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BB73 · 11-02-2010, 03:35 AM

Hi everybody,

I just wanted to let you know about my improvements done on my little shelter i put up on my balcony.

This pic shows how it was at the beginning. It turned out, that it could keep the temperature just about 2 ° C ( 4° F) above ambient temperature, so I started thinking of what to do.
First, I added a layer of bubble wrap which I attached to the inside, but this didn't help much to keep temps higher.

I read about simple solar heating of swimming pools and adapted that for my greenhouse. Water has a very good heat capacity. I bought a 200 liter (50 gallons) water tank, which will be connected to black irrigation waterpipes, which will serve as solar heat absorber. A small pump (used for garden fountains) will constantly pump the water from the tank through the pipes and back into the tank.
I'm going to install the pipes at the south facing side inside my greenhouse. Putting them inside makes me able to use the pipes as heat radiator during the night.
Untill now, I just got the tank set up, because I'm waiting for the pump to arrive next week.
Even now the 200 l of water heat up from 10 - 12 ° C in the morning to 20 - 21 ° C at sunset. That's a difference of about 10°C (or 18°F). This energy will be radiated back during the night, so I'm having around 5° C ( 8 - 9° F) above ambient temperature for the first 6 - 7 hours already.
I'm hoping to increase the water temperature to around 30° C (85 F) (at sunset) with the absorber installed.
Even on cloudy days there's still some soalr radiation which will heat up the water. I will keep a electric heating cable as a backup for extreme colds.
The cost for running that heating will be very cheap. Only the pump will use electric power, but consumes only 8 W per hour. Still the set up costs some, but little money, but this can be saved in electric bills. One, maximum two seasons should be enough for amortization - depending on your electric power rates.

Another benefit is, that the greenhouse is not heating up so quickly in full sunlight, because some heat energy goes into the water to be heated up.

I will post some pics after everything is set up and running (hopefully successful)!

11-02-2010, 03:35 AM	#1 (permalink)
BB73 BB73's Photo Gallery Location: Thessaloniki/Greece Find me on the map! Zone: 9a Name: Bernd Join Date: Jul 2009 Posts: 370 BananaBucks : 56,303 Feedback: 0 / 0% Said "Thanks" 228 Times Was Thanked 419 Times in 159 Posts Said "Welcome to Bananas" 56 Times	My greenhouse is getting solar heating Hi everybody, I just wanted to let you know about my improvements done on my little shelter i put up on my balcony. This pic shows how it was at the beginning. It turned out, that it could keep the temperature just about 2 ° C ( 4° F) above ambient temperature, so I started thinking of what to do. First, I added a layer of bubble wrap which I attached to the inside, but this didn't help much to keep temps higher. I read about simple solar heating of swimming pools and adapted that for my greenhouse. Water has a very good heat capacity. I bought a 200 liter (50 gallons) water tank, which will be connected to black irrigation waterpipes, which will serve as solar heat absorber. A small pump (used for garden fountains) will constantly pump the water from the tank through the pipes and back into the tank. I'm going to install the pipes at the south facing side inside my greenhouse. Putting them inside makes me able to use the pipes as heat radiator during the night. Untill now, I just got the tank set up, because I'm waiting for the pump to arrive next week. Even now the 200 l of water heat up from 10 - 12 ° C in the morning to 20 - 21 ° C at sunset. That's a difference of about 10°C (or 18°F). This energy will be radiated back during the night, so I'm having around 5° C ( 8 - 9° F) above ambient temperature for the first 6 - 7 hours already. I'm hoping to increase the water temperature to around 30° C (85 F) (at sunset) with the absorber installed. Even on cloudy days there's still some soalr radiation which will heat up the water. I will keep a electric heating cable as a backup for extreme colds. The cost for running that heating will be very cheap. Only the pump will use electric power, but consumes only 8 W per hour. Still the set up costs some, but little money, but this can be saved in electric bills. One, maximum two seasons should be enough for amortization - depending on your electric power rates. Another benefit is, that the greenhouse is not heating up so quickly in full sunlight, because some heat energy goes into the water to be heated up. I will post some pics after everything is set up and running (hopefully successful)!