : A. Chemical Treatment

1. Short term - Cl2, must be repeated every 3 to 5 weeks, corrosion factors
2. Long term - ClO2, takes up to 17 months for system saturation

B. Non-Chemical Treatment

1. Short term - Thermal eradication - must be repeated every 3 to 5 weeks
2. Long term - Industrial size copper silver ionisation (Ionization)

Looks like best to avoid! :shock:

hygicell wrote:

you can obtain efficient evaporation cooling by dipping cloth in water and hanging it on clotheslines
or better have the right type of cloth with it's lower rim dipped in water: capillary action will suck up the water,and keep the cloth moist
choose the cloth color according to purpose: black to absorb heat, white to reflect light on plants

frank

Would this really make a difference in a greenhouse Frank?

Maybe have the cloth dipped in the water.... as you say.... and some sort of air blower trained on it.... but evap cooling is said to only bring temps down about 2 degrees I heard. What you think?

black in winter and white in summer?

steve

evap cooling temp differentials are related ONLY to the relative humidity of the air (actually dry bulb temp and barometric pressure do play a small part, but by far it is the RH that matters. at 100% humidity you get 0.2 degree drop at 0.1% humidity you get almost 20C differential. and yes you require air flow over the wet cloth to make it work.

http://www.humidity-calculator.com/index.php

steve

additionally if this is being done in a closed volume (ie not open to outside air, best scenario is to have outside air blown through wet media) then it is pointless

Sleepe

Still slightly under the weather, however, internal air was pushed through an external 'porus' mass. When all water had evaporated (or given up its 'potential 'cooling') the flow was reversed. There was no 'moisture' to return.
BTW Slightly off topic

hygicell

steve wrote:

evap cooling temp differentials are related ONLY to the relative humidity of the air (actually dry bulb temp and barometric pressure do play a small part, but by far it is the RH that matters. at 100% humidity you get 0.2 degree drop at 0.1% humidity you get almost 20C differential. and yes you require air flow over the wet cloth to make it work.

http://www.humidity-calculator.com/index.php

one of the most funny sayings I ever encountered was (please don't take offense, it is only humor):

Quote:

you can't have it all:
you can't have a gordy woman and lots of room in the bed

so indeed if the air is saturated evaporative cooling will not work

but there are solutions to that

remember on one of my drawings (the one on low head aquaponics) there was a detail described as solar chimney?
a pipe painted black exposed to the rays of the sun will act as a very efficient extractor and suck all saturated air out of the vicinity of the cloth
the capacity of the other air in the greenhouse to absorb humidity is greatly increased as it is heated by the sun,

Solar is a wonderful asset

hail the sun :cheers:

frank

Sleepe

I will try once more :roll:

You are not pumping the cooled moist air into the building, you are using it to cool a mass storage unit. You only return the flow (of air) when the 'intermittent' spray of water had evaporated.
Sensibly you have two masses operating alternately ie one pushing the other pulling. It can also be used to store heat.
You have more chance of catching legionella off the wet towel.

hygicell

Sleepe wrote:

You have more chance of catching legionella off the wet towel.

please explain

frank

Sleepe

Your towel is constantly wet, and you would have to move the moist air into the area being cooled.
Legionella is normally associated with poor maintenance and buildings which recirculate part of the air ie large buildings.

Plachon · **Joined:** May 26th, '08, 17:41 **Posts:** 275 **Gender:**

Here is a pedal pump made from recycled materials http://backyardaquaponics.com/forum/download/file.php?id=14978

Plachon · **Joined:** May 26th, '08, 17:41 **Posts:** 275 **Gender:**

Plachon wrote:

Here is a pedal pump made from recycled materials http://backyardaquaponics.com/forum/download/file.php?id=14978

Sorry, I meant to insert the pic, not the link. Here it is

hygicell

Sleepe wrote:

Your towel is constantly wet, and you would have to move the moist air into the area being cooled.
Legionella is normally associated with poor maintenance and buildings which recirculate part of the air ie large buildings.

apparently I have neglected this thread
the solar chimney I proposed is not recirculating the air but extracting it
together with possible legionella

all the drama's I have read about with legionella included either spraying or recirculation.
I am extracting.

frank

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